-ocr page 1-
f-0150
A
SERIES
OF
ELEMENTARY LECTURES
ON THE
VETERINARY ART:
WHEREIN THE
ANATOMY, PHYSIOLOGY, AND PATHOLOGY
OF THE
HORSE,
ARE
ESSAYED ON THE GENERAL PRINCIPLES
OF
Jfte&ical gcfenct.
veterinary surgeon percivall,
Of the Royal Regiment of Artillery.
To watch, to scrutinize, to inqnire, is labour, and labour is pain. To confide,
to taKe for granted that all is well, is easy, is exempt from labour, and, to the great
mass of mankind, comparatively delightful."—Mills' History of British India.
' Those who seek truth only freely expose their principles to the test, and are
pleased to have them examined."— Locke.
*e=s=
LONDON:
- ■
PRINTED BJT JOHN HILL, BLACKFRIAHS J
f<V                                                                And published by
LONGMAN, HURST, REES, ORME, AND BROWN,
                                                       Paternoster Row.
1823.
-ocr page 2-
ENTERED AT STATIONERS' HALL.
-ocr page 3-
TO THE
'Vtttvimvvi jHrtrical IS^amintng QommitUt,
AND TO THOSE
DISTINGUISHED TEJCHERS
OF
HUMAN MEDICINE,
WHO,
WITH LIBERALITY UNPRECEDENTED,
Have gratuitously opened to
€f)e "Ftttvimvn Pupil,
THE
SOURCES OF HIS FUNDAMENTAL MEDICAL KNOWLEDGE,
THESE LECTURES
Are inscribed, in testimony of
RESPECT, ESTEEM, AND GRATITUDE,
By their most devoted Servant,
THE AUTHOR.
a 2
-ocr page 4-
PREFACE,
•dN elementary zeork on veterinary subjects, should it be
deemed worthy of a place among the many approved in-
troductions to various other branches of science, has lit-
tle need of commendation, and none of excuse, in making
its appearance before the public. Too long have the mem-'
bers of the profession experienced the inconvenience of not
having by them some accurate synopsis of the scattered
elements of their art; too long, indeed, have the medical
profession in general looked forward to some scientific pro-
duction of this nature.
But, could we plead this pressing demandthis deside-
ratum in veterinary literature, as an apology for obtruding
ourselves thus early upon public notice, it might still be
regarded as an unqualified act in us, to attempt the ex-
position of the principles of an art of which the prof essors
themselves have only published on detached parts. Con-
ceiving, however, that the present essays, (in the form of
lectures,) concise as they confessedly are, might prove use-
ful in the absence of more elaborate composition, and daily
witnessing the pernicious influence of books on farriery,
written by individuals unacquainted even with the rudi-
-ocr page 5-
PREFACE.
VI
ments of the art they treat on, we have ventured, tiotwith-
standing the above acknowledged truth, we fear prejudi-
cial to them in the minds of some, to lay them, in their
present state, before the public.
Having offered our reasons for undertaking a work, we
hope, at some future period, to be able to complete; it only
remains to crave for it> that liberal examination, and in-
dulgent censure, for which those eminent characters, to
whose protection we have consigned it, are so universally
and so justly esteemed: assuring them, that, however un-
finished the superstructure may be found, the foundation
has been laid in practical investigations, anatomical and
pathological, in an ample field of observation and
ejrpe-
rience.
Royal Horse Infirmary, Woolwich,
May, 1823.
-ocr page 6-
CONTENTS.
Page
Introduction ••«•«...............................-....*<••■ ix
LECTURE I.
OntheBlood ............................................. 1
LECTURE II.
On the Blood—Serum—Red Globules—Coagulable Lymph—Diseases
of the Blood—Venesection................................ IS
LECTURE III.
On the Arteries ........................................... 32
LECTURE IV.
On the Physiology of Arteries—Pulse.......................... 43
LECTURE V.
On the Diseases of Arteries—Inflammation.................... 56
LECTURE VI.
On Veins—Physiology of Veins —Diseases of Veins—Blood-spavin
—Wounds of Veins a...................•................. 86
LECTURE VII.
On the Absorbents—Absorbent Glands.......,................ 107"
LECTURE VIII.
On the Physiology of Absorbents—Diseases of Absorbents ........ 118
LECTURE IX.
On Cellular Membrane—Diseases of Cellular Membrane .......... 131
LECTURE X.
On the Brain and Nervous System—Brain—Nerves—Physiology of
the Brain and Nerves..................................... 144
LECTURE XI.
On Neurotomy—Diseases of the Nerves—Tetanus ..."............ 168
LECTURE XII.
On the Muscles—Tendons—Diseases of Tendons—Bursa? Mucosa?—
Diseases of Bursa; Mucosas................................. 196
LECTURE XIII.
On the Physiology of Muscles—Diseases of Muscles—Stringhalt—
Palsy .................................................. 216
1
-ocr page 7-
CONTENTS.
Vlll
LECTURE! XIV.                                        rage
On Glands—Secretion—Diseases of Glands .................... 251
LECTURE XV.
On Bones—Diseases of Bones—Exostosis—Marrow ............. 234
LECTURE XVI.
On Cartilage—Diseases of Cartilage—Ligaments and Joints—Dis-
eases of Joints—Ossification—Division of Bones—Prominences and
Cavities of Bones........................................ 262
LECTURE XVII.
On the Skeleton—Spine —True Vertebra;—Cervical Vertebra?—Dor-
sal Vertebrae—Lumbar Vertebra?—Os Sacrum—Ossa Coccygis—
Diseases of the Spine—Fracture and Anchylosis .............. 287
LECTURE XVIII.
Pelvis—Ossa Innominata—Sternum—Cosla?—Bones of the Fore Ex-
tremity—Scapula—Os Humeri—Radius et Ulna.............. 305
LECTURE XIX.
Carpus—Os Scaphoides—Os Lunare—Os Cuneiforme—Os Trapezium
-—Os Trapezoides—Os Magnum—Os Unciforme—Os Pisiforme—
Bones of the Leg—Os Metacarpi Magnum—Ossa Metacarpi Parva
—Diseases of the Metacarpal Bones—Splint.................. 318
LECTURE XX.
Os Suffraginis—Ossa Sesamoidea—Os Corona?—Diseases of the Pas-
tern Bones—Ringbone—Os Naviculare—Os Pedis--Diseases of
the Navicular and Coffin Bones............................ 330
LECTURE XXI.
Bones of the Hind Extremity.—Os Femoris—Patella—Tibia et Fi-
bnla—On the Tarsus—Astragalus—Os Calcis—Os Cuboides—Os
Cuneiforme Magnum—Os Cuneiforme Medinm—Os Cuneiforme
Parvum—Os Metatarsi Magnum—Diseases of the Bones of the
Hock—Spavin.......................................... 343
LECTURE XXII.
Bones of the Head—Bones of the Cranium—Ossa Frontis—Ossa
Parielalia—Ossa Temporum—Pars Squamosa—Pars Petrosa—Os
Occipitis—Os Sphenoides—Os Ethmoides.................... 359
LECTURE XXIII.
Bones of the Face—Ossa Nasi—Ossa Unguis—Ossa Malarum—Os-
sa Maxillaria Superiora—Ossa Maxillaria Anteriora—Ossa Palati
—Ossa Spongiosa vel Turbinata, superiora et infenora—Vomer—
Maxilla inferior vel posterior—Diseases of the Bones of the Head 368
-ocr page 8-
INTRODUCTION.
The Veterinary Art, according toils present ac-
ceptation, comprehends a knowledge of the external form,
as well as the internal structure and economy, of our
principal domestic quadrupeds; their appropriate ma-
nagement; the nature, causes, and treatment of their dis-
eases ; and the art of shoeing such as require it.
The horse, and his varieties—the mule and ass, the
dog, the ox, the sheep, the pig, and some others, come
equally under the ministering hand of the veterinary sur-
geon : the comparative value however of the horse, desig-
nates him as the object of his primary, we had almost
said his sole consideration ; so that the rest, regarded as
another and an inferior class, have but little of his time
or study devoted to them.
The veterinary art, become a science, alone preceded
in practical benefit by that of medicine, of which it is a
luxuriant and aspiring branch, has for its objects the pre-
servation in health, and restoration from disease, of an
animal nearest to man himself in the scale of animated
-ocr page 9-
X                                  INTRODUCTION.
nature; whether we contemplate his beauty, his worth,
or his general and extensive use. Perhaps no age, nor
country, has so elevated the horse beyond the common
level of the brute creation as this : he is housed, clothed,
and fed, at a cost only exceeded by that appropriated to
his master, to whose gains he is instrumental, or to whose
diversions he is indispensable ; his life is watched with a
peculiar care, and his loss too often irreparable. If the
veterinary art be estimated as beneficial and important in
exact ratio to the value of the animal to whose well-being
all its objects are directed, surely at no antecedent period
has it merited the same degree of encouragement as at
the present: should we, therefore, not have been suc-
cessfully engaged in our efforts to cultivate and improve
it, let us hope, at least, that such attempts are deserving
of commendation !
Had it not been for the fostering patronage of some of
the most exalted characters in this country, the veterinary
art must still have lain prostrate at the feet of ignorance
and superstition; no less a personage, however, than our
magnanimous King himself, ever distinguished for pro-
moting that which is nationally useful and beneficial, has
deigned to raise it into importance and respectability, in
appearing as the Patron of the Veterinary College. Were
not this of itself full and sufficient testimony of the pre-
sent consideration of our art, we might adduce that very
respectable and honorable list of governors of the insti-
-ocr page 10-
INTRODUCTION.                                       XI
tution, the bare perusal of which will evince, that the
nobility, the talent, and the wealth of our nation, have
subscribed to its protection, its advancement, and its dif-
fusion.
But let us descend a little into detail—we shall findj
by pure and plain matter of fact, that, prior to its being
grafted upon the luxuriant stock of science, great num-
bers of our horses became prematurely unserviceable :
the natural consequence of which was heavy and continual
national expenditure; not to glance at the ineffective
state to which our cavalry and other horse departments
were necessarily reduced. Let us take, by way of exam-
ple, the present system of shoeing horses. In the course
of a long experience we have ascertained, that, by a skil-
ful performance of this branch of our art, we can prevent
many of the diseases, and them the most formidable, to
which the foot of the horse is liable ; enable horses to go
with ease to themselves, and safety to their riders; and
preserve them to use to a much longer period than here-
tofore. On the other hand, to sketch a picture of the me-
lancholy effects resulting from the practice of shoeing in
the hands of professionally unscientific persons, when the
horses belonging to the Honorable Board of Ordnance
were first placed under the superintendance of veterinary
surgeons, numbers of them, highly valuable in other re-
spects, were cast for death purely because their feet were
incurably diseased.
Thrush, and its sequel canker, corns,
-ocr page 11-
INTRODUCTION.
Xll
grease, aud all those varieties of disorganization induced
by mal-treated inflammation of the parts within the hoof,
consigned multitudes of them to the knacker's knife :
whereas, since the eye of science has controled the hand
of the smith, we will venture to assert, that not a single
horse has been lost to the service from either of the above-
named diseases; arid that at the present day the three first
—viz. thrush, canker, and corns, are almost unknown ;
and the last of so rare occurrence, that there are not ad-
mitted into the Infirmary a dozen cases in the course of the
year.
We might bring forward here many—very many
other instances of the benefit, not more obvious than great
and permanent,. the country has experienced from the
practice of our art under the direction of those acquaint-
ed with its principles : but we trust that the one here ad-
duced, which a reference to recorded statements will at
any time evince the truth of, stands in need of support
from no concomitant, nor lacks confirmation from any
corroborative evidence.
To the breeder—to the proprietor of a large stud*—
to the gentleman of the turf—and to every individual who
feels an interest in the well-being of his horse, the veteri-
nary art cannot but appear in a most favorable light. The
first, by enabling him to trace out the perfections and
* By the word stud is popularly and here meant, a collection of
horses
simply.
-ocr page 12-
INTRODUCTION.                                     XH1
imperfections of male and female, by developing the na-
ture of those diseases to which each may be disposed, and
by informing him what are and what are not ingenerate,
it renders competent to produce, by certain unerring laws,
an improved and matchless progeny; to the second it is
both useful and profitable, in teaching him the means of
prevention, as well as those of palliation and cure, of dis-
order in his stud ; the third it fills with renewed hope, in
having restored to the goal of contention, his broken-
down but celebrated racer; the last it contributes in no
trifling degree even to the happiness of, in administering
to those maladies which his old and favorite horse may
have contracted in his service.
To the enlightened practitioners of medicine of the
present day, we need say but little to convince them, that
veterinary inquirers may, from time to time, by extensive
opportunities in comparative anatomy, add something to
the general fund of medical knowledge ; and that, so far,
they may now and then consult veterinary works with ad-
vantage. Indeed, so much analogy is there throughout,
between the structure and economy of the horse and
those of the human subject, and so alike are the chief
phenomena of pathology, that the surgeon has but little
to do to become the veterinary surgeon, though the con-
verse of this, unfortunately for the latter, by no means
obtains. And where is the surgeon who would not him-
self direct the treatment of his sick or lame horse, in pre-
-ocr page 13-
xiv                                INTRODUCTION.
ference to calling in the village blacksmith?—a man
whose knowledge is necessarily confined to that of nail-
ing the shoe to the foot ? He would not permit a shoe-
maker to visit one of his own patients, why should he al-
low the blacksmith to prescribe for his horse? The the-
ory
of medicine in the human subject, is the theory of
medicine in the brute ; it is the application of that theory
—the practice alone that is different: whether we pre-
scribe for a man, or a horse, a dog, or a cat, the laws
of the animal economy are the same in all, and one, and
that an unerring system of principles, built upon ascer-
tained and established truths, is to dictate our practice in
all. We might as well, in reference to the principles of
each, attempt to separate surgery from medicine, as insist
that either of these arts, in theory, is essentially different
from the veterinary : every day's experience only serves to
confirm this—our belief; in shewing us how often the dis-
eases of a horse arise from the same causes as those of a
man, exhibit the same indications, and require a similar
method of cure. Were this not true, how is it that the
testimonial for practice—the diploma cf a veterinary sur-
geon, owes its stamp of importance and indisputable
qualification to the signatures of practitioners of human
medicine ? Will it be said, that these distinguished cha-
racters are, as physicians and surgeons, unacquainted with
the principles of veterinary science? This is no new
doctrine—it has not originated in our time : Vegetius,
-ocr page 14-
INTRODUCTION.                                  XV
fourteen hundred years ago, when he was collecting ma-
terials for his work, De Arte Veterinarid, wisely, not
only consulted the veterinary surgeons, but also the phy-
sicians of the day ; nam (inquit) mulomedicinse doetrina
ab arte medicinse non adeo in multis discrepat, sed in
multis plurimisque consentit.
The advantages resulting to the veterinary surgeon from
a knowledge of the different branches of human medicine,
can alone be duly appreciated by its possessor : without
it, he is but ill prepared to meet the medical literati of
the day ; with it, he stands as an effectual barrier to im-
proper interference on the one side, and to the dissemina-
tion of doctrines flimsy or absurd, on the other. The
young veterinarian we would admonish to be very cau-
tious how he admits empiricism into his counsel—how,
in other words, he practises that which his judgment
may condemn : pin your faith upon no man's sleeve, but
look for yourself as you proceed,
is inscribed on the di-
rection-post which points out the road to professional ce-
lebrity. To the old practitioner we would fain hint, that
nothing is so effectual a barrier to advancement—nothing
so prejudicial to the art, as to continue in the use of re-
medies purely because they were the infallibles of those
who went before : let him be wary how he vainly piques
himself of his experience; for he who reposes himself
on practice, to the utter exclusion of theory, we do not
care what his experience may be, is but a dabbler in the
?
-ocr page 15-
INTRODUCTION.
XVI
art, and one that tampers with the lives of animals unfor-
tunate enough to be placed under his care *.
In order to convey some idea of the present state of
veterinary science, it may not be amiss to take a hasty re-
trospective view of our art, from the institution of the Ve-
terinary College. This establishment may be said to have
had its origin in the Odiham Agricultural Society; who,
in the year 1785, first occupied themselves about the im-
provement of the veterinary art, then in a very neglected
condition: it is M. Sainbel, however, who came over
to England in the following year, with a view of pub-
licly teaching it, and who afterwards became professor,
whom we must regard as the founder of the College. We
* We recall to memory here an anecdote so pertinent to this
part of our subject, that we cannot forbear relating it. A farrier
who was subpoenaed on a horse-cause, was opposed, as evidence of
the contending party, by a young veterinary surgeon. The son of
Vulcan, who had from the beginning eyed his professional anta-
gonist with all the spleen and self-sufficiency so peculiar to his
sect on such occasions, as one of comparative ignorance, when put
in competition with him, the possessor of grey hairs and venerable
looks, during his examination by the counsel, to whom he was re-
plying in a most haughty and assuming tone, was asked by the
judge, "and pray, sir, how long have you been a farrier?" to
which our hero, astonished that his lordship had not heard of his
professional fame, nor of that of his progenitors, answered, " how
long a farrier, my lord ! I was horn a farrier, my father before me
was a. farrier, and so was my grandfather ! ! !"
-ocr page 16-
INTRODUCTION.                                      XVH
may consider this, therefore, as the epocha of scientific
farriery in England; though, long before, there had been
much written on the subject, particularly by the French,
who, for a considerable time anterior to this, led the way
in vetennary pursuits; which only required selection and
arrangement, by a person of good discriminative talent,
and sound medical knowledge, to convert it into materials
fully sufficient for laying down the rudiments of veteri-
nary science. To the lot of Mr. Coleman, the suc-
cessor of M. Sain eel, and present professor to the
College, fell this gratifying task : what professional fame
this gentleman has acquired in its acquittance, or with
how much respect and esteem he is looked up to by the
members of the institution for the services he has ren-
dered it, need not be the theme of our pen. Seeing, then,
that there was much useful, though imperfectly digested
matter to be obtained from the perusal of works on far-
riery *; and that to this was to be added all that bad any
relation to the art in comparative anatomy, physiology,
chymistry, human surgery and medicine, which were at
that time, and have been ever since, making rapid strides
* From a long list of French authors we may adduce, Sojlley-
sel, Bourgelat, La Fosse, Vitet, and Sainbei, as excellent
sources of practical information : among numerous of our own
wnters on farriery, &c. Blundeville, Markiiam, Newcastle,
onapE) Gibson, Bracken, Bartlett, Osmer, Clarke, and
Stubbs are the principal contributors.
b
-ocr page 17-
XV111                             INTROnUCTION.
in advancement, we shall find that our art was suscepti-
ble of very considerable improvement, in a very short
space of time; and that we ought not to be at the pre-
sent day, remembering that this happened thirty years
ago, so young and inexperienced in the practice of it as
many seem inclined to believe. It is now quite time
that we were acquainted with the anatomy and physio-
logy of the horse, so far as our practice demands;
and it is to be hoped that we are making daily progress
in our pathological knowledge: though this last is a
branch of comparative slow growth, and one that is
peculiarly shy of bringing forth fruit. We shall, at ano-
ther time, prosecute an inquiry into the existing state of
veterinary science in this country ; consider the national
means provided for its improvement and diffusion, in the
establishment of the College; analyze the system of
education therein pursued, comparing it with those now
adopted at the principal continental veterinary schools, and
with that originally proposed by M. SA1NBEL ; ascertain
what progress has absolutely been made, notice the dis-
coveries, and endeavour to trace each to its respective and
proper source ; and offer such hints and suggestions for
the further benefit and advancement of our art, as strike
us not to be unworthy the attention—nay, serious consi-
deration of those more immediately concerned in the
welfare and promotion of this very useful branch of ge-
neral knowledge.
-ocr page 18-
INTRODUCTION.                                      XIX
It is far from our intention here to enumerate the "dis-
coveries"
that have been made, even in our own time; suf-
fice be it for the present to observe, that, with the power-
ful aid of our cotemporaries in medicine, whose path is
our nearest way to perfection, we are rapidly effecting a
complete revolution in the veterinary art. We have had,
and we still have, great obstacles to contend with:—pre-
judice, envy, obstinacy, and ignorance; we hope, how-
ever, to find none of them insurmountable; on the con-
trary, in process of time, as we advance in knowledge
and importance, to tread them one and all under foot.
Let us act towards one another as become the respecta-
ble members of a liberal profession, engaged in one com-
mon cause, whose promotion is the interest and the be-
nefit of us all—let us go hand in hand, and unanimously
and resolutely oppose the incursions of that individual
who would sell our present rank and prospective prefer-
ment to fill a private purse ; while we unsparingly lavish
our praises and our honors upon him, who, in being a
real and unsophisticated friend to our art, contributes to
the welfare and advancement of every one of us.
Although we abstain from, indeed our limits will not
admit of our making mention of the progressive improve-
ment the art has undergone, even since the foundation of
the College, we shall take a hasty review of the principal
literary productions of the professors and members of the
institution.
b2
-ocr page 19-
XX                                      INTRODUCTION.
Charles Vial de Sainbel, the founder of our
College, now no more, if we are to repose faith on what
he wrote, and on what he had but time to lay the foun-
dation stone of, had great and important designs indeed
in view, to the aggrandizement of veterinary science. His
career, however, was of so short duration, that he has only
left us—besides an excellent and unpractised plan for the
education of eleves veterinaires—a work, translated into
English, containing some very pithy Observations on the
Art of Veterinary Medicine; an Essay on the Propor-
tions of Eclipse;
another, which obtained a prize giveu
by the Royal Society of Medicine, on the Grease and
Watry Sores on the Legs of Horses;
a third, oh the Glan-
ders;
and a few short Observations on the Cholic, or
Gripes.
That Sainbel, had he lived, would have pro-
ceeded on sound principles, may be inferred from his
fourth observation on the veterinary art. " The object
of this art is therefore not only congenial with that of hu-
man medicine, but the very same paths which lead to a
knowledge of the diseases of man, lead equally to a know-
ledge of those of brutes.
An accurate examination of the
interior parts of their bodies, a studious survey of the ar-
rangement, structure, form, connexion, use, and relation
of these parts, and of the laws by which they are intended
to act, as also of the nature and property of the various
foods, and other agents, which the earth so liberally pro-
vides for their support and cure ; these form in a great
-ocr page 20-
INTRODUCTION.                               XXI
measure the sound and sure foundation of all medical sci-
ence, whatever living individual animal is the subject of
our consideration."
First in the catalogue of works of more modern vete-
rinary writers, in volume and importance, presents itself
that of Professor Coleman ; wherein the Structure,
Economy, and Diseases of the Foot of the Horse, and the
Principles and Practice of Shoeing,
are treated of with
great clearness and ingenuity : the descriptive part is well
illustrated by several highly finished paintings. Messrs.
Moorcroft, Bracy Claek, Goodwin, Budd,
and Powis, have also written on this subject. Mr.
Goodwin, whose is a good practical work on shoeing
horses, has given us a synoptical display of the vari-
ous methods adopted, in this branch of our art, by dif-
ferent nations; and introduced some modification in the
present practice of it; which, in our opinion, will be
sootier or later carried into effect; even by the adherents
to other systems; and may be so, we also think, without
any concession of their present tenets.
Professor Peall has published some Observations on
the Diseases of the Horse, and his Stable Management;
unrivalled by any book of the kind, either for the practi-
cal matter it contains, or the liberal and scientific style in
which it is written.
Mr. Bracy Clark has presented us with an inte-
resting Essay on the Pots of Horses and other Animals ;
wherein the transformations, and other curious incidents
-ocr page 21-
XXli                               INTRODUCTION.
connected with the natural history of that little animal,
are with much science and research developed to us.
The same writer has published another Essay on the
Gripes of' Horses;
and, more recently, a work entitled,
The Reformed Veterinary Pharmacopoeia.
Mr. Sewell, assistant professor to the college, we be-
lieve every member of the profession will attest, has long
and unremittingly exerted himself in the augmentation of
veterinary knowledge; and, we feel pleasure in adding,
with no ordinary success. Among other innovations in
practice, of small comparative import, we must not lose
sight of the operation, called neurotomy, the merit of
which is the exclusive right of Mr. Sewell. It is illi-
beral! it is false, to assert that it is not! But Mr. Se-
well has treated the groom's oracle* with deserved
contempt-------with silence.
The following members of the institution have also
become authors; some of general treatises, others of es-
says, dissertations,
&c. the bare mention of whose names
we must be content with here, or we shall extend these
preliminary observations much beyond their prescribed
limits: viz. Messrs. Boaedman, Lawkence, Wil-
kinson, Shipp, Smith, Ryding, Feron, Burke,
and Denny.
* Treatise on Veterinary Medicine in four volumes, &c. &c. by
James White, late Veterinary Surgeon to the First or Royal
Dragoons. Vide Vol. III. p. 148 of the 13th edition.
-ocr page 22-
INTRODUCTION.                                 XX1U
Science, then, may at length be said to have dawned on
the veterinary art—society has, now, long regarded it as
one of adequate utility to merit its support and encou-
ragement—the Veterinary College has been established
thirty years, and has dispersed its members throughout
the united kingdom. Notwithstanding all this however,
had not others, under less favorable circumstances than
our own, have been well received upon the arena of pub-
lic decision, we should not yet have ventured to have
made our appearance at the same tribunal.
It has been said, and with much truth, that he who
would be of essential service to the profession as an au-
thor, should take up the investigation of one subject, and
confine himself to that alone : thus has medicine attained
its present pre-eminence in this country. It appears to
us however, that, before any science, or art, can make
great progress, it is requisite that every member of it be
furnished with a synopsis of the fundamental principles
of that science, or art ; and that, for the want of such im-
plements, many are deterred from lending their aid, who
would otherwise prove very useful laborers in the vine-
yard. To this end, it is not enough that these rules for
their guidance be propounded to them once, or twice, or
even thrice ; but it is absolutely necessary that there be
some authentic records of them kept, accessible to every
individual of the profession : so that the students may
av»il themselves of them in the absence of their teachers ;
-ocr page 23-
XXIV                                  INTRODUCTION.
the members refer to them at pleasure; and the public
in general be informed of the pretensions of its practi-
tioners, by a display of that knowledge which they are,
or ought to be, in the possession of.
No man supposes that his watch can be repaired at
the anvil, though there be those who send their horses to
the blacksmith to be cured of their disorders : they know
that this blacksmith is unacquainted with the mechanism
of a watch, and yet they intrust a machine to him, to
which, in point of complication of structure, a rattle bears
more affinity to a watch, than a watch to it! Why then are
gentlemen so blind? Is it that a horse is of less value
than a watch ? No ! It is that the vile trash diffused in
treatises on farriery, is so truly disgusting to a man of com-
mon reflection, that he forms his opinions of the art by
those he entertains of the book, and considers it specially
adapted to the genius of his groom or coachman, or suit-
ably lodged within the skullcap of his blacksmith or
bell-hanger—below the dignity of a man of education,
and incompatible with the habits of a gentleman! " Mi-
serable animal I" says Sainbel, " bereft of speech, thou
can'st not complain, when to the disease witli which thou
art afflicted, excruciating torments are superadded, by
the ignorant efforts of such men, who, at first sight, and
without any investigation to lead them to the source of
thy disorder, pronounce a hackneyed, common-placed
opinion on thy case, and then proceed with all expedition
-ocr page 24-
INTRODUCTION.                                  XXV
to open thy veins, lacerate thy flesh, cauterize thy sinews,
and drench ihy stomach with drugs, adverse in general to
the cure they engage to perform*."
To those who may regard the veterinary profession in
other light than as one, not only deservedly established
upon the basis of respectability, but, from its objects,
necessarily requiring ability and a knowledge of medicine
to practise with advantage, we would put the following
questions of Vegetius; (a writer we have already
quoted;) and then ask them, if these arguments, surely
excellent, if not elegant of their kind, were tenable at that
day, with how much more force and truth can we apply
them at the present ?
Quis aut nosse curas jumentorum erubescendum pu-
fet, cum optima jumenta habere gloriosum sit 1 Quis
vituperationi det id posse curare, quod laudi ducitur pos-
sidere ? Forsan ipsa opera mulomedicorum videtur ab-
jectior, notitia aut ciirationis non solum honestissimis, sed
etiam disertissimis convenit: ut provisione et ordinatione
sollerti curatis animalibus et damnis careant, et volupta-
tibus perfruantur.
Highly respectable as every member of the law and di-
vinity professionally is, and great as the honors are con-
ferred on some of the most eminent, yet do we find in-
Vide Saijibel's General Observations on the Art of Veterinary
Medicine.-
-ocr page 25-
XXvi                             INTRODUCTION.
stances, too numerous indeed, of chicanery and apostacy
in both these professions : shall we then brand the vete-
rinary art with stigma because one who professes it
swerves from that course which circumspection might,
and honesty ought to dictate ? The man who barters
his reputation for dirty pounds, shillings, and pence—be
he who he may—whether he preside over or be a member
of it, forfeits the confidence and good-will of a profes-
sion he living dishonors, and dead leaves a name, a blot
jn its history.
That individual has ever appeared to us as the most
skilful and best practically informed veterinary surgeon,
caeteris paribus, who is most familiarly acquainted with
the natural habits of the horse, as well as those various
states in which he is placed by art;—either in the stable,
upon the turf, in the field, or upon the road:
" A skilful horseman, and a huntsman bred;"
and for the same reason, that he is regarded as the most
able physician, who has well informed himself of the ha-
bits of life and constitution of his patient. In the selection
of a hackney, for example, we should estimate that man's
judgment at little, who was not only a good horseman him-
self, but who had not ridden a variety of horses of that
denomination ; nor should we consult him in the choice
of a racer, who was not perfectly conversant in the trials
and performances of horses of various breeds, and differ-
-ocr page 26-
INTRODUCTION.                                SXV11
ent shapes; neither would we give him credit for any
but fanciful knowledge of equitation, who could not set a
sauteur in a school, or cross the country upon a well-
trained hunter.
Let it not be understood, however, that we coincide
with that system of education which would train up the
61eve vet£rinaire in a stable, or a blacksmith's shop, ra-
ther than initiate him in the different branches of litera-
ture: surely, the study of medicine in the horse involves
nothing so ecurien in its nature as to render it necessary
to be stalled for its attainment! The student of medi-
cine receives clinical instructions, and is an attentive ob-
server of the progress of disease ; but it is neither requi-
site, nor advisable, that he should spend that time in the
wards of an hospital, which he now, with such in-
calculably greater ultimate advantages, devotes to classi-
cal and other learning! Without a due share of practical
knowledge, it is true, our medical acquirements are ever
leading us into error; and this is the only excuse we can
make for them who are eternally bewildering themselves in
framing plans in the cabinet for the farrier to look through
when they enter the forge. In fine, it appears that a
happy combination of medical science with equestrian
skill in the same individual, will eminently qualify him as
a veterinary surgeon. Were the art intrusted to the first,
U would, at no remote period, dissipate itself in specula-
tion and refinement; and were it in the hands of the last,
-ocr page 27-
XXV111                                INTRODUCTION.
it would rapidly sink again into that abyss of ignorance
and blind humiliation, from which—and woe be to him
who from sinister and selfish motives would again darken
and enslave it—it is rising fast into the horizon of science.
But to conclude these preliminary observations—
With all that was known prior to the institution of the
College—with that vast accession of convertible science
for which we are indebted to human medicine—and with
what has since been added by later writers, we purpose
to compile a regular course of lectures on the veterinary
art; parts of which we shall submit from time to time,
until the whole be completed, to the perusal of those de-
sirous to acquire an elementary knowledge of it. For
students we principally design them: should they, how-
ever, be deemed worthy of the attention of others, we
shall feel amply repaid for our time and application.
The anatomical part of the work is taken from our own
dissections—without adherence to the details of others.
The veterinary practitioner does not require so accu-
rate an anatomy as the surgeon: he has seldom to cut
down on an artery; never to amputate a limb. There
are some parts of the animal, indeed, of which a know-
ledge would lead to little or no practical utility what-
ever: such are many muscles of the back, loins, neck,
and head—the minute structure of the brain and nervous
system— the precise course of blood-vessels removed from
external injury; and some others.
-ocr page 28-
INTRODUCTION.                             XXlx
Our physiology we adapt to the popular doctrines of
the day.
To compose our pathology, we avail ourselves of the
labors of those few who have written from their own ob-
servations ; and we have copious notes of our own to re-
fer to, as well as a large assemblage of records, collected
by ourselves and others in the course of a very extensive
practice of nearly thirty years duration, in the service of
the Honorable Board of Ordnance.
Such are the materials we have the use of iri the con-
struction of our work, and such are our pretensions to
public notice : our aim is to lay down principles funda-
mental to the attainment of a knowledge of the veterinary
art.
                                __________
Before we enter on the immediate consideration of
these lectures, it will be proper to sketch an outline of
their contents ; and explain what we mean by the ana-
tomy, physiology, and pathology of the horse.
In order to obtain a thorough knowledge of any science,
it is expedient to commence with the most simple, and
proceed progressively to the most complicated parts.
This is the course pursued by our most eminent teachers
of the anatomy and physiology of the human body; and
it is that which we have observed in the compilation of
these lectures.
Were the term anatomy strictly confined to its deriva-
-ocr page 29-
XXX                           INTRODUCTION.
tion, it would simply imply the dissection of parts; but,
according to its present acceptation, we mean by it—a
knowledge of the structure of the component parts of an
animal, and of separating and distinguishing those parts
from one another.
Anatomy may be divided into human,
and veterinary .-—the former being that which restricts its
inquiries to the human species ; the latter, that which ex-
tends them to all our domestic animals, from the horse,
its special object, downwards. From a comparison of
the two, we derive comparative anatomy.
-By physiology, we mean a knowledge of the actions or
functions—the economy or use of parts.
As parts, by performing different actions from those
which are natural to them, are altered in regard to their
original structure, so we have a third division, termed
pathology.
In order to elucidate these objects of inquiry, let us
take some part of the body, and thus methodically exa-
mine it: say, for example, the hoof. We describe it to
be of certain relative dimensions, and definite shape; to
be divided into crust, sole, frog, and bars; to be composed
of horny fibres, either regular or irregular in their course;
and to be firmly attached to the parts within : all this is
comprised in its anatomy. Its physiology, is that of con-
taining and protecting the soft, or sensitive parts ; of sus-
taining the animal's weight, and preventing slipping; and
of expanding in due ratio to the force with which the
-ocr page 30-
INTRODUCTION.                                    XXXI
foot is put down, and thus counteracting the effects of
concussion. By knowing its healthy appearances, we
become acquainted with its morbid, or pathological con-
ditions : we find it contracted, preternaturally upright,
small, convex, flat, or concave.
The constituent parts of the body may be disposed in
three classes. The first will comprehend the organs of
locomotion:
—the bones and muscles. The second, those
subservient to nutrition and sensation:—the viscera, blood-
vessels,
and absorbents—and the brain and nerves. The
third, those destined for the reproduction of the species :
the parts of generation in both sexes.
Anatomy, then, may be considered to be a knowledge
of the materials, and of the manner in which these mate-
rials are connected in the construction of the animal ma-
chine. Its framework, that upon which all the other
parts are distributed, to which they are attached, and by
which they are sustained, is constituted of hard, inflexible
parts, called bones: if an animal fracture one of the prin-
cipal bones of the leg, its pillar of support being lost, the
limb can no longer uphold the body. Bones, however,
not only afford stability, attachment, and support to the
other—the soft parts, but serve to contain the more im-
portant of them, and defend them from external injury :
such as the brain, the thoracic, abdominal, and pelvic
viscera.
By contrasting the skeleton with the living animal, we
-ocr page 31-
XXXli                                INTRODUCTION.
mark the proportion which the bony fabric bears to the
bulk of the whole body : we perceive that the bones, di-
vested of flesh, form but an outline of the original animal.
Now the flesh is divisible into a very considerable number
of distinct portions, which anatomists call muscles; and
these parls it is that we are to regard as the essential
agents "of motion : the bones are the passive, these are the
active locomotive organs. To the muscles, the limbs
chiefly owe their bulk and form ; of them a considerable
part of the trunk is composed ; and by them all the mo-
tions of both are executed. They uphold the body while
standing, move it from one place to another, and render it
fixed at pleasure; they direct the eyes to the objects of
vision, erect or depress the ears as befits the vibration of
sound, and give motion to the jaws for the comminution
of food : they are also the agents of respiration, and are
concerned in a variety of ways with other important func-
tions, a detail of which would be ill-timed in this hasty
review of them.
Were the limbs composed of but two, or three bones,
they would be but ill adapted to perform that variety and
extent of motion which they now do, in transporting the
animal from place to place ; on the contrary, we find
them, most wisely, to consist of several, differing in size
and shape, so arranged and accommodated as to act with
facility, and surprising rapidity: to give strength, and ad-
mit of speed, no less than one and twenty are found in
-ocr page 32-
INTRODUCTION.                                XXX1U
the fore extremity. The ends of bones, shaped so as to
fit into each other, are covered by cartilage, better known
by the name of gristle; and are fastened together by
dense, fibrous cords, denominated ligaments; whose in-
ternal surface is lined by a membranous bag, containing
what is called joint-oil—in technical language, synovia.
Thus is constituted a. joint: in the motion of which, the
nice adaptation of the bones, and due tensity of their li-
gaments, prevent dislocation ; the cartilages, like cushions
of support, guard against concussion ; while the synovia
is a true joint-oil for the lubrication of the whole.
Next we come to take a view of those organs concern-
ed in the maintenance of life. In order to furnish nutri-
ment to the system, the animal, irresistibly compelled by
the sense of hunger, takes in from time to time a certain
proportion of food ; which, after it has undergone tritu-
ration by the teeth, and has been moistened by saliva, is
conveyed by the esophagus, or gullet, into the stomach.
Here the several matters of which it consists are reduced
to a soft, uniform mass, called chyme; and this is further
converted within the intestines, into which the stomach
impels it, by the admixture of different juices; the two
most remarkable of which are furnished by the liver and
pancreas—the bile, and pancreatic fiuid. .At this time,
a milky and highly nutritive essence separates itself, and
Is absorbed by numberless capillary tubes, called lacteals,
a,|d conveyed by them into the system; while the resi-
c
-ocr page 33-
Xxxiv                            INTRODUCTION.
duary matters, feculent in their nature, continue their
route through the guts to be expelled at the anus.
The blood, the nutritive fluid to the animal as the sap
is to the vegetable, is conducted to every part of the
body by a system of vessels, named arteries ; whence it is
re-conveyed to the heart by others, similar in composi-
tion and distribution, called veins; and this perpetual
motion of it, is what we denote by the term circulation.
Having, however, once performed this circuit, wherein
it has served the purposes of nourishment, growth, and
reproduction, and supplied the various secretions—such
as bile, semen, urine, and saliva, it is unfit for the like uses
again, until it has been exposed to the influence of the
air. This is effected in the lungs, and is the ultimate de-
sign of respiration.
Thus constituted—with the instruments of motion, and
the means of preserving and repairing itself—still does
the machine require an active principle—a primum mo-
bile—a spring that gives impulse to the whole, ere it
can possess the power of self-operation. This alone re-
sides in the brain and nervous system—the organ of sen-
sation and motion; whose presence essentially distin-
guishes the animal from the vegetable. By the faculty
of motion, animals are enabled to perform certain actions;
by that of sensation, they obtain a knowledge of what is
passing around them. The only sense that pervades al-
most all classes of animals, is that of feeling : the others,
-ocr page 34-
INTRODUCTION.                            XXXV
which appear to be only modifications of it, in a more
exalted and susceptible condition, are by no means con-
nected with their vitality. The eye is so constructed that
it can feel the rays of light; and the ear so formed as to
take cognizance of the vibrations of sound; buton nei-
ther of these senses has life any dependance; for a blind
horse is as much alive as one whose vision is perfect; and
there are some animals in which sight and hearing are en-
tirely wanting. Indeed, scarcely any parts of animals
present greater varieties than the organs of sense : in the
human subject, the power of feeling is inherent in an emi-
nent degree in the tips of the fingers; in the horse, we
find no proper organ of feeling—it is probably compen-
sated for by the super-excellence of that of smell; and so
exquisitely fine is this sense in the dog, that even the
tracts of the light-footed deer are followed by him with
a certitude truly surprising.
The term of life of every animal being fixed, at a more
or less distant period according to its kind, it was neces-
sary that it should be provided with means for the propa-
gation of the species. Among the higher classes, gene-
ration is the effect of the concurrence of the sexes; each
of which possesses an assemblage of organs, mutually
adapted to this end: but in the lower orders, the sexes
are now and then combined in the same individual; or
generation is performed without any copulative act at all.
In the male, the testicles separate a peculiar fluid from
-ocr page 35-
XXXvi                            INTRODUCTION.
the blood, known by the name of semen; and the chief
use of the penis is to conduct this fluid into the uterus
or womb of the female; in order to excite in the ovum,
therein contained, a disposition to growth and develope-
ment. In one of two small glandular bodies, placed within
the belly of the female, named the ovaries, is formed the
ovum; whence, through a tube denominated the oviduct,
it is transported into the womb : here the little embryo,
exposed to the influence of the seminal fluid, gradually
developes itself, acquiring the precise form and attributes
of its parent; until the period of its consummation has
arrived, when it is launched into the world to provide for
itself.
-ocr page 36-
VETERINARY LECTURES.
LECTURE I.
On the Blood.
xVCCORDING to the course which we observe in
the compilation of these lectures, the blood presents it-
self as the first subject of our consideration; and with
real advantages to the student is it made so by our
teachers of human anatomy, whose arguments in favor
of this method are so instructive, that we cannot pass
them over here entirely unnoticed.
The body is said to be composed of two orders of
parts—solids and fluids. Of the latter the blood consti-
tutes the chief bulk; indeed it may be regarded as the
matrix, if we may be allowed the term, out of which all
the others, as well as the solids themselves, are formed
and re-produced. But the fluids of the body differ from
the solids, inasmuch as they afford, from the uniformity
°f their properties, a composition of a more simple and
intelligible kind—than is presented to us, by, perhaps, the
least complicated of the latter ; a fact that might of itself
V.
-ocr page 37-
2                                  On the Blood
induce us to treat of them in the beginning of the course.
Another and obvious advantage, however, resulting from
such an arrangement, is this: that in investigating the
properties of the fluids, it is seldom or ever necessary to
advert to the solids; whereas, if we were to reverse this
order, we should find ourselves often much perplexed to
render our descriptions intelligible, for want of an ade-
quate knowledge of the former, and more particularly of
the blood ; so that, in fact, we may look upon a thorough
acquaintance with the properties and uses of the blood,
as, in a great measure, the ground-work of our future ana-
tomical, as well as physiological acquirements. More-
over, regarding the blood, in an anatomical point of view,
as constituting a part of the body, it must indubitably be
considered as by far' the most essential: at the same
time, it has been so much submitted to observation and
experiment, that we may safely say, none has received
more splendid elucidations from the most celebrated
writers on human medicine; and add, that few still pre-
sent a wider field for future research. When we con-
template the names of a Harvey, a Hallee, and a
Hunter, and reflect on the time and labor these eminent
physiologists bestowed on their investigations, relative to
the nature, the uses, and the motion of this fluid, we shall
be still further convinced of the importance of our pre-
sent subject, and regard it as one having additional claims
to our primary and profound consideration.
Blood may be defined to be, a fluid circulating within
the heart, arteries, and veins of a living animal. From
the uniformity of its appearance, it has received the
name of an homogeneous fluid; and such indeed it appears
to be, while circulating within its vessels in the living
body: the lapse of a few minutes, however, after its
-ocr page 38-
On the Blood.
3
detraction, presents to us a mass composed of dissimilar
parts, or one of an heterogeneous nature.
The color of the blood is red in all warm-blooded
animals ; though it is said to vary in its shades of redness
in different classes of them*. Of its doing so in dif-
ferent parts of the same animal, we have full and fa-
miliar demonstration : in the common domestic fowl, for
example, some parts—'as the wings and breast, are white ;
others—as the legs, of a faint and dusky red hue ; while
the heart, liver, &c. present all the common appearances
that the same organs do in quadrupeds. On the other
hand, many animals, called cold-blooded, possess blood
entirely colorless: e. g. in the insect tribe, it is thin,
limpid, and transparent. Again, there are others in
which a red blood circulates in those parts more imme-
diately connected with life: such are fish, whose vital
organs are red, though their muscles are perfectly white.
Without further digression, however, to prove that color
is not an essential property of blood, we may advert to
some parts of the horse, which are wholly supplied with
this fluid in a colorless form: the transparent parts of the
eye are a familiar example of this, in which the vessels
are too minute to admit of the entrance of the coloring
particles. On the contrary, blood in some parts of the
body is so intensely red, that its color approaches more
to that of the Modena red, or purple—as is the case with
that contained in the pulmonary arteries, and venous sys-
tem in general; while in others, its hue is of the bright-
est scarlet—of which the pulmonary veins and larger ar-
* The blood of the horse is not so red, under ordinary circum-
stances, as that of the human subject; nor is that of the latter so
high colored as that of the clog, so far as we have compared
them.
b 2
f
-ocr page 39-
«
4
                                  On the Blood.
teries afford the best examples. To the dark-colored
portion, the name of venous blood has been applied; to
the bright red, that of arterial: it will be seen, however,
from what has been before stated, that these epithets are
not in strict conformity to the laws of the animal economy.
The shade of red, then, not only varies in the blood of dif-
ferent species of animals, but in that of the same animal,
from the darkest Modena, or purple hue, to a perfectly
limpid brightness. With the exception of that flowing
within the pulmonary vessels, the blood changes its co-
lor, from the bright scarlet, or arterial hue, to the dark
red, or venous, in passing from arteries to veins—a
change, the intensity of which depends on the rapidity
with which it circulates from one set of vessels to the
other; so that, as might be expected, stagnation in any
part will have a similar effect on it. Rest, therefore, or
what is, in a measure, equivalent to it, tardiness of mo-
tion, will be attended with an alteration in the appear-
ance of this fluid. If, for example, you tie a cord around
your arm, that part more remote from the heart, will be-
come turgid, from distention of its vessels with blood;
which (blood) will rapidly undergo a change, from a more
or less bright red, first to a Modena, and ultimately to a
dark purple, or black hue—changes solely referable to its
detention by the ligature. Under extraordinary rapidity
of circulation, the result, though not altogether the con-
verse of the former, is still very different, inasmuch as the
arterial character is preserved by the blood in its course
through the veins ; and this appearance will be in pretty
exact ratio to that of its augmented celerity. The com-
mon operation of venesection affords a good illustration
of this : when you first open the jugular vein, the blood
which spirts out, is of a dark venous hue, but in a. short
-ocr page 40-
Ou-Jhe Blood.                                  5
time, the stream assumes a reddish tint, and often, parti-
cularly when the orifice in the vein is large, becomes
quite of the arterial character; a change simply owing
to its quicker circulation from artery to vein, and its
consequent accelerated flow in that vessel from which
you are drawing it. Having before stated, that the con-
verse of what generally takes place, happens in the pul-
monary vessels, with regard to the color of the blood, it
•will here be necessary briefly to explain this phenome-
non : let us, however, remark by the way, that in no part
of the body is the contrast greater between the two kinds
of blood, than in these tubes. In the pulmonary arteries,
its color is so dark, that it has not unfrequently been
called by authors, black blood, though it is, in truth, only
of the most intense Modena red ; while, on the contrary,
in the pulmonary veins, nothing can exceed its beautifully
bright red, or scarlet tint. Now, as the pulmonary arte-
ries convey the blood to the lungs, and the pulmonary
veins return it from them, it is evident tiiat this remark-
able and sudden change must have been effected in those
organs: physiology has demonstrated that it is so, and
that it is to be ascribed to the air which they contain, and,
farther, that it is a process essential to the support of the
animal's life. Venous blood is unfit for the various pur-
poses to which arterial is applied; it is, consequently,
sent through the lungs in order to acquire renovated
properties ; and these are made manifest to the eye of the
anatomist, in the alteration of color.
In the more perfect, or, as they have been denominated
in contradistinction to the others, the warm-blooded ani-
mals, the blood is every where found, while circulating in
the living body, to be of a certain degree of heat; and this
Jt steadily preserves in its circulation through the inward
-ocr page 41-
6                                  On the Blood.
parts of the body, uninfluenced by the surrounding tem-
perature*. In all unexposed parts, the heat will ex-
ceed 100° of Farenheit's thermometer; it has been
found however, by experiment, that this degree is
not equally maintained in the more superficial situations
of the body : what these variations are, we have but little
to do with ; though they may be ascertained by the aid of
the thermometer, at any time, with precision. But in the
lower orders of animals, or such as are called cold-blood-
ed, the heat of the blood corresponds with that of the
medium in which they live. We are not, however, to
suppose that the temperature of this fluid is never sub-
ject to variation, even in perfect animals, for it is found to
be much influenced in them by disease : e.g. in the hu-
man subject, in whom the heat of the body is, in health,
9S", it has been known to rise to 110° during fever;
and in all superficial parts, increased heat is one of the
essential symptoms of inflammation.
The weight of a given quantity of blood when com-
pared with a like volume of water, is nearly one-eleventh
more—i. e. water being equal to 1000, blood is about
1090; but its specific gravity will be subject to varia-
tion, according to the state of health of the animal
from which it is taken: it will be greatest in such as are
the strongest, and enjoy the most perfect health.
* The heat of the horse's blood, while flowing into a basin, is
100°. If the bulb of the thermometer be introduced into the
wound, the quicksilver will rise to about 101°. The temperature
of the more superficial parts of the body will, in course, vary with
that of the surrounding atmosphere. Mr. Hunter found, that the
thermometer introduced into a wound two inches deep, made into
the gluteal muscles of an ass, indicated 100°; and that the heat
of the vagina was the same. The interior of the chest of the dog,
he ascertained to be 101°.
-ocr page 42-
On the Blood.                                    7
For many reasons, it is impossible to form a correct
estimate of the quantity of blood contained in an animal;
though, at first view, it appears no difficult task to arrive
at such a knowledge. We have no means, however, of
extracting the whole of this fluid from the body, or of
correctly ascertaining what remains in it after death ; and
though the following experiment may answer every prac-
tical and useful end, still it is by no means conclusive as
a nice computation: it is one that has been frequently
made on the dog, in this instance we repeated it on an
ass about six months' old.
The weight of the animal being ascertained to be 79 lbs.
a puncture was made with a lancet into the jugular vein,
from which the blood, which flowed in a very free stream,
was collected. The vein having ceased to bleed, the ca-
rotid artery of the same side was divided, but no blood
came from itt in a few seconds afterwards the animal
was dead. The weight of the carcase was now found to
be 73 J lbs. consequently it had sustained a loss of 5Jlbs.
precisely the measure of the blood drawn. It appears
from this experiment, that an animal will lose about l-15th
part of its weight of blood before it dies ; though a less
quantity may so far debilitate the vital powers, as to be,
though less suddenly, equally fatal. In the human sub-
ject, the quantity of blood has been computed at about
l-8th part of the weight of the body ; and as such an
opinion has been broached from the results of experiments
on quadrupeds, we may fairly take that to be about the
proportion of it in the horse : so that, if we estimate the
weight of a common sized horse at about 12 cwt. the
whole quantity of blood will amount to 84 qrts. or 10S lbs,
of which about 45 qrts. or 90 lbs. will commonly flow
from the jugular vein prior to death ; though the loss of
-ocr page 43-
On the Blood
s
a much less quantity will deprive the animal of life*.
It is well known, that young animals possess more
blood than old, and that they will, perhaps on this ac-
count, sustain greater bodily injuries, and bear larger
hemorrhages; indeed they are wisely provided with such
an excess, if we may so term it, in order that their
growth may be promoted, and their several organs main-
tained in a state of vigour: but in old, in which the body
is gradually decaying, and the powers of life declining,
the quantity of this fluid becomes reduced. Mr. Wilson,
in bis Lectures on the Blood, Sec. says, that " Fat animals
are found to possess less blood than leaner animals, and
tame animals which are confined, less blood than wild
ones."
Some have formed speculations on the quantity con-
tained in the human body, from the losses occasionally
sustained ; vague, however, must ever be such conjec-
tures ; for it is found that blood to an enormous amount
may be lost, in cases where hemorrhage, not copious
or too long continued, returns at frequent intervals :
thus in uterine and nasal hemorrhages in the human sub-
ject, astonishing accounts have been published of the
* Supposing a man to weigh 12 St. or 168 lbs. the quantity of
blood contained in his body may be rated at 21 lbs. or 2 galls. 2qrts.
and 1 pint. Again, granting that a dog weighs 40 lbs. the amount
of his blood will be five pints. These calculations are useful, and
worth our retention, inasmuch as they serve to guide us in prac-
tice, as to the probable extent to which we may, with safety, carry
venesection in different animals. For instance, we may reckon the
loss of a pint from a man to be equivalent to that of a gallon from
a horse, or to four ounces from a dog, and vice versa; selecting in-
dividuals from each class about the respective weights we have here
■<et down.
-ocr page 44-
On the Blood.                                   9
total admeasurement of the collected daily discharges.
But in all these cases, we are to remark, that it is the
gradual or occasional loss of it, and, consequently, the
time given for its reproduction, (for new blood is made
even while the old is escaping,) that enables these pa-
tients to bear up against the debility ever attendant on
such affections*. Animals, in fact, support losses of
blood well or ill, according as the part, from which it
comes, bleeds more or less freely, or as the hemorrhage
endures for a longer or shorter space of time: on this
principle it is, that a large orifice is in general to be
preferred, in the detraction of blood for inflammatory
disease, to a small one. There are some parts of an ani-
mal that contain more blood than others : e.g. muscle
possesses more than either bone or tendon, and is, conse-
quently, redder; as color in the living body is, for the
most part, dependant on blood. Parts much exert-
ed are found to have more blood sent to them than
others, which, though of similar structure, are less used :
* " I have seen several quarts thrown up from the stomach in a few
hours, even by a very thin puny person : and, on the other hand,
if we had not this proof, we should suppose that there could be but
very little, when a few ounces will make a person faint. I have
an idea however that people can bear to lose more by the stomach
than by any. other way. Besides it becomes a matter of surprise
how little is commonly Tound in the dead body: but I believe in
disease it in some degree diminishes with the body, for more is to
be found in those who die suddenly, or of acute diseases; and even
in some who die of lingering diseases, as a dropsy, we have a con-
siderable quantity of blood. The only way of accounting for this,
Is, that in a common lingering illness there is less blood, and in
a dropsy it coagulates less; for the strong coagulation squeezes out
the serum which I imagine transudcs_after death, and is not ob-
servable." Hunter on the Blood.
                                                4
-ocr page 45-
On the Blood.
10
hence, the muscles of the legs of a fowl are red, but
those of the wing and breast nearly white.
Blood, while circulating in its vessels, is always fluid;
were it not perfectly so, the transmission of it through
numerous capillary tubes to different parts of the body,
could not be effected.
That blood is constantly kept in motion during life with-
in its vessels, is an opinion that has been handed down to
us by the earliest physiologists ; but it was not until the
timeof Harvey, that, what is now called, the circulation
of the blood
was discovered. Harvey demonstrated, that
this fluid, which previously to his time was believed only
to ebb and flow, was conveyed by one set of tubes to
every part of the body, called arteries ; and by another,
termed veins, returned to the heart, or source whence
it came ; that, thence, it performed a second revolu-
tion through the lungs, in order to be rendered fit
for the various and important uses, it serves in its trans-
mission over the body. So that, in truth, there may be
said to be two circulations, the greater and the lesser :
the former, meaning its course over the body in general ;
the latter, that through the lungs. Two of the best,
and at once demonstrative proofs of the circulation,
are the simple experiments of putting ligatures around an
artery and a vein : in the one case, that portion of the
vessel will be full of blood which is next to the heart,
while the opposite part will remain empty; in the other,
the reverse of this will happen ; clearly demonstrating,
that the blood is perpetually flowing in both sets of ves-
sels, and, at the same time, shewing, that its current in
each is in opposite directions.
The blood, though fluid while circulating, possesses
a power of becoming solid—of converting itself into
-ocr page 46-
On the Blood.
II
a glutinous mass, called a coagulum; by which property,
it is variously converted into materials for the growth,
support, and repair, of every part of the body.—
Bones, muscles, &c. are formed from it; the different
organs of the body are kept in a continual state of tone by
it; divided surfaces and fractured bones are glued to-
gether and repaired by it; and lastly, all the secretions
of the body, as urine, bile, saliva, &c. are furnished by
it: moreover, by this power of coagulation, when extra-
vasated from its vessels, are many dangerous bleedings ar-
rested, which might otherwise prove destructive to life.
To the indefatigable exertions of Mr. John Hdnter,
in the promotion of medical science, «re we indebted for
those opinions which attribute to this fluid, while circu-
lating in the living body, a vital principle. In his disser-
tation on this subject, Mr. Hunter prepares the mind for
the reception of so novel, and, at first view, so inconceiv-
able a doctrine, by the following preliminary notice :
" To conceive that blood is endowed with life, while cir-
culating, is perhaps carrying the imagination as far as
it can go ; but the difficulty arises merely from its being
a fluid, the mind not being accustomed to the idea of a
living fluid." And, at another place : " Our ideas of life
have been so much connected with organic bodies, and
principally those endowed with visible action, that it re-
quires a new bend to the mind, to make it conceive that
these circumstances are not inseparable. It is within
these fifty years only, that the callus of bones has been
allowed to be alive ; but I shall endeavour to show, that
organization and life do not depend in the least on each
other ; that organization may arise out of living parts and
produce action, but that life can never rise out of, or de-
pend on, organization." Mr. Hunteu then proceeds to
-ocr page 47-
On the Blood.
w
show, that the principle of life may and does exist in ani-
mal substances devoid of apparent organization and mo-
tion, in proof of which he instances the egg, as a fami-
liar and striking illustration; which, he says, so long as
it retains this principle, resists the influence of external
agents—such as heat and cold, much longer than dead
animal mat er. To support this fact, he made the follow-
ing experiment: he put a new laid egg into 0 of Faren-
heit's thermometer, and froze it—with a view of destroyr
ing its preserving powers, and then allowed it to thaw.
Next he put this egg, and another newly laid, into a cold
mixture: the former was frozen seven minutes and a half
before the latter. From this, and from other similar ex-
periments, the author comes to this conclusion: "Thata
fresh egg has the power of resisting heat, cold, and pu-
trefaction, in a degree equal to many of the more imperr
feet animals, which exhibit nearly the same phenomena
under the same experiments; and it is more than proba-
ble that this power arises from the same principle in
both,"
In the next place, Mr. Hunter demonstrates, by
some ingenious experiments, not widely different from
those just mentioned, an analogy between the coagula-
tion of the blood and the contraction of muscle detached
from the body.
He reconciles the repugnant idea of life in a fluid al-
ways in motion, and often separated into many portions,
by sajing, that all its parts are similar, and in perfect
harmony with each other. ** Because blood is alive," con-
tinues he, " it has the power of preserving its fluidity;
were it not so, it would be, in respect to the body, as an
extraneous substance. Blood is not only alive in itself,
but is the support of life in every part of the body ; for
-ocr page 48-
On the Blood.
13
mortification immediately follows, when the circulation
is cut off from any part."
" Moreover," he says, " blood itself must be kept
alive ; because, while it is supporting the life of the so-
lids, it is either losing its own, or is rendered incapa-
ble of supporting that of the body. To accomplish all
this, it must have motion, and that in a circle, as it is a
continuance of the same blood which circulates, in which
circle it is in one view supersaturated, as it were, with
living powers, and in another is deficient, having parted
with them while it visited the different parts of the body."
Mr. Hunter also shows a striking coincidence be-
tween the coagulation of the blood and the contraction of
the muscles, a phenomenon we know to depend on life,
and one that he considers as the strongest proof of the
existence of the vital principle.
Animals killed by lightning, or by electricity, have
not their blood coagulated, nor their muscles contracted.
Those that are hunted to death, exhibit the same appear-
ances. In persons who die suddenly—as from blows on
the stomach, or sudden gusts of passion, this strict ob-
server remarked the same coincidence. " The natural
deduction from all these facts and observations," says
he, " I think is perfectly easy; it is impossible to
miss it."
Presuming from these data, that the blood, in common
with the solid parts, is possessed of what he calls the
materia vita diffusa, Mr. Hunter now enters into an in-
quiry of some length and ambiguity, through which we
have neither time nor inclination to follow him, relative
to the nature and disposal of this materia vita; in the
course of which he says, adverting to where the living
principle of the blood first begins, " I am rather inclined
-ocr page 49-
On the Blood.
14
to think that the chyle itself is alive ; for we find it co-
agulates when extravasated; it has the same powers of
separation with the blood; and it acquires its power of
action in the lungs, as the venai blood does."
This is a short but imperfect sketch of Mr. Hunter's
opinions concerning the life of the blood : to say the least
of them, they are extremely ingenious, and are the pro-
ducts of much cautious and laborious investigation,
and, we must admit, as the offspring of so great a mind,
well deserve our serious consideration.
-ocr page 50-
LECTURE II.
On the Blood.
Having treated of this fluid, in our last lecture, as
circulating in the body; we shall, in this, examine its
properties when taken out.
When blood is first received into a vessel, a halitus,
or vapor, emitted from its surface, is observable : a mir-
ror held over the basin becomes obscured by it, and
a peculiar odor accompanies its fumes, which is said to
be more unpleasant in carnivorous than in graminivorous
animals.
We observed, in the last lecture, that blood, although
apparently, was not in reality, an homogeneous fluid ; for
when drawn and allowed to remain at rest, it separates
into two parts : a red solid portion, called crassamentum ;
and a yellowish fluid part, called serum.
This spontaneous separation of its component parts,
is called its coagulation : it takes place, in the blood of
the horse, in the space of about twenty-five minutes; in
that of the human subject, in seven or eight.
These two parts differ in their relative quantities in
different animals, and in the same animal at different
times, depending on the state of the general health of the
-ocr page 51-
On the Serum.
16
subject from which the blood is taken : in some dis-
eases, and in weak subjects, the proportion of serum is
considerably augmented. Richerand, in his Elements
of Phi/siologij,
says, that " in the human subject, the
serum constitutes about one-half, or three-fourths of the
fluid; the coloring matter and fibrina are in inverse ratio
of the serum; and it is observed, that the more brilliant
and red the color of the blood, the greater the proportion
of the fibrous parts." In the healthy horse, the serum
may be computed at about one-half of the whole quantity
of the blood taken away.
On the Serum.
Serum is a fluid of a deep yellow, or straw color, hav-
ing the appearance of being about the consistence of wa-
ter; it is heavier, however, than that fluid, though the
thinnest part of the blood, in consequence of its possess-
ing soryie degree of tenacity.
Though the serum be naturally of a deep yellow, its
color is subject to some variation in disease. In the hu-
man subject, this has been frequently taken notice of in
jaundiced persons, in whom it acquires a brown tinge
from the admixture of bile; and in the horse, in which
jaundice is comparatively an uncommon disease, we have
remarked the same appearance.
It has been asserted, that the proportion of serum, in
a given quantity of blood, constitutes one of the most
material differences between the composition of this fluid
in the horse and of that in the human subject: in the one,
soon after it has been drawn, we discover the coagulum
swimming in serum ; while the other consists of one uni-
form congealed mass, whose surface is scarcely moistened
by serous exudation. In order to form a correct esti-
-ocr page 52-
On the Serum.                                17
mate, however, of the proportion of serum in a given
quantity of blood, it will be necessary to keep the mass
for several days, and this we can commonly do without
its becoming putrid; whereas the blood of the human
subject will putrefy in the course of two days after it has
been drawn, even at the temperature of 50": a want of
such precaution has created much erroneous statement on
this subject.
If we draw a pint of blood from a horse in apparent
health, serum in the following quantities, at the intervals
stated, will be separated. During the first five or six
hours, very sparing exudation takes place; but soon after-
wards, the coagulum becomes surrouuded by it; so that
next day, twenty-four hours from its detraction, we may
commonly pour off from five to six ounces. After this,
its proportion daily becomes less: from one to two
ounces are found in the vessel on the second day, from
half an ounce to an ounce on the third, from three to five
drachms on the fourth, about one drachm on the fifth,
and a like quantity on the sixth; and on the seventh day
generally, at the temperature of 50°, the mass is putrid.
Now, if we sum up the media of these several quantities,
we shall find that the serum amounts to rather more
than half of the whole quantity of blood drawn; we may
fairly take, however, half* as the average.
It appears therefore, that the most essential differences
between our blood and that of the horse, are—first, that
the latter possesses greater preservative powers against
putrescency than the former, when extracted from the
body ; and secondly, that the spontaneous separation of
* " Le serum est un liquide aqueux, transparent, roussMre, et d'une
saveur salee, et dont la proportion la plus ordinaire est d'un tiers d
la mmtii." Trait'c d'Anatomie Veterinaire,
par Gikaiid-
c
-ocr page 53-
On the Red Globules.
18
it, into its elementary or component parts, requires a
longer space of time : it is not true, that there actually
exists any very marked difference between them in re-
gard to the relative proportion of serum.
If serum be exposed to 1.60° of Farenheit's thermome-
ter, it will be converted into a solid tremulous mass, the
effect of coagulation; in which state, a little fluid oozes
out from its sides, termed the serocity: the admixture of
boiling water, of some of the mineral acids, or of alcohol,
also coagulates it. The coagulum of serum is simi-
lar in its properties to common white of egg, or, what is
called, albumen: its serocity has been found by Dr.
Bostock, (in his Analysis of Human Blood,) to consist
of common mucus in conjunction with soda and some
neutral salts.
Serum, or a fluid very like it, is occasionally se-
parated from the blood in large quantities within the dif-
ferent cavities of the body, constituting that disease known
by the name of dropsy. Serum is supposed to be the
menstruum, or solvent of all the secretions.
The crassamentum, or cruor, is composed of two parts:
—the red globules and the coagulable lymph: to the for-
mer the blood owes its color ; to the latter, its solidity
and firmness.
On the Red Globules.
The red globules, or red particles, as they have been
also called, constitute the coloring ingredient of the blood :
they are commonly entangled in the coagulable lymph
during its coagulation, though occasionally some arc
mingled with the serum, tingeing it red. They form, pro-
bably, the least important part of the blood; for in some
animals, many organs of the body are supplied with this
-ocr page 54-
On the Red Globules:                           19
fluid without globules : e.g. in most fish the muscles have
no red blood, aud in the common domestic fowl we know
that the muscles of the wings and breast are commonly
white. In the human subject, and in the horse, there are
also some parts that are supplied only with thin color-
less blood, the best example of which is (as we mention-
ed in the former lecture) the more transparent parts of the
eye, where the blood-vessels are too minute, in a state of
health, to admit of the passage of red globules; though,
under certain morbid affections, they become augmented
in size, and then readily allow of the circulation of the
coloring particles : hence these parts, which were be-
fore colorless and transparent, are now obscured and
filled with red blood. In some animals this fluid is al-
together without the red globules: none has been found
in the blood of insects.
It is to microscopical observations that we owe what
speculations have been offered in regard to the size and
shape of these minute bodies; we say speculations, for,
as yet, authors have not come to any determinate conclu-
sions on this subject. From the extreme diversity of
opinion of those who have endeavoured to ascertain the
dimensions of a globule of human blood—one estimating
it at ^5^TO Part °f a gram °f sand, while another computes
it at 3-(/TO part of an inch, it is evident that much illusion
has ever attended these inquiries. It appears neverthe-
less well authenticated, that their size is not at all in
proportion to the bulk of the animal; for their dimensions
vary but little either in the ox, ass, cat, or mouse*;
and in the skate it is generally believed that they are
larger than in any other animal.
No less discrepant have been the descriptions of au-
* Vide Wilson's Lectures on the Bbod, &c.
c 9,
-ocr page 55-
On the Red Globules
20
thors as to their shape : some have compared them to
rings, others to flattened vesicles, &c. the opinion best
received at the present day, is, that they are spherical;
but, from being possessed of flexibility, occasionally un-
dergo some alteration in form, during their progress
through the smaller blood-vessels of the body.
Though red when viewed in the general mass of
blood, the globules seen in small clusters, or individually,
are yellow, or transparent. In order to explain the cause
of these different shades, nothing more is requisite than
to detach a drop, or two, of port wine within a glass ca-
pillary tube, or of any other dark colored fluid, and it
will be found, if held to the light, to be perfectly limpid
and colorless ; or, if there be more than one, of a light-
er and altogether different shade from that of the fluid
from which they were taken : it is from this cause, then,
that the blood, when distributed in the minute blood-ves-
sels, is of a different hue from that in the trunks. The
color of the globules is affected by atmospheric air: if
you examine a clot of blood in a blood-basin, you find
its upper surface, which has been exposed to the air, of a
bright scarlet, hue, while the under, or that which has lain
in contact with the basin, is of a dark Modena red, or
purple ; but invert the coagulum, and the one will be-
come dark by exclusion from the air, while that which
was before purple, will acquire a scarlet hue from its influ-
ence. In order to prove that this change is effected by the
air, if you place dark colored, or venous blood in vacuo,
its color will remain unaltered. To the same cause is
ascribable that change of color which this fluid receives
in the the lungs of the living animal.
The red globules appear to be the most difficultly
formed of any part of the blood; so that a person who
-ocr page 56-
On the Coagulable Lymph.                     21
lias lost much blood from hemorrhage, looks pale for
some considerable time afterwards ; hence it is also, that
butchers render their veal white, and delicate in appear-
ance, by repeatedly bleeding calves while they are fat-
tening.
The quantity of these particles varies in different ani-
mals, and in different parts of the same animal. Those
appear to have most that are in the best health, and per-
form the utmost labor compatible with their strength;
but in all, they abound in the different glands of the
body, are more numerous in muscles than in sinews, or
bones, and especially in those most exerted, which are
consequently the reddest.
We have before observed, that the globules do not
appear to be equally essential with the other constituents
of the blood : their precise use is not known.
On the Coagulable Lymph.
The coagulable lymph, sometimes described under
the names of jibrine, or Jibrma, and gluten, is that part
to which the crassamentum owes its chief bulk, solidity,
and firmness ; and is of greater importance in the ani-
mal economy than either of the others. During the cir-
culation of the blood it is perfectly fluid, and is so inter-
mixed with the serum and red globules, that we have no
means of separating it.
When freed from the red globules and serum, by wash-
ing, maceration, &c. it is nearly white, or colorless.
The coagulable lymph is a firm, tough, and elastic sub-
stance, of greater specific gravity than serum, exhibiting
a fibrous texture very analogous to that of muscular
""re, hence its name of jibrine, orfibrina.
its toughness, which is often extreme, is not apparent
-ocr page 57-
22                     On the Coagulable Lymph.
till some time after its coagulation; for we have found,
that a coagulum will contract, or become smaller by
squeezing out ^erum, even for a week, or more, after the
blood has been drawn.
We have before stated, that the blood soon coagulates
of its own accord, when taken from the body ; we shall
now briefly point out how its coagulation is affected by
various external agenls. It will coagulate sooner when
drawn from a small orifice, or allowed to trickle down the
neck, or if it be collected in a vessel with a broad ex-
tended surface, or in one of a triangular form ; but if it
be drawn from a large orifice, in a free stream, or be col-
lected in a deep narrow vessel, its coagulation will
be retarded. Heat, above ]25° of Farenheit, acids,
alcohol, and alum suddenly coagulate it; and it will
concrete sooner in the natural heat of the body than in
any degree below it. Neutral salts altogether prevent
its coagulation. Keeping the blood in motion, during
its detraction, does not delay its coagulation; and if it
be kept stirred, while fluid, with a wisp, the coagulum
will assume a distinct fibrous appearance. Blood that
has been frozen will not congeal.
When the coagulation of the blood is from any cause
retarded, the red particles, being the heaviest part, gravi-
tate to the bottom of the blood-basin; and, instead of
being entangled uniformly in the substance of the coagu-
lum, collect chiefly in its lower part; leaving the sur-
face, and a portion below it, entirely without them,
which, from the serum it contains, exhibits a yellow ap-
pearance : to this part the name of buff, or size, has been
given. This state of the coagulum may frequently be
prognosticated, by touching the surface of the blood, a
few seconds after it has been drawn, with the finger: if no
-ocr page 58-
On the Coagulable JLymph.                   23
red particles adhere to it, but it be moist with a yellow-
ish and perfectly limpid fluid, you may safely predict that
the coagulum will be buffy.
Blood coagulates in the body after death; though not
always; for in cases of sudden death, as in horses that
die suddenly from hunting, or racing, or in hares that have
been coursed to death, it remains fluid.
The constituents of the coagulable lymph, are fibrine
or gluten, and albumen.
Various attempts have been made to discover the cause
of the spontaneous coagulation of the blood : the fol-
lowing are those that have been commonly assigned for
it. Cold, from the change of temperature which the
blood undergoes when drawn, was said to be one; if,
however, it be received in the same degree of heat, to
which it was exposed while circulating in the body,
its concretion (far from being prevented, or even retard-
ed) will be accelerated. Rest was said to be the cause
of it; but, as we have before stated, it will coagulate
though it be constantly stirred, or otherwise kept in mo-
tion. Exposure to the air has been thought to account
for it; and, certainly, the process appears to be in some
measure assisted by it, although it is by no means the
principal agent; for blood will congeal even in vacuo,
though it requires a longer space of time.
We concluded our former lecture with some remarks
in illustration of the doctrine of Mr. John Huntek,
in regard to the principle of life being inherent in the
blood : to this cause the same eminent physiologist at-
tributed the coagulation of it. We then briefly stated,
that, among other ingenious illustrations, this author re-
marked the close analogy existing between the coagula-
tion of the blood and the contractions of muscles ; which
-ocr page 59-
24                   On the Diseases of the Blood.
latter phenomenon is universally admitted to depend on
life ; having, however, already agitated this question, it
will not be necessary to enter upon it again here.
The coagulable lymph appears to be the most useful
part of the blood, if we may so express ourselves: it is
one that is common to the blood of all animals. All the
solids are formed from it:—their continual growth in the
young animal, and reproduction in the adult, are effected
by it. By its property of coagulation, wounds, or divided
surfaces, are united ; the fractured extremities of bones
are glued together; and the mouths of bleeding vessels
plugged up, and hemorrhage put a stop to : but it would
be impossible to enumerate all the various and important
uses of this substance.
On the Diseases of the Blood.
All diseases were formerly supposed to originate in a
morbid condition of the fluids of the body j from which
notion, such incorrect ideas were formed of their nature,
as Jed to a mode of practice, either indirectly injurious
from its inertness, or want of efficacy, or positively per-
nicious from its co-operation with the morbific agents
themselves. The ancients supposed, that there was some
peccant, or offending matter floating in the fluids, or, as
they called them, humors of the body; and that nature,
requiring the expulsion of this imaginary acrimonious
matter, instituted a diseased action in the system for that
purpose; which was occasionally to be promoted, but
never suppressed, by the practitioner. To this doctrine,
which is called the humoral pathology, the veterinary art
has long been subservient; and, though it has been of
late years in a great measure rid of such obscure tenets,
still are the humors afloat among our crafty vulcanians
-ocr page 60-
On the Diseases of the Blood.                   25
of modern times, whose practice as often tends to exas-
perate, as to relieve, the sufferings of their unfortunate
patients; however well adapted it may be, to impose on
the credulity of their unsuspecting employers.
The explosion of the humoral pathology has been fol-
lowed by a doctrine—that, although the blood in disease
exhibited morbid signs, it was never diseased in itself;
or, in other words, that it did not contain any morbific in-
gredient. The principal arguments advanced in support
of this opinion, are two : viz. first, that if it were diseased,
as it flows to every part, the niorbid matter it contains,
ought to create general, and not local irritation ; aud se-
condly, that, if it were so in contagious diseases, we ought
by means of inoculation with it, to produce the same ef-
fects as arise from the introduction of the contagious mat-
ter itself. In attacking the first of these positions, we
would ask, if there be any disease which invades alike all
parts of the body?—and why, on the contrary, so many seem
to have a predilection for particular parts ? In the human
subject, for instance, small pox and measles confine them-
selves to the skin ; scrofula affects the absorbent system ;
and the venereal disease, either the organs of generation,
the throat, the skin, or the bones. Again, in the horse, far-
cy is an affection of the superficial, not of the deep-seated
absorbents; and glanders, one confined to the membranes,
&c. of the nose ; and yet all these are, with the exception
of scrofula, contagious diseases, in most of which, if not in
all, probably, the circulating mass is contaminated. The
second of these arguments admits of a more ready reply.
-No one ever imagined that the morbific matter contained
ln the blood, existed in so concentrated a form, as to pro-
duce its effects by inoculation with a single drop of
that fluid; no more than that the venereal virus, diluted
-ocr page 61-
26                    On the Diseases of the Blood.
with fifty or a hundred times its weight of healthy pus,
would convey the disease by inoculation with a fiftieth or
hundredth part of such a mixture. In further illustration
of this, we can, and do medically, not only without any
baneful effect, but with manifest advantage, take minute
quantities of substances of so poisonous a nature, that the
old practitioners were altogether deterred from the use of
them. This subject, however, has of late been put with-
out the pale of disputation by actual experiment. Some
years ago, at the Veterinary College, the blood of a
horse affected with glanders (which is a contagious dis-
ease, and one at all times readily communicable by in-
oculation) was transfused into the veins of a healthy
ass, previously prepared by copious blood-letting : in the
usual space of time, the animal exhibited every symptom
characteristic of glanders, of which it shortly died. Con-
sidering the antiquity of the practice of transfusing blood,
from the vessels of one animal into those of another, it is
somewhat remarkable, that this fact has never been before
demonstrated by experiment; for it is now nearly two
centuries ago, since this operation was first attempted on
dogs, and subsequently on men, with expectations of the
most glittering description : like those who were so soli-
citous about transplantation of teeth, however, the indivi-
duals on whom it was practised, were occasionally seized
with diseases of a malignant and dangerous tendency.
The blood not unfrequently, in the human subject,
exhibits, what are considered as, morbid appearances :
whether this be the effect of what Mr. Hunter calls
"contiguous sympathy—a real increase of animal life"—
or, whether it arise from some variation in the relative
proportions of its constituent parts, or be produced by
some morbific matter contained iu it, we are not about to
-ocr page 62-
On the Diseases of the Blood.                   27
inquire. All we wish to impress here is, that, what is re-
garded as indicative of increased, if not diseased action in
the vascular system of the human subject, is perfectly na-
tural to that of the horse, in his domesticated state: if,
therefore, you examine the blood of a horse in apparent
good health, you expect to find it sizy. It has been,
with great truth, remarked, by some of our best practi-
tioners in human medicine, that an inflammatory diathesis
is by no means essential to the production of buffy
blood : an opinion confirmed by the appearances of
horses' blood in health. We do not believe that this
fact is universally known—we have searched the works
of veterinary authors on the subject, with but little ad-
vantage ; for they have either transcribed their accounts,
which are for the most part erroneous, one from another,
or borrowed them from human anatomy.
Blood is said to be cupped, when the upper surface of
the coagulum, instead of being perfectly even, is concave,
as if it had been scooped out, and the surrounding margin
is elevated, and more or less inverted. This appearance
in human blood, is commonly regarded as a mark of in-
flammatory action, and one that, in combination with cer-
tain febrile symptoms, imperiously calls for a repetition
of blood-letting. But in that of the horse, it has been
asserted, nothing of the kind ever takes place. In order
to show, that, so far from this opinion being a correct one,
cupped blood is by no means unfrequently met with in
veterinary practice, and that it is occasionally seen in
health*, (as often we believe as in disease,) as well as to
* We had a remarkable instance of this, while engaged in some
experiments connected with this subject. A horse, to every ap-
pearance in perfect health, was bled to one pound ; after which he
was galloped (for the space of about twenty minutes) until he
-ocr page 63-
On the Diseases of the Blood.
28
point out the space of time in which healthy blood co-
agulates, and the average proportion of serum contained
in it, we have subjoined the following statement:—
sweated profusely: while under extreme agitation, from the ex-
ertions he had been put to, another pint of blood was drawn,
by unpinning the same orifice. The coagulum of the first par-
cel of blood was sizy, tough, contracted, and deeply cupped:
that of the last exhibited no signs whatever of buff, was extremely
loose and flabby in its texture, so that on being handled it readily
mingled with the serum ; and in a much shorter time than the
first, went into the putrefactive state.
This latter fact is intimately connected with what we have al-
ready advanced, regarding the non-coagulation of the blood after
an animal has been coursed to death; since, had exertion been
continued until the horse sunk under it, the blood would probably
have remained wholly fluid; whereas, in this case, the animal be-
ing only in progress towards that state—being only urged to a
point from which he could recover, the coagulating powers of the,
blood were merely diminished.
-ocr page 64-
STATEMENT.
Horses (in
health) bled,
with the state
of pulse.
Under what
circumstances.
Quantity of
blood drawn.
Space of time
in which it
flowed.
A film of co-
agulum per-
ceptible upon
its surface.
Firmly co-
agulated.
Appearances of the
coagulum.
Quantity of
serum sepa-
rated prior to
putrefaclion.
12, whose
pulses rang-
ed between
40 and 50.
In stables
under ordi-
nary ma-
nagement.
Ib.j.
From J to
1 minute
In about 10
minutes.
In about 25
minutes.
All the coagula
showed buff about
| inch deep ; 7 of
them were very
firm, in 5 of which
the surrounding
edge was elevated
and turned in:
the other two
were cupped. In
2 of the others
the coagula were
soft and flabby.
About one
half of thfe
whole quan-
tity of blood
drawn.
-ocr page 65-
30
On Venesection.
One of the most powerful and efficacious means we
possess of subduing disease, is venesection, phlebotomy,
or blood-letting. There is no remedy quicker in its ope-
ration, nor any more beneficial in its influence, when pro-
perly employed; at the same time, there are few more
pernicious than it in the hands of rash and unscientific
practitioners.
We have two objects in view in taking away blood:
first, that of diminishing the momentum of the circula-
tion ; and secondly, that of allaying the irritability of the
nervous system. Though we can at all times fulfil the
former indication, we do not so certainly effect the latter,
by lessening the quantity of blood in the system ; for in
some cases, the frequency of the pulse, which is depend-
■ ant on nervous irritability, will remain undiminished af-
ter the removal of as much blood as the powers of the
constitution can withstand.
After having drawn blood for any inflammatory affec-
tion, there are certain signs, which may be pretty gene-
rally relied on, that indicate the necessity of a repetition
of the operation ; among the chief of which are, the un-
abated hardness, and strength, combined with frequency
of the pulse and the continuance of pain, or the symp-
toms of it, in the part affected : the sizy or cupped state
of the blood, combined with inordinate toughness of the
coagulum, and a sparing exudation of serum, are also
commonly believed to confirm this indication ; from what
we have advanced, however, in regard to these occur-
rences, it may fairly be questioned how far they are
signs of disordered action.
In drawing blood it is advisable—nay, sometimes indis-
-ocr page 66-
On Venesection.
31
pensable, if we wish to give speedy relief, to make a large
orifice in the vein, or artery, we may select for the pur-
pose : by attending to this, we shall not only often ar-
rest disease on a sudden, but absolutely prevent subse-
quent weakness, by having occasion to take less away,
in the aggregate, during its progress. Dr. Pember-
Ton, in his very useful Practical Treatise on Various
Diseases of the Abdominal Viscera of the Human Sub-
ject,
observes, in speaking of acute hepatitis,—" I find
from numerous experiments made at my desire for this
purpose by different surgeons, that when the orifice is
such as to admit of eight ounces of blood to flow in
three minutes, that then a patient under acute inflamma-
tion will receive every benefit which is expected from the
remedy.
If it flows in a longer time he will receive less
benefit,
and under certain circumstances no benefit at all,
or even absolute injury."
-ocr page 67-
LECTURE III.
On the Arteries.
Of blood-vessels there are two orders:—arteries and
veins; we shall make the first the subject of the present
lecture.
The arteries are elastic tubes, formed for the purpose
of conveying blood from the heart to every part of
the body. These vessels were formerly supposed to con-
tain and distribute air over the animal system, hence the
name of artery ; an opinion that appears to have origin-
ated from the circumstance of their being found empty
after death.
There pre only two arterial trunks, from which all the
branches of the body spring : these arise from the heart,
and have received the names of aorta, and pulmonary
artery : the first, by means of innumerable ramifica-
tions, transmits blood over the body generally; the last
only conveys it to the lungs.
Arteries have been divided into sanguineous, and
lymphatic or serif"erous: those in which red blood ordi-
narily circulates, compose the first class ; their minute
ramifications, which are too small to admit the red glo-
bules, the second.
-ocr page 68-
On the Arteries.                              33
The ventricles of the heart are the sources from which
all the arteries in the body have their origin, by means of
the two trunks before mentioned.
Generally speaking, these tubes take the nearest course
to the organs they are destined to supply. They are
commmonly deeply seated, and run on the inner sides
of the limbs rather than the outer, for the purpose of be-
ing better protected from external injury : in passing over
a joint, they are most commonly found upon its bending
side, by which precaution any preternatural extension of
them in the motion of the part, and consequent obstruc-
tion to the circulation, are guarded against; and for the
same reason, those of the lips, ears, and nostrils, take a
serpentine course. There are some arteries whose ca-
nals are extremely tortuous, in which it is thought the cir-
culation is, by that means, retarded : in this number may
be reckoned those of the brain, testicle, and uterus; there
are probably other reasons, however, for such a pecu-
liarity of course in the blood-vessels of these parts, with
which we are not at present acquainted.
The ramifications of the arteries may be compared to
the branches of trees, of which the aorta and pulmonary
artery form the trunks; their various subdivisions, the
branches. For the vessels into which they divide, like
the trunks themselves, send off others of less diameter ;
and these again, in their turn, become trunks to more mi-
nute ramifications ; until, by repeated subdivision, tubes
°f infinite number and extreme exility, are distributed
over every part of the body.
We find that arteries send off their branches in a some-
what different manner, according to their proximity
0 the heart, or source whence they receive their blood :
•£• some, in the immediate vicinity of that organ, are
D
-ocr page 69-
34                               On the Arteries.
coming off at obtuse angles—as is the case with the pos-
terior cervical arteries; though most of them are leaving
their trunks at right angles—of which the intercostals are
ready examples; such, however, as are farther removed
from the heart, arise at acute angles, as is abundantly ex-
emplified in those of the extremities. The same hy-
draulic laws, which regulate the motion of fluids through
tubes similarly arranged out of the body, must be ad-
verted to here, in order to explain the advantages derived
from this mode of ramification in arteries. If we were
to impel water into a tube of any kind, with which many
others communicated at different angles, we should find
that the fluid ran with more facility into such as took
the same course with the trunk, than into others whose
junction formed a right angle with it; but found its
passage with difficulty into those branches running in
an opposite direction from it. Thus it is with the arte-
rial system, through which the blood is propelled by the
heart to every part of the body: in order to equal-
ize the force of the circulation within the different rami-
fications, we find that those branches nearest to the heart,
or pump, resist its too powerful action by being connected
with the main trunk at obtuse angles ; while those re-
motely situated from it, favor the influx of blood, and
thus, in some measure, compensate for the diminution of
propulsive power, rendered weak in them by their dis-
tance from the heart. Notwithstanding this admirable
contrivance, however, to abate the force of the circulation
in those vessels connected with the larger trunks, it does
not appear that the design is wholly fulfilled; for sur-
geons in operating, on the human subject, on parts
which receive their vessels immediately from the large
arteries, are always particularly careful to arrest he-
-ocr page 70-
On the Arteries.                              35
morrhage; on which account, they often tie branches in
the neck, which they would altogether disregard in the
extremities.
When the trunk of an artery splits into two, or, as we
anatomically express it, bifurcates, the conjoined area
of its divisions is greater than that of the trunk itself;
from which fact, anatomists, of late, have compared their
cavities, taken in the aggregate, in form to a cone—re-
garding the capillaries as the base, and the aorta as the
apex of it: but if we take any branch singly, we shall
perceive that its form is also conical; in this case, how-
ever, the position of the cone is reversed—the origin of the
vessel being the basis, its termination the apex.
The smallest arterial ramifications, which, from their
extreme minuteness, have been termed capillaries, are so
numerous that you can scarcely insert a pin into any part
of the body without wounding one or more of them.
Some structures possess a much more abundant supply
of blood than others ; of course their blood-vessels must
be proportionately more numerous ; hence, they are said
to be more vascular: glands, which are secreting organs,
are of this class ; muscles also possess considerable vas-
cularity, in comparison with sinews, or cartilage.
Arteries are said to have five modes of termination.
The first, and most common, is in veins. An artery
having become of so small size as to acquirethe name of
capillary, is reflected, and ends by continuity of canal in a
vein, the commencement of which is equally minute; so
that the distinction between the two at the point of union
Is lost. Common injections furnish us with abundance of
Proofs of this mode of ending:: every one knows, who
Has been in the habit of injecting feet, that it is no un-
common circumstance for the waxen composition,
D 2
-ocr page 71-
\
36                              On the Arteries:
which is thrown into the pastern arteries, to re-
turn by the pastern veins; the same thing frequently
happens in the testicle and head—indeed, in the course
of dissection, we meet with numerous instances of it.
The second termination is that by ajiastomosis: when
minute arterial branches meet and conjoin their canals,
they are said to inosculate, or anastomose. The coats of
the intestines well injected, present a surface of beautiful
vascular network, in consequence of the very frequent in-
osculation of their smaller arterial branches: anastomosis,
however, is not wholly confined to the terminations of ar-
teries, for we have, in the foot, several communicating
arterial canals of large size. The great advantage de-
rivable from anastomosis, is, that of preventing the possi-
bility of the supply of blood being cut off from any
part, in case of obstruction in the trunks going to it;
for, it is evident, that the larger arteries, although they do
not immediately communicate, must, under such circum-
stances, still receive blood, by a retrogade circulation,
from the inosculating ramifications. Pressure being one
of the most frequent causes of obstruction, we discover at
once, why the arteries of the foot should have been so
liberally provided with anastomosing branches.
Notwithstanding the inosculation of arteries must have
been known soon after the discovery of the art of injecting,
it is not till of late years that surgeons have found out its
importance as connected with operative surgery : the old
practitioners were afraid of obstructing the cavity of one
of these vessels, (by ligature,) lest mortification of the
part, which it supplied with blood, might ensiie; now a-
days, however, no such apprehensions are entertained in
regard to, we may say, any part of the body. We have
tied the posterior aorta of the dog, and many of the
-ocr page 72-
On the A rteries.                              37
larger trunks in the horse and ass, without the least ap-
parent inconvenience being sustained by those animals.
In one of the anatomical schools at Paris, a human sub-
ject was brought for dissection, in which the descending
aorta was obliterated, but the circulation had been suffi-
ciently well carried on by anastomosing branches ; and
Sir A.Cooper has lately published the case of a man who
had an aneurism of the iliac artery, in whom he tied
this vessel a little above its bifurcation : a memorable in-
stance of the vast importance now attached to arterial
anastomosis.
The third termination of arteries is in open mouths—
upon, generally, extended surfaces. The smallest visible
branches of arteries are found to be extremely short; and
though we cannot trace them to their ultimate extremi-
ties, yet are we warranted in asserting, that they end in
this way, from many facts and observations connected
with the economy of the animal in health and disease.
These extreme ramifications have been denominated
exhalents, from the particular office they perform, viz.
that of pouring forth the finer parts of the blood in
the form of vapor : what is called the insensible perspir-
ation, from the skin, is a secretion of this kind ; as are all
those serous fluids, emitted upon the membranous sur-
faces of the larger cavities of the body—the abdomen,
thorax, &c. The numerous ramifications employed in
the formation and repair of different parts of the body,
are also probably of this description; and we believe,
that the materials of which an animal is composed, are
8pewed forth from their minute orifices.
rhe fourth termination is in small cavities, called cells,
°' which some parts appear to be wholly made up : the
spleen and penis are commonly believed to be of this
-ocr page 73-
On the Arteries.
J 8
kind—in these organs the blood is poured into cells,
from which veins arise that take it up again.
The fifth and last termination is in the beginning of a
tube, called an excretory duct: these branches are deno-
minated the secreting, or secerning arteries, in conse-
quence of their having the power of separating some-
thing from the blood of a total different nature from that
fluid itself; which secretion is conveyed by the excretory
duct from the gland, as fast as it is formed within it by
these vessels. The secerning tubes are so minute, that
they can seldom be traced, even if injected, with much
accuracy. In the liver, from their extreme exility and pe-
culiarity of distribution, they have been called penicilli:
probably they may be demonstrated better in the kid-
ney than in any other gland; in the substance of which
we can frequently trace them into small excretory vessels,
called the tubuli uriniferi.
Most arteries are enveloped in a case of cellular mem-
brane, by which they are connected to the surrounding
parts; and in some places this substance is so condensed
as to give them a complete covering, commonly called a
sheath—as happens with the carotid arteries; it is,
however, only an adventitious tegument, and is not to be
regarded as one of its proper coverings.
An artery is composed of three tunics, or coats, con-
nected together by cellular membrane, all of which
possess a certain degree of elasticity : the external or
elastic, the muscular, and the internal, membranous, or cu-
ticular
coat.
It is in the external covering of an artery that the pro-
perty of elasticity essentially resides, hence is derived the
appellation of elastic coat ; a property, which it not only
possesses in the living, but preserves in the dead animal.
-ocr page 74-
On the Arteries.                              39
This covering is peculiar to arteries ; so that any one
at all conversant in anatomy, easily recognizes a vessel
of this class, not only from its peculiar whiteness, but
from the tubular form it preserves, even after its removal
from the body. This coat is said to be made up of con-
densed cellular membrane, disposed in fibres which are
seen running in every direction. It is much more
abundant in the trunks than in the branches ; hence
arises the greater difficulty of distinguishing the latter
from veins, they being comparatively loose and flaccid:
in the aorta it seems to be more than equal in substance
to both the other coats. Being elastic in the longitudinal,
as well as lateral direction, an artery may be stretched
either by elongation, or expansion, and it will still re-
cover its original form and dimensions : in fact, the action
of this coat may be said to be, that of tending to preserve
the natural shape and size of the vessel. If an artery, in
the living body, be divided, the first gush of blood will be
immediately followed by the retraction of its cut extremi-
ties; and this recession of them into the surrounding cellular
niembrane often renders it exceedingly difficult to find
them : this, aided by other means which we shall here-
after point out, becomes Nature's chief resource in the
event of hemorrhage. Aware of this circumstance, sur-
geons, when called to a case of wound from which there
is dangerous bleeding, always make it their primary en-
quiry, to ascertain whether the bleeding vessel be com-
pletely
divided, or not: in the latter case, it is generally
proper to cut the undivided portion, so as_ to give the ex-
tremities of the bleeding artery the power of retracting,
ar»d afterwards to employ pressure, before ligature of it be
"ad recourse to. We have succeeded in stopping alarm-
-ocr page 75-
40                              On the Arteries.
ing hemorrhages from the internal pectoral, and sub-
maxillary arteries of the horse in this way.
The second coat, placed immediately under the elastic,
is called the muscular. In its composition it is fibrous ;
and its fibres are believed to be of the same nature, (for
they appear to possess similar properties,) to those of the
muscles themselves. They are best seen in the coats of
the smaller arteries, which are thicker, in proportion to
their calibre, than those of the large: these afford, many
of them, pretty distinct traces of fibres, taking a circular
course, and putting on the appearance of muscularity.
That they are of this nature, is a fact Mr. Hunter
first attempted to establish by the test of experiment:
having bled a horse to death, he found, that the area of
these vessels was considerably diminished—the aorta
had lost about l-20th of its original breadth, while the
radial artery was contracted to 1-half of its former dia-
meter. The result of this experiment is perfectly con-
sonant with what we have here advanced, and seems to
confirm our observations from dissection, relative to the
proportions of the elastic and muscular coats in the
trunks and branches. Notwithstanding these facts, how-
ever, the existence of a muscular coat has been by some
denied ; who have maintained, that in the substance of an
artery, which is entirely white, any thing like muscular
fibre is indemonstrable : but we know that color is not
essential to muscles, and that those that have it (for there
are many colorless ones) obtain it only from the blood
within them. We have, however, many proofs that ar-
teries possess a power, which, from its effects, can be no
other than muscular: among others, maybe mentioned
the fact, of their action being occasionally increased,
-ocr page 76-
On the Arteries.                              41
Without any acceleration, or alteration, of the pulsations
of the heart: e.g. if a portion of the skin be inflamed, or
if a stimulant be applied to it, we know that a blush will
quickly appear upon the surface, owing to an unusual de-
termination of blood to that part. Now, it is evident,
that the action of the impelling powers must be aug-
mented in order to produce this unnatural flow of blood
to the part; and yet, if we examine the pulse, we are
unable to detect any change in the general circulation ;
consequently, it must be local—one confined to the ves-
sels of the part itself; which would appear to be the re-
sult of a kind of voluntary, or muscular power : by such
reasoning alone, can we explain the act of blushing in the
human subject. We stated before, that these vessels are
found empty after death : this affords us an additional ar-
gument in favor of their muscularity, otherwise they could
not discharge their blood into the veins. There appears
still to be some doubt among physiologists, whether the
muscular coat be employed, or not, in the ordinary cir-
culation.
The third coat, or lining of the artery, is the membran-
ous,
or, as it is sometimes improperly termed, the cuticu-
lar.
It is thin, but very dense; possesses much strength,
but less elasticity than either of the others : that it is
elastic, however, is proved from the circumstance of its
never being thrown into folds during the contracted state
of the vessel. Its internal surface is uniform, smooth,
and polished, to allow of the free circulation of the
blood ; while, from its density, it prevents exudation—an
accident that never occurs in the living animal.
The coats of these vessels are possessed of vascularity ;
or» m other words, have arteries, veins, and, it is thought,
absorbents, entering into their composition. Their arte-
-ocr page 77-
42                           On the Arteries.
nes, which are very small, are called arteria arteria-
rum;
their veins, vena venarum: the former arise
from the neighbouring arteries—never from that which
they supply. Absorbents, we believe, have never
been seen entering their coats ; though Mr. Cruick-
shanks, in bis Anatomy of the Human Absorbents, says,
that he has seen the aorta, almost throughout its whole
length, covered with them.
Arteries possess but little feeling. Many of the larger
trunks indeed are surrounded with nervous filaments, and
some, doubtlessly, penetrate their coats—of which the
aorta and carotid arteries are instances: it appears,
however, that the circulation will continue in vessels in
which all sensibility is destroyed ; were this not the case,
paralytic parts could not support their life.
The only arteries having valves, are the aorta and pul-
monary artery, and they only at their origins from the
heart: we shall describe the formation and use of a valve,
when on the veins.
-ocr page 78-
LECTURE IV.
On the Physiology of Arteries.
.I_N our definition of an artery, we said, that it was an
elastic tube formed to convey blood from the heart to
every part of the body. That this is the passage of the
blood, experiment, as well as ocular demonstration, have
long removed beyond the sphere of doubt: if you put a
ligature on an artery, the vessel becomes turgid between
the heart and the obstructed portion, but empty beyond
it; and if you examine through magnifying glasses the
transparent web of a frog's foot, the circulation in it may
be readily seen. Considering the circulation, then, as a
physiological truth—a point no longer contestable, and
knowing that the blood flows from the heart, through
the arteries, to the different parts of the body, we are na-
turally led to enquire by what means its motion is effected.
We are to look on the heart as the primary agent in the
circulation: by its operation, which has been compared
to that of a pump, blood is impelled into the channels of
these vessels, to be by them conveyed and distributed
over the system at large; whence it is returned to the
-ocr page 79-
41                  On the Physiology of Arteries.
heart by another set of tubes—the veins. Though the
principal cause of the blood's motion, however, is the
beatings, or contractions of the heart, we are not to re-
gard the arteries as the mere channels of its transmission
—as, in fact, altogether passive: on the contrary, they
contribute much to its current, and in what manner they
do so, we shall now proceed to enquire.
In order to be perfectly intelligible in our discourse
of the economy of these vessels, it will be necessary to
revert to what we advanced in the last lecture, relative to
their property' of elasticity—which was found to reside
principally in the external covering, as well as to that of
muscularity—which we endeavoured to prove was pos-
sessed by some circular fibres, running between the outer
and inner tunics. By the former, we stated, that the ar-
tery was preserved of a cylindrical form, and determinate
dimensions; and by the latter, that it had the power of
contracting its natural calibre : moreover, we observed,
that the property of elasticity was not dependant on life ;
but that the peculiar nature of the muscular was such,
that it owed its powers entirely to vitality. We men-
tioned also, that all arteries were branches of one of
two trunks, which arose from the ventricles of the heart:
and this, we repeat, is an organ by whose operation these
vessels are supplied with blood. Having premised these
data, we trust that the principal causes of the blood's
motion through the arteries will be made sufficiently ap-
parent.
Every artery in the body always contains a certain
quantity of blood, by which its cavity is completely filled :
not, however, that this quantity is invariably the same,
for it varies at every momentary supply from the heart;
but, by the action of the elastic and muscular coats, the
-ocr page 80-
On the Physiology of Arteries.                 45
calibre of the vessel is constantly adapted to the con-
tained blood. It is, therefore, with truth asserted, that
an artery is always full. At every beat of the heart,
a certain portion of blood is thrown into the aorta,
and pulmonary artery; (no matter which we take by
way of illustration, for they both receive it precisely
at the same time, and in the same manner;) which,
being already in a state of plenitude, now become
stretched from distention. The diameter of the vessel
being increased by distention of its parietes beyond
their tone, the elastic coat—the use of which is to
preserve it of its ordinary dimensions, immediately exerts
its counteractive force, in order to restore it to its origi-
nal calibre. The muscular coat also, whose contractions
will be excited by extension of its fibres, is probably at
this instant called into action. What is the effect? By
their united efforts, the column of blood, which has been
thrown into the aorta by the heart, becomes displaced :
it cannot regurgitate into the ventricle, for, as we have
before stated, there are valves at the mouth of this vessel;
its course, therefore, is necessarily into the first and
larger branches that immediately come off from the
trunk itself. A succession of similar phenomena takes
place in the branches as in the trunks ;—they were full
before, consequently the same over-distention happens,
and gives rise to a similar repulsive effort of the elastic
coat; which, assisted by the muscular, aids, in this man-
ner, in the propulsion of the blood to the extreme parts
of the body. It is not to be imagined, however, that
these effects happen in succession in the different arteries ;
on the contrary, the whole arterial system experiences
dilatation, called diastole, and contraction, or systole,
precisely at the same instant; hence the pulse, which is
-ocr page 81-
46                  On the Physiology of Arteries.
occasioned by the former, occurs in every vessel at the
same time.
In this summary view that we have taken of the action
of these vessels in the circulation, we have not, nor shall
we here, advert to the operation and influence of the
heart: suffice be it to say, that the blood is principally
circulated by its contractions, though writers on this sub-
ject have by no means agreed to what extent its power is
exerted. We have observed, that the artery, in resuming
its state of systole, displaces a column of blood—and
that it does this is evident, for blood of itself is incom-
pressible : we have also asserted, that this column is im-
pelled into other vessels ; its regurgitation being pre-
vented by valves, and its advance, we may here add, aided
by the enlarged space into which it flows, in conse-
quence of the aggregate calibre of the branches exceeding
that of the trunks.
Thus far, then, we have considered the elastic coat as
being the chief agent employed in the circulation : indeed,
from its prevalence over the muscular in the larger vessels,
it has been regarded by some physiologists, as the only
one employed in the natural action of these parts. If,
however, we examine into the causes of the motion of the
blood through vessels in the more remote parts of the
body—in which we find the elastic property considerably
diminished, while, on the other hand, the muscular has
become proportionably augmented, we shall feel inclined
to doubt, more especially when we take into our consi-
deration the abatement of the heart's power in these ex-
treme branches, that elasticity alone is equal to the effect.
It has indeed been contended, that the heart is the only
agent employed in the circulation : of such as maintain
this opinion, it may be enquired by what means the blood
-ocr page 82-
On the Physiology of Arteries.                  47
is circulated in foetus formed without hearts ? Such 7m-
sus naturcz have been met with, in which (to reply to the
above question) the circulating powers must have wholly
resided in the muscular fibres of arteries. As far as ex-
periment and observation have gone in the investigation
of this subject, it is now generally believed, that the mus-
cular coat is an auxiliary in the circulation ; and that it
not only contributes to the efficiency of the elastic, but, in
some vessels, exerts a force even superior to it.
In the larger branches, its action will be simultaneous
with, and similar to, that of the elastic coat, with which
it will restore the vessel to its former size, after its disten-
tion with blood from the heart; but in the smaller ar-
teries, it will predominate over the elastic, and further
aid the principal circulating power, by contracting them
beyond their natural calibre. So that, in the one case, it
will co-operate with the elastic, in the other, it will op-
pose it: and, if this be true, in the latter instance, the
elastic coat will be employed in the dilatation, as well as
contraction of the vessel.
In the vicinity of the heart, then, the blood is moved
along its arterial channels, by the alternate extension and
shrinking of the elastic, aided by the successive relaxa-
tion and contraction of the muscular : more remotely from
that organ, by the more forcible contractile efforts of the
muscular, aided by the comparatively feeble action of the
elastic coat*.
* The following extract, from Dr. Thomson's valuable work on
inanimation, would induce us to regard the capillary arteries as
more active and efficient agents in the circulation of the blood,
than they are commonly believed to be. " The experiments and
observations which I have just related (the application ofsti-
muaammonia, to the minute vessels in the web of a frog's foot,)
-ocr page 83-
On the Pulse.
48
Arteries convey blood from the heart to the different
parts of the body for a variety of purposes. We mentioned
in our last lecture, that by blood the body was nourished,
and its growth promoted—all which is effected by the
open mouths of these vessels ; hence, they have been
compared to a set of workmen, continually employed in
conveying materials for the formation and repair of the
animal machine. In some places they form bone ; in
others, muscle; and in others again, tendon ; although
the blood which they convert into these different parts, is,
in all of them, precisely similar in its properties, being
pumped into them at the same instant by the heart. In
addition to this, however, the arteries produce all the se-
cretions of the body : the hoof itself is nothing more than
a secretion, which the coffin arteries furnish from the
blood ; urine is separated from it by the emulgent arte-
ries; and semen, by the spermatic. Inflammation, which
is commonly a healthy process set up by nature to
repair losses the body may have sustained by accident,
or disease, consists in a change of action of the arterial
system.
On the Pulse.
By the alternate contractions and dilatations of the
heart and arteries, is produced that well-known motion
of them, called their beating, or pulse.
prove undeniably, I conceive, the existence of irritability in the
smaller or capillary arteries of cold-blooded animals, and conse-
quently the possibility of irregular distributions of the blood in par-
ticular parts of the body being produced, independently of the heart,
by the vital, contractile, or irritable power inherent in even the
minutest branches of the arterial system." Vide Thomson's Lec-
tures on Inflammation.
-ocr page 84-
On the Pulse.                                49
At every injection of blood from the heart, the parie-
tes of the arteries are distended beyond their natural di-
mensions—an effect only perceptible in such vessels
as are tightly bound down to the adjacent parts, by the
immediate touch, or compression of them; but if, as is
generally the case, the artery be but loosely connected
to the surrounding parts, then will its diastole become
distinctly visible, in consequence of this sudden influx of
blood displacing it, and, at the same time, somewhat
contorting its canal. A vessel, under these circumstances,
may be seen to advance a little, or leap from its place ;
in consequence of being rendered serpentine in its
course, by the gush of blood which the heart has just
impelled into it; and it is from this cause, that such an
artery produces that jerking sensation under the fingers,
commonly called the pulse. We have a familiar in-
stance of a similar effect taking place in injecting these
vessels : if one of them happen to be excessively dis-
tended with wax, it will, unless prevented by surrounding
attachment, always be thrown into a serpentine form; and
then it is not only stretched in a lateral, but also in a rec-
tilineal direction. Again, if, in operating, you lay bare an
artery that is but indistinctly seen, and tie aligature around
!t, you will at once render it perfectly distinguishable, in
consequeuce of the momentary jerks, and alterations of
figure, it will undergo, from the impulse of the blood
against the ligature. It is, then, precisely on this princi-
ple, that we feel the pulse by making pressure upon an
artery : by partially obstructing its cavity, we have a pe-
cuhar sensation given to our fingers, called pulsation ;
arising^ we repeat, from the impetus of the blood mo-
mentarily ejected from the heart.
Ihis pulsatory action does not pervade every part of
"E
-ocr page 85-
50                                   On the Pulse.
the arterial ramification : though its effect is said to be
visible in those branches which do not exceed 1-sixth of a
line in diameter, yet does it cease altogether in the ca-
pillaries ; so that the blood in the veins, which are still
further removed from the heart, flows in an even and un-
interrupted stream.
In consequence of functional derangement of the cir-
culatory system being present, more or less, in almost all
constitutional diseases, the pulse is regarded, to a certain
extent, as an index of disease—as an important indica-
tion of its nature and severity : it behoves us, therefore,
to make ourselves well acquainted with the variations to
which it is subject, and to know (as far as medical obser-
vation has tended to distinguish them) the different mor-
bid states of which they are the signs. At the same
time, we are to bear in mind, that, like most other symp-
toms of disease, it is not to be solely depended on—
without a due consideration of all the circumstances of
the case.
In all animals, in a state of health, we find, what lias
been called, a standard pulse: i.e. that their heart and
arteries pulsate a certain number of times within the
space of a minute. In general, the larger the animal
the slower the pulse: e.g. in the human subject, it is
about 72, in the horse about 45, and in the dog about 90.
But the standard pulse of different individuals of the
same species will vary; though not, generally speaking,
with much latitude ; so that we should not deem a pulse
of 65, or any number between that and 80, extraor-
dinary in a man; nor should we pay any attention to
one ranging between 40 and 50 in a horse : we have heard,
indeed, and we think it likely, that the pulse of a tho-
rough-bred horse is somewhat quicker than that of a
-ocr page 86-
On the Pulse.                                 51
korse of ordinary breeding. Again, the standard pulse
will undergo some variation at different periods of life : it
is always more frequent in the young than in the full
grown animal, and slower in the old : the pulse of a new-
born infant is 140; that of a man at sixty years of age,
60; the pulse of a colt, six months old, is about 55 ; and
we think it highly probable, (hat a proportionate diminu-
tion attends old age.
When the pulse, however, much exceeds in number
the standard, it is called a. frequent, or quick pulse: e.g.
one of 55, 60, 70, or upwards, is of this description :
the most frequent we recollect ever to have met with in
the horse, was one of 120. Very simple causes, as well as
most constitutional diseases, and more particularly those
of the inflammatory kind, will accelerate the pulse : exer-
cise, temperature, and alarm of any kind, are the principal
ones. If, on the other hand, the number of pulsations in
a minute be less than forty, it is denominated a slow pulse.
This kind of pulse is, in general, an indication of disease
in the brain; and is very commonly met with in the le-
thargic, or sleepy stage of staggers. A remarkable in-
stance of preternatural slowness of pulse, occurred in a
horse to which we were giving black hellebore : we
counted not more, at any one time, than 24 beats in a
minute*.
But the pulse, without any regard to its frequency, may
* A grey galloway, who had a chronic ulcerative affection of one
side of the sexton nasi, with tumefied submaxillary glands of the
same side, took hellebor: nigr: rad: Siss : this produced consider-
ate nausea, loathing of food, &.c.; accompanied with exceeding
slowness of pulse, and great irregularity of it, which continued for
about twenty-four hours ; the pulse, then, gradually rose to its na-
tural frequency.
E2
-ocr page 87-
51                                 On the Puke.
vary in many respects from what is considered as its na-
tural, or healthy state.
In the first place, it may be hard, or soft. Hard, if
the artery is beating with increased force, but with di-
minished diameter; so that it feels like the vibrations of
a tight cord under the'fingers: such is commonly the
nature of the pulse when active inflammatory disease is
present in the system. Not unfrequently, the artery is
reduced to an extremely contracted state—conveying to
your touch the sensation of a wire ; from which circum-
stance, it has been called the small, thready, or wiry
pulse : it is not uncommonly found in horses that are
griped, or who labor under inflammation of the bowels ;
in other cases, it is strongly characteristic of membranous
inflammation, be it in whatever part of the body it may.
A soft pulse is one in which the coats of the artery are,
from relaxation,preternaturally distended by blood, so that
the vessel is more than its ordinary size : under these cir-
cumstances, it is easily compressed by the fingers.
In a strong pulse, as its name implies, the artery (of its
usual calibre) is beating with increased force; in a weak,
with diminished: the former is frequently present during
inflammation of the lungs, after the first bleeding; the
latter, in such subjects as are much debilitated from
disease.
An oppressed pulse is one in which the elastic and mus-
cular coats of an artery are in such a state of extension,
that they are unable to contract with their usual force
upon the contained blood. In those sudden and severe
attacks of inflammation of the lungs, to which young
horses are especially subject, either from hot stables, or
over-exertion, this is the condition of the heart and larger
arteries at the commencement: hence nothing is more
-ocr page 88-
On the Pulse.                                 53
common in these cases, than to find the strength, as well
as frequency, of the pulse increased after venesection;
Jn consequence of the plethora of the vascular system
being relieved by the evacuation.
The pulse is said to intermit, when the intervals be-
tween the beats are of unequal duration : it is sometimes
called an irregular pulse.
There are several parts in an animal more convenient
than others for feeling the pulse. By applying the palm
of our hand to the left side of a horse, immediately be-
hind, and a little above his elbow, we perceive, more or
less distinctly, the pulsations of the heart against the sides
of the ribs; so that we may, pretty accurately, count
them: we meet occasionally, however, with horses in
which the motions of the heart are so indistinctly felt,
(which generally arises from excessive fatness,) that we
are compelled to repair to some other situation. If,
therefore, we are sometimes foiled in our attempts to
learn the frequency of the pulse by endeavouring to feel
it at the heart, it is evident, that we should at no time
estimate its strength, weakness, &c. from such a fallacious
source. It is by the compression of an artery alone against
some hard body—as bone, that we can at all accurately
ascertain the state of the pulse, and perhaps no ar-
tery is better adapted for this purpose than the submax-
]Hary, as it crosses the posterior margin of the lower
Jaw: here we have an opportunity of including the vessel
between our finger and thumb, and of making different
degrees of pressure upon it, with a view of learning
"*e force, as well as frequency, with which it is beating.
lne temporal, carotid, and pastern arteries, are also, now
and then, resorted to for this purpose. It demands, how-
ever> sonie attention, and much varied practice, to acquire
-ocr page 89-
54                                 On the Pulse.
that acuteness of feel—that tact, which guides the ex-
perienced practitioner in his prognosis, and at,once dis-
tinguishes the man of science and observation, from the
intermeddling bungler: to this end, there is no more
ready way, than, first, to gain a perfect knowledge of the
pulses of different horses in a state of health, and, after-
wards, compare them with those of others variously af-
fected by disease.
In forming our opinion of the pulse, we are to be, in
some measure, on our guard against any accidental cir-
cumstance that may tend to influence it: e.g. in the hu-
man subject, it is well known that the appearance of the
surgeon not unfrequently accelerates the pulse of the
patient: alarm of any kind will similarly affect that
of the horse. The sensation' of cold has a considerable
effect on the pulse-—it has the power of diminishing the
frequency of action of the heart and arteries : if a horse
that has a pulse beyond the standard, (in regard to quick-
ness,) be exposed to an atmosphere, the temperature of
which is very considerably less than that from which he
has just been removed, his pulse will be soon reduced in
frequency, though it will beat with more force than be-
fore ; hence it is, that cold is said to give tone to the or-
gans of circulation ; and so, in truth, it does, by lessening
their frequency, but augmenting their power of action.
There are some medicines that, when introduced into
the system, diminish the celerity of the pulse : among
those most efficacious in the horse, may be mentioned
digitalis, and ivhite and black hellebore. By the use of
digitalis, which, it is believed, operates on the heart and
arteries through the medium of the brain, the pulse may
be considerably lowered, and occasionally rendered inter-
mittent. White hellebore has the same effect by causing
-ocr page 90-
On the Pulse.
55
nausea—and this it does most effectually and safely,
when properly administered. Aloes will, very frequently,
soon after its exhibition, occasion a refusal of food, from
its producing some degree of nausea; but we have not re-
marked, that it is attended with much alteration in the
quickness of the pulse. Barytes, given in large doses,
will cause the pulse to intermit.
In most diseases the pulse becomes much more fre-
quent than in health ; and for this reason, one of our chief
objects in the treatment, is to reduce it to its natural
standard; or, when it continues excessively quick, the
animal must, eventually, sink from exhaustion of its vital
powers. Venesection is, as we mentioned when treating
of the blood,' one of our most efficient remedies for this
purpose ; aud exposure to cold is occasionally employed
with the same view : there are two medicines, however,—
digitalis and hellebore, which, when properly exhibited,
will prove of the greatest utility to us in practice in ful-
filling this indication.
-ocr page 91-
LECTURE V.
i*^* ^sr^ **r<* ■**+ *<*+ «rVs* .#\/v rf\*N* ^r*r v\*s/«
0« rte Diseases of Arteries.
Every organic part of the body is liable to disease :
and disease may be defined to be, that change in a part
which is characterized by alteration, or suspension of
its functions, by pain, and by other well known signs col-
lected from observation. Were we to say with some,
that disease consists in any alteration from the healthy
state, we should not only be perplexed in correctly de-
fining what health is, but find ourselves compelled, in
strict conformity with this opinion, to pronounce, at
least, two horses out of three unsound. There scarcely
exists a horse, that has exceeded five years old, the pe-
riod of full growth iu this animal, that has not a splint*;
but we do not consider the animal, on that account, even
the less valuable, much more as unsound: unless the
splint perceptibly alter the functions of the part, be
painful, and so produce lameness; and then, it accords
with our first definition, and comes under the head of dis-
ease. Were we to attend more closely to this natural di-
vision of health from disease, we should meet with less
* A splint is nothing more than an osseous tumor upon the
side of the leg.
-ocr page 92-
On hrftammalion.                          57
difliculty in determining the soundness, or unsoundness
of horses; less frequently differ in our opinions on this
point; and seldom have occasion to incite them who em-
ploy us, to encounter the uncertainty of the law.
The most dangerous diseases to which the body is sub-
ject, are those of the blood-vessels; for as the vascular
system is of the utmost importance in anatomy and phy-
siology, so are its diseases of the greatest consideration in
surgery and medicine. In saying thus much, we allude
to that condition of an organ, or of the constitution at
large, implied by the word
Iriflammation.
A part is said to be inflamed when it manifests the
following signs: 1st. increased redness; 2dly. szoelling ;
3dly. pain; 4thly. increased heat. Now we shall take
up the consideration of these symptoms in the order they
are here enumerated, and illustrate each by examples
drawn from the most obvious and familiar occur-
rences.
We labor under considerable disadvantage in not
being able, generally speaking, to inspect the surface of
an inflamed part in the quadruped : the hair effectually
precludes all our attempts to expose its color. In
some organs, however—in the eye, for instance, the
redness is the primary symptom ; that by which we
form our opinion of the intensity of the disease. Every
one has seen the white of the eye bloodshot; and more
close observers have remarked, that, under high inflam-
mation, every now and then, small red vessels are seen
traversing the transparent part of it; obscuring its bril-
liancy, and thus impairing, or destroying vision. Pre-
-ocr page 93-
58                             On Inflammation.
cisely the same appearance is put on by the skin, or any
other part, when inflamed ; of the truth of which, .we have
often an opportunity of convincing ourselves, by examin-
ing the legs of horses denuded of cuticle and hair, from
the application of escarotic blisters. Now to explain
the cause of the redness. It is simply owing to the pre-
sence of the red particles of the blood—they circulating
in greater abundance in the smaller vessels of the in-
flamed part, and being admitted into others which in
health only convey the serous, or transparent parts of that
fluid: a theory that admits of the readiest possible de-
monstration. In the first place, we can often inject a
part that has been inflamed during life*, although we
could not have shewn its vascularity in a healthy condi-
tion : secondly, if by any irritant, chemical or mechani-
cal, we excite inflammation in a part of an animal, before
transparent and colorless, it will so gradually assume a
red hue, that we may actually detect the globules in their
passage into vessels previously serous and invisible.
The tumor attendant on inflammation, is referable to
two circumstances. It may simply be caused by disten-
tion of the part, from dilatation of its vessels; or it may
be dependant on the effusion of coagulable matter into the
cellular membrane, and consequent expression of serum
around it f, The tunica conjunctiva of the eye is the
* We are not to expect invariably to find parts red in the dead
animal, though they have been the seat of inflammation during its
life. " The redness of parts which have been slightly inflamed
not unfrequently disappears after death, so that it is sometimes dif-
ficult to discover the precise spot which, during life, had been the
seat of inflammation." Thomson's Lectures on Inflammation.
f" The swelling in inflammation is accompanied with a greater or
-ocr page 94-
On Injiarnmation.                            59
best instance of the first: frequently, in violent opthal-
rnia, we see it swollen and wrinkled, when we evert the
eyelids, to ascertain the degree of the existing inflamma-
tion ; though, every now and then, this is dependant on
vcchymosis*. Of the last, instances enough present them-
selves, but the best we have is that of the disease called
strangles: we hardly need advert to the swelling here—it
constitutes the very essence of the affection itself, and is
to be ascribed, in the incipient stage, to the effusion of
coagulable matter and serum into the cellular membrane,
between the branches of the lower jaw, and the skin of
the throat. If we cut into the tumor in this state, we
find the centrical and larger part of it, consisting of a so-
lid mass, which has recently been found to be, the albu-
niinous part of the serum in a coagulated form ; and the
less degree of stretching or tension. In the earlier stages it seems
to be produced solely by the unusual influx of blood; but no very
great increase can be produced by this circumstance alone. As the
inflammation, however, proceeds, a quantity of serous fluid is
usually poured out into the interstices of the cellular membrane,
in the parts contiguou s to the seat of inflammation. Thisproduces
a kind of swelling which pits under pressure of the finger, and is
distinguished by the term cedema. In some cases, where the in-
flammation runs high, the effused fluid is found tinged of a red co-
lour. In other rare cases instead of serum, coagulable lymph, or,
as it is now termed, the fibrin of the blood seems to be effused.
When this happens, the swelling continues after every other mark
°f inflammation has disappeared, and remains often during the
whole of after life. Swelling and tension, therefore, seem to de-
pend partly on the inflamed vessels being unusually distended with
blood, and partly, perhaps chiefly, on the effusion of serum and
other fluids into the surrounding cellular membrane." Thomson's
■Lectures on Inflammation.
■Ecchymosis is an effusion of blood from the vessels of the in-
flamed part.
-ocr page 95-
60                             On Inflammation.
surrounding parts to be filled with serum in a fluid state,
which appears to have been squeezed out from the sides
of the coagulum. Even in this latter case, however, we
do not mean to assert, that distention does not contribute
to the tumefaction ; though very triflingly so, we appre-
hend, when compared with what is the effect of effusion.
Increased heat, next to be considered, is, too often, the
only satisfactory test we have of deep-seated and destruc-
tive inflammation : to disease in the foot indeed, it is al-
most our only guide; for lameness itself is, generally
speaking, but a fallacious symptom—at least, as far as
it tends to direct us to the seat of disease. On this ac-
count, heat is a sign that we should be nice in our ex-
amination for; inasmuch as the acuteness of touch, on
such occasions, not seldom distinguishes the practised ve-
terinarian, from the closet inquirer on the one side, and
the all-knowing farrier on the other.
It may at first seem strange, that so great a man as
John Hunter, should have doubted that the heat of
an inflamed part was actually increased; rest assured,
however, that he did not do so from theory; on the con-
trary, we find this opinion (as we know the groundwork
of all his doctrine) to be the result of experiment, made
under his own immediate observation. His words are,
" As inflammation is the principal instance capable of
producing local increased heat, I have taken the oppor-
tunity of examining inflammations, both when sponta-
neous and in consequence of operations. I have also
made several experiments for that purpose, which are si-
milar to operations, and cannot say that I ever saw, from
all these experiments and observations, a case where the
heat was really so much increased, as it appeared to be
to the sensations." Mr. Hunter, in one experiment,
-ocr page 96-
On Inflammation.                                 6l
having ascertained the heat of the rectum in the dog—
an«, in another, in the ass—threw up a solution of corro-
sive sublimate; this excited a high degree of inflamma-
tion, but, in neither case, was the heat increased more
than one or two degrees. Indeed, in one instance, where
"e had injected the same solution into the vagina of a
young ass, after having remarked its natural temperature,
which was 100", the thermometer fell, two hours af-
terwards, to 99°, and continued so till the succeeding
day, when it rose again to 100°: "This experiment,"
he says, " was repeated several times on the same ass,
with the same result." There is much fallacy, how-
ever, in these experiments ; for it is well known, that the
interior parts of the body possess the power of main-
taining an equalisation of heat, which will not be al-
tered by placing the animal in a higher or lower tem-
perature ; or, as it now appears, under the influence of
inflammation. Had Mr. Hunter have made the exte-
rior of the body the subject of his experiments, he would
have found the heat of it not only perceptibly, but ac-
tually increased under inflammation*. To prove this, we
have nothing more to do than to ascertain the tempera-
ture of any external part—say any part of the skin, for
* As, indeed, he did in a patient on whom he operated for hy-
drocele : a thermometer introduGed into the cavity of the tunica va-
ginalis,
and kept in close contact with the testicle, indicated a tem-
perature of 92°; next day, however, when inflammation had come
on> it rose to 98J°.—"But even this," says Mr. Hunter, "was
n°t equal, probably, to that of the blood at the source of the circu-
lation in the same man." This experiment, and others that he
maile, prove that the heat of an inflamed part never exceeds that
ot the blood at the heart: in more or less approaching it, however,
temperature of most external organs, under inflammation, be-
comes very perceptibly and demonstratively augmented.
-ocr page 97-
62                             On Inflammation.
it will vary under different circumstances, and then ap-
ply a blister to it: the heat of it, as soon as the blister
takes effect, will rise considerably; though, we believe,
seldom, or never, become equal to that of the interior of
the body. The cause of this increase of temperature is
to be referred to the unusual flow of blood into the in-
flamed part, combined with the accelerated circulation
of it.
The fourth symptom of inflammation is pain; one
which, like redness, though probably always present, we
derive, comparatively with surgeons, but little advantage
from, in ascertaining the precise nature and degree of ex-
isting inflammation*. Increased sensibility is accompa-
nied by increased irritability ; so that those circumstances
which but little affect the part in health, produce ex-
treme pain under inflammation : this will throw some
light on the cause of pain—which we here refer, to ten-
sion of the nervous texture, and possibly pressure on it,
from tumefaction of the surrounding parts. Though
the horse cannot be said to complain of pain, his expres-
sions of it, to those acquainted with his habits, are
often too well marked to pass unnoticed:—the hang-
ing head—the drooping eyelids—-the pendulous lower
lip—together with the gloomy aspect, and general torpor
of the animal, strongly denote dull and continual pain:
on the other hand, the wild and unnatural stare—the ge-
neral irritability of frame—and his frantic, but unavailing
* A remark of peculiar force in regard to inward inflammatory
affections. " Pain," says Dr. Thomson, " when conjoined with
other constitutional symptoms, is one of the surest marks which
we possess of the existence of inflammation in the internal parts of
the body:" and, we may add, one of whose kind and seat the ve-
terinary surgeon is too often painfully ignorant.
J
-ocr page 98-
On Inflammation.                             6.3
plunges for relief, we need not add, feelingly portray the
ao°ny he is in. In local inflammation, not of sufficient
lntensity, nor importance, to affect the general health, we
'nay form some idea of the pain, by the degree of pres-
sure the animal will bear upon the part without flinch-
lng: for instance, in the adhesive stage of strangles, the
horse very seldom evinces any great deal of tenderness,
When we feel the tumor; but if we touch the swelling,
ever so lightly, when the suppurative process is far ad-
vanced, the animal suddenly snatches away his head, and
requires the benumming aid of a twitch, before he will
allow us to proceed in our examination.
The terminations, or effects of inflammation, are of
four kinds: viz. adhesion, suppuration, ulceration and mor-
tification.
When the sides, or edges of a clean-cut wound are
brought together, and confined in contact by suture,
plaster, or other means, they will commonly unite. Now,
it was formerly supposed, that the blood itself, extrava-
sated within the wound, was the bond of union in this
case—that it coagulated, and glued the divided surfaces
together : recent and more accurate examinations, how-
ever, show that it is not the crassamentum of the blood,
hut the coagulable part of the serum, which, from its re-
semblance in its properties to albumen, has been deno-
minated albuminous matter, that cements them : and
this, now, in common medical language, is best known
hy the name of adhesive matter. There is no such pro-
cess as what Mr. Hunter called union by the first in-
tention *:
we know of no other mode of union than that
"y adhesion.
'As extravasation arises from a rupture of a vessel, it is of ser-
-ocr page 99-
(54                             On Inflammation.
Should the wound remain unclosed, or should loss of
substance happen in any part of the body, either from
abscess, ulceration, or sloughing, adhesive matter'is still
the repairing material; but, in these cases, it is effused
in the form of little rounded eminences, at first yellowish,
but afterwards red, in consequence of acquiring blood-
vessels from the surrounding texture. This constitutes
process of granulation.
Now, there are some parts of the body more likely to
take on the adhesive inflammation than others : what are
known as the serous membranes, are parts exceedingly dis-
posed to this process. We often find the lungs glued to
the sides of the chest, in horses that have died of acute
inflammation of these organs, in consequence of the ar-
teries of the pleura, (which in health furnish a fluid for its
lubrication,) having effused adhesive matter : this is not
near so common an occurrence in horses, however, as in
the human subject. Now and then, we find adhesions
among the intestines, and other abdominal viscera; for
the peritoneum, like the pleura, is one of the serous mem-
branes. It has been asserted, that the horse's skin is na-
turally insusceptible of the adhesive inflammation : we
believe, however, that both experiment and observation
will evince the shallowness of such an opinion; and that
vice in the re-union of that vessel; if there are more solids rup-
tured than a vessel, as in a fracture of a bone; it becomes a bond of
union to those parts, and this may be called union by the first in-
tention ; but the union is not that of the two parts to each other,
but the union of the broken parts to the intermediate extravasated
blood ; so that it is the blood and parts uniting, which constitutes
union by the first intention." Hunter On the Blood.
This is one of the few doctrines of Mr. Huutek's, which subse-
quent investigations have shewn to be erroneous.
-ocr page 100-
On Inflammation.                          6.5
11 is not to the want of healing powers, but to the means
we are compelled to employ to keep the parts in contact,
as well as to the difficulty of managing our patient, that
We are to ascribe our frequent failures;—but as we shall
have occasion, in our lecture on the diseases of veins, to
enlarge somewhat on this subject, we forbear to offer
wore at present.
The adhesive inflammation, though it every now and
then do mischief from not being checked, or kept within
Proper bounds, is to be considered as a restorative, or
healing process—one to which, in many instances, the
preservation of life itself is owing. Without it, all acci-
dents or operations must have proved eventually fatal: by
11 a broken leg is united, and rendered as strong, if not
stronger than ever—albuminous matter effused, ce-
ments the broken ends of the bone, and ultimately be-
comes bone itself—or it glues the lacerated surfaces of
muscles together, and is converted into new skin, should
the old have been much injured, or destroyed. A bleed-
ing vessel is only safely'and effectually plugged by adhe-
sion ; for although the clot of blood within it forms the
temporary cause of arrest of the hemorrhage, it is the ad-
hesive matter, afterwards effused, that permanently seals
tne mouth of the vessel. In fine, be what parts they
way that are lost, adhesive matter is the material out of
^hich they are regenerated : gradually it assumes the
"aUire of the substance defective, acquires vascularity
and sensibility, and, at last, becomes a part of the solids
'hernselves.
Suppuration consists in the formation of purulent
atter. Those arteries which, at another time, spew forth
Utt»nous substance, take on here a different action,
v
-ocr page 101-
66                             On Inflammation.
and pour forth a fluid of a cream-like nature, to which has
been given the name of pus—in vulgar language, matter.
Now, in the human subject, the formation of pus (in ab-
scess) is denoted by two remarkable alterations ; one af-
fecting the part itself, the other, the constitution. With
regard to the former, the pain in it, which during the ad-
hesive process had been dull and uniform, as soon as the
suppurative has commenced, becomes, what surgeons
call, darting and pulsatory: this, combined with the ge-
neral enlargement of the tumor, the elevation of its centre,
the blush upon the skin, and last, and most characteristic,
perceptible fluctuation, leave no doubt as to the state of
the part; though the pus may be, and often is, deep-
seated. Then, as to the constitutional symptoms—the
formation of matter, if it be at all considerable, is gene-
rally ushered in by a shivering fit; the pulse also com-
monly undergoes some variation about this period.
In the horse, generally speaking, we must content our-
selves with a cautious examination of the swelling itself.
Should the case be one of external abscess, the increased
hardness and tenderness of the tumor, the tensity of the
skin covering it, together with its perceptible prominence,
will indicate that suppuration is likely to ensue ; though
the period of distinct fluctuation, is probably that alone
at which we can safely offer an opinion. We are not
going to contend that even extensive suppurations in the
horse, are always preceded by shivering; but we think
differently from him, who would assert that nothing of
the kind ever happens : we have certainly seen young
horses, having strangles, in whom something very anala-
gous to a cold fit was present about the period of
suppuration ; and that there often is an accession of fe-
-ocr page 102-
Ou Inflammation.                             67
brile symptoms—such as acceleration of pulse, quickened
respiration, and general heat of body, will, we suppose,
not be doubted*.
As there are particular structures in the body disposed
to take on the adhesive action under inflammation, so
there are others in which a suppurative process almost
always ensues. All mucous surfaces, generally speaking,
are of this description : if a horse contract a catarrh,
(which is an inflammation of the mucous membrane
lining of the nose,) we have not adhesive matter, but pus
discharged from the nostrils. Most wisely and provi-
dently is it so ordained by nature; for had these parts
been equally disposed to the adhesive process, every com-
mon cold must have terminated in roaring—and occa-
sionally proved destructive to life. Indeed, we some-
times find that mucous surfaces do throw out adhesive
matter; and they scarcely or never do so, without its
being productive of some ill consequences: the interior
of the trachea, for example, every now and then is coated
with adhesive matter, giving rise to croup in the human
subject, and roaring, or thick wind in the horse. It is
from the readiness with which mucous membranes run
into suppuration, that an opening into a joint is attended
with so much danger to life : unless the cavity be speedily
* During our pupilage, we remember that Professor Coleman
made no mention of fever in his lectures : we concluded, there-
fore, that its presence was, and we believe is still, denied. In many,
Judeed in most books of farriery, it is described. We are here
close upon the confines of this very important, and interesting
question ; we must, however, and we do so with some reluctance,
inasmuch as its discussion would be opportune enough in this
place, reserve what we have to say on it for another part of the
course.
-ocr page 103-
68                             On Inflammation.
closed, general suppuration of it takes place, ulceration
ensues, and anchylosis, either partial or complete, is the
ordinary event. Should we succeed, however, in pro-
ducing early the adhesive process in the opening, we seal
up the joint, and guard against these truly melancholy
and irremediable consequences.
Hitherto, we have considered inflammation, and its ef-
fects, as consisting in an increased action of the arteries :
we have now to show, that it sometimes appears to give
rise to altered function on the part of the absorbents.
When parts are removed by absorption, without any, or
proportionate deposition, they are said to ulcerate. It
was formerly supposed, that ulceration could not hap-
pen without suppuration ; but we now know, that the
presence of pus is not necessary, inasmuch as it, now and
then, takes place without it: the best example of this is
aneurism— of which we have seen but one case in the
horse, though it is a common disease in the human sub-
ject. Suppuration is, however, generally a concomi-
tant of ulceration ; and it would appear, that the pres-
sure of the pus is the stimulus to the absorbents to act,
as is well illustrated in a common abscess. Though, re-
lative to this process, is this very curious fact—that ab-
sorption always proceeds to the skin, and never internally;
for if an abscess form between the abdominal muscles and
the peritoneum, we believe that the matter will invariably
make its way to the skin. Pressure however cannot,
in all instances, be adduced as the cause of ulceration;
for in glanders, a disease the very essence of which is
ulceration, no such excitant is present.
The fourth termination of inflammation is in gangrene,
mortification,
or sphacelus. These terms are perhaps,
strictly speaking, not synonimous; in common use how-
-ocr page 104-
On Iitflammation.                             69
ever, they are considered so, and as such we shall adopt
them here. Arteries, in which inflammation is gene-
rated and supported often as a salutary process, now and
then, from excess of inflammatory action, become the
agents of destruction to the parts to which they are dis-
tributed—even themselves the destroyers of their own
vitality. Blood in undue quantities is impelled into a
part by the increased action of its arterial trunks ;—the
vessels of the part itself are rendered powerless by disten-
tion ;—at length every channel becomes overloaded,
blocked up, and unable to relieve itself;—and the part
dies from obstructed circulation. Another cause of ob-
struction, but a very rare one, is the adhesive process
taking place in the interior of arteries, and obliterating
their canals.
You will not infrequently meet with accounts of mor-
tification in horses in books on farriery, or hear some of
their followers of the present day assert, that a horse
died as rotten, as a pear.
But the truth is, that we have
no instance of mortification in the horse—defining it to
be, a total destruction of the powers of life—the death ol
a part; at least, we have never seen, nor even heard oi
one in which we could place any reliance on the judg-
ment of our reporter. Horses who die of severe inju-
ries, followed by high and extensive inflammation, sin!
prior to the gangrenous stage, and they appear to do sc
from excessive nervous irritation. The nearest approach
to sphacelus, and one which we can adduce, if we can any.
as an example of it, is that condition of the lungs where
death has quickly supervened on acute inflammation of
"lem: even here however, the parts cannot, correctly
speaking, be called gangrenous.
-ocr page 105-
70                           On Inflammation.
Inflammation has been divided into several kinds, or
species. When its attack is sudden and violent, and its
progress quick, it is termed acute; but when of a tardy,
lingering, and milder nature, the epithet chronic serves to
denote it. Again, inflammation may either be healthy,
or unhealthy, a distinction that appears to relate to some
peculiarity of constitution; or it may be simple or com-
mon,
or morbid or specific. -Any inflammatory affection
arising from ordinary causes, is simple or common:
those alone are morbid or specific, produced by parti-
cular causes, and not under the power of ordinary re-
medies.
The causes of inflammation are generally ranked under
three heads:—the remote or predisposing; the occasional
or exciting; and the proximate : we shall consider them
in this order.
That may, in a general light, be looked upon as the re-
mote cause of inflammation, which renders a part more
susceptible of the action of the immediate or exciting
cause; or which, in common medical language is said to
impart a predisposition. Particular constitutions are
said to be predisposed to particular diseases; and here
the predisposition would seem to be inherent in the ori-
ginal conformation, or contexture of parts : white-legged
horses, we know, are predisposed to grease ; light ches-
nuts, to disease In general; narrow chested, to pulmo-
nary affections ; and large long-necked horses, to be-
come roarers. As an external agent, inasmuch as
heat is by far the most frequent exciting cause, cold ap-
pears to be that which predisposes the oftenest: when
we say, that a horse has caught a cold—by which we
mean an inflammation of the membrane lining the air
i
©
-ocr page 106-
On Iriftummation.                            71
passages—we do not believe that cold has absolutely pro-
duced the disease, though it is named so from this cir-
cumstance; on the contrary, we suppose that heat, in al-
most all cases, has been the exciting cause*.
The exciting causes of inflammation are various and
numberless : they may all, however, be reduced under
two general heads. In the first class are comprehended
all such as act by their stimulant, or Chemical properties :—
heat, canlharides, turpentine, the mineral acids, the caus-
tic alkalies, &c. The second class includes those whose
operation is purely mechanical: as pressure, friction,
wounds, bruises, fractures, &c.
The proximate cause of a disease may be considered
as its essence;—that on which its presence depends—with-
out which it could not exist—and by whose changes its
nature must be perpetually altered. The opinions of the
most distinguished medical men, have varied exceedingly
in respect to this important subject; more perhaps than
on any other with which we are acquainted. The ancient
medical philosophers, unacquainted with the circulation
of the blood, supported for a long time the doctrines of
* It would appear from the following paragraph, that Dr. Thom-
son considers cold, in this case, as a direct excitant of inflamma-
tion. " In some instances cold, or a diminution of temperature,
seems to act more directly upon the parts with which it comes in
contact. We have examples of this in the inflammation of the mu-
cous membrane ofthenose, fauces, trachea, and bronchia,from the
inhalation of cold air; and in the production of rheumatic inflam-
mation from the accidental exposure of some part, or other of the
body to cold. The application of cold, in the instances I have
mentioned, seems to have somewhat of a directly exciting effect;
and perhaps the same remark is still more applicable to the local
cflects of cold in the production of the inflammation accompany-
ing the state which is usually denominated frost-b?te."
-ocr page 107-
72                             On Inflammation.
fluxion and congestion*: these were exploded by their
more enlightened successors, who adopted in their stead,
those of obstruction—first promulgated by the celebrated
BoEEHAAVEf, and of spasm—the theory of the inge-
nious Cullen %.
Even at the present day, very eminent medical men are
divided in their opinions, relative to the state of the ca-
pillaries under inflammation : some contending that they
* By fluxion is meant a flow of the humours, or blood, to any
particular part; by congestion, a stagnation of them: both giving
rise to inflammation.
t Boekhaave thought, that the minute vessels were blocked up
from the thickness, or viscidity of the blood, in some inflamma-
tions ; while in others, the same effect happened in consequence of
the larger globules having been impelled into them ; which last he
called an error loci. With regard to the first of these—viz. viscidity
of blood, no such condition of it can be demonstrated : we believe
that the blood in all parts preserves its fluidity alike. But, in re-
ference to the second, we do not deny the fact; we believe that the
globules are circulating within vessels, before impervious to them.
His deductions, however, we cannot admit;—we consider the error
loci,
as he terms it, to bean effect, and not a cause of inflammation ;
but that no obstruction whatever ensues, since the circulation is
still carried on, though the part be inflamed.
I Dr. Cullen's theory, like Boerhaave's, is one of obstruction ;
instead of attributing the cause of it, however, to the blood, he
transfers it to its vessels: " The cause of obstruction,'' he says, " is
spasm of the extreme arteries supporting an increased action in the
course of them." Now, the very condition which we know to be
an effect of inflammation, is pre-existcnt to the spasm;—viz. con-
gestion ; so that spasm would be a consequence, and not a cause
of it, as the error foci of Boerhaave's evidently is. But we have
no proof that these vessels are in a state of spasm; and even if
they were, are we sure that it would be productive of inflam-
mation.
-ocr page 108-
On Inflammation.                             73
arc acting with diminished force ; while others maintain
that their action is preternaturally increased. Both par-
ses admit, however, that blood is contained in the in-
flamed part in an unusual quantity, and that these vessels
are, consequently, dilated beyond their natural diameter :
they also agree, in rejecting all idea of stagnation. It
Would carry us very much beyond the prescribed limits
cf this lecture, to enter into a detail of the facts, and in-
genious arguments, by which each has supported its
favourite theory: but with relation to the doctrines
promulgated in our metropolitan medical schools, we be-
lieve that the latter is the one more generally espoused.
We would refer those who wish for information on this
important subject, to Dr. Thomson's excellent work on
Inflammation : in which, from some experiments that
Were made on the frog's foot, whereby a state analogous
to inflammation was induced, the author has come to the
following conclusions: "First, that the velocity of the
blood, so far from being always diminished in inflamed
vessels, is often increased, particularly in the commence-
ment of inflammation; and that this increase of velocity
may continue in the capillary vessels from the commence-
ment to the termination of that state. This increased cir-
culation, I am inclined to believe, exists in a greater or
'ess desree in that state which has been denominated ac-
es
tu'e inflammation. Secondly, that a diminished velocity
ln the circulation through the inflamed capillary vessels,
"'ay take place in the very commencement of inflamma
ll°n, and may continue during the existence and progress
°' lhat state. Thirdly, that this diminished circulation in
-•' e '"flamed capillary vessels takes place, however, more
requently in the progress than at the commencement of
1,1 animation in healthy and strong persons; and that it
-ocr page 109-
74                             On Inflammation.
is probably a state which occurs in those inflammations
which have been denominated passive."
■ " If this view of the state of the circulation in inflamed
vessels be just, it will follow that inflammation is some-
times attended by an increased, and at others by a dimi-
nished velocity in the circulation through the capillary
vessels of the inflamed part; and consequently that nei-
ther of these two states ought to be included in the defi-
nition which we give of inflammation."
Inflammation is treated either by constitutional, or lo-
cal means : we shall first consider the former.
Constitutional remedies are required when any vital
or important organ is the seat of disease, which gives rise
to sympathetic irritation in the system at large. Should
the stomach, or intestines be inflamed, we know that the
heart and arteries will pulsate with more than ordinary
strength and frequency, and that other febrile symptoms
will manifest themselves; which, unless checked by
timely and proper means, may run on, with redoubled vio-
lence, until the animal die from exhaustion. A punc-
ture in the foot—a contusion on a bone*—or an open
joint, will not unfrequently destroy life in this manner.
Our principal constitutional remedies are such as act on
the system by depletion: they are, in a general sense,
comprised in the epithet, antiphlogistic.
We possess no means so effectual for the relief of in-
flammation as venesection. Whenever the case is at all
urgent, either from the magnitude or importance of the
part inflamed, and the constitution and condition of your
* We have seen two or three cases in which death has super-
vened from accidents of this nature, though the external wound
has heen but slight.
-ocr page 110-
On Inflammation.                              75
patient are good, draw blood with freedom; and do this
as near to the seat of disease as circumstances will permit.
Supposing the case to be one of inflammation of the la-
minae*, lose no time in opening the inferior coffin "artery,
and taking away three or four quarts of blood; an oper-
ation that will not seldom arrest the disease in the onset :
again, should the horse be the subject of staggers,
speedily have recourse to copious venesection, from
the jugular veins, whereby you detract blood from the vi-
cinity of the brain, and gain the advantage of a local, as
WeB as a constitutional effect f. We before stated, that
blood in acute inflammatory disease should be drawn
from a large orifice: we may add here, that the effi-
cacy of the operation will commonly be greater the soon-
er it is put into force. Of such value is this reme-
dy in veterinary practice, that it is on many occasions
the only one in which we place confidence for the cure ;
indeed, there are some cases that will not admit of any
thing else being done, that can have any effect in restoring
the animal to health. It is not only our most important
Cleans of cure, but that which of all others is most uni-
Vcrsally adopted: a horse is seldom brought to us with
any constitutional disorder whom we do not bleed; and
with the greatest advantage do we do so, since almost all
tne diseases we have to treat, essentially consist in acute
"'flanimation.
Vulgarly called, fever in the feet.
t V/e have no means of drawing blood from the part itself;
ut we generally can (and should be continually on the alert in
Practice to reap the advantage) take it from a vessel connected
Wlt" il : a pint of blood let from an artery going to, or a vein im-
mediately derived from the diseased part, is equal to half a gallon
drawn from the sygto atlargc.
-ocr page 111-
76                             On Inflammation.
Though venesection is highly beneficial, generally
speaking, in violent inflammations, there are cases of a
specific nature, in which it should be altogether omitted,
or had recourse to with considerable caution ; inasmuch
as we seldom have seen good result from it, and we are
not sure that it has not been occasionally productive of
harm. In the suppurative stage of strangles, bleeding is
never necessary; nor, indeed, in the adhesive, unless we
wish to avoid the formation of matter. In glanders, we
have never witnessed any benefit from venesection: and
we abstain from it commonly in the chronic stages of
farcy.
JsText in importance for the abatement of inflammation
comes purging. Though not so potent a remedy, it is
one even of still more extensive adoption than blood-let-
ting : for a case rarely presents itself, requiring our aid,
in \vhich purgatives, in one form or other, are not impe-
riously indicated; so valuable, indeed, is a purgative me-
dicine to us, that, were we not in the possession of any,
we might lay aside all other curative means, as insuffici-
ent to establish the utility of our art.
Aloes, almost the only medicine on which we can de
pend as a purgative for horses*, is to be administered
in doses apportioned to the size and apparent strength of
constitution of our patient, and to the impression we wish
to make on the system. To a horse in health, under or-
dinary stable management, we give about six drams f;
to one with staggers, a disease in which there is much
* We shall discuss this question at large, in our lecture On Pur-
gation, and Purgative Medicine.
f R Aloes Vulgar. Ext. Pulv. 3vj. vel Ji.
01. Menth. Piper, gtt. xx.
Syrupi — q. s. ut ft. Bol. statim sumcnd.
-ocr page 112-
On ItifiaAmation.                          77
l°rpor of the bowels, we would give twelve: but the
judgment of the practitioner will best determine the dose.
Wow numerous the cases are in veterinary practice, cura-
k'e by the administration of a single dose of purgative
Medicine, and how important an article aloes is in our
Pharmacopoeia, will best appear in the course of these
•ectures.
Should the first dose of aloes not take effect, it is sel-
dom safe to repeat it, in ordinary cases, under the space
°f twenty-four hours—the period at which its operation
commonly commences.
Sometimes we exhibit aloes in a laxative form : with
this view, we give two or three drams, or from that to
half an ounce*, once a day, or every other day, until purg-
ing is produced. Now and then, an alterative medicine
is compounded of it—the efficacy of which simply de-
pends on a still smallerdivision of the aloes : we give one,
and even half a dramf, once or twice a day, or every other
day, according to the nature of the case.
Calomel in large quantities will purge a horse : not
^variably however, for we have given it in half-ounce
doses without its having been productive of even a laxa-
t«ve effect. Let it be noted here, in respect to this
Medicine, that it is one that cannot with safety be ad-
ministered as a purgative, and, therefore, one which
we never think of employing with that object—unless in
* R Pulv. Aloes. Vulg. 3L vel 31J. vel 311).
Pulv. Glycyrrh. Rad. Jss.
Pulv. Zingib. ----- 31.
Syrupi-------------q. s. ut ft. Bol. omni die, vel om. alt.
die sumend.
T Ut supra.
-ocr page 113-
78                             On Inflammation.
conjunction with aloes*, whose operation it is said to
render more violent.
It is a principle in physic—one a scientific practi-
tioner never loses sight of, that medicines which excite nau-
sea, diminish, in a very perceptible manner, the power
and frequency of action of the vascular system, and dis-
pose the skin to perspiration. Now, veterinary surgeons
bleed in inflammatory disease with good effect, and purge
with good effect, and yet we are told, that they do not
nauseate with good effect. The horse's fauces are so con-
structed as plainly to demonstrate'that it was not intended
he should vomit, as a man does ; and only one half
of his stoaiach is susceptible of the operation of medicine :
but, opposed to these facts, we have two others equally
true, in practice ;—the one is, that when we excite efforts
to vomit, no ill effects whatever result; and the other,
that the greatest benefit is derived from nausea, a state we
can at any time produce and regulate with equal certitude.
The root of white heleboref is the medicine we have been
in the habit of employing for this purpose for the last ten
years, and we feel no scruple in adding, with the best ef-
fects ;—it lowers and weakens the pulse, relieves the dis-
tended vessels of the inflamed part, and promotes that
smooth and glossy condition of skin, which is evidence-
sufficient, in the horse, of our having excited diaphoresis :
R Hydr. Submur. Si-
Aloes. Vulg. Pulv. 3 v. vel ^vij.
Syrupi-----------q. s. ut ft. Bol.
-)■ Neither ipecacuanha, nor the tartarized antimony possesses
virtue as a horse medicine. Very large doses of them may be
given—two ounces of the latter, without producing any apparent
effect.
-ocr page 114-
On Inflammation.                             79
these are not fabricated reports—they are the result
or long experience and close observation, and such as we
are not likely to concede to argument grounded upon any
analogical or theoretical conclusions. The common dose
*s a scruple* of the powdered root, once, twice, or thrice
a day, according to the effect we are desirous of produc-
Ing: during its exhibition we are frequently to examine
the pulse with attention, in order that we may detect its
influence on it as early as possible, and either omit its
subsequent use altogether, or give it in smaller doses, or
at longer intervals. The effeot of nausea is further indi-
cated, by the horse's becoming suddenly dull and torpid
~-by his hanging his head down, or resting it upon the
manger—by his refusing to eat, or drink—and by his froth-
'ug at the mouth : which last event is characteristic of ex-
cessive nausea, and only precedes, should the medicine
be carried further, distressing and unavailing efforts to
vomit. Even this effect of it, however, is attended with
no danger, and only requires a little time to subside.
On the whole, next to aloes, it is the best medicine with
which we are acquainted to combat acute inflammatory
disease ; and the only one we are yet in possession of as a
diaphoretic.
Diuretic medicines, classed with those whose effect is
*° restore the suppressed secretions, while they act as
evacuants, are serviceable in inflammation. Common
turpentinef, resin, and soap are the remedies generally
'Hade use of to excite the action of the kidneys: con-
joined in various proportions, or simply mixed with other
ft Pulv. Rad. Veratri 9j. vel 9ij.
Pulv. I'lor. Anthemidis 5ss.
%rupi q. s. ut ft. Bol. bis terve die sumend.
-Te>ebinthi?M Vulgaris of the London Pharmacopoeia.
-ocr page 115-
80                             On Inflammation.
substances, perfectly inert, according to the fancy of the
practitioner, they form our common diuretic, or urine
ball*.
These balls should be given, in the generality of
cases, about every other day; though sometimes they
are required every day, and even twice a day, towards the
decline of disease : their use is more especially indi-
cated, where any dropsical depositions are left, we are
anxious to promote the absorption off.
If narcotic medicines are of service to horses, we have
yet to learn what they are, and in what cases they should
be exhibited : we occasio»ally give opium, but never with
a view of allaying pain and irritation, or procuring sleep.
With reference to diet and regimen—generally speak-
ing, it is proper to substitute bran for corn, or beans;
and feed with green meat, in lieu of hay, should it be in
the spring, or summer season : unless the case be one of
inflamed bowels, and then, probably, the animal should
* R Terebinth. Vulgaris ,?ss.
Ol. Juniperi--------31.
Pulv. Glycyrrhizse q. s. ut ft. Bol. alternis diebus su-
m end us.
Or the following:
R Resin. Flav. Pulv. ^ss.
Saponis duri-----■ 3ij.
01. Carui-------- 3L M. ft. Bol. omni die sumendus.
f We would remark here, for the information of the young and
inexperienced practitioner, that the horse is an animal very suscep-
tible of the action of diuretics; so that too large doses, but more
especially the too frequent repetition of them, will never fail to in-
duce a state of general debility, should they not be followed by ne-
phritis. Let their effects, then, always be inquired into ; and,
where we have occasion to administer them often, let the general
health and condition of the horse be particularly attended to.
-ocr page 116-
On Iiiflammalion.                             81
be fed with fermented provender. Now and then the ap-
petite is so bad, that scarcely any food at all is taken:
when this is the case, we should not allow the horse any
other drink than what contains some nutritive ingredient;
—-either water-gruel, barley-water, decoction of arrow
root, or infusion of linseed, will commonly be preferred by
him ; and prove an excellent panada until his appetite be
restored. Sometimes it becomes necessary to drench him
with one or other of these fluids, in order to support life,
until the power or inclination return of feeding himself.
With the exception of lameness, and some few other
cases, which require a stationary condition, what is called
a loose box, is the best possible situation for a diseased
horse: here he moves at pleasure, puts himself into
that posture most easy to himself, and favorable to his
cure, and experiences altogether an indulgence which
we should by no means think lightly of in practice. In-
dependently of this, however, it may happen that exer-
cise becomes necessary; and when it is, let it be confined
to that of walking: we know of no instance in which a
sick horse is benefitted by trotting, or galloping; but we
have met with many, where simple disorder has been
converted by it into alarming and fatal disease.
The local, or topical means we possess for the abate-
ment of inflammation, are few and simple. One of the
most powerful is the application of cold: this reduces the
temperature of the inflamed part, lessens its acquired, or
morbid sensibility, and lowers the action of the arterial
trunks connected w'ith it. The coldest water, or ice it-
se"> may be employed for this purpose ; the first by
means of cloths frequently renewed, the last by being
"■closed in thick coarse bags. Few practitioners, how-
everj put faith enough in cold water to employ it without
G
-ocr page 117-
82'                            On Inflammation.
medication; and by far the most common addition to
it, is the superacetate of lead—in the proportion of
about half an ounce to a quart; which gives it an as-
tringent, and, some think, a sedative virtue : to this it is
advisable to add about two ounces of distilled vinegar,
in order to prevent any decomposition. As a wash which
proves by evaporation still more refrigerent, at the same
time that it possesses the astringent and sedative proper-
ties of the former, we may combine spirits of wine with
it*; or we may use simply spirits of wine and water -j*.
With regard to the lead wash, it is by no means clear to
us that it possesses any advantage, as an application to
the skin of the horse, over common water; inasmuch as
the preparation itself, even in ounce doses, taken into
the alimentary canal, is perfectly innocuous. As a com-
mon astringent lotion, the sulphate of zinc dissolved in
water—half an ounce to a quart, is one of the best; or we
may substitute common salt for the zinc, adding double
the quantity : recollect, however, that, generally speak-
ing, neither of these last is to be applied to a surface
acutely inflamed ; for they both possess slightly stimu-
lant, as well as astringent properties; and this gives them
the preference in many chronic affections.
Sometimes warm applications are to be preferred to
cold; but so undefined are the cases in which each is
proper, that one practitioner will frequently employ the
former, while another insists that the latter is more effica-
* The liquor plumbi subacetatis saves much trouble in making
the Goulard lotion—about two tea spoonsful of it are sufficient
for a pint of water. To make this an evaporating lotion add two
ounces of spirits of wine.
f R Spts.Vini. Rect. fiij.
Aq. Fontanas------lb.j. M. ft. Lotio;
i
-ocr page 118-
On Inflammation.                        83
cious : in the generality of instances, we should use the
cold. Strangles, where we wish to promote the suppura-
tive stage, is the only case which now occurs to us, in
which most practitioners would order a warm bath, or a
poultice, rather than a cold wash. Heat itself—dry heat,
has the effect of exciting or increasing inflammation ;
but when united with moisture, it diminishes inflamma-
tory action, by exciting perspiration upon the surface,
and consequent evaporation : so that its ultimate effects
are, probably, not very different from those of cold. Bran
is occasionally used for poultice ; but it is very inferior,
on many accounts, to linseed meal *, which we now,
therefore, always prefer.
In cases of extravasation of blood from a blow on a
part, or where the cellular texture is filled with adhe-
sive matter, and the inflammation that has given rise to
it, is on the decline, what are called discutient lotions f
—such as discuss the swelling by rousing the action of
the absorbents, are often of service.
Blisters, rowels or setons, rubefacients, sinapisms, and
the actual cautery, are remedies in the veterinarian's ca-
talogue, whose operation is different from those already
detailed. In regard to them all, we may lay it down as
an invariable rule, that they are not to be employed to a
* Pour as much hot water into a pan as you think sufficient for
the poultice you are about to make, and then stir in linseed meal,
until the mass acquires a proper consistence.
t What we are in the habit of employing is this:
R Ammoniae Muriat. ,f ss.
Spts. Vin. Tenuioris' ~) . „.....,..,. .
Aceti___________j swg. jviij M. ft.Lotio.
or this,
R Liq. Ammon. Acet. |          _ . „, ft T ..
c„, tT. _.                  J- sing, f vj. M. ft. Lotio.
&Pts. Vin. Rect.           J 6 ° J
G 2
-ocr page 119-
•                                            o
84                             On Irtfiammation.
part inflamed ; on the contrary, they do good by exciting
inflammation in a part itself free from it; though the
nearer they are applied to that originally diseased, the
greater benefit is likely to result. Some of them simply
produce a determination of blood to the part they affect,
and thus relieve (as we say, by derivation) the neigh-
bouring inflammation : this is the case with what we
may call rubefacients—though their effect as such is not
ordinarily visible on the skin of the horse, and with si-
napisms. Others—as blisters, rowels, and setons, not
only inflame, but excite a discharge from the parts they
are applied to, and thus act by evacuation, as well as re-
vulsion : in addition to these more apparent effects, how-
ever, they seem to lower the action of the vessels sup-
plying the inflamed part, and work altogether a salutary
influence, that we are not able probably well to explain.
The effects of inflammation are best met with blisters,
and stimulants of various kinds. When the primary action
has subsided, and an adventitious deposit remains, our
object is to re-excite inflammation, with a view to its ul-
timate removal. Blisters exceed in efficacy all other
means for this purpose ; and though we occasionally
make use of stimulants, and now and then of escharo-
tics, we hardly ever succeed so well in the end.
The actual cautery, (firing,) considered as the veterina-
rian's last resource, is one of his most potent, and when
properly handled, one of his most effectual means to re-
new inflammatory action, and excite absorption : it does
the former by its immediate stimulating effects ; the latter,
it commences by stimulation, but-promotes considerably
afterwards by pressure, having the same effect as a tight
bandage applied to the part.
La Fosse appears to entertain the same empirical no-
tions about firing, as the common farriers do in this coun-
-ocr page 120-
On Aneurism.
So
try : " Ce que les medicamens ne guerissent pas, le fer le
guerit: ce que le fer ne guerit pas, le feu le guerit: et ce
que le feu ne guerit pas, il faut le regarder cotnme in-
curable."
On Aneurism.
An aneurism may be said to be, any tumor formed
upon an artery, so as to communicate with its interior.
Aneurism, commonly as it is seen in the human sub-
ject, is so rarely met with in the horse, that we should
not have thought it necessary to have made any mention
of the disease, had there not been in the museum at this
place, a very fine specimen of aneurism of the thoracic
aorta.
It is a-dried preparation, about the size of a com-
mon pumpkin, perforated underneath by two large circu-
lar apertures, through which it has discharged its contents
into the chest. The sac is in many places extremely thin,
and puts on internally, so far as we can examine it in
its present state, the appearance of ulceration : but whe-
ther it consist of an adventitious substance, or be a dila-
tation of the coats of the vessel, (though we are much in-
clined to regard it as the former,) it is not easy to deter-
mine. In a word, all we know concerning it, is, that it
was brought from the slaughter-house, and has been
many years in our possession : as a preparation we think
it valuable, being one of the few specimens to be met
with of this disease *.
* Writers, in general, have been silent on this subject: a further
proof of the rarity of these cases. Mr. Feron, in his Treatise en
Farriery,
has entered into some description of the nature of aneu-
risms, without having particularized such as belong to the horse;
So that we are at a loss to know whether he has had any cases of
tne kind, and if so, what they were.
-ocr page 121-
LECTURE VI.
On the Veins.
The veins are those vessels which convey back to the
heart the blood distributed by the arteries to the different
parts of the body.
The veins commonly exceed the arteries in number, as
well as size; according to some writers, in threefold
proportion: in some parts, however, they correspond in
both these particulars to the arteries—as in the lungs;
while, on the other hand, in others, they are manifold their
number—of which the foot is the best example.
There are ten principal venous trunks. Two, called
the venae cavaj, return the blood from the body generally
to the right auricle of the heart: eight, denominated pul-
monary veins, convey it from the lungs into the left auri-
cle. In addition to these, there is a small vein, named
the coronary, unconnected with any trunk, which empties
itself into the right auricle.
The veins, unlike the arteries, are divided into two or-
ders :—a superficial, and a deep-seated order. The for-
mer take their course superficially, being commonly found
immediately beneath the skin, hence sometimes called
subcutaneous: the latter, of smaller size, for the most part
-ocr page 122-
On the Veins.                                87
accompany the arteries; two of them, thence called venae
comites, are frequently found running with a single arte-
rial trunk. The superficial and deep-seated sets have
free communication, by means of anastomosing branches,
with each other; of which the common operation of ve-
nesection affords a good demonstration. If, for example,
you are drawing blood from the shoulder of a horse, and
you take up the other fore leg, you know that the blood
will flow in a much freer stream, than if you allow the
animal to favor the limb from which you are taking it;
for, by making him exert the muscles of the bleeding leg,
the blood is pressed from the deep-seated into the su-
perficial veins.
Veins take their origin in four different ways. The
first, and most common, is that from the termination of
arteries, which we endeavoured to prove, when speaking
of those vessels, was by direct continuity of canal. The
second source from which they spring, is from the inte-
rior of cells : the corpora cavernosa penis and the spleen
are considered as instances of this. The third mode of
origin is also from the internal surfaces of cavities, but
which are called sinuses: these are much larger than cells,
and are found within the layers of the outer membrane of
the brain, called the dura mater. The fourth, and last
venous root, is that from the termination of other veins;
Well instanced in the vena porta?—a vein that supplies the
liver with blood, (therefore somewhat similar to an ar-
tery,) from the extreme ramifications of which other
minute venous radicles proceed.
All the veins iu the body ultimately conjoin so as to
*°fm ten trunks; which, as we have just stated, pour
their blood into the auricles of the heart.
Veins, although elastic in their composition, have not,
-ocr page 123-
On the Veins.
88
like arteries, a proper elastic coat. They have only two
coverings :—a muscular, and an internal or membranous
coat.
That these vessels are elastic, may be proved by
simple extension of their substance, either in the dead, or
living animal—the vessel will be found, after being
stretched, to contract itself to its former dimensions: it
would appear however, that they are more elastic length-
wise than in their diameter; for we know that they do not,
when empty, maintain their cylindric shape, nor preserve
circular apertures when divided.
The external or muscular coat of these vessels, is much
thinner than that of the arteries; and its fibres are less
distinct, being only traceable by the naked eye in some
few of them: no wonder, therefore, that its existence, by
some anatomists, should have been altogether denied.
But there are facts which seem to prove the presence of
such a coat, however indemonstrable it may be by actual
dissection. We frequently see the superficial veins after
exertion, especially those of thorough-bred horses, distend-
ed with blood : now, if in this condition the animal be al-
lowed to remain at rest, and more particularly, if he be re-
moved into a cold atmosphere, in the course of a short time,
we shall no longer perceive the subcutaneous vessels
equally numerous, nor those, still in view, equally turgid;
from which it is evident, that the veins must have pos-
sessed a power of contraction—or how could they have
rid themselves of their redundant blood ? Again, in
bleeding, we know, if pressure be made on the jugular
vein for a short time previously to opening it, that the
blood will gush out with considerable force, as soon as
the lancet is introduced ; and this appears to arise from
the elasticity of the vessel; for if the vein be examined
after some blood has been drawn, we shall find that it has
-ocr page 124-
On the Veins.                                89
absolutely become smaller in its calibre^ than it originally
was ; a fact we cannot '.veil account for, unless we admit
the muscularity of veins*.
The second, internal, or membranous coat, is per-
fectly smooth upon its inner surface, dense and elastic in
**S texture, and possesses more strength than that of an
artery : we say this, because if you make a ligature ever
so tight on a vein, you will not divide this tunic, un-
less you cut through the vessel itself, as is invariably the
case, when you draw one even moderately tight on an ar-
tery. By its smoothness internally, it affords free and un-
interrupted passage to the blood; and by its density, ex-
udation is prevented.
These vessels are furnished with their vasa vasorum ;
consisting of minute ramifications from the neighbouring
arteries, and of small veins, called vena; venarum, which
avoid emptying themselves into the trunk from the coats
of which they return the blood. Nerves, and there can
be no doubt absorbents, enter also into their compo-
sition.
Within the cavities of veins, are many semicircular,
loose, membranous projections, called valves : there is
commonly but one, sometimes two, and at others three
°f them, attached to the circumference of the vessel. In
a section we took from the central portion of the jugular
vein, eight inches in length, we found, on slitting it open,
tvvo pairs of valves in the upper part, at the space of two
"iches apart, and in the lower, three single ones—a tri-
cuspid valve, whose edges were accurately adapted to
Slumenbach says, that the muscular coat exists in the
iar§est trunks only.
-ocr page 125-
go                                On the Veins.
each other: making altogether three sets of valves within
the space of eight inches of vessel. The valves are thin
and semitransparent, and are by some authors considered
as reflections of the internal tunic: Mr. Hunter con-
tradicts this opinion however ; and says, that their struc-
ture—what is totally different—is tendinous and inelastic.
There are some veins in the body without valves—those
of the brain, abdomen, and chest: the smaller venous
ramifications are also of this construction; an exception
familiar to those who have injected the veins of the foot,
which is always done contrary to the course of the blood.
It was the aforegoing discovery, that first led some
physiologists to attribute to valves the function of sup-
porting the column of blood, contained in the veins, in
its passage to the heart: whether they serve such a pur-
pose, or not, however, is to us of little importance; we
shall, therefore, dismiss the question altogether without
remark. One use of a valve, be it placed where it may—
in a machine, or in a blood-vessel, is to admit of the pas-
sage of a fluid in one direction, and to prevent its re-
flux. Now, that the valves of veins perform this use, is
at once proved by attempting to inject them contrary to
the circulation of the blood; which, it is well known, we
are unable to do, even by the employment of all our
strength : so that a column of blood, in flowing back to
the heart, having once passed a valve, (or set of valves)
can never regurgitate, be the forco, tending to displace it
in the vein, applied in what direction it may.
Veins differ from arteries in the following particulars:
in having but two coats, and them so thin, that the color
of the blood appears through them; in wanting suf-
ficient elasticity to retain their cylindric form; in having
-ocr page 126-
On the Physiology of Veins.                    91
valves • in being more numerous, and, generally speak- -
Ulg> larger; in having no pulsation; and, lastly, in the
tllr>ction they perform.
There are certain peculiarities of the veins of some
Parts which it will be proper to take notice of. Some
°f those about the head of the horse, are remarkably dif-
ferent in their structure from the veins of other animals—
they strike us at once as peculiar in having several sacculi,
0r pouches, along the course of their canals, formed by
"•'atation of their parietes, which much resemble so
'toany aneurismal enlargements : there is commonly one,
but sometimes two, of these found underneath the mas-
seter muscle, on either side of the face. These venous
reservoirs are probably of the same use to the animal as
'he sinuses of the dura mater—preventing any thing like
interruption, or even retardation, to the return of blood ;
^hich, in consequence of the almost incessant action of
tr,e posterior jaw of' the horse, more especially while
grazing, (for he is an animal commonly found feeding,)
^'ght otherwise have been occasioned.
On the Physiology of Veins.
Blood having been distributed by the arteries to the
uirterent parts of the body, and having furnished such ma-
terials as from their nature they required, is returned by
l"e veins again to the heart: so that the veins may be said
0 perform a subordinate function to the arteries. The
arteries, as we before stated, have not only to convey
lo°d throughout the system, but, by some unknown
ear»s, to convert it into the various component parts of
e "°dy, as well as to separate the secretions from it;
lereas these tubes have nothing more to do, than to
ca«ry back to the heart the unexpended blood.
-ocr page 127-
92                    On the Physiology of Veins.
Now, it has long been a question among physiologists,
to what causes the motion of the blood in the veins was to
be attributed ; for, when we recollect how distant many
of them are from the heart, that the blood in them is flow-
ing from a larger into a smaller space, (taking the compa-
rative aggregate calibres of the trunks and branches,) and
that it is, in many places, flowing contrary to its own gra-
vity, we shall perceive that no inconsiderable force is re-
quired for this purpose. By some, the vis-a-tergo, as it
has been called, or the force of tiie heart from behind,
has been supposed equal to the effect; while others, with
more appearance of feasibility, have regarded the veins
themselves as not altogether passive in its transmission.
Indeed, if we consider the propellent power the left ven-
tricle must possess, in order to move such a mass of blood
through these tubes, so remote from its operation, and,
at the same time, calculate the sum of resistance opposed
to it, by the interposition of the capillary system, and va-
rious other causes, we shall be inclined to seek further for
agents of propulsion. On the other hand, we are not to
reject the power of the heart altogether, merely because
the blood flows with an uniform stream in the veins; for
the absence of pulsation in them, is no proof that the mo-
tion of the blood is not influenced by the contractions of
the heart: the extreme division which this fluid undergoes
in its circulation through the capillaries, and the tortuosity
and complication of the numberless small veins, account
for the regular and uninterrupted stream which we meet
with in their larger branches. To prove that this is the
explanation of the fact, if you open a vein that has free
and direct communication with the extremity of an artery>
the blood will flow from it with the same pulsatory mo-
tion, as if the artery itself had been penetrated; but if the
-ocr page 128-
On the Physiology of Feins.                    93
ein De one of large size, remotely situated from any arterial
°H)munication, or if it be one that springs from the union
numerous capillaries, that smooth and even stream,
itli which the blood circulates in the trunks, will be ob-
servable here. Th ese facts, then, lead us to conclude,
nat the force of the heart is not sufficient of itself to pro-
Pel blood through the venous system.
■rrom the collected accounts of writers on this subject,
]t seems highly probable, that the blood, flowing in the
Vems, receives additional momentum from the reaction of
tne capillaries—which we spoke of in a former lecture :
and that it is further urged on by some contractile force
resident in these vessels themselves. That the blood is
advanced in its course by the action of those muscles con-
t'guous to veins furnished with valves, is, without doubt,
"Well founded, as far as an occasional auxiliary is concern-
ed, as the common operation of bleeding demonstrates ;
■°r it is in consequence of muscular pressure upon the
veins about the head, that the motion of a horse's jaw ac-
celerates the flow of blood through the jugular vein : as
such, however, it cannot be ranked among the essential
causes of the blood's motion in them.
Although the blood hi the venous svstem for the most
Part flows without intermission, the large veins near the
fieart have a sort of pulsatory action excited in them ; so
"'at, at first sight, on laying them bare, we might suppose
neni to be the trunks of arteries : they pulsate, however,
*rom a different cause ; in consequence, of a portion of
'°od regurgitating into them, during the systole of the
uncles, there being no valves placed at their termination
llue heart, to prevent such reflux. This retrogade mo-
°n °f the blood may be observed in the vena? cavaj,
-ocr page 129-
94                     On the Physiology of Veins.
jugular, and pulmonary veins; so that, in them, the
blood really appears to ebb and flow : a circumstance
probably that led the ancients into error concerning its
real course.
We mentioned in a former part of this lecture, that
veins were more numerous than their correspondent arte-
ries, and we adduced the foot as a good instance : an ex-
amination of this organ furnishes us with some facts that
seem to point out the utility of this disparity in their num-
ber and size. We find that the sole and sides of the foot
are parts crowded with these vessels, and we know that
these parts are most of all subject to pressure, and, as a
natural consequence, to obstructed circulation: this Na-
ture has in a great measure prevented, by supplying them
plentifully with veins, and those veins without valves; so
that the blood may flow in every direction with equal fa-
cility. For the same reason, are many parts furnished
with superficial and deep-seated veins, and others with
veins with no valves: in the former case, the actions of
muscles are the chief cause of pressure ; in the latter,
the motions of the viscera, as well as the variations of
volume and site to which they are liable, have a similar ef-
fect.
There is one vein in the body whose distribution and
use are so different from any other, that it requires a dis-
tinct consideration: we mean the vena portae, a ves-
sel formed by the union of those veins that return blood
from the organs of digestion. ,It supplies the liver in a
similar way to what arteries do other secreting organs of
the body; and, like them, separates a peculiar fluid from
the blood ; so that, in effect, it is more properly of an ar-
terial than a venous description.
-ocr page 130-
On the Diseases of Veins.Blood-spavin. 95
On the Diseases of Veins.
There is but one disease met with in the veins of horses,
and that the result of external injury : we must, however,
in comformity with custom, say a few words on a suppo-
sed varix of these vessels, called
Blood-spavin.
In the human subject, the veins of the legs now and
then become varicose; by which is meant, a dilatation of
their coats in consequence of preternatural distention :
under these circumstances, the valves in them perform
but imperfectly their office ; the veins themselves become
tortuous, bulge, and occasionally burst in various places,
forming small tumors, or bloody ulcers, in the skin,
which, from the appearance of the blood through them,
are of a purple color. Such have many veterinary wri-
ters* conceived to be the nature of blood-spavin—a dis-
ease that has no existence but in the pages of their works.
The horse, as far as our observations have gone, is not
troubled with varix ; and we much doubt that the veins
of this animal have ever become spontaneously varicose,
though we have none whatever, that something like varix
may have been produced in them, by the remedies com-
monly recommended for the removal of a blood-spavin.
We allude here to the use of ligature—a practice long ex-
ploded by the scientific veterinarian.
If ever you examine a horse said to have blood-spavin,
(for it is by no means a very common occurrence,) you
will perceive a soft fluctuating tumor upon the inner and
Bracken was the first who detected the fallacy of such an
opinion.
-ocr page 131-
96                                Blood-spavin.
fore part of the hock, in the course of the principal vein,
which is at that part superficially placed. At first view
of it you are convinced from the unnatural prominence of
the part, that there must be disease; and so there undoubt-
edly is ; though it is not of that kind which its name so
emphatically expresses. Dissection has fully developed
its nature. There is placed here a little membranous bag,
called a bursa mucosa; which contains in a natural state,
a certain quantity of mucous fluid; from a too copious
secretion of which, it happens, now and then, that this
sac becomes distended, preternaturally enlarged, and in
this condition constitutes a disease, called bog-spavin ;
the nature of which will be hereafter more fully explained.
The vein, passing immediately over this bag, compress-
ed, and diminished in calibre by enlargement of it, can-
not transmit blood, at this part, with the usual facility
or quickness ; the consequence is, that a preternatural
distention of it happens immediately below the tumid bur-
sa, thence extending as low down as the first valve: and
this has been mistaken for a varix, or some such thing,
and denominated a blood-spavin.
A blood-spavin, then, is purely a distention* of that
vein which passes superficially over the inner and fore
part of the hock-joint; solely produced by, and conse-
quently coexistent with, a bog-spavin. Be the cause of
such obstruction, however, what it may, the same thing
will happen : hence, if we tie this, or any other vein, we
shall produce instantly, in truth, a blood-spavin, and pro-
bably, by allowing the ligature to continue, in process of
time,
a varix.
From what has been said about the nature of this sup-
• We would call a varix a dilatation.
-ocr page 132-
On Wounds of Veins.                         97
posed disease, it is obvious that the only remedy is that of
removin" the cause of obstructed circulation through the
vein: how this is to be attempted, will be pointed out
when we come to consider a bog-spavin.
On Wounds of Veins.
It is of the ill consequences occasionally arising from
the common operation of bleeding, that we are now go-
ing to treat. When the jugular vein is opened by a
phleme, or lancet, and the necessary quantity of blood
taken away, the edges of the cutaneous wound are brought
together, and maintained in contact, by the insertion of a
pin, about which is twisted a skein of common tow. Now,
under ordinary circumstances, what happens in the closure
of the wounded vein, is this. First, a coagulum is formed
by the blood extravasated into the surrounding cellular
substance, between the wound in the skin and that in the
vein, by which the latter is so effectually plugged, that
all further efflux is put a stop to. Then, from the lips of
the orifice in the vein, in consequence of inflammation en-
suing, adhesive matter is poured out; which, in the course
of a few days, resembles in its texture the parietes of the
vein with which it is continuous ; while, in the interim,
the coagulum is daily diminishing, until, at length, it is
wholly removed by a process of absorption. Lastly, the
new-formed membrane, occupying the site of the punc-
ture from the lancet, is with difficulty distinguishable from
the coats of the vein themselves*.
If, from the use of a bad or dirty instrument, from in-
expertness in the operator, from inattention to pinning up,
* Vide an excellent paper on this subject by Mr. Travers, in the
first part of the Surgical Essays, by Messrs. Cooper and Travers.-
H
-ocr page 133-
qq                        ' On Wounds of Veins.
from subsequent friction, or, may be, from irritability of
habit, any separation between the edges of the wound be
permitted, so as to destroy union by adhesion, tumefac-
tion of the neck, in the course of the Vein, frequently en-
sues, and the horse is said to have an inflamed neck from
bleeding.
It is ever a most reprehensible practice to
bleed with rusty, ill-conditioned phlemes, or lancets : both
the lacerated wound they inflict, and the rust or dirt be-
smeared by them upon its edges, are causes which pre-
vent union, and dispose parts to take on unhealthy ac-
tion ; the practices of striking phlemes with improper
force, and of not holding them in a precise line with the
course of the vein, are also censurable. Peculiarity of
constitution has but little to do with mischief of this kind
in the horse, however often it may be the source of it in
the human subject. Another cause to which this acci-
dent may be referred, is that of not neatly and carefully
pinning up the neck. For this purpose, your pin should
be small, and so inserted through the lips of the cutaneous
wound, that it pierce them about the centre, and take
sufficient hold to prevent the probability of its being torn
out. This being done, and the blood sponged from the neck,
it is an excellent practice to rack the horse up,so as to con-
fine his head, for, at least, an hour, after the operation ;
in which time a firm coagulum will have formed: should
it happen that he has to go some distance after bleed-
ing, this precaution may be taken with advantage, prior
to feeding, even on his return home. For it sometimes
happens, that horses—either from rubbing their necks
after bleeding, from the pressure of the collar in draught,
from friction by the rein of the bridle, or from some sud-
den and violent movement of the head and neck, or even
from hanging the head down for long—have fresh bleeding
-ocr page 134-
On Wounds of Feins.                         S9
excited from the orifice ; and this may be so profuse, as,
if not arrested, to prove fatal: more commonly however
the hemorrhage stops of itself, or a second pinning up is
had recourse to; and it is this accident that frequently
gives rise to an inflamed vein.
Inflammation occasioned by one or more of the afore-
mentioned causes, attacks the internal, or membranous
coat of the vein; and proves, if it be not soon subdued,
a source of much troublesome disease in the neck; as
every practitioner, who has seen these cases, is well
aware of. The first appearance indicative of the ap-
proach of this disease, is the separation of the cut edges
of the integuments, which are commonly redder than
Usual, and sometimes everted. Soon after, a little sa-
nious discharge, at first tinged with blood, and afterwards
mingled with pus, appears at the wound; the surround-
ing skin becomes tumefied, tight, and hard; and the vein
itself, above the orifice, feels like a hard cord under the
fingers in its course to the head. As the disease advances,
the secretion of pus becomes more distinct, (though in
some cases the serous effusion still continues,) and the
tumefaction of the neck increases, accompanied with ex-
treme tenderness, which the animal fully evinces by flinch-
ing from the least pressure. About this time, there is
commonly some constitutional irritation—denoted by
quickened respiration, frequent and strong pulse, refusal
of food, sparing evacuations of foeces and urine, and
general heat of body, n ore especially of the mouth.
Under these circumstances, if the animal be not relieved,
the head becomes enormously swollen on one side, ac-
companied with more or less disturbance of the senso-
num ; ancj to such an alarming height has the irritative
fever m the system run, that even death itself has been
h 2
-ocr page 135-
100                        On Wounds of Veins.
k hown to happen, where the case was treated from the
first with all possible attention. In describing how this
disease may terminate fatally, we have been recalling to
mind the particulars of a case of a horse belonging to
an officer of the royal artillery ; where a dirty phleme had
been the exciting cause; but of which, unfortunately,
there were no minutes made ; nor were the parts inspect-
ed after death with sufficient care, to inform us to what
extent the disease had proceeded. This is the only in-
stance of fatality in the horse with which we are ac-
quainted, though doubtlessly there are many others : in
the human subject some cases are also related which
have ended in death.
We believe that this accident is more frequent among
horses than men ; and it has been asserted, that the dif-
ficulty of producing union by adhesion is the cause of this :
when we advert, however, to the means we are compelled
to use to close the wound, to the too frequent non-obser-
vance of all subsequent precautions, as well as to the un-
tractable nature of our patient, it appears to us, that we
shall find ample causes for its more frequent occurrence
among horses, without ascribing it to this, which, we
humbly submit, will not apply to the case before us*. If
* In the Essay on the Wounds and Ligatures of Veins, to which
we have already, in a note, made reference, we find, as part of a
communication from Mr. Coleman, the following;—" I have no
doubt that inflammation of the wound sometimes takes place in con-
sequence of the mode used to stop the bleeding; but I should ob-
serve that the most simple wound through the integuments of horses is
scarcely ever healed by the first intention.;
and it is this disposition to
suppurate and resist adhesive union,
that is probably the most fre-
quent cause of the external wound after bleeding not uniting by the
first intention in horses, the same as in the human subject." That
even a clean-cut wound through the skin of the horse, if it be ex-
-ocr page 136-
On Wounds of reins.                        101
it were to be referred to the insusceptibility of the horse's
skin to the adhesive inflammation, instances of it must
happen much oftener than they do; not only from inat-
tention to the animal after the operation, but even under
the most judicious management: which, by the.bye, they
seldom or never do. Let us ask any surgeon, what would be
the effect of pinning up arms as we do the necks of horses?
^—and, more particularly, if his patient happened to be a
maniacal one, by whom his injunctions to keep the arm at
rest, and in a certain position, were altogether disregarded ?
Could we make use of a proper fillet, or of adhesive plas-
ter, and impress on our patient the necessity of keeping
his head and neck still, lest he disturb the wound, we will
venture to assert, that we should not have to complain of
the powers of healing of the skin, nor of those of any
other organized part of this animal. Why have we not in-
flamed veins in the thigh, or the arm ? If they arise from
defective healing powers, these cases ought to be quite as
frequent as those of the neck ; whereas, they are compa-
tensive, treated in the ordinary, slovenly, careless manner, seldom
heals by the first intention, we admit; but that the lips of the
wound made in bleeding, unless they be afterwards separated by
violence, rarely or never fail to adhere, is, to us, undeniable. No^
thing is more common, in the present improved state of veterinary
surgery, than to close the incisions made in performing neuro-
tomy,
without any suppurative process: and could we preserve the
nice adjustment of the divided parts, without the employment of
suture, and other irritative means, we are of opinion that adhe-
sion would invariably ensue. These facts, with what we have ad-
vanced above, induce us to depart from the opinions contained in
this citation: and we are the more anxious to express ourselves
openly and intelligibly on the subject, inasmuch as we are differ-
ing (and with all deference we do so,) with Professor Coleman, on,
a point purely practical, and by observation alone to be decided.
-ocr page 137-
102                      On Wounds of Veins.
ratively rare in practice—to many, unknown : and one rea-
son appears to us self-evident;—because they are removed
out of the way of external injury.
As to the exciting cause of inflammation of the inner
tunic of a vein, various opinions have been offered. Ob-
struction of its canal, has been adduced as one ; without
foundation, however, for ligatures on the veins of horses
are not attended with any inconvenience. Exposure
of its cavity, has been introduced as another; but were
this the cause, we should probably have fifty, or a hun-
dred cases, where we now have but one.
Inflammation in the vein would appear to be an exten-
sion, through continuity of substance, from that of the ex-
ternal wound, which always precedes, we believe, though
it is not invariably followed by, it—the textures are dif-
ferent, but the same arteries send off vessels to both
parts; and though this will not explain why inflammation
is excited in the vein, it may serve to point out the best
means of prevention :—the effectual and speedy closure
of the external wound.
We have observed, that this disease is sometimes con-
fined to the adhesive process—a thin ichorous discharge
only shewing itself at the external wound; very common-
ly, however, especially if the case be neglected, or mal-
treated, abscess forms within the cavity, which now and
then extends upwards for a considerable distance. In
either case, the most common termination is the oblitera-
tion of the affected vein ; or, as it is vulgarly expressed,
the loss of it. Every one, in the course of his practice,
has met with horses having no vein on one side.
We shall now make mention of, and endeavour after-
wards to account for, a circumstance, which, at first view,
appears so singular, that it has hitherto, we believe,
-ocr page 138-
On Wounds of Veins.                    103
baffled all attempts to explain it: viz. why inflamma-
tion of the jugular vein in the horse should extend itself
towards the head—contrary to the course of the circula-
tion, while the same disease in the human arm, invades
the vein as it proceeds to the heart—corresponding to the
passage of the blood. It appears, that although obstruc-
tion be not the exciting cause of this disease, it is that
which directs the course of it when produced; for, it is
our opinion, it will invariably be found to proceed in
that direction in which the vein is blocked up. Let us
see how this will apply to the cases before us, and, first
of all, take a view of what happens in the human arm un-
der these circumstances ? It is either from the basilic,
or cephalic vein, (two superficial venous trunks at the
bend of the elbow,) that surgeons draw blood; which
veins freely communicate with others, particularly the
deep-seated, just below the part commonly punctured :
in the event, therefore, of its canal, near the orifice, be-
ing obstructed, the vein will not be choked up below, in
consequence of the free anastomosis existing between it
and the contiguous trunks ; in which the unimpeded cir-
culation will preserve a continual flow of blood up to the
obliterated part. But above the orifice no vessels of
communication are found, nor can the blood take a retro-
gade course from the axilla; consequently, there is no-
thing to prevent that portion of it—that contained in the
upper part of the vein, from forming a clot. From the
human arm let us advert to the horse's neck. It is from
the jugular vein (the internal jugular of the human sub-
ject) that we extract blood commonly in the horse ; a
Ve'n of large size, and the only one, with the exception of
the vertebral, which returns the blood from the head and
neck : the horse has no external jugular vein, If, then,
-ocr page 139-
104                        On Wounds of Veins.
this vein be obliterated at the part we bleed, whether is
the upper or the lower portion of it more liable to ob-
struction ?—to the formation of a coagulum ? The lower
part will not, for, having once emptied itself, (and this it
will do probably even by gravitation,) no fresh supply of
blood can be sent to it: but the upper, on the contrary,
being full, must remain so ; there being no communicat-
ing channels by which the blood can be carried off.
Here, then, we have an exception to the principle laid
down by surgeons, relative to this accident: viz. that ob-
literation is always found next to the heart.
Knowing
that the same cause, under the same circumstances, will al-
ways produce the same effect, we would resolve this ap-
parent anomaly in the laws of the animal economy, by
saying, the same cause is operating under different cir-
cumstances.
Subsequent inquiry and experiment have fully borne us
out in this solution of a mystery, apparently the more ab-
struse the more it was investigated by the laws of pa-
thology ; for we are ready to confess, that our theory was
framed before our hands were busied in experiment. It
naturally suggested itself, that, if our explanation was
correct, other veins similar in their distribution and com-
munication to the cephalic or basilic of the human sub-
ject, when inflamed, would swell towards the heart. Re-
ference to our own cases proved the fact, and subsequent
inquiries among our friends have corroborated it: both
the saphena and plate veins of the horse, when inflamed,
tumefy upwards; and the reasons are obvious—they
need not repetition*.
» The rarity of these cases, and the interest this question has
excited in the profession, induced us to follow up our inquiry by
-ocr page 140-
On Wounds of Veins.                        103
The mode of treatment found to be most successful by
veterinary practitioners, is, in some respects, very differ-
ent from what surgeons are in the habit of adopting. If
the tumefaction and induration, in the course of the vein,
have extended to the head, a blister is by far the best ap-
plication, without any regard to fomentations, evaporating
lotions, &c. which are only of use in the more incipient
stages. At the same time, you should produce a slough,
and excite the adhesive action in the vein, by the intro-
duction of some caustic, or of the actual cautery : the lat-
ter is by far the preferable remedy. In the use of it we
avoid all force—the mere searing of the sides of the
wound is all that is required; our objects being to pro-
the still less fallacious test of experiment. It was proposed, that
these and other veins should be inflamed by irritation—in fact, that'
they should be placed, as nearly as possible, under the same circum-
stances as the jugular, when so affected from the cut of the phleme.
We found it somewhat difficult to induce a suppurative condition
of these veins, though we employed for the purpose rusty lancets,
escharotics of various kinds, ligatures, and frequert separation and
friction of the external wound; but, perhaps, some of these means
in another case, (for we have not had an opportunity of repeating
our experiments) might succeed. An intimate friend of ours,
Mr. Cherry, Veterinary Surgeon at Clapham, to whom we had
communicated our ideas on this subject, made several attempts to
inflame the inner tunic of veins by passing pack-threads through
them ; but in no one instance did he succeed—the ligatures, on
the fifth day, were ulcerating their way out, and the interior of the
veins presented no change but a very slight thickening of the lin-
ing membrane : there was no blush whatever perceptible. The
results of these experiments, which, we must confess, were by no
means so satisfactory as we could wish, favored our theory: we
would rather that others should pursue some such tract of investi-
gation however, than hastily receive that which is still matter of
debate.
-ocr page 141-
106                         On Wounds of Veins.
cure a free opening, and a discharge of healthy pus. The
introduction of the cautery, without the application of a
previous or accompanying blister, we have frequently ob-
served to be followed by aggravation of the disease—ar-r
resting the discharge, and thereby considerably augmenting
the tumefaction : we, therefore, seldom or never separate
the cautery from the blister, though the latter may, in
course,often be made use of without the iron. Could weex-
tract blood from the part itself, much benefit, doubtless-
ly, would ensue ; but it is rarely necessary to draw it from
the system, unless the. constitutional irritation run high.
Purgatives in full doses are always proper; and the sub-
stitution of bran for corn is a good regimen. There is
one circumstance regarding the treatment of inflamed
necks, which is not held in proper estimation by the ma-
jority of practitioners; and that is, the position and motion
of the head and neck : by keeping the head constantly ele-
vated, and as immoveable as is compatible with the ha^
bits of the animal, we contribute much towards the abate-
ment of the existing inflammation.
A
-ocr page 142-
LECTURE VII.
On the Absorbents.
There is a vascular system in an animal body, which,
from a knowledge of its being employed in absorbing, or
taking up substances, anatomists have called the absorb-
ent:
it is altogether distinct from the arterial and venous
systems, though it differs from them, as we shall hereaf-
ter learn, more in regard to its economy than its struc-
ture. The absorbent vessels are, comparatively speaks
ing, of late discovery; if we take into our calculation
their general distribution, and extensive use in the animal
constitution.
These vessels were formerly supposed to be of two
different kinds; hence they received the names of lac-
teals
and lymphatics: appellations that have not been laid
aside, though more recent experiments have shown, that
there exists no real distinction between them, either in
relation to structure, or function. The lacteals were first
discovered. They were seen, first of all, upon the sur-r
face of the viscera of the abdomen, in animals opened
soon after a full meal, containing a fluid similar to milk
111 Us appearance : a circumstance implied in their name.
Not long after, others of a similar description were found
-ocr page 143-
108                          On the Absorbents.
in various parts of the body ; which, from being filled
with a thin, transparent, watery fluid —lymph, received
the name of lymphatics. These vessels are now divided,
according to their relative situation, into superficial and
deep-seated absorbents : the former are plentifully distri-
buted under the skin, and pierce it in prodigious num-
bers ; the latter are commonly found accompanying the
principal blood-vessels.
The absorbents have but one principal trunk, called
the thoracic duct; which takes its course along the in-r
ferior part of the spine, within the cavity of the thorax,
and terminates in the left jugular vein, near its junction
with the axillary : by it, all the absorbed fluids are re-
ceived, and poured into the circulating mass.
The absorbents, generally speakiug, run in company
with the principal veins, according as they are superfi-
cially or deeply placed ; though, unlike them, they take a
singularly tortuous course : if, therefore, we wish to find
these tubes for the purpose of injecting them, we ought
always to be guided in our search by the situation of the
venous trunks. Hence, we know, in farcy, (a disease of
the superficial absorbents,) that buds are commonly per-
ceived upon the inside of the thighs, and may be traced
in the direction of the vein from which we bleed. In
their passage, the branches conjoin their canals, so as to
form a set of tubes, less numerous, but of greater indi-
vidual diameter; whose united area grows smaller as we
approach the thoracic duct: by which construction, the
course of the contained fluid is much accelerated. These
vessels do not ramify alike in all parts; in some, they ex-
hibit an arborescent appearance : e.g. the ramifications
of the lacteals within the folds of the mesentery, much
resemble the branches of a tree; in others, they form a
-ocr page 144-
On the Absorbents.                         109
sort of network in their distribution: e.g. upon the sur-
faces of the lungs and liver.
Like the blood-vessels, the absorbents anastomose in
every part of the body ; in consequence of which, the pas-
sage of fluids through them is much facilitated, and all
obstructions rendered harmless so long as any of the
communicating branches remain pervious. Indeed, so
provident has Nature been in regard to this principle of
anastomosis, that an obliteration of the thoracic duct it-
self, would not necessarily prove destructive to life; for
Mr. Cruikshank has demonstrated a communication
between the lacteals and lymphatics, by which the chyle
might still be conveyed into the circulating mass; Ac-
cording to this writer, anastomosis takes place not only
between the smaller branches, but between the larger
trunks, and even the glands themselves.
In all animals, the structure of which has been ex-
amined, we believe that absorbents exist; they are found,
however, in greater abundance in some parts of the body,
of the same animal, than in others : this appears to be the
case in the mesentery, lungs, and lker ; while none have
hitherto been discovered in the brain, though, from what
we know of the composition and economy of that organ,
\ve have no reason to doubt their presence there. If we
believe that a fluid is continually poured into the lateral
ventricles, we must admit that absorbents exist in order to
prevent its accumulation: an effect never met with in
health, though it occasionally happens in disease. Mr.
CrtjiKshank, who has bestowed much pains in the com-
pilation of his work on the Anatomy of the Absorbing Ves-
sels of the Human Body,
says, that " the lacteals are three
*f not four times more numerous than the arteries and
Veins," and, that "in the extremities of the human body,
-ocr page 145-
On the Absorbents.
no
the superficial lymphatics are vastly more numerous than
the cutaneous veins—fourteen trunks frequently accom-
panying one cutaneous vein:" and further, that "the
deep-seated lymphatics are at least double the number of
the arteries they attend."
The absorbents arise from five different sources. First;
they proceed from the interior of the villous coat of the
intestines. To be satisfied of this mode of origin, we
have only to kill an animal about three or four hours after
a copious meal, and lay open the abdominal cavity; and
we shall perceive the mesentery streaked with numerous
white lines, which may be traced into as many small white
specks upon the inner surface of the intestines; which
specks, or spots, are the mouths of so many lacteals. If
the parts are dissected, and steeped in spirits of wine, the
chyle in the lacteals becomes inspissated: so that, in this
way, you may make a very elegant preparation of them,
and examine them with much more facility. From the
microscopical observations of Mr. Cruikshank, and
others, it appears that these vessels arise by small orifices
belonging to short radiated branches; and that many of
these unite to form one absorbent trunk—one lacteal.
The second mode of origin is that from the interstices
of the cellular membrane, or rather, from the interior of
its cells: by throwing quicksilver into them, in some
parts, the absorbents become immediately injected—as is
the case when any is poured between the membranous
envelopes of the testicle. In addition to this proof,
however, we infer their existence in the cellular mem-
brane from a well known fact, which could not otherwise
be satisfactorily explained. We mentioned, when on the
arteries, that many of their minute branches were called
exhalents, in consequence of emitting, in the form of
-ocr page 146-
On the Absorbents.
Ill
vapour, an aqueous fluid into the cellular membrane •
and that, although this secretion was constantly going on,
there was no accumulation of it, excepting under some
circumstances connected with disease. It is evident,
therefore, that there must be a proportionate absorp-
tion ; and we know of no other means by which such a pro-
cess can be effected, but by the mouths of these minute
vessels.
The third source from which they spring, is the large
cavities of the body : viz. those of the belly, head, and
chest: in them, there is also an exhalation from the ex-
tremities of the arteries, which requires to be continually
imbibed by those of the absorbents. Fluids injected into
the bellies of living animals, are soon afterwards im-
bibed by these vessels, in which alone they have always
been detected: Mr. Chuikshank says, that "of six
pints of warm water (thrown into the belly of a dog) after
six hours not more than four ounces remained."
The fourth place of origin is from the surface of the
skin ; of which we have demonstration from injection, as
well as ample proof deduced from various phenomena
exhibited in the economy of this part. If an injecting
pipe be inserted under the cuticle, or scarf skin, of the
scrotum, and the quicksilver be allowed to extravasate,
numbers of these vessels will be filled : independently of
this however, were it not for the presence of absorbents,
how could we explain the operation of mercurial ointment;
which, we know, when rubbed upon the skin of the hu-
man subject, will produce the same effects as if it had
been taken into the stomach ? We shall have occasion to
illustrate this more fully, iu treating of the physiology of
these vessels.
The fifth and last origin, is that from the interior of an
-ocr page 147-
On the Absorbents.
i 12
excretory duct*: where they appear to have been distri-
buted for the purpose of preventing the duct from burst-
ing, by relieving the distention it is occasionally s.ubject
to, from some obstruction in its canal. When this hap-
pens in the hepatic duct, bile is absorbed into the system,
giving that yellowness to many parts of the body, seen in
the disease called jaundice ; for it has been found by ex-
periment, that if the duct of the liver be tied, the absor-
bents of that organ become shortly afterwards filled with
bile ; and any pressure on it, or other cause of obstruc-
tion, would of course have a similar effect.
Some make mention of a sixth origin of the absor-
bents:—from the extremities of arteries; which they
instance by saying, that if you throw quicksilver into the
spermatic artery, it will fill the absorbents of the cord :
this is certainly true—we have preparations demonstra-
tive of it, but it is an event most probably referable to
extravasation of the metalic injection ; for, as we have
just stated, if mercury be simply thrown under the mem-
branous coverings of the testicle, (without seeking for
vessels underneath,) the absorbents will be as completely
injected, as if we had inserted the pipe into one of their
ramifications. After all, however, that has been said
about the different modes of origin of the lymphatics, we
are compelled to acknowledge, that their orifices have
never been seen : in consequence of their extreme minute-
ness, as well as from the transparency of the fluid they
contain, they have hitherto eluded the observation of
our most diligent anatomists—they are supposed to be
similar to those of the lacteals.
* A tube, by means of which, the secretion of a gland is convey-
ed into the organ destined for its reception,
-ocr page 148-
On the Absorbents.                           113
The principal termination of these vessels is in the tho-
racic duct; which, we before mentioned, was to be con-
sidered as the trunk of the absorbent system. It is placed
beneath the spine, commencing in its lumbar region,
where it is formed by the junction of three large absor-
bent vessels:—one of which is the main trunk of the lac-
teals; the others are branches of considerable size, form-
ed by the union of absorbents coming from either of the
hind extremities. The thoracic duct at its origin is
somewhat larger than elsewhere, which dilated portion of
it has received the name of receptaculum chyli: in its
course along the spine, it is first placed to the right, and
then to the left side of the aorta, and ultimately ends in
the left jugular vein, near its junction with the axillary.
There is on the opposite side of the neck an absorbent
trunk, of comparatively small size however, in which the
absorbents from the right side of the head and neck, and
from the off fore extremity terminate: this empties itself
into the right jugular vein.
It is thought, that an absorbent has three coats :—an
elastic, a muscular, and an internal or membranous; but
these tunics are so extremely thin and pellucid that they
cannot be separately demonstrated. If you distend one
of these vessels with quicksilver, and then make an open-
ing into it, the metallic injection will be ejected with such
a degree of force as to lead you to suspect that the vessel
must have contracted, or it could not so suddenly have
emptied itself, and recovered its original calibre : and it
ls evident, that to elasticity alone can be ascribed such a
contractile power in the dead body.
-Anatomists, in general, believe that these vessels have
a muscular coat, though they rather infer its existence
from the well-known functions that they perform, than
1
-ocr page 149-
114                            On the Absorbents.
from any proofs of its presence afforded by dissection :
some however assert? that they have seen fibres, closely
resembling muscular, in the thoracic duct of the horse,
which vessel, they tell us, possesses contractile powers;
and if this be true, we may fairly conclude, that its nume-
rous ramifications are similar to it; though their minute-
ness and the semi-pellucid nature of their coats, render it
perhaps impossible for us to detect any distinct arrange-
ment of fibres. One of the best arguments in favor of
their muscularity, is the degree of irritability they are said
to shew on the application of stimuli to them : e.g. if an
absorbent be touched, either in the living or recently dead
animal, with any stimulant, it will be seen to contract on
its contents, in the same way that muscular fibres are
known to do; or if a lacteal be emptied by. puncturing
it, or by making pressure upon it, it will be immediately
filled again ; and, to all appearances, from the impulsion
of fluid into it by the communicating ramifications.
Like arteries and veins, the absorbents possess an in-
ternal coat, but it appears to be one of a much denser and
stronger texture ; for, in injecting these vessels, you will
find that a single trunk will of itself support a very heavy
column of quicksilver, and that the vessel will still contain
the metal, though the exterior coat be cut through.
Valves are exceedingly numerous in this system of ves-
sels ; though they are very irregularly placed, being found
in some absorbents in great numbers, while in others they
are comparatively scarce. We observed, when on the
veins, that, according to the opinion of Mr. Hunter, the
valves in them were not to be regarded as continuations
of the lining membrane, and Mr. Cruikshank, we
find, thinks, that they differ in structure from it in the ab-
sorbents : he says, in allusion to this part of our subject,
«
-ocr page 150-
On the Absorbents.                            115
"It never struck me as a good argument, that because
one substance was seemingly continued from, or went into
another, it was therefore the same kind of substance."
These valves are situated in pairs, and we not unfrequently
find three or even four pairs within the space of an inch :
there are no absorbents without them. If you examine
a distended absorbent, you perceive that it is knotty, or
irregular in its canal: this appearance is owing to the
valves, which are placed in pairs at every joint, or coi>
traded part of the vessel. The small abscesses in farcy
assume that remarkable appearance called buds, in conse-
quence of the valves intercepting the diseased portions of
these tubes*.
The valves perform the same office in absorbents as
they do in veins : viz. that of preventing any retrogade
motion of the circulating fluids, and, it is thought, that of
sustaining in part the weight of their column, by frequently
intercepting it. In support of this hypothesis, Mr. Cruik-
shank says, "that the thoracic duct in horses has few
valves, compared with the same duct in monkeys, where
it is quite crowded with them :" but by subsequent re-
searches into comparative anatomy, he was by no means
well borne out in this opinion.
Absorbents have their vasa vasorum. The above wri-
ter mentions, that he has injected in quadrupeds the ar-
teries on the coats of the lymphatic vessels, and seen them
ramifying very elegantly through their substance ; and he
goes on to say, " these arteries must have their corres-
ponding veins, and I can have no doubt of their being at-
* The valves do not appear to be diseased in farcy, when the
lining membrane presents a surface of ulceration: another, and to
us a conclusive proof, of the difference of texture of these parts.
I 2
-ocr page 151-
On the Absorbent Glands.
116
tended with lymphatics." Without taking the trouble,
however, of attempting to inject these vessels, we caii
frequently demonstrate their vascularity, when they are
in a state of disease—as in the inflammatory stage of far-
cy prior to suppuration : hence we find, that they in no
wise differ in this respect from arteries and veins.
Nerves also, in all probability, enter into the texture of
an absorbent; for we are informed by the same writer,
that the thoracic duct is surrounded by nervous filaments.
It would appear, however, from some experiments relat-
ing to absorption, that these vessels can perform their
action without the nervous energy.
On the Absorbent Glands.
Small glandular looking bodies are found in various
parts of the body,commonlylooked upon as appendages to
this class of vessels—as forming a part of the absorbent sys-
tem, with which they are so generally connected. Though
these organs are called glands, we have no reason for con-
sidering them as such : indeed, much doubt is still enter-
tained by anatomists as to the real nature and use of them.
They are commonly of an oval figure ; and vary in size,
from the bulk of a small pea to that of a walnut. There
are very many of these glands in the mesentery, through
which the lacteals are passing : also in the loins, upon
the inside of the thighs, in the breast, and under the jaws,
every practitioner knows, that the kernels, as they are
called, in farcy, are occasionally found. These glands
are for the most part of a reddish color in their substance ;
though, in exception to this, there are a few at the roots
of the lungs which put on a dark blue, and sometimes
black appearance. From the number of these small bo-
dies in various parts, the circulation in the absorbent sys-
-ocr page 152-
On the Absorbent Glands.
117
tem is not likely to be much impeded by obstruction of
one, or even a cluster of them ; for, as many have no
immediate communication, morbific virus commonly af-
fects but a limited number of them.
The lymphatic glands are enveloped in separate cap-
sules, loosely connected to the surrounding parts by cel-
lular membrane. We do not know precisely in what
the minute structure of a lymphatic gland consists ; though
the opinion of its being cellular—i. e. made up of small
cavities, or cells, seems to be the best received among
modern anatomists. Mr. Cruikshank observes, that
" In quadrupeds it is very easy to demonstrate the cellu-
lar structure : both in asses and horses, the glands on the
mesentery are most distinctly cellular:" many of these
cells communicate one with another. An absorbent, prior
to piercing the substance of one of them, divides itself
into several branches, called vasa inferentia, from the cir-
cumstance of their dipping into, and terminating in, these
cells, into which they are supposed to deposit their con-
tents. Other similar ramifications, arising from the op-
posite sides of them, by which the fluids are again taken
up, have received the name of vasa efferentia. To these,
by some, a third set has been added under the appella-
tion of vasa circuita, which pass over the exterior of the
gland without having any communication with its cells:
these vessels (if such exist) appear to be useful in giving
passage to the fluids into other glands, in case of any ob-
struction in that over which they ramify.
The lymphatic glands are very vascular—they possess
numerous arteries with corresponding veins, which latter
vessels are without valves*. It appears that their nerves
are of very small size, and but few in number.
Vide Crwxkshank, on the Absorbing Vessels of the Human "Body.
-ocr page 153-
LECTURE VIII.
On the Physiology of the Absorbents.
Absorption was formerly supposed to be a pro-
cess carried on by the veins, to which the absorbents them-
selves were regarded as appendages; an opinion that
maintained celebrity until the time of Mr. John Hun-
ter : he it was that first proved, by many ingenious and
well-conducted experiments, that this function was prin-
cipally, if not entirely, performed by the absorbent system.
He first demonstrated, that the lacteals, and not the me-
senteric veins, absorbed and conveyed certain fluids from
the cavity of the intestines into the circulation. By inject-
ing milk, and other fluids colored and scented with vari-
ous substances, into the bowels of an animal, he found
that the lacteals were uniformly filled with them ; while,
on the other hand, the mesenteric veins either remained
empty, if the circulation was stopped in them by tying
the mesenteric arteries, or contained blood, when no liga-
tures were used, which exhibited no tests whatever of
any admixture of the injected fluids.
With regard to the economy of the lymphatics, although
we cannot demonstrate their functions with equal certi-
tude by experiment, we may infer it to be similar to that
J
-ocr page 154-
Oh the Physiology of the Absorbents.            119
of the lacteals, from the many phenomena relative to the
healthy and morbid actions of the body, which we could
on no other principle than that of a process of absorp-
tion, satisfactorily explain. We said, in the foregoing
lecture, that the lymphatics arose from every part of the
body, and that their trunks were more numerous than those
of the arteries and veins taken collectively ; we have no
right, therefore, to argue from their minuteness, their in-
capability of performing the functions ascribed to them.
Mr. Hunter, to whose labors we are indebted for
much information on this subject, was first induced to be-
lieve that absorption was performed by the lymphatic
vessels, from an attentive observance of different facts
connected with disease, which he found inexplicable on
the, then, more current opinion of the veins being the
channels of absorption. This acute physiologist first re-
marked, that poisons, said to be absorbed and conveyed
into the circulating medium by the veins, did not take the
course of those vessels, but, on the contrary, might be
traced along that of the lymphatics. The venereal virus,
for example, which is commonly absorbed from the glans
penis, produces effects in the groin, by creating irritation
in the absorbent glands there ; and they, iii consequence,
swell, become hard and painful, and form, what is called,
a buboe. Now, this is not the course of the veins, but
of the absorbents ; which indeed may frequently in this
disease be felt, or even seen, running along the dorsum
penis into the glands in the groin : and that these vessels
are not veins, but absorbents, may be proved by the fact,
lhat if the swollen glands be extirpated before the poi-
son has passed beyond them, the disease will be as effec-
tually eradicated, as if the specific itself had been admi-
nistered. Again, if a horse be innoculated with glandered
-ocr page 155-
120           On the Physiology of the Absorbents.
matter in the nose, in the course of three or four days an
ulcer will be seen at the place of innoculation, accompa-
nied with one or more small tumors under the jaw : in this
instance, although the disease appears to take the course
of the superficial veins, dissection has demonstrated that
those vessels are in a state of health, and that it is the lym-
phatics alone, with the glands in which they terminate, that
are affected. From a consideration of the above facts
then, it appears undeniable, that these vessels are, as their
name imports, the channels of absorption ; and that no
such function can be assigned to the veins, as far, at least,
as the actual inspection of parts warrants such an asser-
tion : still it is light to remark, that there are writers of
the present day who think that the veins participate in
this process.
In some instances, the virus conveyed by these vessels
and poured into the blood, contaminates the whole circu-
lating mass: the experiment we related when on the
blood, relative to transfusion, seems to put this opinion
out of the reach of doubt.
The absorbents not only possess a power of imbibing
fluids, but even of taking up the hardest solids themselves,
of which we see daily examples in the disappearance of
bony tumors: exostoses, in the form of splints, spavins,
and ringbones, are removed, on this principle, by the effect
of blisters; and strangles we have all seen, prior to sup-
puration, give way to absorption. But another and
more striking instance, is the removal of extravasated
blood : if a man gets a black eye, which is nothing more
than an effusion of blood under the skin in consequence
of a rupture of some small blood-vessels, we know that
the swelling will gradually diminish, and slowly lose its
black or blue tinge, until, at length, the part resumes
-ocr page 156-
On the Fhyuolooy of the Absorbents.           121
{and it does so by a process of absorption) its natural size
and appearance. Parts of the body that have lost their
vitality, are detached and thrown off in the form of sloughs
by an act of absorption : these vessels erode, as it were,
such particles of living matter as are in immediate contact
with the dead, and the latter is ultimately cast off by gra-
nulations, which spring up from the living surface under_
neath. It has been observed, that new or recently form-
ed parts are absorbed with more readiness than old.
On no other principle than that of absorption, can we
explain the well-known action of mercurial ointment rub-
bed upon the surface of the human skin ; the constitu-
tional effects of which are nearly the same as if so much
had been actually introduced into the stomach; though, in
the one case, it is carried into the system by the lympha-
tics; in the other, by the lacteals. We have made some
trials of mercurial inunction on the skin of the horse,
where it is uncovered by hair, but we have never been
able to produce salivation, without the aid of the internal
exhibition of some preparation of mercury; and calomel
is the most effectual for this purpose. Tartar emetic
also, a very small quantity of which will vomit a man
when taken, has a similar effect on him by inunction.
Physiologists had no sooner ascertained that the process
of absorption was the function of these vessels, than other
inquiries were instituted to learn by what means solid
matters were removed and conveyed by them into the
circulation. Various conjectures have been formed on
this curious process : some imagining that they had teeth,
for the purpose of comminuting or breaking down
the solids; while others thought that capillary attrac-
tion, or suction, was the power by which this extra-
ordinary function was performed. Others, with more
-ocr page 157-
122           On the Physiology of tlie Absorbents.
plausibility, offer as their opinion, that all solid matters
are dissolved, or reduced to a state of fluid, prior to the
absorption of them : bone, for example, say they, prior
to its being absorbed, is dissolved by the phosphoric acid
contained in the blood; this opinion however, like the
preceding, is purely hypothetical, nor indeed do we at
present know how the process is effectuated.
It would appear, from some facts, that the orifices of
these vessels possessed something like the power of selec-
tion: e.g. poisons, generally speaking, will not be taken
up by them, unless the surface of the skin be abraded.
You may besmear any part of the skin with the matter of
farcy and glanders without infecting the animal; and we
have several times rubbed it upon the pituitary membrane
without contagion : but if you produce the least abrasion
of the surface, the absorbents almost invariably imbibe tin
virus. .Again, the lacteals have other fluids than chyle pre-
sented to their mouths ; both bile and pancreatic juice
flow over their orifices, and yet these fluids are never de-
tected in their canals.
It is now well known, that absorbent vessels will take
up gases in contact with the surface of the body, though
doubt still exists as to the absorption of fluids : hence
mercurial fumigation in the human subject causes saliva-
tion, and yet it appears that mercury in a state of solution
in water will not produce it. A similar result has been
observed from some experiments made with spirits of tur-
pentine : if the hand be immersed in this fluid, and care
be taken not to inhale its fumes, no absorption of it ap-
pears to happen; but let a person inhale the vapors of it,
and its presence can be demonstrated in the urine, with as
much certainty as if it had been introduced into the sys-
tem through the medium of the alimentary canal. It
-ocr page 158-
On the Physiology of the Absorbents.           \'2S
still remains to be decided, and it is a question replete
with interest to the veterinary surgeon, whether we have
any infectious disease in the horse—any that may be com-
municated by the inhalation and absorption of noxious
vapors : we know, that glanders and farcy are contagious,
but whether we can pronounce them to be communicable
by the breath, or susceptible of being engendered by a
polluted atmosphere, seems as yet undetermined: at
least, we believe, that we shall find advocates both pro
and contra.
With a view of ascertaining whether nutriment could
be supplied to the system by means of the absorbent
powers of the skin, emaciated persons, labouring under
disease of the organs of deglutition, having been first ac-
curately weighed, have been put into baths consisting of
nutritious fluids of various kinds, such as milk and soup :
these patients however derived no benefit from the ex-
periment, nor did they receive any augmentation of weight
but what was satisfactorily accounted for without any re-
ference to absorption. Under such circumstances, how-
ever, although the lymphatic vessels refuse to take up
nutriment presented to them in the form of extraneous
matter, they are actually nourishing the body—by convey-
ing its adeps into the blood : hence the cause of the ex-
treme emaciation of these people is explained, as well as
the sustenance which the body appears to receive (for it
essentially does not) from the very sparing quantity of the
ingesta. And now that we know why extreme pain
long continued, or any other cause of defective appetite,
should throw an animal so rapidly out of condition, and
leave him so debilitated, we shall not feel surprised at a
horse, who has simply picked up a nail in the foot, wast-
ing away in flesh, however fat he might previously have
-ocr page 159-
124          On the Physiology of the Absorbents.
been ; for the pain caused by this accident is often so ex-
cruciating, that not only does all desire for food leave him,
but even death itself occasionally ensues.
The matter absorbed, having once entered the orifices
of these tubes, is propelled, it is supposed, by the action
of the muscular tunic, through their various ramifications
into the receptaculum chyli, where a commixture of the
chyle, from the lacteals, and lymph, from the lymphatics,
takes place; which fluids are, in union, poured by the
thoracic duct into the left jugular vein, to be circulated
with the general mass of blood. It is not improbable,
that the passage of the absorbed fluids is somewhat assist-
ed by the occasional pressure to which these vessels are
subjected, in almost all parts of the body.
The lymphatics, like the arteries, are constantly in ac-
tion, but their function, as we have seen, is very differ-
ent ; for they are removing the various materials of which
the body is composed, and re-conveying them into the
blood, from which they were originally formed: hence
the latter vessels have, and not inaptly, been regarded as
a set of workmen employed in depositing new materials,
while the absorbents have been compared to others
who are clearing away the rubbish and worn-out parts,
and carrying them back to the general elaboratory; where
they are either decompounded, and in part again ren-
dered fit to serve some purpose in the animal economy,
or cast off altogether as excrementitious. This change
is continually, and almost imperceptibly, going on in
every animal body; but the processes of deposition and
absorption do not bear the same relative ratio at all ages :
in the young animal, for instance, in which the body has
not attained its full growth, the arteries deposit more
than the absorbents remove, hence the increase of every
A
-ocr page 160-
On the Physiology of the Absorbents.          125
part is accounted for ; but at the time of puberty, when
an animal has arrived at perfection of growth, these two
orders of vessels are nicely balancing their operations ;
while in old age that of the absorbents predominates,
and the animal experiences a gradual decay of the pow-
ers of his constitution. We are to consider the lympha-
tics, therefore, as the means of removing that which is
superfluous or noxious, and the lacteals, as the channels
for the conveyance of nutriment; at the same time, how-
ever, that these vessels serve such important ends in the
system, they sometimes prove, as we shall hereafter ex-
plain, the vehicle of its infection, and even, now and then,
of its destruction.
We have various means of exciting the action of the
absorbents. Many medicines are employed for this pur-
pose ; some of which appear to possess a specific ac-
tion over them, while others operate through the medium
of the excretories of the system. In the human subject,
one of the most powerful is mercury, employed in various
forms : to such an alarming extent, indeed, may this re-
medy be carried, that the gums will uicerate, or be
absorbed, and the teeth loose and drop out, from its in-
fluence : and even the jaw-bone itself has been known
to become carious during its improper administration.
Hence, one of the most ready means surgeons possess of
dispersing a tumor, is the inunction of it with mercurial
ointment; and in this case, the medicine has little or no
local effect, but produces absorbtion principally from its
influence on the absorbent system.
Strong diuretic and purgative medicines increase the
action of the absorbents ; for under their operation, it
appears that these vessels are excited to do more than
ordinarily, in order to repair the losses sustained by the
-ocr page 161-
126           On the Physiology of the Absorbents.
constitution during the continuance of such evacuations :
hence it is, that these are among the best remedies we
can employ in dropsical affections. How often.do we
see swelling of the legs removed by a dose of physic, or
the use of a few diuretic balls; and a similar effect is well
observed in watery farcy, in which strong doses of aloes
and calomel, combined with diuretics, are the most ready
and efficacious means we can adopt to reduce that enor-
mous tumefaction of the limbs, so alarming a symptom in
this disease.
Exercise, while it accelerates and strengthens the cir-
culation of the blood, proves a stimulus to the absorbent
vessels; of which we have ample proof in the diseases
above mentioned, not to notice the numberless instances
we have of it, more particularly in the autumnal season
of the year, in horses whose legs are filled in the morn-
ing, but become fine as soon as they have been walked
out for a short time.
Friction also tends to promote absorbtion. Merely
hand-rubbing the legs will frequently reduce common
dropsical accumulations in them; indeed, it seems to
have the same effect as gentle exercise has—accelerat-
ing the circulation, facilitating the return of blood
through the veins, and, at the same time, increasing the
action of the absorbents. In the human subject, mer-
cury, but a short time ago, was almost always introduced
into the system, for the cure of the venereal disease,
through the medium of the absorbents of the skin: in
this case, friction is necessary to impel the ointment
through the pores of the cuticle, at the same time that it
rouses these vessels into action. In some instances, pres-
sure alone will effect a diminution in the size of a swollen
part: hence, the constant application of a tight bandage
-ocr page 162-
On the Physiology of the Absorbents.           127
to an enlarged leg, will often reduce it; and with the
same view, some old practitioners recommend that sheet-
lead be bound tightly upon the leg for the removal of
splints.
In the human subject, digitalis, when internally admi-
nistered, both from its nauseant and diuretic effects,
proves a stimulus to these vessels: we are not prepared
to say whether its use be attended with similar good ef-
fects in the horse.
Absorption is augmented by the application of stimu-
lants to the surface of the skin: this fact is best shown
in the use of blisters to those kinds of tumors we are
not able to discuss by other means : need we mention
windgalls, and a variety of exostoses. Now let it be
observed here, that the first effect of a blister is to excite
the action of the arteries, so that the swollen part is ren-
dered absolutely larger than it was before ; but its ulti-
mate one is to provoke that of the absorbents, which im-
mediately set about the removal of the swelling.
Heat, whether it be combined with moisture or not,
will cause absorption; though its modus operandi ap-
pears to be different according to the means which we
employ in its application, as fomentation and the actual
cautery plainly show us.
Physiologists are not agreed as to the use of the ab-
sorbent glands in the animal economy. It has been sup-
posed, that the lymph, in passing through them, expe-
riences a more perfect union, or combination of its ele-
ments, or, in other words, undergoes a process of assimi-
lation, or animalization, and that this renders it fit for
commixture with the general mass* of blood : the fact of
the venereal virus in the human subject, although conta-
-ocr page 163-
128              On the Diseases of the Absorbents.
gious if taken from a chancre, being quite innocuous
when obtained from an ulcer in the throat, is advanced in
support of this hypothesis; it may be urged, however,
against it, that there are some substances which do not
appear to undergo any change in their passage into the
system.
On the Diseases of the Absorbents.
The absorbent vessels, and their glands, are liable to
become inflamed from two causes:—from simple ir-
ritation, and from the external application of various
poisons. In horses, they are seldom diseased from the
first cause, though we have seen them thus affected : if,
for example, any irritant of an active nature, be applied
to the membrane lining the nose, so as to cause some
corrosion of its surface, you will have corded absorbents
and tumefied submaxillary glands, the effects of ulcera-
tion in the nostrils, putting on altogether the appear-
ance of glanders ; but differing essentially from that dis-
ease, inasmuch as it will soon subside from the use of
common depletive remedies. In the human subject, this
kind of irritation is very common, in consequence of these
vessels being much more susceptible of injury than in
horses : merely tying the shoe too tight, will not very un-
frequently disease the whole limb, by inflaming the ab-
sorbents ; which appear like so many red lines upon the
surface of the skin, taking their direction to the groin,
where the absorbent glands, called the inguinal, are also
commonly enlarged. In men, they inflame less frequently
from the absorption of poison than from common irrita-
tion ;—not so in horses; in them, the introduction of poi-
sonous matter into the system,isthe chief source of disease
-ocr page 164-
On the Diseases of the Absorbents.             130
of the absorbents, and their glands; of which we have,
but too frequently, fatal instances in the destructive ra-
vages of glanders and farcy.
We might, a priori, have supposed, that these vessels
were diseased, at least in function, in all cases of dropsi-
cal accumulation ; otherwise, the fluid would have been
taken up by them in the same ratio in which it was effused
by the arteries; far from being owing to defective ab-
sorption however, these vessels are actually enlarged in
their calibre under such circumstances, and have, in
reality, been performing more than they ordinarily do.
The chief cause of this disease appears to be increased
action, combined with diminished power in the circulat-
ing agents—the heart and arteries; by which more blood
is thrown into the capillaries than can be returned by the
veins. Bleeding, therefore, in such affections, is generally
a good practice, as it tends to abate the quickness of the
pulse, at the same time that we are making use of the
remedies before enumerated, to rouse the absorbents into
still greater action. But in farcy, which is a disease of the
absorbents themselves, the dropsy commonly attendant,
is probably owing to defective absorption, in consequence
of obstruction in these tubes.
The absorbent glands of the mesentery are by no
means unfrequently diseased : indeed so common is this
disease in the ass species, that we meet with it often
in apparent good health. There is an affection of the
same nature to which scrofulous children are very sub-
ject ; in whom it is known to be present during life, by
Preternatural enlargement, tension, and hardness of the
belly^ accompanied with more or less disorder of the
bowels, and marks of general ill health. Here we might
conclude our remarks on this hitherto uninvestigated
K
-ocr page 165-
130             On the Diseases of the Absorbents.
subject; had not an extensive range of practice afforded
us opportunities of deviating from the trodden path of
generalization, and of coming to something determinate
about a disease, with which we have only been made
analogically acquainted.
In almost all the cases we have met with, (and they
have been pretty numerous,) in which dissection has
shown general disease of these parts, loss of condition has
[been a marked and uniform symptom during life, accom-
panied with some perceptible change in the appearance
of the excrement—though this may be only occasional—
and with more or less irregularity in the discharge of it.
These symptoms, which may be said to constitute the first
stage, are succeeded by others not less characteristic of
a disease, that, if it be extensive, and the horse young,
is not unlikely to end in death. Irritation of bowel su-
pervenes, probably giving rise to a dull and heavy pain,
so that the horse lies down during most part of the day,
manifests considerable depression of spirits, loses his ap-
petite, and continues to fall away : about this time his
pulse becomes frequent—we have known it to rise to
100°—his breathing is in some degree quickened, and
other signs of constitutional disturbance are present.
The case is now alar-ming—the practitioner is ignorant of
its ntfture—and
the animal unrelieved, dies in a state of
extreme emaciation. Seeing, then, that this is the com-
mon course of a malady we have not devoted that atten-
tion to which, every one who has his profession at heart
will coincide with us, weought to have done, we shall con-
elude this lecture by admonishing veterinary practitioners
against inattention to diseases denominated chronic; of
which this is one of the most important*.
• These glands, when diseased, are met with in a variety of
-ocr page 166-
LECTURE IX.
On Cellular Membrane.
V^ELLULAR membrane is the general connecting
medium, if not a constituent, of every part of the body.
states. The common appearance is what is called schirrus; but
even this is extremely variable, as to the precise nature of the
change the gland has undergone. Without any attempt to trace the
progress of this and other morbid changes, much less to couple
them with their diagnostic symptoms, which present medical sci-
ence, even in the human subject, does not admit of, we subjoin
descriptions of several specimens of this disease now in our mu-
seum.
No. 2. A cluster of mesenteric glands, having a lobulated appear-
ance, attached by aloose fold of mesentery to the duodenum. Alto-
gether they are about the size of a hen's egg, firm and solid through-
out, and exhibit a yellowish inorganic texture within: all the
glands connected with the small intestines were similarly diseased.
The case was fatal.
3. A mesenteric gland enlarged and schirrous. The change
this has undergone, is of a scrofulous nature: its central part con-
tained a curdly cheesy matter, such as is found in parts so diseased
ln the human subject.
94. Several cancerous mesenteric glands, belonging to the large
■ntestines. They contained considerable collections of curdled pus,
which, by ulceration, had discharged itself into the gut. Death
ensued.
K 2
-ocr page 167-
On Cellular Membrane.
132
By it the coats of arteries and veins are knitted together,
as well as loosely connected to the surrounding parts;
and these vessels, together with almost all other parts,
are found to possess much of it in their ultimate compo-
sition. The various membranes of the body, by mace-
ration, or boiling, may be entirely resolved into cellular
membrane; though it exists in them in so dense and
compact a form, that its general character is much altered:
even bones themselves, by being long steeped in diluted
muriatic acid, may be converted into a soft substance,
which appears to be chiefly cellular membrane ; and we
know, that it unites the minutest jibrilla of muscles, so
as to form fasciculi, and by continued union of them, a
complete muscle.
There are two kinds of cellular membrane in the body:
—one, from its net-like tissue, is called the reticular; the
other, from containing adeps or fat, the adipose. We
shall first speak of the reticular membrane.
The reticular membrane varies somewhat in its quan-
116. Specimens of two schirrous mesenteric glands of very large
size: when taken from the horse, each weighed 14 lbs. Internally
they consist chiefly of schirrous deposit; an unhealthy-looking
pus was discharged from them in some places; and here and there
are depositions of bone. Their peritoneal covering is considerably
thickened, indurated, and altogether altered in texture: it may,
in some parts, be with propriety called cartilaginous. The case
proved fatal.
151. Thickened and tuberculated mesentery, with cancerous
glands. In the subject from which this preparation was taken, the
mesentery and its glands presented a sheet of scrofulous disease.
Some of the glands were in an enlarged and schirrous state; others
contained a curdled and bloody pus; in addition to which the me-
sentery itself was studded with hard, white, solid tubercles. This
case ended in death.
                                                   ^^H
-ocr page 168-
On Cellular Membrane.                      133
tity in different parts of the body: upon the ribs, and
more especially about the breast, it is abundant and loose
in its texture ; but upon the belly, and about the head, it
is dense, and so short, that we can scarcely pinch up the
skin, or insert a rowel, though we effect either with the
utmost facility in the chest, or under the jaw. Al-
though the quantity of this substance depends in some
measure, as we shall hereafter find, on the condition of
the animal, it is always plentiful in parts possessed
of much motion : hence, we find it long and loose in the
scrotum, (where it invests the testicles,) upon the inside
of the elbow and thigh, and under the jaw ; and in the
human body, we always find it thickest—most con-
densed, in parts exposed to pressure, more especially
in the palms and soles.
The reticular membrane is made up of fibres, inter-
woven and disposed in such a manner as to form innu-
merable cells, or small cavities : and this it was, that first
gave rise to the name of cellular membrane. These
cells have a free communication with each other; a fact
demonstrated by occurrences of the most common and
familiar kind : who has ever seen the carcass of a calf
inflated by the butcher, in order to give the veal a fatter
aud whiter aspect, will need no farther proof. There
are many phenomena, however, connected with disease,
which verify the same thing : in emphysema, (a swelling
of the skin from the admission of air through a wound
communicating with the cells of this membrane,) the air
very commonly diffuses itself over the whole body; and a
w°und in the chest, or one at the point of the elbow, is
m°st likely to be attended with this appearance. Again,
in anasarca, (an effusion of water into this substance,) or
m ecchymosis, (an extravastion of blood ;nto it,) the fluids
-ocr page 169-
134                     On Cellular Membrane.
invariably, after a time,occupy the most depending parts :
hence the tumefaction of the legs, breast, and belly, in
the first of these diseases, more than that of any other
parts.
Into the cells of this membrane, during life, is poured
forth a serous fluid, in the form of vapor, by the exhalent
extremities of the arteries ; (which we formerly described
as terminating upon the surfaces of these minute cavities;)
from the evaporation of which, that peculiar odor, so
constantly perceived in flaying an animal recently dead,
is emitted.
The reticular membrane does not put on the same ap-
pearances in all places:—it is, in most structures, opaque,
but there is one part where texture is so extremely
fine and delicate, that it is perfectly transparent: we
mean the eye, in which there is a Cellular bag, called the
tunica v>trea> through which the rays of light pass with-
out the least interception. These cells possess a certain
degree of elasticity: if, for instance, we include a por-
tion of skin between our finger and thumb, it will suddenly
recoil on being liberated, and recover its original situa-
tion ; a circumstance principally attributable to the elas-
tic property of the subjacent cellular membrane.
This membrane is not very vascular : the blood-vessels
found ramifying within it, are chiefly distributed to other
and neighbouring parts; so that, when violent inflamma-
tion is excited in it, sloughs of it not uncommonly take
place ; and this happens when we introduce any caustic
under the skin ; the core which comes out, being chiefly
dead cellular membrane. Absorbents appear to exist in
great numbers in it; for if we but extravasate quicksilver
nntier the skin, in some parts of the body, it will find its
way into many of these vessels. Although tlus part is not
-ocr page 170-
On Cellular Membrane.
135
very sensible in a state of health, it becomes so in dis-
ease : the simple introduction of a probe into the cavity
of an abscess, is a sufficient proof of it; there can be no
doubt, therefore, but it possesses nerves.
The adipose, or fatty membrane differs from the reti-
cular in two material points of structure : first, in its cells
being perfectly circumscribed cavities, i. e. such as have
no communication whatever with each other; and se-
condly, in containing, instead of vapor, fat; which, at the
temperature of the living body, is oil. Knowing this
then, you will at once discover why the adipose membrane
should have entire cells : had they resembled those of the
reticular, what must have been the consequence ? The
oil, or fat, like the water in anasarca, would have gravi-
tated to the most depending parts, and have accumulated
in such prodigious bunches about the legs, that progres-
sion must have become irksome, with great difficulty per-
formed, or altogether impeded: on the contrary, as
the fat is at present disposed, the animal carries it about
with the utmost comparative ease. We have said, that
adeps is met with in the form of oil in the living body ;
and in the human subject, and those animals that feed on
flesh, called carnivorous, it retains much of its oily nature
after death ; but in horses, and other graminivorous ani-
mals, it concretes, and exhibits that appearance we are all
so well acquainted with by the vulgar name of fat.
From exposure to the air fat becomes firm and hard:
though if we break it into pieces, it still shews that it is
every where intersected by pieces of skin or bladder,
which, in fact, are nothing more than the membranous
Cells containing it. About the kidneys, the adeps, which
in fat animals is deposited there in considerable quantities,
assumes a whiter and harder aspect than in other parts,
-ocr page 171-
] 36                      On Cellular Membrane.
for which reason it is commonly called suet. In many
parts of the body, there is little or no fat ; and when we
reflect on their nature and functions, we are .persuaded
that its presence must have proved extremely inconveni-
ent to them : the eyelids, for instance, had they been
loaded with fat, could not have moved as they now do;
nor could the penis, so constucted, have answered the
purposes for which it was designed. Young animals have
more fat than old, anil have it deposited more upon the
superficial parts of their body; in fact, the young of almost
all the different species of the higher animals are enve-
loped in fat; well instanced, in the infant, the puppy,
and the kitten. But it is not so with the foal, the calf,
and some few others, which immediately after birth have
the power of following their dams, in search after food :
fat to them would have proved burdensome, without an-
swering the same useful purposes, for which nature seems
to have given it to the young of most other animals. We
frequently see very fat young horses—indeed most of the
three and four years old horses, purchased of dealers, or
of the breeders, have considerable depositions of fat be-
tween the skin and abdominal muscles ; or, to express
ourselves in the jockey's phrase, are "fat upon the rib."
The prodigious bulk that beasts, fed for the purpose, will
attain, is almost incredible : a prize ox has weighed two
hundred stone* ; and a prize sheep, forty stone*. In the
human subject also, we have had astonishing instances of
corpulence : Lambert weighed fifty-two stonef. In re-
spect of the latter, it has been remarked, that fat people
do not in general live to a great age. As the cells of
the reticular membrane are filled with a serous exhalation
f A stone is 8 lb. f Horseman's weight, 14 lb, to the stone.
-ocr page 172-
On Cellular Membrane.                     137
from the terminations of the arteries, so we believe those
of the adipose to be with fat: we have no anatomical
proof of the existence of any distinct gland for the pur-
pose, but we suppose it to be a secretion from the arterial
ramifications distributed over their interior. In almost
all animals that are healthy, copious food of a nutritive
kind, and privation of exercise, will increase the deposi-
tion of fat; but in the human subject, and, indeed, in
many quadrupeds the spirits appear to have very con-
siderable influence over this secretion. We see num-
berless examples of people, who appear to enjoy the best
bodily health, and yet are constantly meagre, though their
food and habits of life tend to an opposite state ; and we
may occasionally observe horses and dogs, particularly
circumstanced, in which, from their natural leanness, or
poorness upon the rib, something of a mental nature would
appear to operate ; indeed, it is a well known truth, that
if you separate a horse of an irritable disposition from
others, with which he is accustomed to be stalled, he will
fall away in condition, in consequence of, what is vulgarly
called,fretting from being alone; and so much does this
act of segregation affect some, that we have known them
even refuse their food. Those horses are commonly the fat-
test that are fed on easily digested food—as bruised corn
aud chopped hay, and that have little or no exercise : a
fact well appreciated by the horse-dealer, whose horses
are fine, and fit for sale, but incapable of fatigue.
Constitutional diseases, generally speaking, extenuate
the body, and more particularly those of the acute or
painful kind ; hence, the irritation caused by a simple
puncture in the foot, will, if it be of long duration, induce
a state of emaciation: under such circumstances, the ab-
sorbents are supposed to act with more than ordinary
-ocr page 173-
138                      On Cellular Membrane.
effect, and to take up the adeps from the interior of its
cells.
It has been supposed, that fat is placed near the surface
of the body, in order to defend the more internal parts
of it from cold: this opinion, however, is not a very
tenable one, when we consider the many facts connected
with the subject. It has been thought to, and probably
does in some measure, facilitate the motion of various
parts. That it gives great beauty, not only to the hu-
man form, but to that of horses, and other quadrupeds,
no one will deny : it fills up many inequalities of surface
the bones and muscles would otherwise present; the
unsightliness of which we witness but too many in-
stances of in half-starved cattle. But the principal use
of fat seems to be, that of serving as a store, from which
the animal can derive nourishment, when debarred of it
from other sources ; as if Nature, all provident, whenever
She has more chyle than is required for the immediate
supply of the animal economy, lays it up, as bees do
honey, to nourish the system, in part or wholly deprived
of aliment by accident or disease : in no other way can
we explain, why it should diminish in quantity when the
animal takes little or no sustenance, or account for the
extreme emaciation apparent before death caused by
starvation.
We have slready stated, that cellular membrane not
only varies in quantity in different parts of the body, but
that it exists every where in more or less abundance, ac-
cording to the condition of the animal; a fact we may,
at any time, obtain full demonstration of by dissection ;
though we need scarcely trouble ourselves so far, for the
inspection of fat and lean stock, will of itself afford us am-
ple conviction. The addition of cellular substance is al-
-ocr page 174-
On Cellular Membrane.                      iSQ
ways attended with a proportionate deposit of fat, which
is not merely confined to subcutaneous situations, but
pervades the texture of parts, and more especially
of the muscles : a horse, under such circumstances, is
said to be gross, to have flesh loose and Jlabbt/, and to be
soft, and unfit for work. Young horses recently brought
up to London for sale, or others just taken from grass,
or that have been fed on soft meat in the stable, and
little exercised, are all fat and^Vic to the eye, but not in
condition for work.
The common and simple manage-
ment that such "horses require, to put them into condition
for regular work, is to give them nothing but dried proven-
der of the best kind ; to exercise them gently at first, and
exert them more by degrees ; and occasionally administer
moderate doses of aloes, by way of emptying the bowels,
and exciting the powers of absorption, in order to get rid
of some of their superabundant fat. By these means, we
disencumber the muscles of their useless cellular and adi-
pose matter, reduce the weight of the carcass, and im-
prove the wind : in fact, we put the animal in a fit condi-
tion to go to hard work, or, in common language, season him.
In order to prove that such changes will take place in the
composition of his body, let us only recall to mind, for a
moment, the difference between the flesh of the stall-fed
ox, preparing for the butcher, and that of the beast daily
yoked to endure hard labor: reverse the states of these
animals, however, and you will soon render the one fit
for the knife, whose flesh before was hard and black;
while the other wiil every day lose his elasticity and
plumpness of feel, until his muscles become firm and hard,
and altogether without fat. But the horse, in comparison
with other beasts, may be said to possess but little adi-
pose matter—he is an animal not equally disposed to be-
-ocr page 175-
140             Diseases of the Cellular Membrane.
come incapacitated from such a cause; for, though we
every now and then see horses enormously fat, we never
hear of one whose legs are overpowered by the weight of
his body, or that cannot support himself under ordinary
exertion; instances of which are always to be met with
among pigs, oxerij and sheep. Not only do horses pos-
sess less cellular substance in their composition than
these animals, but some species appear to have it natu-
rally either in much less quantity, or of a more dense and
compact texture than others: the thorough-bred horse,
for instance, exhibits, in this respect, a very different
structure from the cart-horse; in him the skin, the
muscles, and even the bones themselves, are less in vo-
lume, much closer in texture, and appear altogether to
be composed of finer and more compact materials. We
may discover a similar, though less obvious difference in
the contexture of the greyhound and the bull-dog : and
we may even find very evident traces of the same thing,
in the component parts of a delicate female, when com-
pared with those of a robust and vigorous athlete.
Diseases of the Cellular Membrane.
In this place, abscess is commonly considered. An
abscess may be said to be, a collection of pus within a
cavity formed by the cellular membrane.
In the formation of abscess, the adhesive inflammation
almost always precedes the suppurative; so that adhe-
sive matter, and probably a little serum, are first depo-
sited, producing a consolidation of the cellular substance;
and this afterwards becomes the nidus for pus, by glu-
ing the membrane tightly to the skin on one side, and
to the muscles on the other : hence arise the swelling and
induration in strangles, prior to the effusion of matter.
-ocr page 176-
Diseases of the Cellular Membrane.            141
In this stage, the swollen part feels hard, hotter than usual,
and the animal flinches from pressure; which symptoms
denote the continuance of inflammation, and its progressive
course into the suppurative stage, unless it be put a stop
to by the timely administration of our resolvent remedies.
The suppurative process having commenced, at first only
a little purulent matter is deposited in the centre of the
tumor, by the mouths of those vessels which before ef-
fused lymph: this, by its pressure, excites absorption of
the inner contiguous layer of adhesive matter, a process
that now keeps pace with the secretion of pus internally;
until, at length, the swelling, before diffused and hard, is
converted into one perfectly circumscribed, soft, and
fluctuating. At this time, in the human subject, if the
abscess be of large size, there is usually a fit of shivering,
followed by some degree of fever; and in young horses,
we may often discover something of the same kind, du-
ring the progress of strangles, when the collection of pus
is considerable. There being now no interposition of
substance between the contained matter and the skin, ul-
ceration of it ensues ; so that the integument covering an
abscess becomes extremely thin, and always more so at
its most prominent part; where, in common language, it
is said to point: at this time, surgical interference gene-
rally evacuates the abscess, though, if it- be left alone,
it will discharge itself by a small opening at the spot
where it points, and, in this way, it is said to burst. With
regard to the progress of abscesses in general, they mostly
make their way to the surface, so as to evacuate themselves
by the skin: there are however instances, in which the
different outlets of the body, as the alimentary canal,
and trachea, become the medium of its ejection. But
should pus be effused underneath parts, which, from their
-ocr page 177-
142             Diseases of the Cellular Membrane.
vital powers being com paraiively weak, do not readily
ulcerate, it will diffuse itself over a larger surface, in-
stead of taking a direct course to the skin : hence it
is, that purulent matter collected under tendinous struc-
tures, dissects its way among the muscles, and makes
inroads and sinuses in various directions, unless free
vent be given to it by incision. In like manner, if
pus form under horn, a part wholly inorganic,—as in
quittor, ulceration will give it issue by some circuitous
route ; for (and the reasons are obvious) no absorption of
the horn can take place : this at once explains, why we
are so solicitous about discharging matter collected un-
derneath the horny sole—lest it might occasion ulcera-
tion of the sensible laminse, and present itself at the co-
ronet, under the form of quittor.
It is generally a good maxim, to make an opening into
an abscess as soon as the maturation of it is complete:
let it be understood, however, that no harm will result
from a contrary mode of treatment; for it is now univer-
sally believed, that no ill consequences are to be appre-
hended from the absorption of pus. How often do we
see strangles suppressed without any apparent ill effect!
—indeed, it is the best practice, if proper evacuants be at
the same time administered : we say this in opposition 1o
a budget of prejudice, founded on ignorance, and a stub-
born adherence to erroneous tenets. But in some cases,
and more especially in abscess of the foot, we should dis-
charge the pus, however small in quantity, as soon as
its presence is ascertained : otherwise, as we have already
shewn, much mischief is likely to ensue.
There are three modes of opening an abscess at pre-
sent adopted in veterinary practice: viz. by incision, by the
actual cautery, and by seton. Each of these operations
J
-ocr page 178-
Diseases of the Cellular Membrane.            143
has its advantages, and may be preferred according to
the nature of the case, as we shall find when we come to
treat of particular abscesses. Fomentations and poultices
are occasionally of service in promoting the processes of
suppuration and granulation; but in the generality of
cases, from the inconvenience with which their use is
almost always attended in the horse, not to say the fre-
quent impracticability of employing the latter, we do not
have recourse to them : stimulants, more especially blis-
ters, will best promote the suppurative state, and as for
the process of granulation, that needs little or no assis-
tance from art; except where there is any destruction of
ligamentous, cartilaginous, or bony parts. The most
troublesome cases of this kind are those termed poll-evil,
and fistula: it is so seldom, however, that any thing like
skill dictates the practice of the farrier, that we are not
surprised at the tediousness and frequent incurableness
of these diseases.
-ocr page 179-
LECTURE X.
On the Brain and Nervous System.
X HE brain, with the situation and general appearance
of which we are all more or less familiar, is that soft white
mass which fills the cavity of the skull. In no animal is
the cranium so large, in relation to the face, as in man;
in none therefore is the brain, whose magnitude is al-
ways correspondent with that of the skull, of proportion-
ate bulk. In horses, this organ is but small when com-
pared to the size of the body; though there are some
differences (quite unimportant in an anatomical point of
view) in the dimensions, as well as form, of the heads of
horses of different breeds*.
The brain is divided into three portions, all of which
* " The brain of the shark does not weigh 3 ounces although the
animal itself is generally 300 lbs. weight. The brain of the sheep,
with respect to the whole weight of the body, bears the proportion
of 1 to 150. In a dog the proportion is less: it is as 1 to 100. As
we ascend in the general scale of rational beings, the magnitude
of the brain bears an increased and strongly marked proportion to
the size of the system in general. In the African, it is as 1 to 54.
In an European, as 1 to the 50th part of the system altogether."
Saumarez's System of Physiology,
-ocr page 180-
On the Brain and Nervous System.            145
are continuous in substance : the cerebrum, so large that
it occupies at least 3-fourths of the interior of the skull;
the cerebellum, or little brain; and the medulla oblongata.
That portion of medullary substance which extends from
the brain through the whole length of the spinal canal, is
called the medulla spinalis, or spinal marrow.
No viscus in the body is so well defended from external
injury as the brain : on every side it is enclosed by bony
walls, well constructed to make great resistance, and more
especially so at those parts where external violence is likely
to be received. The interior of the skull is variously fur-
rowed and indented by the more projecting parts of the
organ, to which, in every particular, its figure is nicely
adapted ; for it is by the shape of the brain that that of
the cranium is moulded, inasmuch as the formation of the
one precedes that of the other. The relative situation
of the divisions of the brain, differs in the horse from that
of the corresponding parts of the brain of the human sub-
ject; though both organs, in regard to the bones of the
cranium, are similarly lodged : e.g. the cerebrum, which
forms the upper and anterior portion in the human sub-
ject, constitutes the lower and auterior in the horse;
while the cerebellum, which in the former is placed be-
low and behind the cerebrum, in the horse is placed a-
bove and behind it. This difference, however, is but ima-
ginary, being entirely referable to the position of the head ;
for if we place the horse's head upon a table, so that it
rest upon the branches of the lower jaw, we shall find no
difference whatever in the relative situation of these parts.
The brain has three coverings, called its membranes, or
meninges; the dura mater, the pia mater, and the tunica
arachnoides.
Of these, the exterior is the dura mater;
which, though called a membrane, is of a dense, tough,
h
-ocr page 181-
146             On the Brain and Nervous System.
and inelastic texture, being chiefly made up of tendinous
fibres. It is so firmly adherent, by means of numerous
little processes, to the sutures of the cranium, that it is
with difficulty we separate them, afterhaving sawn through
the bone; and this union is further strengthened by blood-
vessels, which pass between it and the internal table of
the skull; for, in truth, this membrane is supplying the
place of an internal periosteum. There are several broad
expansions, similar in texture to the dura mater itself,
stretched across the cavity of the skull; the chief use of
which seems to be, to prevent one portion of the brain
from resting upon, or compressing another: there are
also some canals, or sinuses, within the folds of this mem-
brane, which, like so many reservoirs, receive the blood
as it flows from the veins coming from the interior of the
brain. Upon its inner surface it is smooth, being lubri-
cated by a fluid furnished by its blood-vessels : it has no
other connection with the subjacent membraues, although
it lies closely applied to them, than it has with the brain
itself;' and that is, through the medium of the many small
veins terminating within its folds. The blood-vessels
of this membrane, though not numerous, are of sufficient
magnitude to admit easily of injection: it is a good illus-
tration of the truth of the remark, " that the capillaries
are not abundant in fibrous texture." By some the pre-
sence of nerves is altogether denied to it; though there
are writers who are inclined to believe, that they have
seen something like nervous filaments in its texture : in
a sound state, we are pretty certain that it possesses no
sensibility ; for it may be cut, or irritated in various ways,
without giving the animal any apparent uneasiness.
The pia mater is that membrane which closely enve-
lopes the substance of the brain, dips down between its
-ocr page 182-
On the Brain and Nervous System.            147
convolutions, and adheres to its surface by numberless
minute blood-vessels, easily lacerated by stripping it off
■with the forceps. It differs altogether in its texture and
appearance from the dura mater; presenting a smooth
surface exteriorly, but a rough and villous one next to the
brain, and being composed of a beautiful network of blood-
vessels, united together by a delicate cellular tissue : it
is, in fact, the immediate source from which the brain de-
rives its blood, and, at the same time, the medium through
which the unexpended blood is returned to the sinuses of
the dura mater.
The third membrane has, from its extremely thin and
delicate texture, been compared to the spider's web, in
allusion to which the name of membrana arachnoides has
been given to it. It is placed between the two others,
closely adheres to the pia mater, and separately invests
the cerebral eminences and depressions, without, like that
membrane, insinuating itself between the convolutions j
from which circumstance, it is, with pains, demonstrable
in some places about the base of the brain. Though
there can be no doubt but it possesses organization,
hitherto the most successful injections have not shewn any
blood-vessels in its substance. Of its use, we dare not
speak : physiologists are unable to say for what purpose
so delicate and transparent a structure is here interposed.
From the vascular connection which subsists between
the scalp, upon the exterior of the skull, and the dura
mater, upon its interior, we have at once an explanation
of that apparent anomaly in pathology, viz. that external
injuries of the skull frequently induce symptoms of in-
flammation of the brain, or its membranes : in the human
subject, such wounds are always considered, on this ac-
count, as dangerous, and, indeed, it not very unfrequent-
£ 2
-ocr page 183-
I
148                               On the Brain.
ly happens that they prove mortal. Though we have
never seen a case of this description in the horse,
there does not appear to be any good reason' why we
should not be cautious how we make or treat wounds of
such a nature.
A fluid, differing from serum in its properties, though
like it in appearance, is occasionally effused between the
dura mater and tunica arachnoides, or, more commonly,
underneath the latter membrane, (as well as within the
substance of the brain itself,) constituting a disease, term-
ed hydrocephalus: it rarely happens in horses, but in the
human subject, and more especially in children, it is by
bo means an unfrequent cause of dissolution.
On the Brain.
We have already given an outline of the situation and
division of this organ ;—we shall now make some general
observations in regard to its structure. If a vertical sec-
tion is made of any part of the brain, we perceive that its
interior presents two substances of different colors: the out-
er of these, of a dirty greyish hue, is called the cineritious,
or cortical part; the inner, which is white, and of which
the chief bulk of the. organ is composed, the medullary.
The cortical part is not always the outer; in some places,
the relative disposition of the medullary and it, is reversed ;
it is that, however, in which the blood-vessels of the or-
gan are most conspicuous; for, in consequence of being
closely invested by the vascular pia mater, it receives the
numerous ramifications of arteries transmitted by that
membrane for the nourishment of the interior parts of
the brain. On the other hand, in the medullary por-
tion, the blood-vessels, which in health only convey the
colorless parts of the blood, are so minute that they es-
-ocr page 184-
On the Brain.                              149
cape notice; unless, occasionally, here and there, when
it has heen inflamed, the bloody specks upon its divided
surface, denote the division of those that have become
of sufficient magnitude to admit the red globules.
By the investigations of the best anatomists, the brains
of animals appear to be of a fibrous nature ; and in many
parts of the human brain (which is larger than that of
any other animal) the disposition and course of its fibres
have been traced : such inquiries, however, have, unfor-
tunately, not led to any elucidation of the sensorial func-
tions, nor are we aware that they have been attended
with any advantageous result in regard to its pathology.
After all, the truth is, that the intimate structure of this or-
gan is still unknown to us. With regard to the cineritious,
or cortical part, there is much reason to believe, that it is
almost wholly constituted of the ramifications of blood-
vessels of extreme exility; from which, others, still more
minute, are distributed to the substance of the medulla.
It is here worthy of remark, that in no instance does
Nature so invariably present us with the same structure
and arrangement of parts as in this viscus : in almost
every other in the body, we can discover some little va-
riation, in this respect, in different subjects; but in the
brain, the same uniform appearances ever present them-
selves on dissection : so intimately united do structure
and function seem to be in*this organ. The cerebrum
is divided into two halves, called hemispheres, each of
which is formed of parts precisely similar, in every par-
ticular, to each other; so that, in fact, every part of the
organ may be said to be double, i. e. its two halves are
constituted of several small portions, which are not only
perfectly alike in structure, but are of corresponding
-ocr page 185-
On the Nerves.
loO
symmetrical forms and dimensions: a remark that not
only applies to the brain itself, but one that holds good
with regard to the spinal marrow. An animal, therefore,
has, to all intents and purposes, two brains; and, proba-
bly, for the same reason that he has two eyes, two ears,
and a double tongue.
The arteries which supply the brain, are the two ver-
tebrals, besides two other considerable branches from the
carotids, called the internal carotids: its blood is returned
from the sinuses of the dura mater by the vertebral and
jugular veins. It is on the supply from the vertebral ar-
teries, however, that this organ mainly depends, for the
preservation of that energy essential to the support of
life ; for if ligatures be put on these vessels, the animal
speedily dies; whereas both the carotids may be tied
without occasioning any apparent ill effects.
On the Nerves.
The nerves are soft, white, fibrous cords, proceeding
from the brain and spinal marrow to all parts of the body.
From the brain issue ten pairs of nerves, called the ce-
rebral ;
and from the spinal marrow, thirty-^ix, denomi-
nated the spinal: making, altogether, forty-six pairs of
nerves in the body.
In some animals, among which may be ranked the
horse, the nerves, in generat, are larger than those in the
human body; though the brain of the latter far exceeds
in bulk the same viscus in the quadruped. " The spinal
marrow," says Rich era nd, " and the nerves, in the dif-
ferent animals furnished with them, are larger in propor-
tion to the brain, according as the animal is more distant
from man in the scale of animation." .
-ocr page 186-
On the Nerves.                              151
At their origin, the nerves are covered by the dura
niater, and a membrane similar to, if not a continuation
of, the pia mater; but the tunica arachnoides cannot be
distinctly traced upon them: these coverings, however,
seem to proceed only to a short distance, for if we exa-
mine the vagina, or sheaths, in which they are afterwards
inclosed, we shall find them to be nothing more than con-
densed cellular membrane. It is to this covering that
the compactness and density of a nerve are chiefly owing;
when deprived of it, but a slight degree of pressure will
destroy its texture : indeed, there are some nerves whose
pulpy nature would subject them to perpetual contusion
and laceration, were it not for the protection afforded
them by this compact cellular envelope.
The substance of the nerves, like that of the brain, is
fibrous. Their fibres, which are connected together by
cellular membrane, take a serpentine course, as may be
seen by a close examination of the numerous white lines
upon their surface ; so that if we unravel a nerve, we
shall find it to be made up of an infinite number of jibrilla,
or filaments, the minutest of which still retains a serpen-
tine form. Some have imagined that these fibrils are tu-
bular ; others, that they are cellular; but, in truth, we
must confess ourselves still unacquainted with the inti-
mate structure of the nervous system. It has been ge-
nerally supposed, that nerves were inelastic in themselves,
and that any extension, or contraction, they admitted
of, arose from the elasticity of their component cellular
membrane; Sir E. Home, however, has proved, by some
ingenious experiments, that they possess a power of re-
traction when divided in the living body; a circumstance
which, of late, cannot altogether have escaped the obser-
vation of those, who have performed the operation oineu-*
-ocr page 187-
On the Nerves.
152
rotomy *• This retraction does not seem entirely to de-
pend on any inherent contractility of tissue, otherwise ex-
tension of the nerve would be a necessary preparative ; on
the contrary, it happens under the most complete state of
relaxation ; an effect that will not take place in the dead
subject under similar circumstances.
A nerve is said to have two extremities:—a cerebral,
and a sentient: the former is that part by which it is con-
nected with the brain, or spinal marrow; the latter, that
by which it terminates in the various structures of the
body. It has been usual to say, that the nerves arise, or
have their beginning, from the brain, though it would ap-
pear, from some recent investigations into their composi-
tion andfunctions, that we might, with equal propriety, re-
gard them as deriving their origin from the organs to which
they are said to be distributed, and as ending in the senso-
rium. Supposing, however, that they do issue from the
brain, there still remains some difference of opinion re-
specting their beginning, or roots. By some it is thought,
that they are not continued from the substance of this
organ, but are merely attached to its surface; though
there are nerves which we certainly appear to trace be-
yond the superfices—into the interior of it, as is the case
with the optic ; so that although it is customary, for the
sake of anatomical detail, to assign certain parts of the
brain as the beds or origins of certain nerves, we are still,
in truth, ignorant of the manner in which their original
or radical fibres are disposed. It would appear, from
many familiar facts, the result of experiments and patho-
logical observations, that the nerves distributed to one
side of the body, arise from the opposite side of the
* Vide Lecture XI.
-ocr page 188-
On the Nerves.                             153
brain; and if this be true, there must be somewhere a de-
cussation of them : if an injury be received on the left
side of the skull, the right side the body will become pa-
ralytic; an effect that would not happen, unless there
was a ready communication between one side of the
brain, and the nerves of the opposite side of the body,
by means, in all probability, of direct continuity of fibre.
If one column of the spinal marrow be cut through, the
animal will become paralytic, not on the opposite, but on
the same side; a fact, which, although it at first view ap-
pears contradictory to what we have just stated, in truth
tends to confirm this opinion : for the medulla spinalis is
composed of two columns, the fibres of which decussate
each other in the same manner as those of the nerves are
supposed to do.
The nerves, generally speaking, soon after their origin,
form various communications with others in the vicinity;
in many parts, by such frequent intercourse, that a kind
of nervous net-work is formed, to which the term plexus
is applied : some nerves, however, pass directly from the
brain to their destinations, without either receiving, or
giving off any communicating ramifications—such are
the optic and olfactory. In their course, the nerves ge-
nerally proceed in straight lines to the parts to which
they are distributed; deviating only, like the arteries, for
their own safety, or for some wise and evident purpose.
Sometimes they run with the blood-vessels, sometimes
alone : we commonly find a nervous trunk, and in some
places two, accompanying the principal arteries and veins
of the extremities. The branches of the rrerves, for the
most part, come off at acute angles : those springing im-
mediately from the trunk, send off others of smaller size.
-ocr page 189-
154                             On the Nerves.
until filaments of such minuteness are formed, as to be
invisible to the naked eye.
The twig-like ramifications of nerves end in two dif-
ferent ways : either by inter-communication—which is si-
milar to the anastomosis of arteries, or by sentient extre-
mities within the substance of those organs to which they
are distributed. In the retina, a part of the eye entirely
composed of the expanded termination of the optic nerve,
an extremely delicate tissue, of a pulpy consistence, and
semipellucid yellowish appearance, is observable; from
which, it has been conjectured, that the extremities of
other nerves may be somewhat similar: but, to confess
the truth, we do not know what form they actually as-
sume—we think it very probable, that their mode of ter-
mination may vary according to the nature and texture of
the part in which they are expended. The nerves are
very unequally distributed to different parts: the organs
of sense, the skin, muscles, and mucous membranes are
plentifully supplied with them; the serous, fibrous, and
medullary membranes receive but few ; and none have yet
been detected in either cartilage or tendon*.
A ganglion is a little knot or swelling upon a nerve, per-
fectly natural to it. We find them in various parts of the
body; more especially about the neck, chest, and abdo-
men. From the fact of their being peculiar to those nerves
which run to parts possessed of involuntary motion, they
have been regarded as the means whereby such functions
* And yet the granulations of these parts possess sensibility, of
which we have recently had a very marked instance, in the case
of a broken knee. The horse never failed to snatch up the leg,
every time the granulating edges of the extensor tendon were
touched with the probe.
-ocr page 190-
On the Physiology of the Brain and Nerves. 155
are supported ; hence those nerves of the eye which are
dispersed upon the iris, have them, while others going to
the muscles of the organ, whose actions are under the in-
fluence of the will, are without them : the opinion, there-
fore, to say the least of it, is an ingenious one, though
this is insufficient proof to establish it.
On the Physiology of the Brain and Nerves.
The brain, in a physiological point of view, is to be
regarded as the primary organ of sense'—the sensorium;
as the seat of perception, in which cognizance is taken of
all impressions made on those organs to which nerves are
distributed; and as the source of volition, or the part
from which the will is transmitted along the nerves to the
organs of voluntary motion. If the brain of an animal is
severely injured, or diseased, a state of general insensibi-
lity is induced, and the body rendered incapable of mov-
ing itself: it does not follow, however, that all feeling be
lost, even though the brain itself be removed, for the
spinal marrow alone has been found capable of preserv-
ing a degree of sensation. That a violent blow on the
head, or pressure from any cause, no matter what, upon
the brain itself, will deprive an animal of sensation and
voluntary motion, we have frequent opportunities of wit-
nessing in horses suffering from the effects of severe falls
more especially from falls backward, upon the vertex, in
the act of rearing; from which accident, it is not uncom-
mon for them to remain for several days perfectly sense-
less ; all attempts to rouse them proving ineffectual: you
may c.ut or burn them, hold a lighted candle to the eye,
or discharge a pistol close to the ear, and every part will
remain as motionless as if the animal was dead. In op-
-ocr page 191-
156 On the Physiology of the Brain and Nerves.
position to this, there are particular morbid conditions of
the organ, in which its functions are preternaturally ex-
cited : inflammation is, perhaps, the most common cause
of this derangement; hence it is that we account for the
extreme irritability of horses in the mad stage of stag-
gers, and the uncommon degree of force with which they
exercise their muscular powers, during the continuance of
the paroxysm.
Though sensation and voluntary motion are so exclusive-
ly cerebral functions, that they cannot be duly perform-
ed unless direct communication be kept up with the sen-
sorium, in a perfectly sound and impressible state, it is
different with regard to those motions that are involun-
tary. When a horse becomes stunned from a blow, or
during the lethargic stage of staggers, although sensation
and the power of locomotion are nearly, or quite lost, still
does the heart beat, the chest expand, and the alimentary
canal continue to digest food. An admirable instance to
show how needful Nature has been in the preservation
of life, even during the disturbance of organs more imme-
diately its source and seat: for had these parts been sub-
ject to the same laws as govern the motions of the limbs,
death must have supervened on every accident of this de-
scription : whereas, now, life is supported, while the
brain is recovering from the effects of the mischief.
It is a curious fact, that, although the brain is the or-
gan of feeling, there is one part of it, apparently of itself,
devoid of sensibility ; viz. the cortical, or cineritious por-
tion ; which has been cut, torn, taken out, and otherwise
injured, in the living animal, without causing any very
evident marks of pain ; and this will appear the more ex-
traordinary, when we consider that but little pressure
upon its surface will instantly occasion violent and dan-
-ocr page 192-
On the Physiology of the Brain and Nerves. 157
gerous effects. Also the medullary matter may be
pierced to a certain extent, from the surface of the cere-
brum, without much inconvenience; and even a little of it
may be removed without any ill consequences : we must
be exceedingly cautious, however, in making this experi-
ment, not to penetrate too deep into its substance, or the
shrieks of the agonized animal will soon inform us of the
extreme sensibility of its interior parts. Instances have
occurred in the human subject, in which patients have
lost, or had removed, from time to time, large portions of
the cerebrum, without any apparent derangement at the
time, or subsequent disturbance of the intellects.
Concussion of the brain, a very frequent accident in the
human subject, though comparatively a rare one in the
horse, produces symptoms very like those arising from
immediate compression of the organ. In violent degrees
of it, the patient is rendered perfectly insensible, though,
in less severe cases, only stupor and partial paralysis en-
sue : in either case, it is a disease never unattended with
danger, and one which very frequently terminates in death.
Violent injury, or disease of one side of the brain, de-
prives parts of the opposite side of the body of the pow-
er of motion, and, but not always, of sensation : paralysis,
or palsy, is the general term used to denote this affec-
tion, though it is sometimes.specified by the word hemi-
plegia.
This state is commonly induced by pressure
upon the brain, or spinal marrow, either the effect of
the depression of a piece of bone upon its surface, or by
the effusion of blood, or pus, upon or within its sub-
stance ; we are, therefore, in such cases, not to apply our
remedies to the paralysed parts, but to seek for the cause
whence the nerves of these parts take their origin. The
extent of paralysis will depend on the nature of the
-ocr page 193-
158 On the Physiology of the Brain and Nerves.
cause, but chiefly on the part affected : if, for example,
only a single nerve be compressed, or injured, those or-
gans which it exclusively supplies, will be rendered para-
lytic ; but if it be the spinal marrow, then all those parts
receiving nerves posterior to the seat of injury will be
affected; and should the mischief be anterior to the
origin of the phrenic nerve, in the neck, the diaphragm
will be palsied, and death ensue.
In wounding the brains of living animals, in various
ways, experimenters have generally found, that convulsions
seized that side of the body on which the sensorium was
injured, and paralysis the opposite : when, however; one
column of the spinal marrow was divided, the parts on the
same side were paralysed, but the others remained un-
affected.
There is one circumstance, connected with the phy-
siology of the brain, about which much has been said by
such writers as have noticed it in the course of their
experiments, without having, in a satisfactory manner, en-
tered into an explanation of it. When we lay bare the
brain of a living animal, we perceive (especially if we put
our hand upon it) an evident rising and falling of the sur-
face—alternate states of inturgescence and subsidence.
Thus far, the subject admits of ready exposition: these
motions simply depend on the diastole and systole of the
heart, with which they are perfectly synchronous—the
sudden influx of blood into the large arteries at its base,
produces its elevation, while its depression is the effect
of the momentary cessation of action in the injecting
powers. But there are other motions to which this
organ is subject; and the confusion of these with the for-
mer, has probably tended to create the contention among
authors respecting the causes of them : experiment, how-
-ocr page 194-
On the Physiology of the Brain and Nerves. 159
ever, our only safe guide in these matters, shows that the
latter, which are but occasional, aud consequently irre-
gular, are dependant chiefly on respiration, though they
may be influenced by any thing that tends to accelerate,
retard, or impede the reflux of venous blood.
In order to convince ourselves that the brain is af-
fected by respiration, and that this is the common cause
of alteration of its volume, we have only to observe the
fontanels of children, or inspect the brains of living ani-
mals, exposed for that purpose.
How far we are to regard the brain and nerves as con-
cerned in the production of animal heat, yet remains to
be determined : it is a question that has excited consider-
able interest of late, in consequence of some truly inge-
nious experiments of Mr. Brobie's. When all connec-
tion was cut off between the brain and respiratory
organs, by severing the head of an animal from the body,
this gentleman found,* that, (respiration being artificially
supported,) although the blood appeared to undergo the
usual changes, and the respired air its ordinary alterations,
the heat of the body diminished; and diminished, not-
withstanding the circulation of the blood was kept up to
its natural standard : more, however, we forbear to say on
the subject, until we have occasion to speak of the phy-
siology of the organs of respiration.
The nerves, we may consider, as so many cords of com-
munication between the brain and the several organs of
the body, by which the two grand functions—sensation
and volition, are supported. If the nerves going to any
voluntary part—say the fore leg, be cut through, the limb
18 not only deprived of its sensibility, but of all power of
voluntary motion : you may prick, or injure it in any way,
and the animal is perfectly unconscious of your doing so;
-ocr page 195-
] 60 On the Physiology of the Brain and Nerves.
and even if he were, he could not move the leg, for the
muscles will now no longer obey the will. Not, how-
ever, that the nerves themselves possess any power of
motion, though they are to be regarded as the indispensa-
ble agents of the brain in all such movements as are re-
gulated by volition. In like manner, though the nerves
be the organs by means of which parts are endowed with
sensation, they of themselves, unconnected with the brain,
are wholly devoid of feeling : you may prick, or cut, for
example, the extremity of a nerve, whose communication
with the sensorium is cut off, without the animal's even
knowing that you are touching it; but you have only to
irritate the opposite end, and you give rise to instanta-
neous convulsions. Precisely the same thing happens if
the nerves be tied, or otherwise compressed : you may cut
or burn the parts to which they are going, apply light to
the eye—if it be the optic nerve, or sound to the ear—if
auditory, and no effect whatever, will, in either case, be
produced.
The functions of volition and sensation, are, in them-
selves, entirely unconnected ; i.e. they may subsist inde-
pendently of each other—one will remain where there is
a total absence of the other. Cases of paralysis in the
human subject often occur, in which the lower extremi-
ties retain their feeling, though the patient has lost all
power of moving them : the reverse of this has also been
noted.
The nerves going to the organs of sense, possess a
power of being acted on by peculiar stimuli: e.g. the
nerve called the optic, which is distributed to the inte-
rior of the eye, receives the impressions of the rays of
light, and transmits them to the brain, where perception
of a peculhr kind is created, and the result is vision ; in
-ocr page 196-
On the Physiology of the Brain and Nerves. 161
like manner, the vibrations of sound affect the auditory
nerve, which is spread over the internal parts of the ear;
odors of all kinds are perceived by means of the olfactory
nerves, belonging to the nose; while the tongue, through
the medium of nerves called the gustatory, is endowed
with the faculty of tasting: moreover, in the human sub-
ject, the extremities of the fingers have a power of feel-
ing, distinct from that of common sensibility. All these
organs however have, in common with every other part
of the body to which nerves are given, what is called or-
dinary sensation; and this may remain unimpaired,
though the proper sense of the part is entirely lost. If,
for example, we are deprived of vision, by some disease
or injury of the optic nerve, our eye is still affected by
such stimuli as act on parts possessed only of common
sensation—like them it can feel heat and cold; in like
manner, though we be deaf, yet are our ears not de-
void of ordinary feeling ; nor is our nose deprived of its
general sensation, because a common catarrh may have
destroyed its power of smelling. The reverse of this
however will not apply: no part that has lost common
feeling, is in the least affected by its appropriate stimulus ;
nor is one set of nerves having a specific susceptibility,
influenced by the peculiar excitant of another. For ex-
amples, no part of our body is endowed with that pecu-
liar faculty of feeling which resides in the points of the
fingers; or, in the horse, in the extremity of the nose:
the eye is not affected by the sound of a cannon, nor the
ear by the most intense light; the tongue cannot smell,
nor can the nose inform us of the sense of taste.
The agent producing sensation, is not, generally
speaking, in direct contact with the extremity of the
nerve: when we feel any thing, the nerves of our fingers
M
-ocr page 197-
162 On the Physiology of the Brain and Nerves.
do not touch the body felt, for the cuticle (which is itself
an insensible part) is interposed ; through which, conse-
quently, we ascertain the physical properties of a sub-
stance, in a similar manner to what we do, though more
imperfectly, through a thin glove. This covering appears
to be necessary, to defend the sentient extremities of the
nerves from the action of those external stimuli, which,
were they allowed to come in immediate contact with
them, would be productive of acutely painful sensations :
hence we find the delicate expansions of the olfactory
nerves upon the pituitary membrane, always besmeared
with mucous, to them a sheath of defence against pungent
odors, or other irritating matters.
If the trunk of a nerve be in any way irritated, the sen-
sation produced in it, will be transmitted through its va-
rious branches to the parts to which they are distributed :
if, for example, the ulnar nerve, which passes over the el-
bow, be compressed, or accidentally struck, we know that
a peculiarly unpleasant feeling will be experienced in the
little and ring fingers, in which parts its ultimate ramifi-
cations are dispersed. So curious is this phenomenon,
that if the nerve be irritated even after its division, still
will the effect be felt, the same as if it were conveyed
along the undivided branches: hence it is, that persons
after having undergone the operation of amputation, of-
ten complain of a pain in their hand, or foot, though the
limb be absolutely in another room. When we speak
of our feet, or hands being asleep, that well-known ting-
ling sensation in them, is the effect of the nerves of the
part recovering their sensation, which has, for a longer or
shorter time, been suspended, in consequence of com-
pression of the trunk, or branch, from which they
spring.
-ocr page 198-
On the Physiology of the Brain and Nerves. 163
Nerves deprived of those coverings which Nature has
provided for them as a shield or defence from external
agents, acquire extreme sensibility: hence the pain of a
blistered surface, and the excessive irritability of an in-
flamed mucous membrane. The mere exposure of their
trunks, in a denuded state, however, is not attended with
painful sensations, or even the touch of them under such
circumstances ; but if they be pricked, cut, or otherwise
injured, convulsions immediately ensue : nothing can il-
lustrate this better than the operation of neurotomy*—■
we detach the nerve from its surrounding connections,
and clean it, with little or no apparent inconvenience to
the animal, but no sooner does the bistoury wound its me-
dulla, than his struggles remind us of the acute pain we
are inflicting.
Connected with our present subject is a curious phe-
nomenon, physiologists have characterized by the term
sympathy; about which little else is known, than that
certain effects, with many of which we are all more or
less acquainted, are referred to such a source. Not
only will one nerve that is, from any cause, unnatu-
rally affected, give rise to a similar condition of its
fellow of the opposite side of the body, but derange-
ment in one set of nerves in a particular organ, will
occasion more or less disturbance in those of another,
with which they have not the least communication,
nor apparent relation. In the optic nerves, the first of
these cases is well exemplified: how often do we see—
nay, we generally prognosticate, that when one eye has
become the subject of opthalmia, the other will be,
sooner or later, also inflamed. If ahorse receive a punc-
* Vide Lecture XI.
M 2
-ocr page 199-
]64 On the Physiology of lite Brain and Nerves.
ture in the foot, simple as the wound is, yet will it often
increase the irritability of the heart so much, that the
pulse will rise to twice or thrice its ordinary quickness,,
and the animal at length sink from sympathetic fever:
and this is the more surprising, when we recollect, that
large flesh wounds, or even the division of the nervous
trunks themselves in the legs, are comparatively trifling
accidents. Nothing is more common in the human sub-
ject, than for disease of the testicles to excite vomiting;
and in susceptive females, merely beholding an unpleasant
sight, or perceiving a disagreeable odor, will now and
then have a similar effect. Breathing itself is a natural
sympathetic action ; for an animal is first compelled to
respire in consequence of experiencing an uneasy sen-
sation in the chest; (probably owing to congestion of
blood there;) though it seems afterwards to be car-
ried on through the influence of habit. Perhaps in
no instance is the action of sympathy better illus-
trated, than by observing what happens between that
part of the throat, called the epiglottis, and the muscles
of expiration; if the former be irritated, the latter will
be immediately thrown into convulsive action : in com-
mon catarrh, to this part, being inflamed, even air
itself becomes an irritant; hence cough is generally
an accompanying symptom, and one that is always
aggravated by the respiration of cold air. For the same
reason, horses cough when the weasand is tightly com-
pressed between the finger and thumb, a practice com-
mon with our horse-dealers. In disease we have nu-
merous and striking examples of the influence of sym-
pathy ; indeed, its effects are more or less observable in
all constitutional affections. In the disease called stag-
gers, the symptoms of which indicate more or less disturb-
-ocr page 200-
On the Physiology of the Brain and Nerves. 165
ance of the cerebral functions, the exciting cause is very
frequently overdistention of the stomach, the brain itself
being only sympathetically affected : and again, what is
more common than to say>" a horse is looking unhealthy
in his coat," or more demonstrative of ignorance than not
to know, that the cause of it is not to be sought after in
the skin, but in the alimentary canal.
The nerves then support sensation and volition in the
body, and its different sympathetic affections, as well as
the peculiar functions of the several organs of sense: how
far they are employed in the generation of animal heat,
we repeat, we have still to learn. In man, who holds
the first place among animated beings, the brain is not
only to be considered as the seat of sensation, and the
source of volition, but as the organ of the mind—the
part in which all those intellectual powers, for which he
is so pre-eminently distinguished, reside. Not, how-
ever, that the actions which support life are greater in
him on this account; on the contrary, they are known to
be weaker; for, we find, in proportion as the sensorial
functions are few and limited, so, in general, are the
powers of animation strong, and the restorative means
great: hence it is, that a polypus, one of the simplest
animals in nature, may be cut iu two, and both parts will
survive and grow again, and produce two distinct polypi;
, and hence it is, that the living powers of the foetus are
greater than those of the adult, although it can neither
see, nor hear, nor smell, nor taste. Such, indeed, is the in-
fluence that the mental operations have over the corporeal
in man, that there is no animal equally subject to disease,
or in whom its ravages are so extensive and insupportable:
We may yet go further, and say, that those persons whose
-ocr page 201-
166 On the Physiology of the Brain and Nerves.
passions are easily moved, present us always with the
most unfavourable aspect under disease; a remark made
long ago by those engaged in the practice of medicine.
How, or in what manner, the functions of the nervous
system are carried on, is a mystery which physiology has
not hitherto unveiled to us: though this, like other inex-
plicable phenomena, has not wanted speculative opinions,
some of which probably have tended to elucidate, though
they have one and all failed to unravel the secret.
Some have contended, that the nerves were so many
vibratory cords, and that impressions were conveyed along
them by an oscillatory motion, or vibration of them ;
others have thought that they were hollow, and trans-
mitted a certain fluid, with astonishing rapidity, through
their canals; while physiologists of more recent date,
seem inclined to resemble the nervous functions to the
phenomena of electricity, more especially to that species
of it now known by the name of galvanism.
From a multitude of experiments, the reproduction of
nerve has been so fully demonstrated, that no one at the
present day is sceptical of the fact. Whether, or not,
its precise original tissue be renewed, it is not worth our
while to enquire ; suffice be it to observe, that the nerve
is re-instated in its functions, which, to all appearances,
are carried on with as much celerity and regularity as ever.
An old experiment, but one that sets this question at rest,
is, that if the nerve which forms one of the par vagum,
or eight pair, be cut through in the horse on one side
only, no inconvenience is perceived to result; but if
the pair be divided, the animal becomes immediately con-
vulsed, and expires. If, however, there be an interval
of two, or three months between the division of these
-ocr page 202-
On the Physiology of the Brain and Nerves. 167
nerves, the animal not only survives, but appears to expe-
rience from the last operation, as little annoyance as he did
from the first: a circumstance that cannot fail to convince
us of the fitness of the regenerated portion of nerve, of the
opposite side, as a substitute for the original formation.
Veterinary practice, however, has of late adduced so many
instances of the reproduction of injured nerves, that no
member of the profession can harbour a doubt on this
point: were it not, indeed, for this power of Nature to re-
store parts to their pristine condition, we should not have
to recur to the operation of neurotomy, in those cases
where a portion of nerve has been once excised.
If a nerve be simply divided, union of it ensues, and
consequently sensation returns, in about two months;
but if a portion of it (say an inch) be excised, and the di-
vided ends allowed to retract, union and restored sensa-
tion cannot be timed : we have known them to be pre-
sent at the expiration of two years; and we have heard of
some few cases in which no signs of their return have
ever been noticed. In these cases, after a short interval,
the retracted ends are formed into little, hard, round
knobs, having a cartilaginous feel, and possessed of ex-
treme sensibility. They vary in size, from that of a pea
to a hazel nut; so that it is not uncommon, when neu-
rotomy
has been performed at the fetlock, to perceive
them formed into little prominences under the skin ;
which, in some horses, are the seat of sudden, dropping
lameness, in consequence of being struck, in going, by
the opposite fore foot*.
* Though the question of the regeneration and consequent re-
solution of function of a nerve simply divided, no longer remains
undecided in our mind, we submit the following extract from Mr.
-ocr page 203-
LECTURE XL
<*v#- **+*-s*+ *** +*r *w *+* ^srv <*^^ *v*
-
Ow Neurotomy.
^Neurotomy —for so we take the liberty to name
an operation, hitherto called, (and we cannot help thinking
Swan's valuable practical work on this subject*—one grounded
on experimental inquiry, in further confirmation of this, to us at
the present day, an important point. " It will be seen from these
experiments, in the first place, that after a division of a nerve, the
extremities of the divided portions (retract,) become enlarged and
more vascular, but especially the upper portion; and coagulable
lymph, having the appearance of white of egg, is effused, which
soon becomes vascular. In a few days the coagulable lymph from
each portion becomes united, and anastomosis forms between the
blood-vessels; the coagulable lymph gradually assumes a firmer
texture, and the number of the blood-vessels diminishes, and the
newly formed substance appears to contract, like all other ci-
catrices, so as to bring the extremities of the divided portions
nearer and nearer to each other. It is difficult to determine
from an experiment on the limb of an animal the exact time
at which the nerve performs its functions. In eight weeks
after the division of the sciatic nerve, I have observed a rabbit
to be in some degree improved in the use of its leg, but at
* A Dissertation on the Treatment of Morbid Local Affections of Nerves:
to which the Jacksonian Prize was adjudged by the Royal College of
Surgeuiis.
-ocr page 204-
■ On Neurotomy.                             169
with equal impropriety,) sometimes nerving, sometimes
unnerving, consists in the division and excision of a por-
tion of nerve, with a view of allaying pain, and relieving
lameness.
If the withdrawal of pain not to be assuaged by other
means;—if the restoration of an incurably lame horse to a
state of comparative soundness ;—if one, or both, we say,
be considerations of importance, the first on the score of
humanity, the last on that of interest:—then neurotomy
will take the lead of modern discoveries in veterinary
science. As an emanation from that institution to which
the veterinary art, as an useful branch of natural know-
ledge, owes its rise and progress in this country, it is our
duty to regard this operation in a favorable light: when
we find, however, that the professed objects of it are no
less than those we have here represented, with how much
more exultation should we, as veterinarians, hail the dis-
closure of such a valuable addition to our present prac-
tice. Such, we cannot entertain a doubt, are the opinions
of its zealous promoter; such we believe those of its nu-
merous advocates to have been ; and sucli would they
have continued to be, had they faithfully followed the in-
the end of eighteen weeks it was not perfect. When the nerves of
the leg of a horse have been divided just above the foot, they are
sufficiently restored to perform their functions in a very great de-
gree in six or eight weeks ; but it must be observed that these
•nerves are only formed for sensation,
and it is very different with the
nerves of voluntary motion"—" the re-union is sometimes accom-
plished by granulations." " Secondly, I would observe, that punc-
tures and partial divisions of nerves heal in the same way as when
there has been a total division; and that, even on the first inflic-
tion of the wounds, the functions of the nerve are very little im-
paired.''
-ocr page 205-
170                            On Neurotomy.
structions of him, who first taught them this improve-
ment in their art.
Who this was, we need scarcely mention-at so ad-
vanced a period from the first promulgation of the dis-
covery ; indeed did we not imagine that we should be ac-
cused of a dereliction of what is due to that gentleman from
the profession at large, and of esteem on our own part,
we should think it unnecessary to state, that to Mr.
Sewell, assistant professor to the veterinary college, be-
long the merit, and the reward, resulting from its almost
universal adoption. The most flattering testimony our
discoverer could possibly have received, are the futile at-
tempts that have been made to usurp the authorship of
his production; the most solacing, the unequivocal
marks of approbation conferred on it by a committee of
the governors of that institution, which is not a little be-
nefitted by the very extensive practical application of it.
We shall, in the first instance, take a view of the opera-
tion itself—looking into its merits and demerits—explain-
ing how it relieves, and in what manner it should be per-
formed, and then consider its applicability in practice.
Knowing that the nerves, as agents of the brain, convey
sensation to and from every part of the body, and that
one of the best and most obvious proofs that such is their
use, is simply the division of them, at first, it might seem
perfectly natural, that we should resort to such an oper-
ation to remove pain, which, in fact, is nothing more than
preternaturally acute sensation : we must recollect how-
ever that the nerves have other functions to perform, and
some, perhaps, with which we are not hitherto acquainted,
and that the division of them is not effected without lesion
to other parts—considerations, possibly, that have hi-
therto much restricted surgeons from similar attempts on
-ocr page 206-
On Neurotomy.                          171
the human subject. It was not to be expected, however,
that some experiments of this kind would not be made
on horses ; and, accordingly, we find that long ago, at the
veterinary college, some, consisting in simple division,
Were instituted; but the result proved fruitless : and we
ourselves divided the nerves of the arm for lameness in
the foot, in the year 1812, without being aware that the
experiment had been previously made. All this does
not detract one single iota from the praise due to Mr.
Sewell; on the contrary, it contributes to enhance
the value of his production, and to shield it from the
scurrilous attacks of dabblers in the art: for however
correctly some may insist, " that it is not a discovery,"
We contend, that it embraces all the advantages of any
one of modern date, and reflects so much the more credit
on its author, inasmuch as it has been raked from among
many rejected and valueless gewgaws of the present day.
It may now be asked, why we did not succeed ? Purely
because our knowledge of the distribution of nerves was
defective, and therefore practically of no use to us : we
thought we had divided all the nervous trunks of the arm,
and consequently had paralyzed the leg and foot; but,
in truth, we had not done so much to produce that effect,
as if one of the pastern nerves only had been severed;
for there were others left uncut, to carry on sensation, and
thwart the sole object we had in view : such errors does an
imperfect anatomy lead us into. For aught we know, the
nerves may have been divided many years ago, but if this
be an argument against the operation, why should we still
adhere to the same principles in our practice of shoeing,
when so many said-to-be new and valuable systems are
offered to our notice at this day ? Many of the improve-
ments in shoeing have been received with as much fer-
-ocr page 207-
127                              On Neurotomy.
vor for their promotion as ever neurotomy was, but few
have borne even the test of argument, and much fewer
that of experiment: neurotomy, on the other hand, after
the severe ordeal it has passed through, is still practised
by those who have not expected from it more than was
held out in the first instance, but have steadily persevered
in it as an useful addition to their catalogue of remedies.
Mr. Sewell never hoped eodem collyrio mederi omnibus,
but contented himself with adopting it as a last—an only
resource ; so that an pis aller he can incur but little cen-
sure for having practised it; and he may, and not seldom,
have the gratification to see the prematurely worked-up
hunter rescued from the slaughter-house, and restored
to the service of his compassionate master.
Our object in performing this operation, is to destroy
sensation ; and in doing this in the foot, we have not
found, that the growth and uses of that organ, so far as
its preservation in health goes, sustain impairment: we
believe that every part remains in statu quo, so long as
the whole be preserved from the effects of external vio-
lence ; and, under certain circumstances, we think that
the organ itself is even benefitted by the change. We
know also for certain, that the formation of horn conti-
nues undiminished*. Notwithstanding these facts, how-
ever, there is an argument against neurotomy, which we
cannot altogether refute, though we shall endeavour to
deprive it of some of its main supports; and that is, that
if the nerves of the foot are, comparatively speaking, of
so little use, as from this statement they would appear
to be, why is it so plentifully furnished with them,
• * It has been remarked to us, that more horn is in some cases
produced after this operation.
-ocr page 208-
On Neurotomy.                             173
it not being in the horse the organ of feeling? This
operation has certainly taught us one, if not two impor-
tant uses of nerves to the foot, which did not occur to us
before: viz. that they (the nerves) are the safeguards of
that organ in health, and, if we may be allowed the ex-
pression, its nurses in disease ; they inform the animal
when the foot is impaired, and warn him that it will be
still farther injured by being made use of:—pain is the
consequence of injury, the limb is favored, and the dis-
ease in it arrested simply from repose ; so that it now and
then subsides without medical aid. But in the insensible
foot, the reverse of this is the case : the disease is aggra-
vated by the animal's using the part as he would were it
perfectly healthy ; (he being totally unconscious of its pre-
sence ;) and a destruction of the organization of the foot,
if not the loss of life itself, may happen in consequence
of a comparatively trifling accident. Withal, however,
this is not so formidable an objection as one would at
first imagine; for, regarding the horse as an animal im-
mediately under the superintendance and management of
man, the keeper of him in health, and his attendant in
disease, it is not to be expected, that any malady would
remain long in a part so often examined as the foot, with-
out being detected ; which, in fact, is tantamount to our
being informed of it by the animal himself.
Do such horses go with that natural ease and freedom
that others possess ?—in other words, is there any differ-
ence in the action of a horse that has been so treated ?
We have always thought, and we still believe, that the
animal loses a something, probably a kind of feeling
which affects his tread sufficient to inform his rider, that
his feet are not what they originally were; for there can-
not be a doubt, (and this is one of the happiest instances
-ocr page 209-
174                             On 'Neurotomy.
in confirmation of it,) that the horse feels the ground upon
which he treads ; and so far, we contend, the foot is the
organ of feeling. We do not pretend however to restore
organization ; we do good by still more impairing that
-which remains : like the mechanic who cannot imitate
the exquisite workmanship of his master, we are content
to save the machine, imperfect as it is, from total destruc-
tion, by the removal of that which appears to be incom-
patible with its present operation. Having thus canvass-
ed two objections, which, to us, appear to have more
weight than any, or even all others, that can be urged
against the operation; we shall, or we shall overstep our
limits, dismiss this part of our subject, by saying—that,
whatever they be, they do but in a small degree deserve no-
tice, when contrasted with the benefit resulting to a horse
crippled and useless, and of no value to his possessor.
The place of operating has now become a subject of
dispute: some prefer the fetlock, the part first deter-
mined on ; others, above it; others again, operate above
the joint on one side, and upon, or below it on the other.
Mr. Sewell, and all who follow his directions, choose
now the sides of the large pastern bone—below the fet-
lock,
for the operation*. We have performed it in all
these different situations; but as our cases have been
very inferior in number and variety to those of the assist-
ant professor, we rather submit to his opinion than ven-
ture one of our own. Mr. Sewell's object in excising
the large pastern nerve, is to preserve sensation around
* Should the fetlock be the seat of lameness, (which, by the bye,
it rarely is so as to require the operation,) we must divide the me-
tacarpal nerves ; taking care to cut off the communication of the
anastomosing branch.
-ocr page 210-
On Neurotomy.                             175
the front of the foot—a part, in general, free from dis-
ease : and this is now fulfilled, since the nerve that goes
thither, is a branch from the metacarpal.
The operation is by no means difficult to him acquaint-
ed with the anatomy of the part. The horse being cast,
and properly secured, and the affected limb extended and
placed in a convenient position for the operator, an in-
cision, about 1| inches long, is to be made upon the side
of the large pastern bone, opposite to, and in the direc-
tion of, the large pastern nerve ; then, having cut through
the cellular substance, so as to lay bare the trunk of this
nerve, (anteriorly to which, and in contact with it, lies the
artery, which must be carefully avoided,) raise it with a
tenaculum, and divide it by the introduction of a probe-
pointed bistoury, as high up as the external wound will
admit: lastly, clean it from surrounding adhesions, and
detach it from the continuation of the trunk below, so as
to excise a portion about 3-fourths of an inch in length.
The operation requires to be performed on each side, there
being two separate trunks below the fetlock; and, of
course, on both legs, should both be affected. To close
the wound, we rather employ adhesive plaster than su-
ture, with straps of which the pastern may be encircled,
if the hair be closely shorn off: where suture is preferred,
the interrupted is the best, and about three or four stitches
are sufficient. The legs should be bandaged* after the
operation, and the horse not allowed to lie down during
» We commonly dip the bandages, previously to applying them,
lr» the saturn wash. It is also a good practice, to give a dose of
Physic, and keep the horse, during his confinement, on bran, in-
stead of corn. We may observe, that, in many cases, the bandages
0I% are sufficient.
-ocr page 211-
17G                             On Neurotomy.
the first night, or be moved for the three or four following
days, lest the parts be disturbed, and union by adhesion
defeated.
Though the operation admit of very extensive and di-
versified application, its subjects have been from the first
represented to be, what all subsequent experience has
shewn they ought to be, horses incurably lame; by which
we mean, cases that will not admit of relief by any other
means.
Had those who so enthusiastically listened to
Mr. Sewell in the first instance, but attended to this
short and simple precept—one that, not a little to his pre-
sent satisfaction, he has forcibly inculcated all along, they
would not have lost the confidence of their employers,
nor have reaped so short a harvest, nor have brought the
operation itself, within their sphere of practice, into
early disrepute. Surely, if any thing can convince us of
the truth of what we have just advanced, it is the unde-
niable fact, that, while many others have exploded neuro-
tomy from their practice, in consequence of the nume-
rous failures they have experienced, Mr. Sewell now
performs it with redoubled confidence, seeing that he
seldom meets with an unsuccessful case. And this has
arisen, in the greatest measure, we repeat, from a mal-
selection of subjects; though there are, doubtlessly,
faults in operating on, as well as in the management of
these horses, to which we may ascribe the unfortunate is-
sue of many untold-of cases. To our esteemed friend,
Mr. Sewell, with whom we have had some very inte-
resting communications on this subject, we are indebted
for many truly valuable and incontrovertible facts rela-
tive to neurotomy; some of which we shall now submit
to the consideration of those, hitherto led astray by false
-ocr page 212-
On Neurotomy.                             177
representations, or who may have been deterred from
operating for want of more authentic and more extensie
information.
Mr. Sewbll has operated on upwards of five hundred
horses ; and the general result of the practice shows, that
in about eight cases out of ten, full and complete success
has manifested itself, so long as the horses have remained
under his care ; for want of proper subsequent treat-
ment, however, and attention to his directions, some
few out of this number have turned out unfortunately.
Lest, then, our adversaries accuse us of cloaking, or
wishing to compromise that which, to them, may appear
a very serious and even insurmountable objection, we will
tell them, once for all, that instances are not, nor ever will
be wanting of failure, and of failures such as some have
thought proper to depict, as the dreadful effects of a cruel
operation.
But even the simplest operations may be the
forerunners of dangerous disease, if the subjects of them
are neglected, or mis-treated ; and, knowing this, should
we find that horses of this description have been regu-
larly hunted during whole seasons, indiscriminately used
as hackneys, and put to work in coaches and post chaises
upon the pave, or roads equally hard and uneven, all
which is in direct incompliance with the instructions re-
ceived by their owners, are we to feel surprised at some
unfortunate issues, or to decry the operation on their ac-
count ? But to shew how far many of these animals are
relieved, and how great are the advantages reaped by
their possessors, Mr. Seweu has received the following,
gratifying communications, accompanied with the assur-
at>ce, that many horses operated on, performed as well as
eyer they had, when they were in a state of soundness.
In a Manchester caravan several of these horses ran, in
N
-ocr page 213-
178                             On ISeurotomy.
heavy draught, for upwards of two years, at the rate of
six miles an hour, between London and Bamet: said to
be one of the most laborious stages on that road.
A postmaster, who had had several of his horses ope-
rated on, sold them at the expiration of the season of
employ, (during which time they had been in regular
work with others,) and informed Mr. Sewell, that he
received from ,£18. to £15. for each, though he valued
none of them at more than £S. prior to the operation.
Also in the "York and Lay ton coaches, some have run
for more than two years, (in the course of which time
they have travelled many thousand miles,) with perfect
satisfaction, and no little profit to the proprietors, after
having been given up as utterly useless, and destined to
slaughter.
To pass from these reports, which may serve as in-
stances of what such horses are capable, and of the space
of time we may calculate to continue them in laborious
employ, and, above all, in work attended with much con-
cussion and occasional contusion of the joints and sensi-
ble parts of the foot, and to take a still more pleasing
view of the practice of neurotomy, let us, for a minute,
inquire if any and what benefit has accrued to the army
from it \ And we can state here, that the veteriuary sur-
geons of several regiments of cavalry, both at home and
abroad, are ready to testify, that many horses, belonging
to their respective regiments, have been retained in the
service, and thereby the expence of purchasing others
saved, in consequence of having been subjected to neuro-
tomy. In none, perhaps, has it been more successfully
practised abroad, (and to the credit of their veterinary
surgeons be it said,) than in the 12th Lancers, and 18th
Hussars. Soon after the disembarkation of the latter re-
-ocr page 214-
On Neurotomy.                             179
giment from the continent, an order was received to
draught and sell about one hundred of their ineffective
horses: after the selection had been made, it was remark-
ed, that not one of the horses that had been operated on
appeared among the non-effectives.
In the Royal Artil-
lery, out of three that have been neurotomized, a very fine
horse has recently been cast, who would otherwise have
been sold two years ago, the period of his being subjected
to the operation : during this time, therefore, he has
been serving in the place of one that must have been
purchased of the dealer*.
In the Hanoverian cavalry also neurotomy has been
practised; and we are informed that it continues to be so
with success.
These facts, collected from quarters to which access is
open to us all, leave, we should presume, no doubt in the
unprejudiced mind of its application in a military point
of view, and of the policy of such a practice as a mea-
sure of public economy : indeed, " did it but render
horses serviceable for one campaign only," as one of our
most distinguished generals of cavalry observed, " it
should still be considered as of national utility."
We find by reference to Mr. Goodwin's New System
of Shoeing,
(page 89,) that neurotomy has been introduced
into the king's stables ; and we have understood from
that gentleman, that the royal establishment has, in se-
veral instances, derived peculiar advantages from it: we
say peculiar, for here it has restored horses of such value,
that their loss could not easily have been repaired. Mr.
* In the dragoons, horses of this description have been trans-
ferred, either in consequence of reduction, or departure for India,
from one regiment to another: this was the case in the 13th Light
Dragoons.
N2
-ocr page 215-
ISO                             On Neurotomy.
Goodwin is at issue with Mr. Sewell as to the place
of operating; and we are inclined to believe, that the
latter gentleman attributes some of the failures .parti-
cularized in his publication to this circumstance: but,
from the inferiority in number, and consequent variety of
our cases, when compared with those of the assistant pro-
fessor, we have no doubt Mr. Goodwin will, with us,
see the propriety of conceding a point we must at
present contend under such manifest disadvantages.
Our discoverer has not probably yet ascertained to
what extent neurotomy may, one day or other, prove
beneficial: he tells us, that he himself, by operating in
the usual manner, averted a locked-jaw from a horse in
which tetanic symptoms had shewn themselves from dis-
ease in the foot; and we will leave it even to his oppo-
nents to say, whether the two following remarkable in-
stances of its good effects, (the one Mr. Sewell's own,
the other communicated to him by a very respectable
practitioner,) do not evince the truth of this assertion.
It was found, that a mare, given up as a breeder in con-
sequence of being incurably lame, was not visited by the
ordinary periodical astrum for the male; but that the
venereal desire returned in due season, as soon as she
had undergone this operation. No doubt, it was the ha-
bitual pain the animal felt, that deprived her of healthy
and natural feelings; and if this was the theory of the
operator, we highly commend him for it, and consider the
thanks of the breeder due to him for so valuable a hint.
Last of all, we will venture to affirm, would the neuroto-
mist think of handling his knife in a case of this kind; and
we will ask Mr. Sewell himself, flattering as that gen-
tleman's views may have been when he first practised the
operation, whether such a prospect had ever presented
-ocr page 216-
On Neurotomy.                             181
itself, as to render the barren female, "by it, again suscep-
tible of impregnation ?
The other case we allude to, scarcely less worthy of
mention than the former, to which indeed it bears much
analogy, is this. A stallion of some celebrity, a crip-
ple before, in consequence of lingering and continual pain
in his fore feet, became at length so reduced in condi-
tion, and lost so much of his wonted energy, that all
desire for the female left him; so that mares brought to
him in the season for covering, were taken away again
unnoticed. It was suggested, that neurotomy be per-
formed ; and the suggestion proved not only most cre-
ditable to its author, but happy in its result; since the
horse was reinstated by it in good health, and again ena-
bled to perform his copulative functions with all his ac-
customed vigour.
Some have had recourse to neurotomy, and we think
justifiably, in canker. Supposing the case to be inveter-
ate, and there be found, as there almost always are, con-
siderable trouble and difficulty in applying the dressings,
we would, without hesitation, recommend the practi-
tioner to divide the nerves going to the foot: pain being
removed, the animal will make pressure upon the dis-
eased parts, and thereby much accelerate the healing
process.
Lastly, we may make mention of a case which has
opened the door for the introduction of neurotomy into
human surgery : whether the practice suggested itself
from its high veterinary repute, or not, we will aot pretend
to say; but as the case is a novel one, we have subjoined
the particulars of it in a note *.
The subject of this operation was a man who had a large,
sngy, bleeding ulcer of the leg, attended with such excruciating
-ocr page 217-
182                                 On Neurotomy.
It would answer no end to detail here individual cases,
whether fortunate or unfortunate in their
issue : our de-
pain that not only was he deprived of rest at night, but was
often obliged to get out of bed. At length, from profuse hemorrhage
and excessive pain, the case became so alarming that there
was little prospect of saving life, unless the limb was amputated.
The patient worn out by the terrible anguish he endured, resolved
to make this sacrifice, but, says Mr. Swan, "knowing that the
branches of the external popliteal or fibular nerve were the princi-
pal cause of the pain, from their connection with the ulcer; I de-
termined first to give him the chance of saving his limb by cutting
out a portion of the nerve.''
This operation—neurotomy—was per-
formed in the way we have here recommended, and the edges of
the wound brought together with adhesive plaster and bandage.
After the nerve had been divided, the pain in the ulcer entirely
ceased, and he had no feeling on the top of the foot when it was
touched. Two days afterwards sensation became perfect again in
the upper part of the foot. On the third day there was pain in the
ulcer, which he referred to the tightness of the bandage: it went
off again. Eighth day, wound united by the first intention. After
the operation he never had any spasms in the limb, nor any of the
violent pain which followed the course of the sciatic nerve, and
caused so much suffering. His state was rendered much more com-
fortable by the operation, but he at all times suffered pain from the
connection of the saphenus nerve with the ulcer. Though he ap-
peared to improve in health for a time, subsequent exfoliations
were followed by such a decline of it, that amputation became ne-
cessary two months after the operation. After this, he continued
in good health for three months; when he caught cold and died
of pneumonia. On dissection of the limb, the nerve that had been
divided was enlarged and much thickened: the nerves in the vi-
cinity were also enlarged, and received some new branches from
the divided extremities of the other; " and I think it not improba-
ble," says our author, " that some other branches forming a me-
dium of communication between the divided portions of nerves,
might have been destroyed in the dissection."—"Whether the new
branches had much power in conveying the nervous influence, I
cannot determine. About a fortnight before the amputation of the
-ocr page 218-
On Neurotomy.                             183
Auctions must be made from the largest collection of well
authenticated facts, by them alone our opinions adopted,
and by them aione those opinions maintained. We are
not to listen to this, or to that individual, whose practice,
however successful, has been comparatively limited, to
pay attention to any theoretical doctrine, or to lend an
ear to the pleaders of humanity; but we are to pursue
that course, which their experience has pointed out, on
whose veracity and judgment we can rely, and who have
a professional reputation at stake.
The greatest difficulty we encounter, is a judicious se-
lection of subjects : and here the investigation of the na-
ture, seat, and duration of the lameness, and the proba
ble event of such an operation, are, above all other con-
siderations, to be attended to. But, be the case what it
may, observe, we do not propose neurotomy for the in-
curably lame, but restrict it to the incurably lame and use-
less
horse; though, where but one leg is diseased, and under
some particular circumstances where both are, we may and
do deviate from this general course : like the surgeon who
refuses to operate for cataract before his patient has lost
all useful vision, by thus limiting our views, we shall
never incur reproach, even though a failure be the result.
Furthermore, we would lay down the following rules
for guidance in practice : —
1st. Any kind of chronic lameness about the foot, or
coronet, with the exception of that arising from pumice-
feet, may require the operation.
limb, I pressed on the part where the nerve was divided, and the
Patient said he felt it quite down the leg." Observations on some
points relating to the Anatomy, Physiology and Pathology of the Nervous
System, by
Jos. Swan, Member of the Royal College of Surgeons, &c,
-ocr page 219-
184                             On JScurotomij.
Ind. Should inflammation be present in the foot, pas-
terns, or fetlock, it is always to be reduced prior to the
operation.
3rd. If we suspect ulceration of the joints—of the li-
gaments, tendons, or articular cartilages, we should not
operate; since neurotomy will aggravate the disease, by
enabling the animal to make use of parts, unfit, in their
present condition, to bear either pressure, or motion.
4th. Neurotomy succeeds best in those cases in
which lameness is accompanied by an alteration in the
form and texture of the hoof, (pumice-foot excepted,)
and where all previous disease has terminated in this :
indeed, to some horses lame from anchylosis, partial
or complete, it seems often to convey permanent be-
nefit, by inducing them to exert these parts more,
and thereby obtaining, in process of time, some small
degree of useful motion in joints before stiff and im-
moveable.
Mr. SeWell finds, that in cases of entire section of a
nerve, sensation returns in about two months ; but in
others, in which a portion of nerve has been excised, that
the period of restored feeling can by no means be foretold :
in one of Lis own horses, he ascertained that there was
no sensibility in the foot even at the expiration of three
years ; and in some others, after a longer interval, the or-
gan appeared to be wholly destitute of it. The cast
horse belonging to the Royal Artillery, of which we have
lately made mention, evinced as much feeling as any
other would have done, whenever we pricked, with a
pin, either of his fore feet: this was after an elapse of
two years. Whether lameness invariably returns with
the restoration of sensation, is a question we cannot
-ocr page 220-
On Neurotomy.                             185
decide—it must so much depend on the nature of the
case *.
Mr. Swan, from whom we have both in this and the
last lecture taken the liberty to transcribe on this subject,
says, in relation to this part of it, " that when a portion of
nerve has been removed, the restorative process is set up
in the same way as when there has been merely a division
of the nerve ; but the extremities of the divided portions
afterwards present such appearances, as to lead to a sup-
position that the nerve will never again be restored."
This had almost induced Mr. Swan to believe so,
when the case of a horse occurred to him, that had un-
dergone neurotomy; in which the lameness returned in
six months after the operation. But as lameness might
have proceeded from other causes, independently of dis-
ease in the foot, its return is not to be attributed, without
a minute inquiry into the nature of the case, to the resti-
tution of feeling. So far from agreeing however with
Mr. Swan's informant—that'■ this is not usually the
case where so large a portion of nerve has been re-
moved," we believe that in the generality of instances
sensation is only lost for a time ; but to this time we can-
not at present set precise limits. How far the process
may be accelerated by irritation from disease in the foot,
vve do not know—in truth, we do not very clearly see the
connexion between them.
We cannot refrain, before we close this subject, from
again enforcing attention to that injunction which is to
direct us in the selection of subjects. The incurably
lame and useless horse,
is him alone for whom we recom-
*t appears to be less likely to return in cases of contraction,
than in affections of joints.
-ocr page 221-
186               On the Diseases of the Nerves.
mend it; our object being to render an animal service-
able during the remainder of his life, who, otherwise,
must have been given up, as utterly valueless', for slaugh-
ter. None who have given the subject of neurotomy the
least reflection, could conceive that the operation was ever
intended to supercede other remedies ; the very nature
of it is such, that, as a dernier resource, it is only appli-
cable to adesperate and hopeless case; and if it succeed in
restoring one of this description, it is of more value and
consideration to us, than if it was only applicable to such
as we can relieve by other and simpler means. In con-
cluding, let us remark, that we do not recommend such
horses being raced, hunted, or put to amj other extraordi-
nary exertions:
they may be driven in harness, and are
more especially qualified for four-wheeled carriages, or
leaders in others ; in short, for situations where no weight
is incumbent upon the body.
In this point of view—its objects being thus circum-
scribed, we dare prophecy, that neurotomy will be known
as long as the veterinary art :—it has hitherto stood the
test of this capricious age, and weathered out the storm
of discordant opinion;—it has ranked high in the estima-
tion of its more enthusiastic advocates;—it has fallen
into disgrace and comparative dread with those who have
misapplied.it;—it has now to rise to a certain point in
the scale of veterinary surgery, where it will remain in
despite of all future controversy.
On the Diseases of .the Nerves.
The nervous system is much more subject to derange-
ment of function, than to disease of structure; we un-
derstand so little however about its physiology, that
we must necessarily be much in the dark in our theory
-ocr page 222-
On Tetanus.                               187
of its diseases : in truth, we know little of them but from
their effects. Perhaps the most painful affection to which
the human body is liable is tic doloreux; one that is
generally believed to be a disease of the nerves, though,
by some writers, the seat of it is referred to the brain;
since no alteration of structure is ever perceptible in
the nerves of the affected parts. One of the most for-
midable, as well as most incurable diseases of veterinary
nosology, is that which we are now going to consider.
On Tetanus.
We have ranked tetanus, or locked-jaw, among the
diseases of the nerves, in order that its effects may be
better understood ; though human nosologists, in gene-
ral, treat of it as a cerebral affection, confessing however,
one and all, that its real nature is still wrapped in ob-
scurity. Instead of accompanying them into the depths
of conjecture, as to the proximate cause of this fatal ma-
ladv, it will be more consistent with our present views,
to detail the symptoms by which it is known, examine
the apparent causes that induce it, and offer such reme-
dies, by way of treatment, as our own experience, and that
of some skilful practitioners, have shown to be most
effectual.
Tetanus consists in a spasmodic contraction, more or
less general, of the muscles of voluntary motion, and espe-
cially of those that move the lower jaw : hence the vul-
gar name for it of locked-jaw, and the technical one of
trismus.
An animal labouring under this disease, has little or
no power over his muscles ; so that he either moves the af-
fected parts with considerable difficulty, or, in consequence
of the severity of the spasm, is unable to move them at
-ocr page 223-
188                                On Tetanus.
all. Its attack is commonly gradual. The horse
first evinces a degree of inflexibility of the neck, in mov-
ing his head, which is, in the course of a day or two,
succeeded by so much rigidity of it, that he is unable to
turn his head to either side, without at the same time
moving his body and fore legs. The groom complains,
that the animal does not eat with his wonted appetite,
and that he either cuds his food, or appears to have some
difficulty in swallowing it: this leads to an examination
of the jaws, which are found either much restricted in their
motions, so that you can only open the mouth to a cer-
tain extent, or completely locked—inseparably closed:
under whicli circumstances, all your efforts to sunder
them prove fruitless, so obstinately are the incisor teeth
maintained in contact by the powerful spasmodic action
of the masseter and temporal muscles. The eye is com-
monly the next object of attention: if, in efforts to elevate
the head, we perceive the haw projected over the cornea,
we may at once pronounce the case to be tetanus, though,
as yet, no other parts than those we have named appear
to be affected; and we have known one case in which the
symptoms made no further progress—but gradually sub-
sided, as if from the timely administration of our reme-
dies. Most commonly, however, the disease advances,
attacking other muscles iu irregular succession, and with
different degrees of severity. The limbs now, should
they have escaped spasm in the primary stage, become
so stiff, that progression is either rendered aukward and
unnatural, or altogether impeded: in severe cases, both
fore and hind legs are stretched out in different directions
under the trunk, so as rather to resemble, in their position,
the four props of support of a common form, than the
limbs of a living animal. At this time, the back and loins
-ocr page 224-
On Tetanus.
189
are shrugged up; the tail is elevate and tremulous; the
hair on end ; the ears erect; the eyes wild, and turned
askaunt; the nostrils expanded ; and the countenance al-
together displays a degree of eagerness and anxiety not
easily mistaken : in short, the poor animal exhibits a
truly impressive and pitiable aspect, too characteristic of
the state he is in to admit of the shade of a doubt. The
spasm is not constant—it remits at intervals, so that the
animal experiences some periodical mitigations of his
painful malady : indeed, this explains that tremulous, qui-
vering motion of the tail, so remarkable in this disease.
In consequence of the diaphragm being occasionally
affected, respiration becomes unnatural: the motion of
the flanks is quicker than ordinary, and is generally at-
tended with some irregularity. The involuntary muscles,
however, do not appear to be much influenced in teta-
nus ; so that the pulse in the beginning is only either a
little quicker than common, or remains altogether undis-
turbed ; though towards the latter stages it will become
accelerated and small, and sometimes irregular: and in
respect to the bowels, though they be confined, then-
torpor is by no means such as would indicate spasm.
But the pulse, though unaltered by the disease, acquires
commonly such extreme irritability, that, if the animal be
agitated, or alarmed in any way, it will often, on a sud-
den, beat with twice or thrice its former celerity, and
then subside, with the alarm, into its natural state.
In this country, we should say that tetanus was a more
frequent disease among horses than in the human sub-
ject : it is one of the most dreadful in the catalogue of
those of the latter ; and, if we may argue from the general
analogy 0f the cases, none that we know of seems to pro-
duce equal suffering in the former.
-ocr page 225-
190                                On Tetanus.
This is a disease of uncertain duration. It commonly
lasts for a few days, or a week, or two, and then, unless
it previously end in death, gradually subsides; it may
however be protracted much beyond this period : in either
case, when the animal recovers, the spasms leave him slow-
ly, and by degrees ; so that it is often a very considerable
time before he regains the perfect command of his mus-
cles. When the attack has been severe, it leaves the horse
much debilitated and out of condition.
Tetanus may arise from one of two kinds of causes: it
may be a consequence of local injury; or it may be in-
duced by some agent, whose iufluence appears to be on
the system at large ; and this has given rise to the division
of it into symptomatic, and idiopathic. In the human
subject, this disease is more commonly produced by
wounds, especially of tendinous structure: thus a punc-
tured hand, though it be a part remote from the brain,
has frequently been the forerunner of a tetanic affection ;
and it has been remarked by surgeons, that tetanus origin-
ating from such cause, is more likely to prove fatal, than
when it appears to have been spontaneous. In the horse
we may often trace it to this source; and we are inclined
to believe, that lesion of tendinous structure is most fa-
vorable to its production : whether this be true, or not,
tetanus often supervenes on the operations of nicking
and docking, and on punctures in the foot; though
doubtlessly, as in the human subject, injuries of parts
of a total different nature may give rise to it. In the ge-
nerality of cases, the disease makes its appearance after the
wound has healed. With regard to idiopathic tetanus,
or that which appears without any very apparent cause,
we have not the same well-authenticated testimony for
referring it to sudden change of temperature, as writers on
-ocr page 226-
On Tetanus.                               191
human pathology can adduce : they have found it to be
a disease more prevalent in hot than in cold climates, and
one of rarer occurrence in Scotland than in England ; and
they have ascertained, that the most frequent cause of it
in warm countries, is the application of cold to the sur-
face of the body when heated. Notwithstanding even
these facts, however, medical men are by no means agreed
in referring it to such a cause ; for if alternations of heat
and cold induced it, we ought to have more frequent in-
stances of it in this country. As far as our own observa-
tions have gone, horses in stables and at grass, both in
summer and winter, are the subjects of it; we cannot,
therefore, under such circumstances, agree with those who
attribute it to cold; and we regard their opinions as still
more hypothetical, who ascribe its origin to worms*.
We are very far from knowing what plan of treatment
is recommendable in this disease: it most frequently
baffles every mode of practice ; though, now and then,
it yields to a class of remedies, which, on repetition in si-
milar cases, proves totally inefficacious ; whereas some-
times the animal recovers, though nothing, or, (what is
tantamount to nothing,) some inert remedies only be made
use of. In those cases where symptoms of tetanus have
followed nicking or docking, if the attack be recent,
and still in an unconfirmed stage, we would most decid-
* At the Veterinary College, have lately been met with two fa-
tal cases of tetanus, in which thecuticular coat of the stomach was
extensively eroded ; in one, indeed, few or no vestiges of it remain-
ed—the surface every where presented ulceration of the internal
c°at, and the muscular was twice or thrice its ordinary thickness.
In one horse the disease was idiopathic; in the other, the sequel
of a wound in the arm: in both, it was believed, that nothing but
aloes had been administered.
-ocr page 227-
192                               On Tetanus.
edly recommend that the extremity of the dock be cut
off with a sharp docking-iron, so as to make a new and
clean wound, or even that the tail itself be removed
—should it have arisen from nicking: in such cases,
however, as are marked by considerable advance of the
disease, little benefit, we fear, is to be expected from these
means. In cases of punctured wounds, or others in which
the external opening is but small, it is generally proper
to enlage the outlet, by making a free incision; in doing
which, it has been a laudable object of practice, in the
human subject, to cut off all communication between the
injured part and the brain, by dividing the nerves*. The
actual cautery, and some of the most active caustics, may
also occasionally be had recourse to with the same view.
Should we not succeed in subduing the approaching
spasms by the fulfilment of this—our first indication, viz-
the removal of the exciting cause—of which indeed there
is but too much apprehension, we are to proceed, without
delay, to the general or constitutional treatment. While
our knowledge of the proximate cause, or nature of this
disease, remains clouded in so much obscurity, we are not
to expect to institute a mode of practice grounded upon
strictly scientific principles: most of our remedies are
purely empirical, or such as have suggested themselves
from the different views that practitioners of human me-
dicine have taken of it. Some who have, and properly
enough, regarded it as a spasmodic affection, have pre-
scribed such medicines as are called antispasmodics, of
which class opium is the chief: it has however failed in
the majority of cases. Camphor and assafcetida have been
* We have made mention of a tetanic attack being averted in
the horse by having timely recourse to this operation; but we are
not in possession of the particulars of this case.
-ocr page 228-
On Tetanus,
193
conjoined with it sometimes, but, and for obvious reasons,
with no good effect; for both these medicines are totally
inefficacious in the doses in which they are commonly ex-
hibited. The cold bath, or what is the same in effect, the
affusion of cold water, and the removal of the horse into
the open air, should he have been attacked in the stable,
has had some very staunch advocates, to whose opinion we
would gladly subscribe, did not the result of our practice
forbid it: all we have to observe further about the expe-
riment, is, that we have failed in every instance in which
the plan, usually recommended, has been adopted. Ve-
nesection has frequently appeared to confer considerable
benefit; and though, like all the others, it has in too
many cases failed to give relief, we should be inclined to
place more dependance in this, than in any individual re-
medy with which we are acquainted ; and in saying thus
much, we think we are borne out in practice: indeed the
supporters of the use of the cold bath themselves, seldom
put much confidence in the sanative effects of cold with-
out the accompanying use of the lancet. We would carry
this practice further than is commonly recommended, and
more especially in those cases where the pulse indicated
any thing like inflammatory action in the system. Ano-
ther remedy, in our humble opinion, only inferior in im-
portance to the former, is the application of a blister to
the skull, and whole length of the spine : for this purpose,
let the hair be closely shorn from the skin covering
the forehead and vertex, from the sides of the neck, di-
rectly opposed to the cervical vertebrae, from the lateral
parts of the withers, and from the ridge of the back and
loins, as far as the tail; having done which, apply a
pretty thick layer of the common blistering ointment to
o
-ocr page 229-
194                               On Tetanus.
the surface. In the course of ten or twelve hours, whe-
ther it have taken effect or not, clean the skin with hot
water, and repeat the ointment; and this should be done,
from time to time, as occasion may require: our object
being to inflame these parts, and keep up from them a
continual discharge*. In addition to these operations,
we must procure evacuations from the bowels ; and no
medicine will insure this effect so well, as from one to
two drams of calomel, combined with eight, ten, or twelve
of aloes; according to the size of the horse, and the exi-
gence of the case : and this we are to take care to admi-
nister as early as possible, lest the jaws become so fixed,
that both food and medicines are inadmissible. Should this
already have taken place, we may try to give a larger
dosef of aloes in solution, and aid its operation by the fre-
quent exhibition of copious glysters composed of this me-
dicine in any emollient menstruum. A loose stall, or a
well-ventilated box of large size, in which he can turn
about loose without inconvenience, is the preferable ha-
bitation for the animal. Should his jaws be so locked as
to render mastication either very irksome, or altogether
impossible, attempts to drench him with water gruel, or
* At the veterinary college, it has of late been the practice to
insert setons in the neck, back, and loins, in addition to the blister,
for our own part, we prefer the frequent repetition of blisters,
f Not less than two ounces according to this formula:
R Aloes Vulg. Pulv. ,fij. vel .f iij.
Potassas Subcarb. ^i.
Acaciffi Gummi f iss.
Aqua? Ferventis ft j. Solve, etadde
Spts. Vini rectificat. Jjj.
-ocr page 230-
On Tetanus.                            195
other nutritive fluid, should be frequently made, in order
to support him under the worst stages of this awful ma-
lady. When the progress of the disease, from its onset,
has not been rapid; when the spasm is not universal;
and when its duration has become considerably protract-
ed ; we may cherish some faint hopes of the animal's re-
covery : under circumstances the reverse of these, how-
ever, we may look forward to speedy dissolution.
o 2
-ocr page 231-
LECTURE XII.
On the Muscles.
M
USCLES are bundles of fleshy fibres, abundantly
distributed over an animal body, for the purpose of pro-
ducing motion of its several parts: muscle andjlesh, in
fact, are synouimous terms. The chief bulk of an ani-
mal is made up of muscle: every motion of his different
organs, both external and internal, is either directly or in-
directly effected by means of muscle; all his power of
action resides in muscle; even the preservation of life it-
self is dependant on muscular motion.
We are not prepared to state the number of muscles in
the horse ; nor would such a knowledge prove of any uti-
lity to us: that in the human subject is estimated at about
five hundred.
Muscles have been divided, according to the course
and disposition of their fibres; first, into rectilineal or
straight, as the rectus abdominis, and sartorius ; second-
ly, into half, and complete pennif'orm, as the vasti, and
rectus of the hind extremity; thirdly, into radiated, as
the obliquus internus abdominis, and serratus magnus ;
fourthly, into hollow, as the bladder, intestines, and
heart.
-ocr page 232-
On the Muscles.
197
Muscles have received various names,according to their
shape, use, attachment, course, comparative size, &c.
thus, we have the rhomboideus, trapezius, and quadratus,
so called from their figure; the levator, depressor, ex-
tensor, and flexor, from their different uses; the supra
et infra spinati, the intercostales, and sterno-maxillaris,
from their situation and attachments ; the obliquus, rec-
tus, and transversalis, from the direction of their fibres;
the maximus, medius, minimus, magnus, parvus, longus,
and brevis, from their comparative size ; the semitendino-
sus, and semimembranosus, from their composition. Our
best writer on veterinary anatomy, Stubbs, has adhered,
in his description of these parts, as nearly as possible, to
the nomenclature made use of by human anatomists ; and
there are so many forcible objections to any deviation
from this procedure, that we shall at all times adopt it,
unless forbid by palpable inconsistency.
In describing the attachments of a muscle, it is found
convenient to divide it into three portions, to which differ-
ent names are assigned. That extremity from which it
arises, commonly connected to some fixed, or very limit-
edly moveable part, is called its origin, or head; the
other, implanted into the part to be moved, the insertion,
or termination of it; while the portion intermediate—be-
tween its head and termination, receives the name of body,
or belly.
Muscles are composed of two substances altogether
different, both in regard to their structure and use. The
chief part of a muscle, (of some the whole,) is consti-
tuted of fleshy fibres, whose color, commonly red, is
wholly dependant on the quantity of blood they contain ;
for if these red fibres be steeped, but for a short time, in
water, they may be rendered perfectly white. Indeed,
-ocr page 233-
198                              On the Muscles.
redness is by no means essential to these organs, for many
of them are entirely colorless ; which we have instanced
in the stomach, the bladder, the intestinal canal, and the
muscular coats of arteries; and yet these parts are simi-
lar, both in structure and economy, to the red and larger
muscles of the body. We know also, that in many fish,
the muscles are white; and we have a good specimen
of the same, in those of the breast and wings of our com-
mon domestic fowl.
The fleshy part of these organs, we have said, is
fibrous; and their fibres are disposed in packets or bun-
dles, called fasciculi, which run in lines parallel to one
another, and are connected together by cellular mem-
brane. At first sight, these fasciculi, or fleshy packets,
appear to be of large size ; but if we proceed to unravel
them, we shall find that the fibres of which they are
made up, are composed of numerous fibrilla, or smaller
fibres, and that they themselves are so many fasciculi:
these again, by prosecuting the examination, will be
found to be divisible into others still more minute; so
that, in truth, the ultimate fibre of a muscle cannot be
discovered. The fasciculi fare much larger and coars-
er in some muscles than in others: e. g. in the glu-
teus maximus, a muscle of the buttock, their texture
is extremely coarse, whereas in the small muscles of the
eye it is remarkably soft and fine ; and even the cellular
membrane, by which they adhere together, varies some-
what in its tissue in these parts. It is for this reason,
that some joints, and also parts of joints, of beef, mutton,
8cc. are much tenderer, and better flavoured than others ;
and therefore commonly preferred for the table.
The fibres of what are called the involuntary muscles,
are in general of finer texture than those of the voluntary,
-ocr page 234-
On the Muscles.                             199
as well as shorter, and extremely irregular in their course:
e.g. the heart is composed of strong and red, but by no
means coarse fasciculi, which, from running in all direc-
tions, enable it to contract its sides with considerable
effect; and the bladder and stomach are furnished with
muscular fasciculi, pale, and slender, and alike differently
disposed.
                                                                        _
Various conjectures have been offered, from time to
time, as to the ultimate structure of these minute fibres ;
but physiologists have not as yet come to any definite
conclusions on the subject. It is generally admitted, that
they resemble in composition the fibrine of the blood,
that they are disposed in straight lines in regard to one
another, and that they are inelastic; for though muscles
appear, when stretched, to possess some elasticity, it is
a property they owe to the cellular membrane connecting
their fasciculi together, and not one inherent in their com-
ponent fibres. The opinions, that their primitive fibrillar
are the continuations of the extremities of nerves—that
they are composed of cells, or hollow tubes, or vesicles,
are now altogether rejected; as well as the suppositions
of their being, in figure, globular, rhomboidal, &c.
The fleshy part of a muscle is extremely vascular.
Though small, its arteries are so numerous, that some
authors have thought that the blood which they contain,
not only served it for nourishment, but had some share in
the performance of its functions. Their veins are pro-
portionally abundant.
Their nerves are small, and ramify extensively in their
substance : lymphatics also have been seen in them in
considerable numbers. Muscles however are not very
sensible parts : when cut, in experiments on living ani-
mals, although their fibres contract as soon as divided,
-ocr page 235-
200                                 Oil Tendons.
and appear to shrink under the knife, we never find any
very considerable pain evinced by the animal at the time;
and, in amputation, surgeons have remarked, that their
patients, generally speaking, complain but little after the
division of the integuments.
On Tendons.
Tendons are to be regarded as parts of, or appen-
dages to muscles. They were formerly supposed to be
made up of fibres continued from the fleshy part,
more closely compacted; this opinion, however, though,
at first view, plausible enough, has been withdrawn, since
their composition and texture have become the subject of
more accurate examination. It is now ascertained, that
tendons, though fibrous, are, unlike muscles, chiefly con-
vertible into glue by long boiling; and that their fibres,
in many instances, are taking a different direction alto-
gether from those of the muscles to which they belong:
the most obvious distinction, however, between muscle
and tendon, and one which sets this question at rest, is
that of function, as we shall hereafter have occasion to
point out.
The fibres of tendons are white, glistening, and inelas-
tic, and possess but little vascularity when compared with
those of muscles : hence arises their disposition to slough
—not a very uncommon effect of injury to them in the
human subject, even as high up as their origin from the
muscles. Nerves cannot be traced into them, and animals
express no pain when they are injured*: but the theca,
* Although tendons appear to have no feeling in health, they are
(or at least their granulations are) very sensible in disease : we have
shown this by pricking and cutting the extensor tendon, divided, or
-ocr page 236-
On Tendons.
201
or sheaths investing them, possess sensibility; and it is:
from this circumstance, that inflammation from sprains
of these parts, is productive of so much pain. Absorbents
in tendons are very scarce; for which reason, ulceration
in them is an exceedingly tedious process : so that if mat-
ter be poured forth under a tendinous fascbia, unless we
discover its presence in time, and give it free issue by
puncture, it will burrow among the muscles, or other soft
parts, and produce extensive mischief; whereas, had it
been collected under the skin, ulceration of the integu-
ment would have readily discharged it, without any surgi-
cal assistance.
Tendons are of different forms'—either round, flat, ex-
panded, or bifurcated—and are continued from the bellies
of muscles to bones, and other parts, into which their fi-
bres are implanted. They are, in general, enveloped in
thin membranous, or cellular sheaths; though in some parts
they have theccE of similar composition to themselves; as
is the case with the tendo perforans, which, at the fetlock,
is enclosed within a theca formed by the tendo perforatus.
The use of tendon is to connect muscles to those parts
destined to be moved by them. Sometimes it serves to
give greater strength to them at their origin. In some
places, more particularly in the extremities, by occupying
less space, tendon preserves the symmetry of parts, and
allows of more extensive action : for this reason, we sel-
dom see any thing but tendon passing over a joint. Were
it not for such an admirable and convenient substitute for
muscle, the legs would be as thick as the arms and thighs,
Partially so, in cases of broken knees: the animal withdraws the
hmb as often as this experiment is made, and commonly evinces
considerable feeling—we have had occasion to make this remark
already, in a former lecture.
-ocr page 237-
202                  On the Diseases of Tendons.
and consequently not only very unsightly, but incapable
of many of those movements which they now perform
with the utmost facility.
Afaschia is an expansion, commonly of tendinous
structure, which serves to bind down the muscles, chiefly
of the extremities, and prevent displacement of them when
in action. If a man have to raise a heavy weight, he fre-
quently makes use of some artificial bandage around his
arm, by which he finds his muscles so supported, while
in action, that he is enabled to perform the labor with
less effort: this explains the chief use of faschia.
On the Diseases of Tendons.
Tendons are subject to inflammation in consequence
of sprains. Those of the flexor muscles of the fore legs are
commonly the seat of this injury : in them it is described,
in most works on farriery, under the head of " sprain,
or clap, of the back sinews." In investigating the na-
ture of this accident, we wish to confine ourselves to the
injury sustained by the tendons themselves, and not
complicate it with that of many other parts in the vici-
nity, which, the least reflection will show, may, and very
often do partake of it in severe cases of this kind.
What is called a sprain, or strain of the flexor tendons
of the leg, does not, in the generality of cases, consist in
any preternatural extension of those parts, but in a lace-
ration of that cellular membrane which connects them to-
gether, and of which the thecae for them is composed, in
their passage between the knee and fetlock-joint. We do
not mean to contend, that in the worst accidents of this
kind the tendons may not be stretched, and even partially
ruptured ; but we would reject the accounts of writers al-
together, in reference to their being torn asunder, as wholly
-ocr page 238-
On the Diseases of Tendons.                   '203
unsupported by the actual inspection of these parts, and
thus far disbelieve that a horse was ever broken dozen.
Professor Peel, who has no competitor as a veterinary
pathologist, in his work on the Diseases of the Horse,
says, " I am strongly inclined to believe that the rupture
of the back sinews in horses, is a very rare occurrence in-
deed, although I am far from denying the possibility of
such a circumstance." In the human subject, it is true
that the tendon of the heel is not unfrequently broken ;
but only reflect, for a moment, on the comparative size
and strength of the tendo achillis and the gastrocnemii
muscles, and then turn your attention to the flexor mus-
cles and tendons of the horse ! Moreover, in dancing or
jumping, the gastrocnemii of one leg are often absolutely
sustaining the weight of the whole body ; but do the flex-
ors of a horse ever do this?—muscles that are not even
believed to be concerned in progression. Lastly, we have
appended 2 cwt. to the tendo perforans without rupturing
it. From these facts, then, and from some others that
might be adduced, we would even deny the possibility of
rupture of the flexor tendons in a sound and healthy con-
dition.
As laceration of the cellular membrane must, in most
instances, be accompanied, not merely by extension, but
by rupture of its blood-vessels and nerves, the immediate
effect of this accident will be more or less extravasation of
blood; and this accounts for the swelling, and (by its
pressure upon the injured nerves) for the tenderness, of-
ten perceptible soon after it has happened: we some-
times meet with cases, however, in which we cannot dis-
cover tumor, or tenderness ; but in them lameness seldom
appears prior to the supervention of inflammation. When
the sprain has been violent, extensive tumefaction of the
-ocr page 239-
204                   On the Diseases qf Te/idoits.
back part of the leg immediately ensues, attended with
considerable pain—if we may estimate it by the limping
gait of the animal, as he is led to the stable : quickly after
inflammation supervenes—the parts become hot, more
swollen, tense, and exquisitely sensitive; and the horse
projects the limb a little, stands tottering with it upon the
toe, and keeps the heel elevated. About this time, the
system sympathizes from the extreme pain in the part,
and symptomatic fever is ushered in :—the horse grows
dull and languid, his flanks heave, his pulse becomes ac-
celerated and strong, and his mouth feels hot and dry;
and to such an alarming degree may these symptoms in-
crease, that, if the animal be not in some way or other re-
lieved, even death itself may step in, and put an end to
his sufferings.
Sudden and violent exertion of any kind, and more es-
pecially at a time when the animal is unprepared for the
shock, is the exciting cause of this disease : racers, hunt-
ers, and such horses as are ridden hard on the road, are
the most common subjects of it. Hard galloping upon
boggy ground—unexpectedly leaping into a blind ditch—
or setting the foot on a sudden in a rabbit hole, frequent-
ly produces it. Perhaps the improper use of thin-heeled
shoes, and the imposition of more weight than, from age
or conformation, the animal is able to carry, may now and
then have the same effect.
The treatment of a slight sprain is very simple. If the
leg be but little swollen, and the lameness inconsiderable,
the use of some refrigerent, or evaporating lotion*, with
a well applied bandage, will be all that is required ; or—
* Either the Liquor. Plum. Subacet. Dilut.; or that in com-
bination with Vinegar, or Spirits of Wine.—Vide Lecture V. Local
Treatment of Inflammation.
-ocr page 240-
On the Diseases of Tendons.                  205
a practice some prefer, immerse the leg in spring water,
and let the horse stand up to the knee in it for several
hours in the day, using the bandage and cold wash only
during the night. When there is much heat, swelling, and
tension of the leg, however, our treatment of the case must
be more active. In the first place, we are to draw blood
to the amount of from four to six pounds; and this we
can always do, with as much effect as locally, by removing
the horn at the toe and puncturing the anterior coffin arte-
ry, or opening the cephalic, or saphena vein, according as
it is the fore or hind leg affected. We should also at
this time exhibit a full dose of purgative medicine*-
Emollient applications are here to be preferred to
cold : fomenting the leg with warm water, or, what is
more effectual, steeping it in the same manner as that in
which we have recommended the use of the cold, will
tend much to the reduction of the inflammation, and con_
siderably alleviate the animal's sufferings. When the
heat and tenderness have much abated, we prefer immer-
sion in cold to warm water, or have recourse to the evapo-
rating lotion and bandage ; taking care, however, not to
apply the bandage tightly, until the animal can bear mo-
derate compression of the leg with the fingers. Rest is in-
dispensable : it is an erroneous practice to turn horses into
loose stables at the onset of this disease ; though it is of
great service to them when the inflammatory action has
subsided ; which you may determine on by the feel, and
by the animal's walking sound.
Nothing is more common in aggravated cases, than for
* R Aloes Vulgar. Ext. 3vij.
Ol. Carui gtt. xl.
Sympi q. s. ft. Bol. for ahorse 0/ordinary size.
-ocr page 241-
20(5                   On the Diseases of Tendons.
much obstinate swelling and induration to remain after we
have entirely suppressed the inflammation. Tumefaction
in the beginning is simply the effect of a coating of adhe-
sive matter, filling up the cellular substance between the
tendons and the skin ; as soon as the case has turned
chronic, however, a gradual change takes place—the effu-
sion becomes organized, and firmly adherent to, and con-
tinuous with the surrounding parts, whose nature, ulti-
mately, it partakes of; gluing the whole together into one
solid mass, tightly binding down the skin, and more or less
impeding the motions of the ligaments and tendons: and
now we perceive why horses continue lame, and some-
times irrecoverably so, after all heat and tension have dis-
appeared. In order to remove this adventitious deposit,
we may first try some discutient*; and, at the same time,
if the season permit, turn the animal into an open pad-
dock for a few hours in the course of the day. Should
this thickening, however, not readily give way, the applica-
tion of a blister, and its repetition about every fortnight,
or three weeks, will generally promote absorption of it.
In old, or prematurely-worked-up roadsters, hunters, and
racers, w hose legs have failed from repeated and aggravat-
ed injuries of this nature, we should, generally speaking,
after having reduced the existing inflammation by the use
of some of the aforementioned remedies, make frequent
use of blisters : we wish to enforce this, in order that time
may be given to the parts to recover their wonted condi-
tion and tone, while we are assisting them to do so, by
refraining from all further violence, and exciting the ab-
* R Amnion. Muriat. ^ss.
Acid. Acetos—Spts. Vin. Ten. ana  f vijj. M.
Some to be rubbed upon the le,g; and a  bandage wetted with it,
kept tightly applied.
-ocr page 242-
On the Diseases of Tendons.                   207
sorbents to remove the interstitial effusion. The com-
mon practice in these cases, more particularly with farriers
and gentlemen horse-doctors, is to fire and blister. Now,
we will not ask these individuals—but we will put the
question, seriously and conscientiously, to any veterinary
surgeon, whether these remedies are required at the same
time—whether there is such an affinity between a red hot
iron and an ointment made of cantharides, corrosive sub-
limate, and lard, that the first can on no occasion be had
recourse to, without being followed up by the last ? With
the intention of gaining a clear view of this important sub-
ject, it is desirable that we should be made acquainted with
the modus operandi of the actual cautery, which appears
to us to have been in part overlooked. First, the cautery
extinguishes the life of the part to which it is immediately
applied; secondly, as a direct and powerful stimulant, it
excites inflammation ; thirdly, eschars appear—the dead
parts scale off; fourthly, furrows, where the skin is defi-
cient, remain to granulate and cicatrize : there is also more
or less interstitial effusion. The fourth and last effect of
the cautery will explain its ultimate and most beneficial
operation—as a bandage; for Nature here does not form
new skin—no ! that would be an expensive and tedious
process ; but She contracts the cauterized edges of the old
to restore its integrity, and, in doing so, braces the parts
underneath with much more effect than we could by the
best contrived bandage. Seeing, then, that excessive sti-
mulation and perpetual pressure are the principal effects
of the actual cautery, and knowing that those of an es-
charotic blister are excessive stimulation and serous ex-
udation from the surface*, we cannot discover, we repeat,
the intimate relationship between them. For the present,
* Vide Lecture IX.
-ocr page 243-
208                 On the Diseases of Tendons.
we will leave the subject here—we fear, we have said
enough to kindle the wrath of those whose opinion we
will not ask, if not to raise up in arms against us some of
our veterinary colleagues : influenced however by a desire
to improve our art, while we avoid all unnecessary torment
in the practice of it, we trust that no misconstruction will
be coupled with our motives.
We are not to make use of the cautery so long as blis-
ters seem adequate to this end; (which indeed we have
very commonly found them to be;) and when we do, we
are not to handle it as if its efficacy was in direct ratio to
the depth to which the skin is scored : a mode of prac-
tice in great repute among farriers, and one as tenaciously
persisted in, we lament to say, by many veterinary sur-
geons. The performance of this operation in such man-
ner as to make the lines penniform, commonly called dia-
mond, or feather firing,
"has," as Professor Peel justly
remarks, "nothing but its fancifulness and antiquity to
recommend it," for, in our opinion, it evinces but little
of the dexterity of the operator, and much less of his
professional judgment.
Without again agitating the question of the propriety,
or necessity, of simultaneous firing and blistering, we may
contend, however curative it may be, that the practice is
dangerous, and therefore impolitic. No man ever fires and
blisters his horse all fours without a remote chance of
killing him. Two cases of the kind have occurred to us,
in one of which, indeed, only the fore legs were operated
on ; but we have had several others related to us: the
horse refuses his food, the legs become enormously swol-
len, inflammatory fever supervenes, sometimes the kidneys
are highly stimulated, and the poor animal dies in the
height of irritation. In hunting and racing stables this
-ocr page 244-
On Bursa Mucosa.                         209
occurrence is not very uncommon ; though it is mostly
veiled in some flimsy narrative, by which the proprietor
and practitioner in attendance alike escape a merited re-
primand. But the practice is so general, and the case,
it would appear, so well denned in which it is proper, that
even if the owner of the horse should not prescribe him-
self, the representations of the groom are seldom unavail-
ing ; so that many hunters and racers are thus inhumanly
tortured once a year, whether they require it or not, not
only with a view of remedying present mischief, but of
preventing that which is to come!
We would here suggest to the practitioner a plan,
which, if properly pursued, will prove of no inconsider-
able service in all cases of lameness from sprains, or lace-
ration of the fibres of the flexor muscles, or tendons. It
consists simply in the elevation of the heel by some addi-
tional substance, either of a temporary or permanent kind,
to the heels of the shoe. In all cases likely to prove pro-
tracted m the cure, we should recommend the shoe being
removed, and raised by calkins at the heels to the extent of
about an inch ; in others of less severity, the practitioner
will be best able to form his own contrivance. Should
a high-heeled shoe have been long worn, we must not di-
minish its thickness at the heel suddenly, nor succeed its
application by the immediate use of a common one.
On Bursa Mucosa.
The bursa mucosae are small membranous sacs con-
taining fluid, interposed between certain parts moveable
upon each other, to facilitate motion.
They may be considered as appendages to muscles,
or rather their tendons ; for it is between tendons and the
parts over which they pass, that we commonly find them:
p
-ocr page 245-
210              On the Diseases of Bursa Mucosa.
hence they exist in great numbers in the extremities; ei-
ther between the tendons themselves—as between the
flexor tendons of the legs ; or between the tendons and
their thecae—as in those of the hock, fetlock, and knee ;
or between tendons and cartilaginous surfaces—as between
the os naviculare and tendo perforans, and within the cap
of the hock; or between tendons and joints—as in the
knee, shoulder-joint, and stifle. Sometimes we find them
placed under the fleshy part of the muscle, in order to
enable it to glide smoothly over some cartilaginous sur-
face : e.g. under the antea et postea spinati of the fore
extremity, and the gluteus maximus of the hind.
These bursas are formed of thin tendinous sacs, lined
by a delicate membrane similar in its texture to the syno-
vial membrane of a joint; which, like it, secretes and
contains a viscid fluid, resembling in appearance the white
of egg. They are connected to the surrounding parts by
cellular membrane, so that (as they are circumscribed)
they may, by a nice dissection, be wholly detached ; and
indeed they are occasionally, by operation, excised al-
together, in consequence of being diseased.
In a physiological point of view, the bursas may be re-
garded as so many small, distinct capsular ligaments; and
being, for the most part, situated between firm and un-
yielding substances, moveable upon one another, they fa-
cilitate motion by preventing friction, and preserve these
parts from the injurious effects of it.
On the Diseases of Bursa Mucosa.
These parts, both in the human subject and in horses,
are very frequently diseased : indeed, so common are these
cases in veterinary practice, that, perhaps, we are oftener
called on to treat them in one part or other, than any other
-ocr page 246-
On (he Diseases of Bursa Mucosa.            211
individual local affection. Different names have been
used to denote this disease, though the nature of it is pre-
cisely the same in all, according to the situation of the af-
fected bursa, or bursa;: e.g. if those about the fetlock
joint are diseased, it is called wind-galls; if those about
the hock, thorough-pin, or bog-spavin; or, if it is that
within the cap of the hock, capped hock. Now and then,
we meet with puffy swellings precisely of the same na-
ture upon the knee; but to these no specific appellation
has been given, in consequence, probably, of their being
of comparative rare occurrence.
If we inquire, by dissection, into the nature of this dis-
ease, we shall find that it consists in the distention of one
or more of these tendinous sacs with an albuminous fluid,
resembling synovia. Inflammation is first excited in the
membrane lining the bag, the effect of which is an accu-
mulation of its secretion : this, in course, preternaturally
distends the cyst, and thus the disease in question is pro-
duced. These encysted tumors may, and do form in
some parts, without our being aware of their existence,
until they have acquired a certain size, which will depend
on their relative situation : as soon as they are large
enough to make their appearance externally, they are
known as puffy swellings, possessing elasticity, and a
sense of fluctuation when compressed by the fingers. Oc-
casionally these swellings grow to an enormous bulk, and
then commonly interfere with the functions of parts to
which they are contiguous. They are, in the first in-
stance, like healthy bursa;, perfectly circumscribed—have
no communication with any other cavity; it frequently
happens, however, that wind-galls and thorough-pins of
long duration, from internal absorption, open into the ca-
p 2
-ocr page 247-
212             On the Diseases of Bursa Mucosa.
vity of the joint. The fluid contained in them also under-
goes some alteration during the chronic stages.
These tumors are commonly the result either of some
injury to ligamentary or tendinous structure, or of impro-
per usage of these (as yet imperfectly formed) parts : over-
weighting, immoderately riding, or injudiciously breaking
young horses, are among the most common forerunners of
this disease. In horses more advanced in life, repeated
acts of violence to these parts from long and forcible ex-
ertion—from what is known as hard work, is the most
common cause of them ; though sprain, or other injury,
may occasionally produce them. Sometimes they arise
from blows; the best instance of which is the capped hock.
As the bursa? mucosas are not very sensible parts in
health, we do not find that pain, or lameness, (the effect of
pain) is a common symptom of disease in them : in those
cases, however, where the magnitude of the swelling is
such as to interfere with the motions of contiguous parts,
lameness may result from that cause alone.
Remedies of various kinds have been from time to time
recommended for the cure of wind-galls. In the human
subject, the treatment of a ganglion (for so the swelling
is called) is exceedingly simple: if it be of small size,
merely giving the part a sharp blow with a book, or some
such thing, in order to rupture the sac, and extravasate
its contents into the adhering cellular membrane, where in
the course of a short time it will be absorbed, is all that is
necessary: but in horses, their size and situation gene-
rally preclude the probability of success by these means.
Puncturing them, or laying them open in order to re-
move the cyst by excision, or to destroy it by the intro-
duction of caustic, has been recommended by several old
-ocr page 248-
On the Diseases of .Burses Mucosa.             213
writers*: knowing, however, as Osmer appears to have
done, the nature of these swellings, we are somewhat sur-
prised that he should have condemned all other remedies,
for the introduction of one, not only very difficult, in many
instances, to put into practice, but at all times more or
less hazardous, from the intimate connection, if not com-
munication, which these swellings so commonly have
with the cavity of a joint. If either of these operations
is ever to be performed, it should be attempted in some
part remote from a joint. Setons are objectionable for
similar reasons.
As our principal object in the treatment of these affec-
tions, is to remove an eyesore, (for, as we have before
mentioned, they do not often occasion lameness,) those
means commonly used to promote the action of the ab-
sorbents, have been had recourse to by most of the old
practitioners in farriery. Pressure, either by means of
sheet lead, or a bandage, is one of the most common;
friction, by means of hand-rubbing, another : both, how-
ever, have generally been accompanied with the applica-
tion of some evaporating or discutient lotion, to which the
good effects have been chiefly attributed. And if the
swelling be recent, and more especially if there be any
concomitant inflammation of the parts in the vicinity, we
cannot do better than apply a linen bandage, kept con-
stantly wet with some mixture of a stimulating and discu-
tient kind f: even here, however, we believe, as much de-
pends upon the proper application of the bandage—nice-?
* Vide Bracken, Osmer, Taplin, and others.
t R Amnion. Muriat. 53s.
Spts. Vin. rect.—Acid. Acetos. ana Jvj. M.
-ocr page 249-
214            On the Diseases of Bursa. Mucosa.
ly adjusting the turns of it to the irregularities of the leg
—as to the lotion itself. This practice will seldom suc-
ceed in discussing the swelling, however effectual it may
prove in the removal of the lameness : we are, conse-
quently, to have recourse to other and more powerful
means, if we be desirous to excite absorption of it. The
use of stimulants of various kinds, is generally now re-
sorted to : as the 01. Origani, and Liquor Ammoniac, ei-
ther separately, or in combination with some inactive in-
gredients. But of this class of remedies, blisters are by
far the best: indeed to their use we should at once be-
take ourselves, if we wish to obtain a speedy removal of
the tumor; and either frequently repeat them, or keep up
a discharge from the surface by means of some stimulat-
ing unguent. Last of all, we may employ the actual cau-
tery, when other attempts to disperse it have proved inef-
fectual : a few longitudinal lines, lightly drawn upon the
surface of the swollen part, will often promote the further
absorption of its contents, when blisters cease to have
that effect; but, then, it will require that the animal be
turned out for about a month afterwards.
Though these affections have been here viewed as dis-
ease, we must not close this lecture without observing,
that we rarely find it necessary to treat them : they seldom
occasion lameness, and are not often attended with in-
convenience. A windgall, if it be recent, and we dislike
the appearance of it, may be got rid of : but it is ever
prudent not to disturb those of older date. A capped
hock is certainly a great deformity, and, as such,
should invariably be treated ; a thorough-pin, or a bog-
spavin, is of less consideration as a blemish: like wind-
gall, they are all to be removed by proper and timely
-ocr page 250-
On the Diseases of Bursa, Mucosa:.           215
means, but commonly resist remedy, and may be regard-
ed as permanent defects, when of long or uncertain du-
ration. We shall have occasion to make some further re-
marks on these local affections, when our attention is
engaged by the parts with which they are immediately
connected.
-ocr page 251-
LECTURE XIII.
On the Physiology of Muscles.
IN a former lecture, we stated, in our definition of a
muscle, that all the motions of the body were either di-
rectly or indirectly the effects of muscular action. Now,
though we are by no means warranted, from our anatomical
knowledge, in taking up so extensive a position, still the
inability of any other known power to produce such phe-
nomena as happen in the moveable parts of the body, even
where a fibrous structure is indemonstrable, leads us to
conclude, that muscular fibres must exist, although they
be so minute as to escape microscopical observation.
Without prosecuting this abstruse question, we shall en-
deavour, in the present lecture, to point out some of those
laws and phenomena at different times disclosed by phy-
siologists, in the course of their inquiries after the myste-
rious causes of muscular motion.
Muscles in the living body possess the power of short-
ening themselves, so as to bring nearer to each other their
points of origin and insertion : a power expressed by the
term contraction, or, from its peculiarity of self-action in
these organs, self-contraction. A muscle during contrac-
tion, at the same time that it is rendered shorter, becomes
-ocr page 252-
On the Physiology of Muscles.                  '217
thick and hard, and appears to swell : to convince our-
selves of these facts, we have only to grasp the fore part
of our arm completely extended, and then flex the fore
arm to its utmost; and we shall feel the biceps flexor cu-
biti, (the muscle performing this action,) which was at
first but indistinct, relaxed, and soft, become turgid,
firm, and rigid under our fingers. Notwithstanding these
changes, however, it has been ascertained, that there is no
absolute augmentation of its bulk ; for if the arm be im-
mersed in a vessel completely full of water, when all its
muscles are relaxed, no superflux of the fluid is occa-
sioned by throwing them into action. The color of a
muscle is not altered during contraction.
But muscles may be in action without being able to
contract their extreme parts : as, for example, when we
are attempting to lift a heavy weight, and are unable to
effect it, all those muscles which would have contracted
had the weight been raised, are still in strong action during
our efforts to accomplish it. A muscle will -act with more
or less force according to the nature of the function we
intend it to perform : if we prepare the muscles of our
arm to lift a heavy weight, and in raising it find, contrary
to our expectation, that it is very light, the hand, with
the weight, will be involuntarily elevated, with a sudden
jerk; and something of the same kind happens, when,
in descending a staircase in the dark, we unthinkingly
step down two stairs instead of one, or vice versa. Under
ordinary circumstances, a muscle cannot remain long in a
state of contraction—its fibres must be relieved by in-
tervals of relaxation: if we hold a weight out at arm's
length but for a short time, we experience an uneasy sen^
sation in the muscles of our arm, the effect of fatigue in
them, and this will continue to increase tintil we find our-
-ocr page 253-
218                 On the Physiology of Muscles.
selves no longer capable of sustaining it; but if we lay
down the weight, and rest the arm for a time, and then
raise it as before, we shall find ourselves as able to sup-
port it as in the first instance. Relaxation, therefore, is
a state necessary for the recovery of muscles from fatigue,
or the re-acquirement of that which enables them to con-
tract as before. Even the heart itself has its momentary
relaxations. It is curious to observe, when a muscle has
continued long in action, how its numerous fasciculi will
relieve each other, by alternate contractions and relax-
ations ; which, as the fatigue becomes greater, occur in
more frequent and irregular succession, producing that
quivering motion so remarkable in a part whose strength
is nearly exhausted.
A muscle, having performed its office, relaxes; and
when relaxed, is completely passive: its belly becomes
again soft, the swelling of it subsides, and its fibres may
be readily elongated; in which condition it may be said
to be at rest. Thus the biceps, which we employ to
bend the arm, having done so, relaxes; though its fibres
remain shortened, until the arm is straightened again
by the action of the triceps extensor cubiti.
No alteration is observable in the tendons, either
during the contracted or relaxed state of a muscle : they
appear to be, as it were, substitutes for cords—to con-
nect muscles to the parts intended to be moved, without
impeding, from their volume, the motion of those joints
over which they pass.
If a nerve be cut through, the muscles to which it is
distributed become paralytic; or if that nerve be com-
pressed from any cause—as from ligature around it, the
same effect is produced : but if it be irritated, violent
contractions of them, called convulsions, ensue. In like
-ocr page 254-
On the Physiology of Muscles.                219
manner, compression or division of the medulla spinalis,
paralyzes all those muscles whose nerves are given off
from it posteriorly to the section, or part compressed, and
irritation of it convulses them ; consequently, the more
anteriorly along the spine this experiment is made, the
greater the number of muscles influenced by it: if it be
before the origin of the phrenic nerve, the diaphram is
rendered paralytic, respiration arrested, and the animal
dies.
The motions of these organs have been divided into
voluntary, involuntary, and mixed. Of the first class are
those of the muscles of the extremities, head, neck, and
tail; of the second, those performed by the muscles of
respiration; and of the third, the actions of the heart,
blood-vessels, and abdominal viscera. The brain being the
centre of all muscular motion, it is along the nerves that
the will, or the requisite stimulus to action, is conveyed
to the voluntary muscles: we will, for example, to bend
our arm, and it is done; but if the nerves be cut through
going to the muscles employed in bending it, we may
will or wish to eternity, and no effect will be produced.
It is somewhat different, however, with the mixed order
of muscles : we may breathe twenty times in a minute,
or we can make a hundred inspirations in that time, but
We cannot suppress respiration altogether; for in spite
of our most resolute determination to hold our breath,
We soon experience so uneasy a sensation in the chest,
that we are compelled to desist from the attempt. On
the contrary, respiration is going on, without any remis-
sion, in such a manner that we are generally uncon-
scious of it, unless our attention be immediately directed
to it by auy incidental circumstance ; so that the actions
performed in breathing, are strictly what they are said to
-ocr page 255-
220                 On the Physiology of Muscles.
be—mixed, or in part voluntary, and in part involuntary.
The motions of the heart and arteries, and those of the
abdominal viscera, are entirely out of the limits of volun-
tary influence : and most wisely is it so ordained, other-
wise we should possess full discretionary power to ter-
minate our lives, by having control over the motions of
the heart, and be in continual hazard of forfeiting our
existence from inattention to them.
It is observed, that muscles increase in size and
power, in proportion to the exertions they are in the
habit of performing : hence is it, that the arms of black-
smiths are so well marked by fleshy prominences, and
the calves of the legs of porters so much larger than those
of others; and for the same reason, thorough-bred horses
that have been in training, are admired for that plump-
ness and cleanness of their muscles by which the trainer
knows that they are in condition to go to work. The
power of muscles is much greater than we could have
had any conception of, from a bare consideration of their
texture and uses : though we have frequent opportunities
of witnessing the astonishing feats of strength which
horses and other animals are capable of, we seldom con-
trast them with the physical powers producing them.
The immense burthens imposed upon the backs of little
half-starved asses, with which they trip along without ap-
parent inconvenience; the high fence and extent of
ground over which a horse will project himself and his
rider; and the mere elevation of the tail—which is often
as much as a powerful man can effect with both hands
—are familiar and striking instances of the force that
these organs are capable of exerting.
We are not to imagine, however, that muscles act to
the greatest advantage in the different movements of the
-ocr page 256-
On the Physiology of Muscles.                221
body ; on the contrary, there is often much expenditure
of force, resulting from their situation and attachment,
in relation to the parts to be moved, being unfavorable
to their mechanical operation : and this, in most instances,
arises from their being connected to bones near to the
centre of motion, and having to raise a weight at the
extremity of a long lever, or from their terminations being
implanted into them at unfavorable angles. The ex-
tensor and flexor muscles of the leg, which have chiefly
to overcome the resistance opposed from the weight of
the pasterns and foot, though they are inserted near to
the top of the cannon, instance the first; while the
proper extensor and flexor of the foot, which are tied
down at the knee, and fixed at sharp angles into the cof-
fin bone, serve to demonstrate the latter. If muscles were
inserted in parellel lines with the bones, no motion
whatever could be produced : they act with more effect
in exact ratio, cateris paribus, as their insertions approach
to right angles ; hence the extreme force with which the
gastrocnemii extend the hock in progression %
On the other hand, there are certain peculiarities of
conformation in the parts to be moved, and of arrange-
ment in the moving powers, which conspire to the fa-
vorable action of muscles. In the instance we have
just adduced, the mechanical advantage afforded by the
protuberance of the os calsis, is very great: the same
adaptations of structure are observable at the elbow,
by means of the olecranon ; at the knee, through the in-
* Knowing this, we discover an important use of the navicular
hone, not adverted to by writers on the foot:—to increase the
angle of insertion of the flexor perforans, and to add so much the
more power to it, in its action on the coflin bone.
-ocr page 257-
222                 On the Physiology of Muscles.
terposition of the os trapezium*; and, we may add, in the
foot, by means of the os naviculare. The pulley, ano-
ther mechanical power, is one, it is not improbable,
that first suggested itself from attention to the construc-
tion of the animal machine: the trochlearis muscle of
the eye is a beautiful instance of this; the flexors of the
pasterns and foot in the hind extremity are also, in their
course over the hock, imitative of the same structure.
Even the enlargements at the extremities of bones much
assist the muscles in their operation, by making wider
angles with their insertions.
The contractile force of muscles is so great, that in the
human subject the tendons, and even the bones them-
selves into which they are inserted, occasionally give way :
we have already shewn that the tendo achillis is some-
times ruptured by the action of muscle, and a fracture of
the patella from the same cause is by no means an unfre-
quent accident. But in the dead subject, the tendons are
stronger than the fleshy parts of muscles: appending
weights to them when taken out of the body will demon-
strate this—the muscle will invariably break first. Profes-
sor Peel mentions an instance of fracture of both the pas-
tern and coffin bones, from leaping : but we apprehend,
that this accident was occasioned by the sudden imposi-
tion of the weight upon these parts, and not by any
muscular force.
The power of a muscle is not in exact ratio to its size,
but depends on its texture, or organization, and the de-
gree of excitation it receives from the brain : thus it is
* By strange perversion of language, this bone is called, because
it is said to correspond, in situation, to one of the same name in
the human subject, os pisiforme.
-ocr page 258-
On the Physiology of Muscles.                223
that thorough-bred horses, in which both these circum-
stances seem to combine, are often stronger than cart
horses whose limbs are very considerably larger.
The astonishing rapidity with which the contractions
and relaxations of the muscles can be effected, is well ex-
emplified in the motions of the limbs of the fleetest race-
horses; in which Hallek conceived, that the elevation
of the leg was performed at speed in -^v of a second.
The extent of motion that a muscle is capable of pro-
ducing, bears some proportion to its length ; though
there are mauy exceptions to this : hence many of those of
the fore and hind extremities, and neck, when they con-
tract, cause the parts moved—the feet and head—to de-
scribe the segment of a large circle. Muscles of great
length however are always weak, when compared to
others—short and thick, and whose points of attachment
are near together : but these last possess, generally speak-
ing, but a very limited action. Haller, in investigating
the all-wise designs of Nature, in the construction and ar-
rangement of these organs, observes, that " all the con-
trivances of human skill end in this, that the moving
power passes through a large space, while the resistance
describes a small one. In the human body, on the
contrary, the effect to be produced is, that the resist-
ance should describe a large, and the power a small arc
of a circle."
It would be productive of no advantage, and taking up
time to little purpose, to make mention of the specula-
tions of physiologists about the cause of muscular mo-
tion ; for after all that has been said and written on the
subject, writers of the present day confess, that we are
still ignorant of the grand secret on what it depends: by
way of briefly summing up, however, the results of their
-ocr page 259-
224                 On Ike Physiology of Muscles.
investigations, we shall conclude with a paragraph ex-
tracted from Dr. Rees' Cyclopedia. "Our knowledge
concerning muscular motions (says the writer of a scienti-
fic article on this subject under the head of muscle)
amounts to this, that certain physical changes are pro-
duced in the fibres under the action of certain causes :
these changes we call contraction and relaxation. When
we say that a muscle acts by virtue of its irritability, con-
tractile power, or contractility, we merely denote this
fact, and express the phenomena in a general word : we
know no more of this irritability, what it is, or how it is
brought into exercise than we do of attraction, or the
force by which the phenomena of dead matter are regu-
lated."
In our last lecture we observed, that muscles in a na-
tural state were not possessed of great sensibility, a fact
that admits of ready proof by experiment; though, that
there may be a feeling created in the voluntary muscles
approaching to pain, in consequence of over exertion,
which we call fatigue, every one is sufficiently aware of:
under disease, however, the muscles often become the
seat of acutely painful sensations, as we shall hereafter
have occasion to notice.
All muscles act either in obedience to the will, or from
the application of natural, mechanical, or chemical sti-
muli. The voluntary muscles perform their functions
under the influence of volition; by them an animal is
enabled to exhibit all the phenomena of voluntary mo-
tion, of which locomotion, the will of producing sound,
or the voice, and the prescribed power over the organs of
respiration, constitute the varieties. But these organs
may also be excited to contract after their communica-
tion with the brain is cut oft", by application of certain
-ocr page 260-
On the Physiology of Muscles.                 23.5
substances of an extraneous nature, denominated stimuli :
the mere contact of any foreign body will generally cause
contractions in a muscle though its nerves be divided, or
even after it be removed from the body. This property,
apparently inherent in the muscular tissue, and not de-
pendant on nervous influence, (in which respect it essen-
tially differs from common sensibility,) is known by the
names of irritability, tone, and contractility: it is one not
only resident in voluntary, but possessed by involuntary
muscles; for these last may be thrown into action by or-
dinary stimuli, though their communication with the brain
be cut off, more forcibly, and for a greater length of time
after all signs of vitality have disappeared, than the for-
mer. The heart has been found to retain this incompre-
hensible property of self-action the longest after death.
This organ, though taken out of the animal, and laid upon
the table, will continue to pulsate, and may be made to
exhibit signs of life, by pricking or wounding it, or the
use of chemical stimuli, or electricity, longer than any
other, and after all attempts to excite action in the volun-
tary muscles have proved fruitless: hence it has been
emphatically designated the ultimum moriens.
The involuntary muscles, during life, are set in action
by what are called natural stimuli—such as are peculiar
to each individual set of organs : the heart and arteries,
for instance, are stimulated by blood, the stomach by
food, and the bladder by urine. Other fluids than blood,
thrown into the blood-vessels, disturb the heart's motions;
some—as atmospheric air, suspend them altogether; and
if blood be introduced into the bladder, it induces con-
vulsions of that viscus. In fact, these several organs may
experience derangement of function, either from the con-
dition of their excitable part (which is commonly a fine
o
-ocr page 261-
226                On the Physiology of Muscles.
membrane) being altered, or from some variation in the
properties of the substances applied to them. If the
blood, for example, be inflamed, or otherwise changed
in its nature, it may derange the functions of the heart;
or urine of an altered composition may disturb the na-
tural action of the bladder. On this principle it is, that
aloes, which is a chemical, if not a mechanical stimulus
to the intestines, produces purging ; and that white hel-
lebore excites efforts to vomit, though it has little or no
effect after it has passed out of the stomach, being no
more efficacious as a cathartic, than aloes is as an emetic ;
and both probably might be introduced into the bladder
without exerting any specific action on it. The degree
of irritability of these parts, or their aptitude for impres-
sion by certain stimuli, will vary from numerous and dif-
ferent causes; among which we may mention, the nature
of the tissue itself, the species of animal, its age, sex, and
temperament. We all know that a thorough-bred horse
is more irritable than another; and some peculiarity in
the texture of his different organs is, probably, the most
rational way of accounting for it: his pulse, we have un-
derstood, is generally quicker than that of one of inferior
blood. Why will one horse purge from three drams of
aloes, and another require an ounce to produce the same
effect ? These, and a host of other phenomena, we can
only explain by saying, that the irritability of organs and
textures not only varies in its degree in different indivi-
duals, but in the several parts of the same animal at dif-
ferent times.
With regard to the influence of the brain and nerves on
the muscles, we have already stated, that the functions of
the voluntary muscles are regulated by the will; but what
the nature of the excitation is that they receive from the
-ocr page 262-
On the Diseases of Muscles.                  227
brain by the will, or by certain stimuli, we know no more
than we do about muscular motion itself. The same
chain of connexion conveys a something to the involun-
tary muscles, equally unknown. Of what, in fact, hap-
pens between the stimulus and the part stimulated, we are
quite ignorant—we can go no further than view, with at-
tention and admiration, the phenomena resulting from
their reciprocal action, and with a knowledge of them we
must rest content.
That the same medium of communication conveys a
something to the involuntary muscles, though equally un-
discoverable, not less essential to their natural action, will
appear from very many facts collected from experiment. If
the nerves going to the stomach are cut through, digestion
becomes imperfect. Paralysis of the lower extremities
is occasionally accompanied with retention of the urine
and faeces. Division of the nerves called the par vagum,
proves fatal, by destroying the functions of respiration
and circulation. And if you remove the brain of an ani-
mal altogether, though the heart continues to contract for
a certain length of time afterwards, its action may be sud-
denly arrested by dropping a little laudanum upon it; and
then all subsequent attempts to re-excite it have no ef-
fect : opium being known to have the power of annihi-
lating the nervous energy.
On the Diseases of Muscles.
The most common morbid affection of these parts is
spasm or cramp; one which may be said to consist in a
continued contraction of a muscle, or of some of its fibres.
Assuming that what we have advanced be correct, as to
the manner in which muscles are acted on in a natural
state, it will not be difficult for us to comprehend the na-
Q 2
-ocr page 263-
228                   On the Diseases of Muscles.
ture of this affection. If the spasm be in a voluntary
muscle, its contractions, before obedient to the will, are
excited either in opposition to it, or without its con-
currence ; if in an involuntary one, either the stimuli are
in excess, or the irritability of the muscle increased, so
that it is preternaturally affected by the ordinary stimuli:
in both cases the spasm is succeeded by relaxation, and
does not recur until induced by fresh excitement. A
dreadful instance of spasm occurs in tetanus, in which
often all the voluntary muscles are more or less affected ;
it may, however, be confined to a few, or even to one
muscle, of which we recollect to have seen two or three
instances at the veterinary college. These horses were
lame from a rigidity, the effect of spasm, of the adduc-
tores muscles upon ihe inside of the thigh. That spasm
is attended with severe pain, we may infer from the symp-
toms attendant on cholic or gripes—a disease that con-
sists in spasmodic contractions of the muscular coat of the
small intestines: the common attacks, however, that
almost every one has had of cramp in some part or other
of his body, has probably informed him of the kind, as
well as degree of pain felt by the animal on such occa-
sions.
We have already made mention of the manner in which
spasm is induced in explaining its nature. The most
common cause of excessive irritability is inflammation,
either in the organ itself, or in the general system, in
which condition of parts common stimuli occasion un-
due and irregular contractions; hence tetanus seems to
be generally induced under an inflammatory diathesis, and
cholic is a common attendant of inflammation of the
bowels. We may also adduce in illustration of extra-
ordinary excitation producing spasm: the gripes may
-ocr page 264-
On Strhighatt.                            229
be often traced to some offending matters taken in,
and perhaps nothing more frequently occasions it, than
cold water drunk at a time when the bowel is in an irri-
table state.
The remedies usually had recourse to for this malady,
called antispasmodics, may be classed under two heads:
those which act by diminishing the irritability of the part;
and those that relieve by producing such an impression
as renders it insusceptible of further stimulation, while
their effects remain. Opium and other narcotics rank
among the first: stimulants, aromatics, and certain other
substances compose the latter;—among which the essen-
tial oils of turpentine, juniper, carraway, aniseed, and
thyme—alcohol, ammonia, and Eether—assafanida, and
camphor—ginger, and numerous others of the same kind,
are those commonly made use of. A class of remedies,
however, that may be considered as a third—one whose
operation is more certain and effectual, generally speak-
ing, inasmuch as it tends to afford permanent benefit, is
that which removes the cause of irritation, As this is in-
flammatory action in the greater number of cases, we are
at no loss to account for the good effects of venesection :
or if it be in gripes, for the salutary operation of purga-
tives, which remove the offending substances from the
alimentary canal. But we shall postpone what we have
further to say on this subject, until spasm of the intes-
tines comes under our immediate consideration.
On Stringhalt.
We reluctantly enter on this subject, since it must be
confessed, we have had but few opportunities of observ-
ing its progress, or of examining into its causes with the
satisfaction we could wish. We need give no descrip-
-ocr page 265-
230                             On Stringhalt.
tion of the action, or peculiar gait of a horse said to have
stringhalt: the greatest novice easily detects it, and sel-
dom fails to make objections to purchase an animal thus
affected. Mr. Feron*, one of the few writers who
has noticed stringhalt, says, " I am convinced, however,
by long experience and observation, that stringhalt, as it
is called, is no disease, therefore can require no remedy."
And in another place, " Indeed in Spain, France, and
Germany,-if is esteemed extremely graceful in their riding
schools,
or manege, particularly when there is a stringhalt
in both hind legs."
This writer has, however, admitted
it to be a disease, to the full scope of the word, in the
very outset of his description by defining it to be " an
involuntary convulsive motion of the muscles, which ex-
tend or bend the hock." In some particulars, stringhalt
bears some affinity to what in human medicine is called
chorea; we do not mean, however, to assert that they are
essentially the same disease, much less do we imagine that
a similar mode of treatment would have any good effect:
all we wish to infer by such an analogy is, that they are both
spasmodic or convulsive diseases, in which the will has
lest more or less of its control over certain voluntary
muscles. Not unfrequently, when the animal has lifted
his hind leg from the ground, which is always done with a
convulsive twitch, the fetlock nearly approaches the belly,
and, by some other remarkable irregularities in its action,
before the foot can be replaced upon the ground, (which
it seldom is in the most advantageous position,) displays
such unnatural movements as to.convince us that volition
has but little power over it during its suspension. Some-
* A Complete Treatise on Farriery, <§c. by I. Fekon, Veterinary
Surgeon, 12th Light Dragoons.
-ocr page 266-
On Stringhalt.                             231
times this irregular action is confined to one leg, but we
believe that it is more commonly seen in both. It is
seldom or never removed.
Such writers as offer any opinion of its nature, suppose
it to be a muscular affection, mistaking, we conceive, the
effect for the cause. We choose rather to refer its seat
to the spinal marrow, or to the nervous trunks passing
between it and the affected muscles ; an opinion we were
first led to adopt, from having observed a broken-backed
horse exhibit all the characteristic signs of stringhalt,
which, in this case, was clearly only an accompanying
symptom of the former disease. It was stated in the fore-
going part of this lecture, that section, or compression of
the spinal marrow, paralyzed muscles, and that irritation
of it convulsed them : now, we know that many cases of
broken-back terminate in palsy ; and, if this be true, why
should not others be productive of stringhalt*—since the
one arises from compression, while the other is merely
the result of irritation ? It is not, however, necessary that
a broken-back be present, for any other cause of irrita-
tion, we apprehend, would induce this disease. Horses are
very subject to injuries of the loins—much more so than
vve seem to be aware of—from being suddenly stopped or
turned, or from being overweighted about those parts;
accidents that are but too seldom detected, since they may
not be severe enough to constitute broken-back, though
they may so far disturb the nervous functions as to cause
stringhalt. Should the injury, or the consequences of it,
be confined to one side, then only one column of the mar-
row will be affected, and but one leg convulsed: the na-
ture and extent of disease in it, will perhaps determine the
degree of stringhalt.
Such is our theory of a disease whose nature, we be-
-ocr page 267-
232                                 On Palsy.
lieve, has up to this time remained unexplained : whether
we have taken a correct view of it, experiment and special
attention to these cases in future, can alone decide. We
have long had it in contemplation to attempt to induce
stringhalt by artificial means; and we intend, as soon as
an opportunity presents itself, to institute some experi-
ments for this purpose.
We so seldom know any thing of the origin and pro-
gress of these cases, and, even if we did, they have gene-
rally endured so long, that it would be labor lost to treat
them. Should however a recent case present itself, in a
horse of value enough to render his recovery an object of
consideration, we may pursue such means as have been
recommended in the equally hopeless one of broken-back.
On Palsy.
Paralysis, or palsy, consists in a loss or diminution
of the power of motion of some parts of the body, either
with or without impairment or deprivation of sensation.
Jn the human subject, it seldom happens that both these
faculties are affected alike : palsied parts are seldom
void of common feeling; though instances have occur-
red, but we believe they are very rare, of the total absence
of sensation, in which the power of motion has remain-
ed. In horses, the hind extremities are most subject to
paralysis, in consequence of the greater frequency of dis-
ease of the spine about the back and loins—commonly
the result of external violence, as from casting; and it is
not an uncommon termination of broken-back. Should
this affection have come on suddenly, and be the effect of
accident, either of the nature afore-described, or a fall
upon (he head, we are to ascertain, if it be practicable,
whether there be compression upon any medullary part,
-ocr page 268-
On Palsy.                             233
from a driven-in portion of bone ; in which case, its ele-
vation or removal is indispensable : it may be owing
to an extravasation of blood, however, and here we
should also be warranted in trepanning, supposing that we
could determine on the precise spot that received the blow,
and the symptoms resisted all other remedies. Venesection,
strong cathartics, and blisters kept open, or frequently
repeated, are the only means in our power, (without the
operation,) likely to relieve, or remove the symptoms:
should the case be a protracted one, and manifest some
favorable changes, we may occasionally confer much sub-
sequent benefit by the insertion of setotis.
-ocr page 269-
LECTURE XV.
On Bones.
Bones are the hardest and most inflexible parts
entering into the composition of an animal: like the
framework of a building, they give strength and support
to all the others, which, in contradistinction to them,
have been called the soft parts.
In the full grown animal the bones are perfectly white ;
but in the foetus they exhibit a bluish cast, from their
blood-vessels being comparatively of large size, and the
blood showing itself through their imperfectly ossified
sides: the bones of the former may be said to possess
much earth, and but little blood; those of the latter, a
large quantity of blood, and but little earthy matter. In
very old animals they turn yellow, and have a peculiarly
greasy feel; a circumstance owing to the transudation of
the marrow contained within them.
If we make a section of a bone, we shall find it to be
of much less solidity and compactness of structure in-
ternally ; and to put on, as we approach its centre, a
spongy and fibrous texture, easily broken down by the in-
troduction of a common scalpel: this substance in the
long bones of the extremities has received the name of
-ocr page 270-
On Bones.
235
cancelli; in those of a flatter and thinner make, of diploe.
Why bones should not have been formed solid through-
out, we can assign sufficient reasons. In the first place,
being hollow, they are considerably lighter, and therefore
require less power to move them ; and in the next, they
are stronger—as may be proved at any time by making
the following experiment. Take two glass cylinders of
equal length and diameter, the one solid, and the other
hollow, and place their extremities upon pedestals, of any
description, and, in this situation, append weights to
their centres : the solid one will break from a less weight
than the tubular. Bones by being hollow, also present a
more extended surface for the attachment of muscle, and
afford a convenient repository for the marrow.
Bones by calcination, or by long boiling*, undergo
some changes in their composition : they lose much of
their original compactness of texture, exhibit a porous or
cellular appearance, and become lighter, whiter, and ex-
tremely brittle. If we examine them, in this condition, a
little more closely, we shall perceive that they are fibrous
throughout, and that their walls only differ from the inte-
rior parts in the greater compactness of these fibres;
for though the shell of a (more especially calcined) bone
appear to be composed of several lamella;, or plates, yet
do these, in fact, consist of fibres so disposed as to form
separate layers. The shell of the bone, then, its most
compact and hardest part, is made up of several lamellae,
which, after burning or long boiling, may be chipped off
in the form of thin scales ; and these plates are rivetted
together by numerous little bony fibres, running in, a
* More expecially in Papin's digester, in which the water is
heated beyond the boiling point.
-ocr page 271-
236                                 On Bones.
transverse direction ; which, from this circumstance, have
been named the daviculi, or nails. According to this
disposition of the fibres, it is evident, that something
like a network composes even the hardest parts of a
bone ; and, if we might be allowed to compare this with
the reticulated structute within it, we should say, that the
shell itself was nothing more than a more compacted
cancelli. What would appear to amount to a develope-
ment of this structure, is a minute inspection of the can
celli of a long bone : these, in the middle, where the shell
is thick and strong, are few and spacious, but abundant
and close at the extremities, where the walls are extreme-
ly thin ; as if the shell at either end had parted with its
internal lamellae to form the cancellated structure within.
We shall find it to be pretty universally the case, that
where a bone grows large and protuberates, its shell
becomes proportionately extenuated, being chiefly ex-
pended in forming medullary or cancellated struc-
ture ; on this account, the largest is the weakest part of
the bone, though, in truth, it contains as much substance
as where the wall is of twice, or thrice the thickness.
This remark not only applies to different parts of
the same bone, but with singular force to the bones
of different animals of the same species: take, for ex-
ample, sections of equal length of the metacarpal bones
of the cart-horse and the thorough-bred ; and the latter,
although much exceeded in diameter by the former, will
weigh just as much, and be not only more compact and
firmer in appearance, but absolutely stronger. This will
serve to shew cause for the prodigious strength possessed
by slight spindle-shanked blood-horses, and their superio-
rity over others, in this respect, which are much larger, and
much coarser in their texture ; and not only weaker, but
-ocr page 272-
On Bones.
237
softer in their nature: and this is probably one of the
happiest illustrations of a remark that we might extend
through a long range in the animal kingdom. In the very
young animal, the bones are solid throughout—not exhibit-
ing any cancellated appearance ; and even in the old, there
are many flat bones which become so thin as to have lost
all traces of diploe. Within the cells of the cancelli are
found numerous little membranous bags, full of an oily
fluid, called marrow, of the nature and uses of which we
shall have occasion to speak in the concluding part of this
lecture.
In addition to the hard—the earthy part, of which we
have been speaking, bones consist of an animal substance
of the nature of cartilage ; to demonstrate which, we have
nothing more to do than to steep them, for a lime, in some
weak acid : by degrees they will lose their hardness and
brittleness of texture, and be converted into a soft flexible
substance, retaining the form of the original bone; and
this, by further maceration, or by boiling, may be resolved
into jelly, or glue. While a bone owes its color, brittle-
ness, and strength to the earthy matter it contains, it is in
this, its cartilaginous part, that its vessels ramify—that its
living principle, in fact, may be said to reside : the earth
is nothing more than a deposition from the mouths of ar-
teries, disposed in a way we have already described ; the
interstices of which are filled up, in the recent bone, by
this, its animal part. In the human subject, there is a
disease surgeons call mollities ossium, in which the bones
become so soft and flexible, in consequence of a deficiency
of earthy matter, as actually to bend under the superin-
cumbent weight, and give rise to considerable distortion :
when this disease—or something probably of the same
nature—occurs in children, they are denominated ricketty,
-ocr page 273-
On Bones.
238
the deformities of which are too well known to require
description here. We have seen mis-shapen foals with
considerable distortions of the legs, chest, and hips; in
which, as the deformity happened after being dropped,
it probably arose from deficiency of earthy matter in the
bones, or some irregularity in the ossific process : in this
animal, however, nature generally removes such defects
during growth, a fact the experienced breeder well knows
how to estimate, in keeping his crooked foals with a view
of their growing straight.
Bone, though it appear to be inorganic to the more su-
perficial observer, admits of its vascularity being demon-
strated with nearly the same facility as any other part of
the body. That it possesses numerous arteries, is proved
by injection ; for if, in the young animal, we throw melted
size colored with vermilion into the principal artery of a
bone, minute vessels may be distinctly seen ramifying
throughout its substance. But in the course of our dis-t
sections, we are often enabled to trace vessels of consi-
derable size into the substance of the larger bones, through
foramina in their walls: one of them, larger than the rest,
commonly enters about the centre of the long bones of
the extremities, to which the name of medullary artery is
given, from its sole distribution to the medullary struc-
ture. Were these demonstrative proofs wanting, however
we have others from which we might infer, with equal
certitude, the existence of blood-vessels in these organs.
If a bone in the living animal is sawn through, blood is
seen oozing from its divided ends, or should the parts
have been previously injected, the appearance of injection
upon the sawn surfaces, affords abundant evidence of
its vascularity. An experiment physiologists have been
in the habit of considering as conclusive on this subject,
-ocr page 274-
On the Diseases of Bones.                   239
is that of feeding a pig, or other animal, with madder—
a substance which will retain its color during the process-
es of digestion and assimulation: in a short time the
bones of the animal, previously white, become red, in con-
sequence of being tinged with the madder ; which effect,
say they, could not have happened in other than organized
structure *. It appears that bones are not sensible in
their natural state, though they are unquestionably so when
inflamed : in the operation of amputation, in the human
subject, for instance, the patient does not complain of any
pain while the surgeon is sawing through the bone; and
as to the vulgar idea, that all the feeling resides in the
marrow, it is hardly necessary to observe, that it is without
foundation : the membrane composing the cells may pos-
sess sensibility, but the fat, or marrow, being a secretion,
cannot feel any more than the saw itself. In the bones of
some animals absorbents may be injected in considerable
numbers, in consequence of their not having valves—as in
fish ; but, though they are probably equally numerous, in
those of quadrupeds we cannot demonstrate them; we
only infer their presence from many phenomena which
we notice relative to these parts, both in health and dis
ease. If such were not the case, we could not account
for their being tinged with madder, nor explain the pro-
cess of sloughing in bones, termed exfoliation—in which
the dead portions are separated from the living, and cast
off in the form of scales.
On the Diseases of Bones.
Though the horse be not obnoxious to those specific
diseases of the human subject so often attended with mor-
* Of late another explanation has been offered.
-ocr page 275-
240                    On the Diseases of Bones.
bid affections of these parts, he is an animal of all others
the most liable to have ossific disease excited in his frame
from external injuries of various kinds, and from exces-
sive exertion. Bones are subject to nearly the same dis-
eases as the soft parts of the body : inflammation in them
may terminate either in the effusion of adhesive matter, in
suppuration, or in mortification. If a bone be fractured,
it will be again united by a sort of adhesive or albuminous
substance, called callus, poured forth from the arteries of
the opposed broken extremities ; which, in a short space
of time, will be converted into bony matter, and effect a
re-union as strong as any part of the original bone. This
kind of inflammation however, which commonly affects
the external or periosteal surface of the bone, is one that
may be, and most frequently is, induced by injury to li-
gamentous structure ; from which it extends to the bone
itself. Abscesses sometimes form within the shell of a
bone, but more commonly in its interior: in these
cases, additional osseous matter is deposited upon the
exterior of the bone, in order to enable it, during the ul-
cerative stage, to sustain the superincumbent weight,
(which it otherwise could not do, in consequence of being
weakened by internal absorption,) through some part of
which a small opening is made, by ulceration, in order to
discharge the collected pus. Something similar to this
takes place in the process of exfoliation, sometimes called
necrosis. When a piece of bone has lost its vitality—best
known by its turning black—absorption is immediately
set up for its removal, during which time new bone is de-
posited around it, lest the old might give way from the
pressure of the parts above; and in this, after a time, holes
are made by ulceration for the discharge of the dead bone,
by small and separate pieces: so that, in fact, a bone dur-
-ocr page 276-
On Exostosis.
241
ing exfoliation, is little or not at all diminished in strength,
and knowing this, we are not apprehensive of fracture,
though the animal make use of the limb during the pro-
cess.
In the same way then in which a slough, or core, is first
detached from the surrounding vital soft parts, and after-
wards cast oft' by the subjacent granulations, so dead bone
is separated from the living j a process surgeons have of
late years, from a vigilance to the operations of Nature,
thrown much light upon : it is, as might be expected,
however, one of slow advance, and one that requires a
long time for its completion.
On Exostosis.
Ah osseous tumor originating from a bone, is call-
ed an exostosis: such is a splint, a spavin, a ring-bone,
&c. Though these are the more familiar instances
of the disease, there is, perhaps, no bone in the body
that has not beer, seen, one time or other, thus affect-
ed : we have now specimens before us of exostoses
of the spine, ribs, pelvis, bones of the haunch, thigh,
shoulder, arm, leg, and a considerable number of the pas-
tern, coffin, and navicular bones; a few of the lower jaw ;
and one, as large as a hen's egg, projecting from the orbi-
tar portion of the frontal bone, and so placed in front
of the orbit, as to render almost useless the eye on that
side. Perhaps no animal is more the subject of this
disease than the horse; and as it very often proves a
source of permanent lameness, we should, by making our-
selves well acquainted with its nature, endeavour to arrive
at a knowledge of the best means of treating it.
Sir A. Cooper, from whose excellent practical essay
R
-ocr page 277-
242                              On Exostosis.
on this subject* we have derived much valuable informa-
tion, divides exostosis, in reference to its seat, into two
kinds, periosteal and medullary; and, again, as to its na-
ture, into cartilaginous and fungous: but it is to that kind
only which is situated between the shell of the bone and
the periosteum covering it, that we have to attend in ve-
terinary practice. From the very accurate observations
of the distinguished surgeon just mentioned, who calls a
tumor of this nature, cartilaginous exostosis of the perios-
teum, "
it originates in an inflammation of the periosteum,
and of the corresponding part of the bone ; and a depo-
sition of cartilage, of a very firm texture, and similar to
that which forms the nidus of bone in the young subject,
adheres to both these surfaces. The periosteum adheres
to the external surface of the swelling, and the swelling
itself is attached still more strongly to the surface of the
bone; it continues afterwards to be secreted as the car-
tilage increases in bulk; for it appears that between the
periosteum and bony mass, cartilage is constantly secret-
ed, which constitutes the exterior surface of the tumor.
Thus, on dissection, we discover, 1st. The periosteum
thicker than natural; 2nd. The cartilage immediately
below the periosteum ; and, 3rd. Ossific matter deposited
within the cartilage, extending from the shell of the bone
nearly to the internal surface of the periosteum, still leav-
ing on the surface of the swelling a thin portion of carti-
lage unossified."
** When the accretion of these swellings ceases, and the
disease has been of long standing, they are found to con-
sist, on their exterior surface, of a shell of osseous matter,
* Surgical Essays, by Messrs. Cooper and Tiuvers. Part I.
-ocr page 278-
On Exostosis.                              243
similar to that of the original bone, of the same cancel-
lated stiucture, and communicating with the original can-
celli of the bone. Consequently when an exostosis has
been formed in the manner here described, the shell of
the original bone becomes absorbed, and cancelliare de-
posited in its place. In the mean time, the outer sur-
face of the exostosis acquires a shell resembling that of
the bone itself. When the exostosis has been steeped
in an acid, and by this means deprived of its phosphate of
lime, the cartilaginous structure remains of the same form
and magnitude as the diseased deposit; and as far as I
have been able to discover, it is effused precisely in the
same manner as healthy bone. From which it appears, that
the formation of these excrescences differs in no respect
from that of the original bone, since they are composed
of cartilage for their basis, and of an earthy salt to impart
to them firmness and solidity; a circumstance which I
have shewn for many years in my lectures." To the
truth of this last remark we can bear witness, as also, as
far as our own observations have gone, to the applica-
bility of the whole of this valuable exposition of the na-
ture of exostosis, to those cases which come under the
immediate notice of the veterinary practitioner.
An exostosis, abstractedly considered, does not appear
to occasion much inconvenience to the animal; so
generally, however, are other parts in the vicinity in-
volved in disease, that the ossific deposit becomes dif-
fused, and renders fixed parts naturally moveable on
each other: thus, so long as a ring-bone is confined to
either of the pastern bones, it is of little consideration;
but should it shew itself near one of the joints, it seldom
fails to produce lameness, which is often of a permanent
nature. Lameness therefore is by no means an invariable
R 2
-ocr page 279-
244                              On Exostosis.
symptom of exostosis; for most splints, many ring-bones,
and even spavins, exist without occasioning any apparent
alteration in the action of the limb ; and we now and then
see an exostosis of prodigious size unattended with the
least perceptible inconvenience to the animal. When
this disease invades ligamentous structure, however, lame-
ness generally accompanies it—as spavins, and recent
splints fully evince; an effect we would refer simply to
the excessive tenderness of that part when inflamed, ra-
ther than ascribe it to the extension of the periosteum
from the bone underneath: a notion borrowed from hu-
man surgery, and somewhat too hastily received by ve-
terinary surgeons. We know that neither spavins nor
splints produce lameness severe according to their size,
nor correspondent with their rapidity of growth; and
that many splints, ring-bones, and other nameless tumors
of the same nature, though of great size and quick growth,
are wholly unattended with lameness. Should the tumor
interfere, either from its bulk, or situation, with the motions
of joints, muscles, or tendons, lameness is a concomitant,
and often irremediable symptom : we have very lately
seen a horse, in which an exostosis as large as a child's
head projected from the point of the shoulder, occasion-
ing so much impediment to the motions of the shoulder-
joint, as to produce considerable lameness, which no-
thing but the removal of the tumor, by operation, could
relieve.
In the human subject, the origin of exostosis, unless it
be traceable to some external injury, can seldom be made
out; but in the horse, its production, almost always, may
be very satisfactorily accounted for. The most frequent
causes of that exostosis which unites and fixes bones to-
gether, before attached by some elastic substance—such
-ocr page 280-
On Exostosis.
245
as spavins and splints, are undue acts of exertion, and the
imposition of weight disproportioned to the strength of
the animal: hence it is that young horses are particularly
liable to throw out splints and spavins, when severely
worked, or overburdened. Any sudden, or extraordi-
nary efforts in action, may give rise to this disease : among
the most common are the improper exercises young and
unbroke horses are put to in riding-schools—throwing
them too much on their haunches, violently backing them,
or too suddenly pulling them up at full speed ; hunting,
and racing also at a tender age, while the joints are yet in
a state of imperfection, very frequently cripple horses
for life, by laying the foundation of exostosis. These
parts are sprained, inflammation is excited in the liga-
mentous substance entering into their construction, and
this extends itself to the bones and periosteum : in the
sequel, the ligament is converted into bone, the bones,
before moveable upon each other, are rendered fixtures,
and the periosteum is raised by cartilaginous and bony-
accretion, which commonly presents itself in the situation
of a splint, a spavin, or a ring-bone; though there are some
peculiarities attending each of these exostoses, which we
shall point out in future lectures. So very prone, how-
ever, is the horse to this disease, that even a blow upon a
bone will be frequently followed by an exostosis. In the
human subject, certain peculiarities of constitution would
appear to favor the production of these swellings: a re-
markable case of this kind is related by Mr. Abeu-
nethy, in which the most trifling injury to any bone in
the body, was followed by exostosis.
In the human subject, various constitutional remedies
have been tried for the prevention, as well as dispersion,
of exostosis; and among others, such as are known to
-ocr page 281-
On Exostosis.
246
act chemically on the osseous matter itself, which is
phosphate of lime : they have all, however, we believe,
failed in affording benefit. In the horse, we must con-
tent ourselves with the use of local means; and these we
shall find to be sufficiently abundant and diversified, if
we take into our account the various nostrums of the
old practitioners. As we do not intend, however, in this
place, to notice any but what are applicable to all cases
of this nature, we must pass over, for the present, these
recipes for modifications of it without remark. Stimulants
of various kinds, in the form of ointments, liniments,
and lotions, have been recommended from the oldest re-
cords of farriery; with the exception however of some
few, among which the essential oils of thyme, and ani-
seed,
and the liquor ammonia are the chief, they have
all been exploded, and even these superseded by the
justly celebrated remedy of blistering: we know of
nothing that tends so much to produce absorption, and
diminish lameness, in so short a time, and with so little
inconvenience to the animal, as a common blister. We
are not to content ourselves with merely trimming off the
hair from the skin and applying a blister in the ordinary
way, but we are either to keep up constant irritation
and discharge upon the surface of the swelling by dress-
ing it with a milder ointment of cantharides, or to re-
excite inflammation in it from time to time by a repeti-
tion of blisters. Could we in the first instance draw
blood from the part, prior to blistering it, it would
doubtlessly have a good effect; we can but seldom how-
ever take advantage of this, and therefore we should
have recourse to such remedies as rank next in point of
efficacy. Various means have been employed to reduce
exostosis by pressure alone : but none (and they are all
-ocr page 282-
On Exostosis.                              247
difficult of application) can be compared with the actual
cautery; which acts not only with more effect than any
bandage, or other contrivance we may make use of, but
is, at the same time, an irritant to the surface. Gene-
rally speaking, we should precede its use on all occasions
by blisters.
Caustics of the most active kind, have been used and
recommended for the removal of exostosis : they are sel-
dom admissible, however, from the vicinity of a joint, and
have but too often aggravated that which they were in-
tended to relieve.
At the Veterinary College it is the practice to divide
the periosteum in splints, with the same view that sur-
geons sometimes make an incision through it in nodes :
and an intelligent friend of ours, a surgeon, for whose
opinions, even on veterinary subjects, we have much
regard, proposes to strip it off in these cases. But a
splint differs as widely from a node in its nature, as the
causes do that give rise to them; and we believe, as
we have just stated, that, although it may partake of
the inflammation, and probably undergoes some exten-
sion, the periosteum is not the seat of pain and con-
sequent lameness. Else, how comes it, that so few
splints are accompanied by lameness ?—that spavins
seldom exist without occasioning more or less lame-
ness F—and that ring-bones only produce it in certain
situations ? If a stretched periosteum be the cause of
lameness, its division, or the removal of a portion of it,
ought to give immediate relief; and the means are as ap-
plicable to spavins and ring-bones, in certain situa-
tions, as they are to splints, or to any other kind of ex-
ostosis : but as we shall have occasion to agitate this
question again, we need not anticipate here.
-ocr page 283-
On Exostosis.
248
Issues, in the form of setons, have been of late sub-
stituted for blisters in some of these cases. To their
employment there appear to be three objections: the
fust, and most potent, is, that their operation is so ex-
ceedingly tardy, even in those instances in which they
seem to do good, that they will not effect in a month,
what a blister kept open, or repeated, will do in a
week; the second is, that they leave a blemish upon the
skin, which requires some time to be effaced; and the
third, that, like all other remedies, they must fail as re-
storatives where ligamentous parts have already become
bony ; on which account, we can expect but little from
them in chronic cases of this description.
The removal of exostosis by an operation, has been per-
formed, we are told, more especially in splints and spavins,
with success ; and no doubt there are cases in which such
a mode of practice would be of advantage; it is, however,
for reasons we shall hereafter mention, not often applica-
ble to spavined horses. Such an operation requires much
skill in the performance, and instruments of a different
description from what the forge can possibly furnish : it
is one that appears to have failed, where we have seen it
tried, both from inattention to' this circumstance, and
from a mal-selection of cases. Of late it has succeeded
beyond expectation in the human subject, and it pro-
mises to be, as a surgical remedy, at some future day, of
very considerable importance; and there cannot be a
doubt of its utility in veterinary practice, were subjects
properly chosen, and more particularly in those cases
where the tumor inconveniences from its magnitude, or
where our object is to get rid of an eye-sore : but it be-
hoves us to provide ourselves with fit instruments for the
purpose, and to be well acquainted with the anatomy of
-ocr page 284-
On Marrow.
249
the parts, before we can hope for success from the per-
formance of such an operation*.
On Marrow.
Marrow is a soft substance of an oleaginous nature,
deposited in the cavities of bones. It varies in its color
and consistence according to the food consumed by the
animal from which it is taken ; being white and solid in
such as are graminivorous, but yellowish and more like
oil in carnivorous animals. Knowing the internal structure
of a bone, we shall have no difficulty in understanding
how the marrow, which is contained in an infinite number
of little spherical bags, is lodged, or rather suspended with-
in the cancelli; for these sacs, which are composed of a
delicate vascular membrane, bear much resemblance to
the cells of the adipose membrane, being, like them,
perfectly circumscribed, and distinct from each other. If
they were similar in their construction to those of the re-
ticular membrane, communicating one with another, we
should find the marrow, from gravitation, now and then
* Sir A. Cooper, in his Essay on Exostosis, has detailed several
cases, in some of which complete relief, in others considerable be-
nefit, have been derived from this operation: one that tends to be
of eminent service in human surgery. Sir Astley concludes his
account, (which we strongly recommend the perusal of to those
who seek further information,) by the following practical remark:
" It appears then, that bones, after operations, unite by adhesion
to the soft parts; if adhesion cannot be produced, healthy granu-
lations arise from the surface of the bone, and cicatrization takes
place upon these, as upon the other parts of the body; and that
there is reason to believe, that these structures may, with properly con-
structed instruments, become much more the subjects of operations, than
they liave hitherto been considered."
-ocr page 285-
250                            On Mar rote.
all collected at one extremity of the bone: an appear-
ance that no one has ever met with.
These medullary cells are furnished with minute arte-
ries, spread out upon their interior, by the mouths of
which, it is supposed, the marrow is deposited, in the
same way, and at the same time, that other parts of the
body receive their fat. Marrow, we said before, being
a secretion, is wholly inorganic in itself; the common
notion, therefore, of its being acutely sensible falls to the
ground as absurd: though the medullary membrane may
possibly feel under certain morbid conditions.
Long ago it was believed by some, that the use of mar-
row was to render the bones less brittle, by oozing
through their pores; we now know, however, that it is
not simply inclosed within the bone, and that, being con-
tained in a membrane, nothing like transudation can ever
happen during life. It is probably serving a similar pur-
pose to that which the fat does: viz. that of supplying
the demands of the system, when the animal, either from
disease or accident, is deprived of a sufficiency of nutri-
ment ; in corroboration of which opinion, it has been re-
marked, that lean animals have little or no marrow, but
that in fat ones, on the contrary, the bones are rilled
with it.
-ocr page 286-
LECTURE XIV.
On Glands.
xjL GLAND may be defined to be, a secreting organ; by
which we mean, one that separates a fluid from the blood
differing in its properties from the blood itself. In this
definition, we have given to the term its most compre-
hensive meaning ; for, by most writers, and indeed in com-
mon language, it is used to designate an organ, not only
furnished with secretory vessels, but with others, called
excretory ducts, whose use is to collect and convey the se-
cretion from it. Were we to view it in this light however,
we must necessarily exclude from our notice many struc-
tures which in their functions are purely secretory; inas-
much as they do separate certain fluids from the blood,
though they present to us a much less complicated appa-
ratus for the purpose. On the other hand, many organs
in the body have received the name of glands, though, as
far as our knowledge of their economy extends, they
perform no such use: the absorbent glands are of this
class, as are also the spleen, the thymus gland, and the
pineal gland.
The classification of glands which we shall here adopt,
at the same time that it appears to be the most natural
-ocr page 287-
252                              On Glands.
and simple, is so comprehensive that it will include every
organ to which the term,g/a/vc?, can be applied, according
to our present view of its nature : it is one grounded pure-
ly upon structure, and one that will much aid us in un-
ravelling the complex parts of the more perfect glands,
by first making us acquainted with the most simple pieces
of secretory mechanism.
There are three classes of glands in the body. The
first, and most simple in its construction, is that of an ex-
tended membrane;
upon which the artenal capillaries, or
exhalents, terminate by open orifices, too minute to be
detected even by our most powerful magnifying glasses :
the peritoneum, the pleura, and the synovial membranes
are of this kind. That this is the minute structure of an
extended membrane, we infer from the apparent simpli-
city of its organization, as well as from the nature of the
fluid secreted by it. In the chest and belly, we know that
an aqueous exhalation is present during life, which has
been found to bear much resemblance in its properties to
the serum of the blood, strained through vessels of ex-
treme exility, without any commixture of the grosser parts
of that fluid; and that this is a secretion from the pleura
and peritoneum, parts whose texture are alike, does not
admit of a doubt in the mind of the experimentalist. The
secretions of these glands, submitted to chemical exami-
nation, have been found to be either of an albuminous
or serous nature ; though it would appear that both are
serving similar purposes : viz. those of lubrification, of
preventing friction, and facilitating motion.
The second kind of gland is called a follicle. This
differs in nothing more from the first than in being of a
different form—the intimate organization of both is pre-
cisely similar: membrane of the same composition as
-ocr page 288-
On Glands.
253
that lining- the different cavities of the body, is thrown in-
to a follicular shape, constituting a bag, follicle, or cul-
de-sac ; into which the secretion is poured by exhalent
arteries, (as it is upon the surface of an extended mem-
brane,) to be pressed out as occasion requires. There are
several of these follicles, or crypto,, as they are also call-
ed, within the nose, opening upon the surface of the
pituitary membrane; and numerous others upon the
skin, out of which you may squeeze an inspissated cheese-
like secretion, not unfrequently, from its appearance,
called a worm: in the urethra, and upon the glans penis,
are some of large size; the white caseous substance at
times collected in considerable quantity upon the latter,
is a secretion from them. The mucous glands belonging
to the lining membranes of the pharynx, esophagus, sto-
mach, and intestines, and those of the glottis, and trachea,
are also of this c'ass.
The third sort, or true gland, is that in whose compo-
sition is an excretory duct; from which circumstance, it
lias received the denomination of a ductiform gland. This
is one of a more complicated structure than either of the
others, and one to which no particular description will
apply in all instances, inasmuch as one ductiform gland
differs from another in the disposition of its component
parts. From one very obvious difference in the construc-
tion of these organs, they have been subdivided into con-
globate
and conglomerate glands : the liver and kidneys
are of the first kind; the salivary and lachrymal glands, and
the pancreas, belong to the latter. The conglomerate
glands are easily resolvable into many distinct portions,
called lobuli, which are connected together by loose cel-
lular membrane ; and these into others still smaller, said
-ocr page 289-
On Glands.
254
to be made up of numerous little granulary bodies, named
acini, respecting the intimate structure of which there has
been much controversial writing. By Malphigi, emi-
nent in the Italian school of medicine, they were believ-
ed to be hollow, with arteries distributed over their sur-
face ; from which the secreted fluid oozed into the cavity,
to be thence conveyed by an excretory duct into the pro-
per receptacle. Ruych, the no less celebrated Dutch
anatomist, on the other hand, contended that the acini
were constituted of clusters of vessels, and that the excre-
tory tube was continuous with the secreting artery. With
regard to the ultimate distribution of the secretory vessels
of the liver, kidney, and testicle, though they are all con-
globate glands, for reasons before given, no single expo-
sition can be correct: we shall, therefore, dismiss the
subject for the present, reserving all minute detail until
we have occasion to speak of particular glands.
All glands are furnished with veins to convey back to
the heart the redundant blood; i.e. that blood super-
abundant for the support of the organ, or for the produc-
tion of its secretion : these vessels are larger than their
corresponding arteries, though not so disproportionately
so as in most other parts of the body.
Some glands are supplied by a single artery, others
have more than one sent to them : e.g. the testicle receives
its blood from the spermatic artery alone; but the pan-
creas, from numerous small ones, called the pencreatic.
Arteries, as soon as they have entered the substance of a
gland, do not appear to possess the same degree of elas-
ticity as before; for in inspecting the interior of the or-
gan, we can scarcely distinguish them from the veins.
The nerves, compared to the size of these organs, are
-ocr page 290-
On Glands.
255
small: they pierce the substance of the gland in company
with its blood-vessels, around which they frequently form
a sort of net-work previously to their entry.
Some glands have but one excretory duct; others, se-
veral : the liver, pancreas, kidneys, and testicle, instance
the first; the udder of the mare, and the lachrymal gland,
the last. Again, some of these organs are furnished
with a reservoir, into which their excretory ducts pour
the secreted fluid, and from which it is again taken up by
other tubes of a similar nature : the best example of this
is the kidneys—in them small vessels, named the tubuli
uriniferi,
distil the urine into a membranous funnel, call-
ed the pelvis, from which it is imbibed and conveyed by
long excretory tubes—the ureters, into the bladder. An
excretory duct is composed of two coats; and the outer
of them is said to be of muscular structure : we are rather
induced to believe so, however, from the function it per-
forms, than from any direct evidence afforded by dissec-
tion ; though it has been asserted, that the ureters exhibit
a fibrous appearance, and that if they be irritated in an
animal very recently dead, they may be seen to contract
like the fasciculi of a muscle. The internal coat is of a
glandular nature: its vessels produce a mucous, which
serves to defend it from the acrimonious properties of the
secretion ; and this has given it the name of mucous coat.
There are some glands inclosed in proper membran-
ous coverings, or capsules; and these envelopes, which
are united to their exterior by reticular membrane, gene-
rally send off processes that pervade the substance of the
gland in company with its blood-vessels ; thereby serv-
ing as their connecting medium, as well as that of its
ducts, nerves, and absorbents. Such a contexture is best
demonstrated in the testicle and kidnev.
-ocr page 291-
250                              On Secretion.
Absorbents may, in general, be easily injected in all
glandular structures; indeed in some, particularly in the
liver and spleen, they exist in very considerable numbers.
Byithe insertion of a pipe under the peritoneal covering
of either of these glands, we may frequently succeed in
filling numerous absorbent vessels upon the surface;
which, from the arborescent appearance they exhibit,
makes a ready and beautiful preparation.
On Secretion.
Pee ha ps no subject in physiology has more at-
tracted the notice of the chemist, at the same time that
it has occupied the attention of the physiologist, than
the one before us: but the researches of these philo-
sophers have only furnished materials for the framing of
theories, which, however much they may elucidate the
mysteries of secretion, still leave the principal pheno-
mena relative to this vital process involved in obscurity.
The simple question, divested of all speculative matter,
is to point out how, or in what manner, fluids, such as
saliva, bile, and urine, are separated, or secreted, by their
respective glands from the general mass of blood—fluids,
though of such various and even opposite properties, so
uniformly elaborated in the same organs, that conversion
or commixture of them is unheard of. The liver invari-
ably produces bile; the kidney, urine; and the testicle,
semen: no one has ever found urine in the hepatic duct,
nor bile in the ureters. Moreover, the same gland in a
healthy state always prepares the same fluid : though, un-
der morbid action, the secretion occasionally is found to
vary in quantity, and somewhat in quality, from that ordi-
narily produced.
-ocr page 292-
On Secretion.                              257
Chemists have endeavoured to throw some light on the
subject, by accurately analyzing blood drawn from the
secreting vessels of different glands ; but, hitherto, no one
has been able to detect any difference in its properties, be
it extracted from whatever part of the body it may : so
that although the component parts of urine, bile, &c. ex-
ist in the blood, yet are we not able to discover either
ready-formed in that fluid.
The best theory—for it is all supposition—is the fol-
lowing. Assuming that the elementary ingredients of all
secretions are contained in the blood, it is said, that, by a
mode of action peculiar to the blood-vessels of certain
parts, they are so elaborated aud combined, as to pro-
duce the very opposite compounds, called urine, bile, se-
men, saliva, &c. By way of illustrating this hypothesis,
the process of secretion has been compared to the fa-
miliar operation of churning: this, we know, in order to
make butter of a good quality, requires a regular and con-
tinual motion of the chuin-stick, and hence it is, that
those who are not in the habit of performing it, not un-
frequently fail in the product. Something of the same
kind seems to happen in the glandular functions. If, for
example, mercury be given to a man, or to a horse, in suf-
ficient doses, his salivary glands will not only secrete more
saliva, but that saliva will be somewhat altered in its pro-
perties ; an alteration we believe to be dependant on some
disturbance in the action of the secreting organ, and not
on any change in its mechanism : in this way, we offer
something explanatory of the nature of diabetes—a dis-
ease in which the urine differs remarkably from that se-
creted in ordinary health. Some phenomena very analo-
gous to these, are presented to us in the vegetable king-
dom. IF, for instance, you ingraft a branch of a peach-
%
-ocr page 293-
On Secretion.
258
tree upon one of a plum-tree, you will not alter the pro-
duce of the graft: notwithstanding the same kind of sap
(which may be considered as the blood of a vegetable)
circulates throughout the whole tree, and, consequently,
through this graft, yet will it bear peaches. According to
the theory before us, we must explain these curious facts
by saying, that the fruit, like the secretion in a gland, is
modified by the peculiar action of those vessels through
which the sap passes. Little as this developes the mys-
teries of secretion and fructification, it serves as recipro-
cally illustrative of two perhaps of the most obscure vital
processes of nature; and here the mind must rest satisfied
in our present imperfect knowledge of intimate organiza-
tion. All we know of the apparatus of secretion amounts
to so little, that we are far from being able to assign the
separation of any one fluid to any particular kind of glan-
dular mechanism : and we have not hitherto had the sub-
ject placed in a clearer light by the science of chemistry.
Whatever be the manner in which secretion is carried on,
its importance in the animal economy may be considered
as two-fold :—those substances which are separated from
the blood, being produced to serve some purpose in the
system; or to be ejected, through its excretory chan-
nels, as useless or injurious.
The action of a gland may be increased by various sti-
muli,
which, in relation to their effects, have received the
epithets of common and specific. Thus, direct mechani-
cal, or chemical irritation of any kind, will affect all
glands : e.g. if a horse happen to have a hay-seed'under his
eyelid, the immediate effect is a flow of tears from the la-
chrymal gland ; and any irritating chemical preparation—
such as nitric acid, will give rise to the same defluxion.
But there are certain substances that only stimulate
-ocr page 294-
On Secretion.
259
particular parts; so that what proves an irritant to one,
may be perfectly innocuous when applied to another:
e.g. aloes acts powerfully on the mucous coat of the in-
testines ; calomel, on the salivary glands and pancreas;
and turpentine, on th<; kidneys.
We are far from knowing what influence the nervous
system has upon the glandular functions: the operation
and extent of such a power have been variously estimated
by different physiologists. That secretion, in some parts,
will go on independant of nervous influence, is seen in the
feet of horses that have been subjected to neurotomy—in
them the horn is furnished in equal abundance; and inflam-
mation and suppuration of the laminae have in too many
instances resulted from subsequent injuries, though the
parts, at the time, were totally devoid of sensibility. On
the other hand, it has been ascertained by experiment,
that the functions of the stomach are so much impaired
by the division of its nerves, that digestion is not perfect-
ed without them ; and, indeed, by no other agency than
that of sympathy, can we explain the well-known ef-
fects which various motions of the mind have on cer-
tain glands. In the human subject, the phenomena of
this description are many: as the most familiar, we may
mention—the presence of tears excited by grief, the se-
cretion of saliva at the sight of food, and the immoderate
flow of urine occasioned by excessive fear. Even in
horses, those who are acquainted with the habits of the
animal must have remarked, that disquietude, or what
might be considered as anxiety of mind, induced by any
cause—as the separation of one from others with which
he has been habitually stalled, will give rise to frequent
staling. Perhaps the best example we have of it, how-
s 2
-ocr page 295-
260                   On the Diseases of Glands.
ever, is in the secretion of semen; which, in stallions,
happens in considerable quantity during the venereal
antrum.
On the Diseases of Glands.
If a gland become inflamed, its secretion will be sus-
pended : e.g. in inflammation of the kidneys, little or no
urine is passed; and when the intestines are highly in-
flamed, costiveness is a diagnostic symptom. Whe-
ther the secretion be altogether suppressed, or not,
however, will depend on the extent to which inflamma-
tion has pervaded the substance of the organ ; for if it be
but partial, there may be some parts actually secreting
more than in a healthy condition. For simply increased
vascular action tends to augment secretion; and thus,
probably, it is, that the medicines which we call purga-
tives, diuretics, sialagogues, and some others, produce
their effects.
The secretion of a gland is sometimes much altered in
its properties, in consequence of more or less derange-
ment of function : e.g. diabetic urine is supposed to ori-
ginate from such a cause; and, now and then, calculous
matter is separated by the kidneys. We have at pre-
sent before us two fine specimens of urinary calculi, which
were taken from the bladder—by no means a common oc-
currence in horses, when we glance at the frequent case
of stone in the human subject.
Glands are subject to enlargement. Several times we
have seen the spleen greatly increased in bulk : in one in-
stance it weighed fourteen pounds, two ounces—about
eleven pounds more than its weight in health.
The organization of a gland suffers a total change,
-ocr page 296-
On the Diseases of Glands.                 261
or rather destruction, sometimes, in consequence of long
continued disease, or frequent relapse of it: the liver is
occasionally met with much altered in its texture ; and
the kidneys undergo morbid changes, which we shall in
a future lecture take particular notice of.
■-.
-ocr page 297-
LECTURE XVI.
I/VNT #"*** ■*«** *V+ *** ^S»v#^#V ****■+* ■++*■
On Cartilage.
Cartilage is that tough, white, and highly elas-
tic substance, better known by the name of gristle; of
an intermediate firmness between bone and the softer
parts of the body; and that by long digestion, in close
vessels, may be converted into jelly or glue.
There are three kinds of cartilage in the body. First,
that which supplies the place of bone during life, and
serves to give form to parts composed of it—-such are the
larynx, the windpipe, the ears, the nostrils, and the car-
tilages of the ribs. Neither bone, nor membrane would
have been suited to the various purposes that cartilage
answers in these parts : had the ears, or nose, for example,
been made of bone, how inflexible must they have been !
—and how continually liable to fracture !—or, if mem-
brane had been substituted for cartilage, a collapse of
the external parts must have ensued, and consequent im-
pairment, if not deprivation, of the senses of hearing
and smelling. The second kind of cartilage is what is
substituted for bone in the foetus ; but in the adult is ab-
sorbed, and bone deposited in its place. The third
kind, called the articular, is that which covers the extre-
-ocr page 298-
On Cartilage.                              263
mities of bones, and furnishes them with those polished
surfaces which, when applied, constitute the chief parts
of a joint: and for this purpose, from the smoothness and
slipperiness of its surface, and its great elasticity, it is ad-
mirably adapted.
Cartilage when cut into, exhibits throughout such an
uniformity of texture, that at first sight we should not sus-
pect it to be, what it is considered by the best anatomists
to be, of a fibrous composition. It is covered by a mem-
brane, called the perichondrium, which differs in no re-
spect from the periosteum—one that we shnll hereafter
have occasion to describe.
With regard to the organization of cartilage, that
which is put for bone in the foetus is extremely vascular :
its blood-vessels can be shown by injection ; and the phe-
nomena of ossification satisfactorily prove the existence
of absorbents in it. But of the other two kinds, and
more especially of the articular, the vascularity has been
often disputed : there can be little doubt, however, of its
being possessed of life—and we have only ideas of life as
connected with organization. Vessels, indeed, may be
injected in the perichondrium, and many of these, most
probably, ramify within the substance of the cartilage;
though they are too minute to admit of red blood, or of
our most subtile injection. Madder has been given to
auimals with a view of discovering it the articular carti-
lages were vascular; but no change of color was effect-
ed in them, as constantly happened in bones: nor do we
believe, that they have ever been found tinged in jaundice
from the absorption of bile. That these parts possess
nerves is still, and with much more reason than the pre-
sence of blood-vessels, questioned by many writers : it is
certain that their feeling must be very obscure, or the
-ocr page 299-
264                   On the Diseases of Cartilage.
great weight they have to sustain would probably prove a
source of irritation, if not pain, to the animal.
On the Diseases of' Cartilage.
From the low decree of vascularity which this sub-
stance possesses, inflammation in it, and its consequences,
are extremely slow operations. Ulceration of the septum
nasi in glanders, is comparatively tardy in its progress as
soon as it has attacked the cartilage; and its granulation,
supposing we could arrest the ulcerative action, would be
a still more tedious process. The most common disease
to which cartilage is subject in the horse, is ossification;
and we believe we may with truth assert, that no old
horse is free from this conversion of structure: the carti-
lages of the sternum, ribs, vertebra?, and foot, are the
most common seats of it. Not unfrequently do we meet
with disease in the articular cartilages : often as a sequel
of severe or mal-treated open-joints, they are either par-
tially or altogether removed, and in such cases the bone
itself is always found carious : they are never regenerated
when once destroyed. Knowing these facts, how futile
and demonstrative of ignorance, are the attempts of those
who pretend to restore groggy horses; in so many of
which, such is the nature of the disease. The carti-
laginous portion of the septum nasi becomes occa-
sionally bony ; as does frequently in very old horses, the
larynx,
On Ligaments and Joints.
Ligaments are strong, white, teudinous cords, serv-
ing to connect bones to one another. These substances
are similar in their composition to tendons ; they may, iu
fact, be said to be composed of tendinous fibres, the ma-
-ocr page 300-
On Ligaments and Joints.                  9.65
jority of which run in a longitudinal direction, intimately
matted together by short and transverse bands: so that
these parts only differ in use, and not essentially either in
structure or organization. Ligaments are altogether in-
elastic. Ligaments have various uses: in a general way,
they may be said>to connect bones together, and serve to
prevent displacement, or dislocation of them during mo-
tion; being inelastic, they will also confine their motions
within proper limits.
It is, then, by the adaptation of the extremities of
bones covered with cartilage to each other, and their con-
nexion by means of ligaments, that that inimitable piece
of mechanism called a joint, is constructed: a structure,
by which muscles are enabled to effect such multifa-
rious and opposite motions of the limbs, and other parts
of the body, not only with much facility, but without any
but a very remote chance of displacing the several parts of
which they are constituted.
There are three kinds of joints in the body. Some, in
consequence of the bones composing them being simply
united by membrane, are called membranous joints : those
of the cranium and face are of this class ; the membran-
ous attachments of which, denominated sutures, seem
chiefly designed to prevent the effects of concussion.
The second kind consists of a substance partaking in
its nature both of cartilage and ligament, hence called a
curtilago-Kgamentous joint: it is one that combines the
elasticity of cartilage with the flexibility of ligament. We
have many instances of this kind of articulation in horses :
all the spliut-bones, as they are denominated, as well as the
ulnas and fibulae, are thus attached ; and a similar union
subsists between the bones of the pelvis, at the symphysis
pubis, and between the bodies of the true vertebra:-
-ocr page 301-
26(3                    On Ligaments and Joints.
Though the motion of this kind of joint must be exceed-
ingly limited, still it possesses sufficient mobility to coun-
teract the injurious effects of concussion to the machine
during locomotion : what are vulgarly called the springs
of the animal, are no other than the joints now under our
consideration ; and that they will have a spring-like ef-
fect, appears evident from the nature of the material of
which they are formed. If, by any force, two bones thus
united be in part separated, or displaced, their elastic con-
nexion will restore them to their former situation, as soon
as the impression, or cause of displacement, is removed.
According to this view of the subject, every time a horse
places his foot upon the ground, the small bones, above
mentioned, are depressed by the weight of the body,
but recover their original situations instantly the force, i.e.
the incumbent weight, is taken off; so that a joint of
this construction becomes highly useful to such an animal
as the horse, by endowing him with that elasticity of move-
ment for which he is so highly esteemed by the finished
equestrian.
The third kind of joint is that inclosed by a capsular liga-
ment; under which head may be comprehended all those
joints of the body properly so called : it is of all the most
complicated, and varies much in its construction, in dif-
ferent parts, according to the nature and extent of motion
required. Every joint of this class is surrounded by a li-
gamentous bag, denominated the capsular ligament; and
very many, particularly those of the extremities, are
strengthened by others, named, from their comparative
length, situation, and course, long, short, lateral, oblique,
crucial, fyc.
Although the opposing cartilaginous surfaces
of bones are of themselves smooth and slippery, still,
when in motion, would considerable friction and conse-
-ocr page 302-
On Ligaments unci Joints.                  '267
quent irritation have ensued, were it not for the lubricating
properties of a fluid that oozes from the contiguous parts
within ; in order to supply which, and to give additional
glibriess, the cavity is lined by a fine vascular membrane,
called the synovial. This fluid—the synovia or joint-
oil,
we suppose to be secreted by the arteries of the syno-
vial membrane:
it does not possess any oleaginous pro-
perties, as the term joint-o;7 would seem to imply, but
resembles more in its appearance the white of egg ; it is,
indeed, of a mucilaginous nature, and has been found to
be chemically composed of the fibrine and albumen of
the blood, impregnated with small portions of some neu-
tral salts. The synovial fluid serves for the lubrication of
joints, and facilitates those complex and rapid movements
which we witness while the machine is in action ; for,
correctly speaking, the articular cartilages are never actu-
ally in contact, in consequence of the interposition of
synovia ; so that there can be no friction ; for none can
happen between a solid and a fluid—a certain degree of
resistance only is opposed. In some diseases of the joints
in the human subject, this secretion undergoes consider-
able changes: in rheumatic affections of them, it often
becomes inspissated, and otherwise altered in its pro-
perties; and in gout, the joints contain, instead of it,
a white solid matter of an earthy nature, known by the
name of chalk-stone. Dropsical accumulations of this
fluid are by no means of infrequent occurrence in horses*.
There is a substance in some parts of the body much
resembling ligament in its general appearance, but dif-
fering in toto from it in one of its essential properties,
inasmuch as it is very elastic : from which circumstance
* Vide Lecture XII. Diseases of Bursa Mucosa:.
-ocr page 303-
268                     On the Diseases of Joints.
it has been named the elastic ligament. One of the best
specimens of this is the suspensory ligament, one that at-
taches the sesamoid bones to the fetlock-joint. These
bones, which in part support the weight of the body, move
backwards and downwards at every step the animal takes,
and most perceptibly during the gallop : in such horses
as have very oblique pasterns, we may frequently observe
that the little tuft of hair growing from the heel, if it be
long, touches the ground at every bound in the canter, or
gallop, the animal makes, though it was removed some
inches from it before : a circumstance owing to the ex-
tension of this ligament. A considerable quantity of this
substance is met with in the neck of the quadruped,
in which situation it is better known by the name of pack-
wax : also between the vertebrae of the back and loins,
there is a similar composition ; though here it is not equally
abundant. This substance, which has received the deno-
mination of ligamentum nuchas, performs the very impor-
tant office of sustaining the weight of the head and neck;
which it does with the aid of comparatively little muscu-
lar force : a knowledge of this fact, will prevent the. pro-
fessional man from being led astray by the mechanical
doctrine of comparing these parts to steelyards, and from
undervaluing horses whose necks are of extraordinary
length, or heads of greater magnitude than common, with-
out a due regard to every circumstance connected with
the structure and economy of these parts.
On the Diseases of Joints.
When the articular extremities of bones are forced out
of their natural or proper situation, the case is called a
luxation or dislocation. Should one bone have left the
socket of the other, so that the capsular and other retain-
-ocr page 304-
On the Diseases of Joints.                     '169
nig ligaments are ruptured, the dislocation is said to be
complete ; but if the displacement be only such as to al-
low of their articular surfaces still being, at some points,
in contact, it is denominated partial or incomplete. Such
accidents, fortunately for its followers, are not often met
with in veterinary practice ; for did they occur in the prin-
cipal articulations, almost insurmountable obstacles would
oppose any thing like reduction. Dislocations however
are not altogether wanting in our nosological catalogue,
though they may be regarded of too rare occurrence to
need any description here. There is one joint in which
it has happened once at this place, and thrice, in the
course of a very short period, in the practice of a veteri-
nary surgeon, then residing at Hertford : we allude to
a dislocation of the patella, or stifle-bone, of which we
shall give the particulars in our anatomy of that bone.
Joints are subject to inflammation from one of two
causes :—either from external injury, or from undue and
long continued exeition of them: we shall first detail (he
effects resulting from the former.
An open-joint, every one knows, is an accident by no
means uncommon in veterinary practice ; either in conse-
quence of falls—as in the case of broken-knees, or of la-
cerations, or punctures from thorns, nails, or sharp in-
struments of any kind. The capsular ligament being
penetrated in these cases, a discharge of synovia, com-
monly mingled with blood, oozes through the wound in
the skin ; which is sometimes of sufficient magnitude
(especially if it be in the knee) to enable us to seethe ar-
ticular surfaces, or, at all events, admits of the intro-
duction of a silver probe, by which we readily learn its na-
ture and extent. We would remark here, en passant, that
in many cases, commonly called open-joints, there is no
-ocr page 305-
270                    On the Diseases of Joints.
division nor injury whatever of the capsular ligament; but
merely the exposure of some bursa mucosa, placed be-
tween the joint and the external wound: the discharge is
of the same kind as in the former case, and we can only
determine which it is by carefully probing the wound.
Most of all, we are likely to make this mistake in the
shoulder-joint and hock, when high inflammation and ex-
tensive swelling are present. Soon after the injury, ge-
nerally speaking, inflammation is set up in the interior of
the capsular ligament, which quickly extends itself over
the internal surface of the joint, and is accompanied
by increased heat, and more or less swelling of the sur-
rounding parts : as a natural consequence, considerable
pain is excited, which the animal seldom fails to evince,
by keeping the limb semiflexed, resting it upon the toe,
and carefully guarding against the imposition of weight
upon it. From the acute sensibility of ligamentous parts
when inflamed, the system quickly and almost invariably
sympathizes; so that, in all severe cases of this nature,
symptomatic fever supervenes: the pulse becomes acce-
lerated, the horse heaves at the flanks, refuses his food,
never lies down, and expresses, by various signs needless
to particularize here, suffering of the most affecting de-
scription ; and to such a height do these symptoms of
general irritation occasionally run, that the most active
and timely measures will not save the animal from falling
a victim to them. The case of a horse of our own, who
received a violent contusion upon the point of the
shoulder, followed by open-joint, is too well impressed on
our mind to escape recollection in this place : we men-
tion it to shew, that, although a joint be not opened in
the first instance, subsequent sloughing may expose its
cavity.
-ocr page 306-
On the Diseases of Joints.                     271
Now, the ordinary effects of an inflammation of the
synovial membrane, are : 1st. a preternatural secretion of
synovia—hence the profuse discharge observed in these
cases ; Ind. an effusion of adhesive matter into the cavity
of the joint; 3rd. a thickening of the synovial membrane
—a conversion of it into a substance resembling gristle,
and an effusion of adhesive matter, and probably serum,
into the cellular substance around, by which the external
parts and those of the joint are firmly cemented together*.
When the inflammation is intense, and has continued long,
abscess is likely to form within the joint; and this will at
length, unless it be opened, burst and discharge itself ex-
ternally by ulceration. About this time, the disease com-
monly extends itself to the cartilaginous surfaces; which,
from their vital powers being extremely weak, exfoliate—
leaving denuded (worm-eaten as it were) the extremities
of the bones, to grate against each other as often as the
joint is moved. These more vascular parts, (the bones,)
unable to bear this, take on inflammation, in their turn,
and restore themselves by throwing out callus from their
ulcerated ends around the joint—the nidus for ossific de-
posit ; a process that ultimately ensues, and anchylosis is
the result.
In a recent case of open-joint, we have but one indi-
cation ; and that is, to heal the wound by adhesion, so as,
at once, to shut up the cavity. Should the wound be a
clean cut—a stab from some sharp instrument, we shall
at all times be able to effect this by having immediate re-
course to proper means. We are to bring the edges of the
wound nicely together, after having cleaned them from
* Vide Pathological and Surgical Observations on Diseases of the
Joints,
by B. C. BrOdie, F.R.S. &c.
-ocr page 307-
272                     On the Diseases of' Joints.
blood, and any extraneous matter that may be present,
and confine them in contact by adhesive plaster*, or
by suture : in either case, to apply a bandage kept wet
with an evaporating lotion. At the same time, we are
to pay special attention to the quietude of the limb ;
which, should it be the knee, will probably best be in-
sured by binding splints to the back part of it, so as to
prevent all possibility of flexion, and by keeping the horse
constantly racked up; or, if the wound be painful, and
this treatment seem harsh, and improper, we must take
care to confine his head by a cradle, lest he gnaw the
bandage : an act a horse will invariably commit when his
suffering is extreme. In fact, our principal object in the
treatment, in this stage of disease, is to prevent inflamma-
tion in the synovial membrane ; and with this view, we
are to employ all the means in our power of closing, as
soon as possible after the accident, the wound leading to
the joint; for while that cavity, which is in its natural
state perfectly circumscribed, remains open, so long will
there be a disposition in its lining membrane to take on
inflammation. Too often, however, either from the na-
ture of the wound, from the admission of dirt, or from our
not having been called in soon enough after the accident,
we are foiled in our endeavours to produce union, and, con-
sequently, are compelled to resort to another class of re-
medies. Having relinquished all hopes of accomplish-
ing the primary indication, and regarding the case as one
that must be restored by a process of granulation, we
* For this purpose the hair must be shorn off around the joint.
It is not a practice commonly adopted, nor perhaps performable in
some cases; but we find it to be very preferable to ligature, or su-
ture, when the wound will admit of it.
-ocr page 308-
On the Diseases of Joints.                   27 3
are to lose no time in applying the actual cautery : the
only effectual means left us of speedily closing the joint.
Procure a cylindrical piece of iron adapted in size and
curve to the wound, and with it, at a dull red heat, cau-
terize the sides of that sinus which immediately commu-
nicates with the joint; taking great care not to introduce
it further than is merely sufficient to sear the cut edges
of parts exterior to the capsular ligament, otherwise it may
be productive of serious mischief. Having done so, we
besprinkle the external wound with some powder, which,
by its absorbent and adhesive properties, will form a kind
of cement with the discharge, and, by filling up the va-
cuities in the divided parts, and becoming a bond of union
between them, artificially prevent another eruption ofthe
collected synovia : common flour, or linseed meal, with
equal parts of either bole Armenian, alum, or charcoal,
will answer this purpose very well. In cases however
where there is much laceration, and the wound into the
joint is of large size, we should combine fomentations
with the above remedies : we may. and with advantage
indeed in some parts—as in the knee, apply a poultice,
and not use the absorbent dressings, until we have suc-
ceeded in abating the inflammation ; but we are not to be
deterred from the occasional use of the cautery, which,
even here, is our surest means in eventually plugging up
the joint. Bandages of all descriptions, however, are
inconvenient to apply, and sometimes do harm; for
which reason, and from the good effects we have ob-
served from it, we commonly prefer the application of a
blister to either poultices or fomentations. We have
seen many severe injuries of this kind converted into a
simple tegument wound by the simultaneous operations
T
-ocr page 309-
G74                    Oh the Diseases of Joints.
of the cautery and a blister, without the employment of
any other local means whatever. Should the joint re-
main open, a circumstance we are fully apprized of by
the nature of the discharge, the cautery must be repeated
with a light and cautious hand, and but moderately heated,
every day until the leading desideratum in the treatment
—the obstruction of the passage to it, be accomplished :
and though from the excess of the external swelling and
heat we may be unwilling to blister, still we have known
good effects result from the practice when the symptoma-
tic fever has not run very high ; for a blister appears to do
good, in these cases, not only by abating the inflammation
within the joint, but, at the same time, by perceptibly
lessening the secretion of synovia, and, thereby, concurring
in its operation with the cautery, in restraining another
emission of that fluid. Local bleeding, where we can
employ it—where blood can be drawn from a vein coming
from the vicinity of the joint, should almost always be
had recourse to in the first instance.
With regard to constitutional treatment, there are but
few cases in which purgatives are not required ; and if the
horse show symptoms of much irritation and pain, we are
not only to administer them in large doses, but to let
blood from three to six, or eight quarts, according to the
urgency and duration of the case, and to repeat this ope-
ration as often as the pulse and general state of the animal
appear to demand.
It has been proposed to sling horses under such cir-
cumstances ; but, in most instances, independently of the
inconvenience attending it, it is not a desirable prac-
tice : in such as are likely to prove protracted, we have
seen much relief given to the animal by the simple
-ocr page 310-
On the Diseases of Joints.                    275
suspension of a very broad piece of sail-cloth under his
belly, upon which he may rest himself, or not, as he feels
incliued.
Should the case, in opposition to all our measures, pro-
ceed to terminate in abscess, some part of the integument
will soon ulcerate and give vent to a copious discharge of
pus from the joint. The treatment now becomes compa-
ratively unimportant: so fast as we close up one place,
the matter, collecting again, breaks out at another; and
even should we succeed in suppressing the discharge by
plugging up the joint, we are to look forwards to anchy-
losis, the only probable termination under these circum-
stances. In the greater number of instances of this
kind, it is our duty to recommend that the animal be de-
stroyed.
With regard to that affection of the joints, which, at first
view, appears to be idiopathic, but which is as much the
effect of injury as the disease induced in them by wound,
erroneous notions seem to have crept into the minds of
some veterinary practitioners, who have been represented
to be the discoverers of morbid appearances, well known in
the leading science of medicine, long before the first brick
of the Veterinary College was laid: it is true, that they
were not universally known to be of so common occur-
rence in foundered, or groggy* horses, but it is not true,
that their existence was unknown even long ago by those
of the profession who had paid attention to the subject.
The discovery to which we here allude is, that certain joints
in the horse, on being cut open, have been found in a state
* The wm&founder is now commonly used to denote fever in the
feet, or its effects: grogginess, and stateness onthe legs, have more
allusion to diseases of the joints.
T2
-ocr page 311-
276                    On the Diseases of Joints.
of ulceration : i.e. the articular cartilages, which, as we
have stated before, are incapable of bearing active inflam-
mation, have ulcerated, or exfoliated, and left the bones
bare and ragged ; a condition of parts that, as we have
also just mentioned, is succeeded by anchylosis. Now,
this disease, like the former, consists in inflammation,
which has its seat principally in ligamentous texture, and
its origin in the synovial membrane : the only difference
between them is, that in the one we have an external
wound, whereas in the other the mischief is done while
the cavity remains entire. In order to learn if our opi-
nions be correct, let us take a view of its progress, symp-
toms, and termination; and then investigate the causes
by which it is induced. It must be confessed, that the
profession lacks much information on this subject—infor-
mation that can alone be obtained from a steady observ-
ance of the origin and progress of this disease in a multi-
plicity of cases, and a fair statement of the symptoms in
each stage of it, as compared with one of the morbid
changes apparent on dissection. In this way, we should
arrive at something like discriminative knowledge in these
cases ; but, at present, by the majority of us, all is ob-
scured and jumbled together under the unmeaning term
groggy; at the very sound of which the common assem-
blage of remedies is summoned to our aid, and the animal
subjected to such an ordeal, as not unfrequently adds
fuel to the fire it was intended to abate or extinguish. It
is certain, that we know, from his knuckling over, from his
tottering and frequently shifting his legs while standing,
from his tenderness before, and from his fumbling gait, that
the horse is "groggy ;'■ but how few are there acquaint-
ed, not to mention the seat, with eveu the nature of the
disease from which it proceeds. If any heat can be de-
-ocr page 312-
On tlte Diseases oj Joints.                    277
tected in the foot, or if it be contracted, or there be that
appearance of it, and mode of going, which indicate
alteration of structure and (he loss of elasticity in the
laminae; or if there be evident marks of disease in the
flexor tendons, or bursas mucosas, or there be enlarge-
ments of any kind, we may form, thus far, a tolerably cor-
rect diagnosis; but when such signs are wanting, and
often when they are present, we must direct our attention
to the joints: too often do we neglect this inquiry, and
regard it either as a case past cure, or one that is only to
be relieved by the all sanative virtues of blistering, firing,
and turning-out. Now if a case of confirmed grogginess.
O                                                                                                                                                CT          OCT                     '
in which lameness has subsisted for a great length of time,
arises from a diseased joint, the progress of the disease
appears to be as follows. In the first instance, inflam-
mation is excited in the ligamentous parts, and, above
all, in the synovial membrane of the joint; and this will be
denoted by such local symptoms as characterize its pre-
sence in other parts : viz. increased heat, tenderness from
pressure, lameness, and possibly swelling. And it is by
no means difficult to detect these signs, or at least some of
them, in every recent case that is brought before us; and
whether they be indicative of the onset, or of the more
advanced stage of disease, surely we may often learn by
closely questioning the proprietor of the horse, as to the
duration of the symptoms, and the number and nature of
prior attacks ; and it is absolutely necessary that we do
this, for without such information our diagnosis must be
ever conjectural, and our treatment liable to error. The
first effect of inflammation of the synovial membrane, is
augmented, and perhaps altered secretion; the second, an
effusion of lymph, or albuminous matter, by which the
ligaments are agglutinated together, and the motions of
-ocr page 313-
27$                     Oh the Diseases of Joints.
the joint interrupted ; the third may be the production of
abscess, but is most commonly the commencement of ul-
ceration—the articular cartilages are removed by the ab-
sorbents, and the extremities of the bones exposed in the
manner we have already described ; and the fbiirth is a
process of granulation from their denuded ends, and here
commences anchylosis. Now, anchylosis, which may be
defined to be, a considerable diminution if not destruction
of motion of a joint, and which is by far the most common
termination of these cases, is effected in this way. The ar-
ticular ends of the bones having become carious, take on
a restorative process—a process of granulation ; in conse-
quence of which, their edges, about the attachment of the
capsular ligament, become surrounded with a coating of
callous matter; and into this little spiculae of bone shoot,
which after a time coalesce around the joint, and render
it less moveable, or altogether inflexible. For so long as
the ossification of the soft parts remains incomplete, some
motion is still preserved, in which state it is called a par-
tial
anchylosis: it is only when ossific union bas taken
place between bone and bone, and all motion destroyed,
that the anchylosis is said to be complete. Supposing
this, then, to be the nature of the disease, we shall, by
scrupulous attention to all the circumstances of the case,
often be enabled to give our opinion with much preci-
sion. We are aware, that the bursa behind the navicular
bone is a frequent seat of it, much more so than either the
pastern or fetlock joint; and it is here so embedded, that
we cannot perceive swelling, though we may often heat
by grasping the heels and quarters: but in the former,
we may commonly detect both by a nice examination
and comparison of either leg.
The inflammatory action we have been describing, there
-ocr page 314-
0/* the Diseases of Joints.                    279
cannot be a doubt, is the result of undue exertion of these
parts. Imposing weight upon horses disproportioned to
their strength, making them perform labor their powers
are inadequate to, or exciting them to some extraordinary
and violent efforts, (in consequence of which the interior
parts of the joint are bruised and inflamed, and its liga-
ments sprained or lacerated,) is the most common cause
of grogginess.
The common mode of treating these cases is bad, inas-
much as it is not varied according to the nature or stage
of the existing disease ; which is to be ascertained, with
as much accuracy as may be, in a way we have already
pointed out, before we determine on the modus curandi.
For the sake of illustration, let us suppose a horse to be
brought to us with all the symptoms of grogginess after
a day's hunting, one that was perfectly sound a few days
before. Being satisfied that the disease is articular,
and knowing for certain that it is in its first, or inflam-
matory stage, our remedies ought to be of that class
which tends to lessen inflammation. Local bleeding is
always highly beneficial; after which, we may immerse
the leg either in cold or warm water, or apply bandages
wetted with an evaporating wash and poultice the feet:
at the same time, we are to exhibit a strong dose of aloes,
and strictly enjoin a state of quietude. We are not to be
satisfied, however, with one bleeding (which may be either
from the toe or veins above*, according to the joint af-
fected) but to repeat it daily, or every second, or third day,
so long as the inflammation continues unabated : and this
we may fairly conclude to be the case while the lameness
remains undiminished f. Having, in this way, subdued the
* The pastern, or cephalic vein.
■\ The directions we commonly give are these : that lbs, iv. of
-ocr page 315-
280                    On the Diseases of Joints.
acute or primary attack, we are no longer to persevere in
the use of depletive and emollient means, but to substitute
counter-irritant; and the best we have are blisters : for the
lameness, or stiffness yet perceivable, is probably the ef-
fect of some effusion of fluid into the joint, as well as thick-
ening and agglutination of the capsular and other liga-
ments, which nothing will so speedily remove as the fre-
quent application of blisters. The Tnfus. Lyttae will an-
swer the purpose; so that there will be no necessity for
trimming. All perceptible heat and swelling having left
the leg, and the lameness being relieved, the stiffness, so
often the sequel of lameness here, will be got rid of soon-
er by turning the horse into a loose place : indeed, should
the case have been of long duration, it is an excellent prac-
tice to give the animal a winter's run in a straw-yard, where
his feet and fetlocks will be continually soaked in muck.
Firing is rarely useful, where blisters do not succeed to our
wishes; but it may be tried, and ought to be in such horses
as have experienced former attacks of the same nature.
When the disease however is only manifested by lame-
blood be drawn from the toe; (of each foot, should both be affect-
ed ;) that the horse stand in a tub containing warm water enough
to cover the fetlock during the day ; that the foot be poulticed with
linseed meal at night, and the leg encircled by a linen bandage,
wetted with the Liq. Plumb. Subacetat. Dilut. that a brisk cathar-
tic be given; and that the horse though tied, never be racked up;
but be kept littered down, so that he may be allowed to life, as soon
as be is taken out of the hath. Next day, or the day after, we bleed
again from the toe, or pastern,-and repeat it every succeeding or
alternate day, until the heat has become imperceptible, and the
lameness diminished. At this time, we order Infus. Lyttae. |j.
to be rubbed around each coronet at night, and the bandage and
white wash to be discontinued. And now the sponge boots may
be worn with benefit, or, should they not be used, the feet must be
kept continually moist with clay-stopping.
-ocr page 316-
On tlie Diseases of Joints.                    281
ness—without any discoverable heat or swelling;—when
it has been of very long duration ;—and when it lias been
preceded by frequent relapses of such symptoms as we
have already detailed:—we may suspect ulceration to be
present. Under such circumstances, it is evident, how-
ever much the most active blisters, and painful firing may
palliate the symptoms, how very injudicious must that
plan of treatment be, which compels the animal to com-
press, and grate upon each other, the ends of bones whose
articulatory surfaces are already destroyed by caries: do
what else we may, rest, if wc hope to relieve an animal
lame from such a cause, appears to be indispensable.
Blisters kept open, or frequently repeated, must here con-
stitute the chief of our treatment: the actual cautery,how-
ever, may now and then be used with advantage, in a more
severe manner than we have m general recommended ; the
object being to excite counter-irritation, and subsequent
discharge. Setons or issues arc always 'proper, and fre-
quently very serviceable in these cases. At the Veterina-
ry College of late, it has been the practice to insert a
piece of tape through the fatty frog, in cases of disease of
the bursa of the tendoperforans, and, we understand, with
much good effect: the frog-seton-needle is used for the
purpose, which is thrust into the cleft of the frog—previ-
ously pared out to receive it, through the fatty frog, and
out at the heel.
We are not to expect to do more for these subjects than
alleviate their suffering, or, what amounts to the same
thing, diminish their lameness : restoring them to sound-
ness is quite out of the question. Should our endeavours
to render the animal again serviceable prove unavailing,
in consequence of the advanced state of disorganiza-
tion these parts have already undergone, our last resource
-ocr page 317-
282                             On Ossification.
is that of dividing the nerves running to the affected
joints; for instructions concerning which, we must refer
to our lecture on neurotomy.
On Ossification.
We cannot close the subject of bones without saving
a few words on this curious process. Those firm, hard,
and compact parts of an animal which we call bones,
were originally cartilage—nay, even nothing more than
membrane during the earlier periods of fetal existence.
Anatomists have been in the habit of considering these
organs in their primitive state, as consisting of a gelati-
nous or cartilaginous substance, in which the osseous
matter was deposited: but Mr. Howship, surgeon, in
an interesting paper on this subject, has shown that they
are originally formed of two membranes, the same that
afterwards become the periosteal and medullary mem-
branes. Within these, cartilage is continually deposited,
until the whole becomes a substance of firm, solid tex-
ture, resembling in shape the bone it has yet to be con-
verted into ; and so much precision has Nature observed
in this respect, that we shall find the fetus, still no larger
than a mouse, corresponding in form, with the utmost
exactness, to the horse that has arrived at maturity. Of
the truth of these remarks, we may, at all times, satisfy
ourselves, by examining the fetus at different periods
prior to birth. This cartilage, as we stated before, pos-
sesses very considerable vascularity, so that in the fetus
we can readily inject it with size and vermilion: it is
thought by some, that its arteries increase in size just be-
fore ossification is about to take place; and, whether
this be the case or not, it is certain that they admit very
readily of injection at this period, and are so numerous as
-ocr page 318-
On Ossification.                            283
lo be seen ramifying thoughout every part of the carti-
lage. At an early period of foetal being, the cartilage
becomes firmer, assumes a whiter appearance, and loses
much of its former flexibility; changes, which, on mi-
nute examination, we find to be dependant on a deposi-
tion of earthy or bony matter within it. This substance,
which chemists have ascertained to be phosphate of lime,
physiologists suppose to be separated from the general
mass of blood by the minute terminations of arteries, and
to be spewed forth by them into this cartilaginous nidus.
Now, the cartilage, unlike the bone it supplies the place
of, is perfectly solid—in it there is no hollow nor space
whatever; it is necessary therefore, prior to the deposi-
tion of bone, that a portion of it be removed: this the
absorbent vessels effect, and continue to do in exact ratio
with the deposition from the arteries. The process of
ossification first commences in the very heart of the car-
tilage ; so that if we make a section of it at this time,
we discover a minute speck of bone in its centre—the
other parts as yet remaining unchanged; and this bony
nucleus increasing in magnitude gradually extends itself
by divergent osseous threads, or fibres, to the surround-
ing parts, until, at length, the interior exhibits a fine net-
work of bone without any remnant of cartilage. This
constitutes the cancelli of the bone, and it is this that is
first formed: and as this part was originally solid, it is
evident that there must be a very considerable absorption
of cartilage before it can exhibit the cellular appearance
so remarkable in the perfect bone. The shell of the bone
is next composed ; and now its body is completed. The
extremities, (that is if it be a cylindrical bone,) though
they ossify in a similar manner, are at this time cartila-
ginous : the radiated osseous fibres from the centre do
-ocr page 319-
284                            On Ossification.
not extend thus far—they have separate foci, or central
points of ossification, which do not make their appear-
ance for some time after the completion of the body ; so
that even at birth the extremities of many bones are
still gristly. In consequence of this, the ends of the
long bones, even after they have become bony, are only,
at first, united to the body by cartilage, and are called
epiphyses, or appendices ; and it is not until the growth of
the animal is considerably advanced that a complete bony
union is effected : if we macerate the long bones of the
legs of a foal, twelve months old, we find that their ends
separate, and hence it is that they are unfit for the con-
struction of a skeleton.
As far as our own observations enable us to give a
statement of the priority of ossification in different bones
—the vertebrae, ribs, pelvis, and lower jaw first undergo
this change; subsequently, the bones of the head, the
scapula?, and larger bones of the extremities ; lastly, the
pastern, coffin, and navicular bones. In the foal, at birth,
ossification has made very considerable advances, com-
paratively to what we find to be the case in the infant,
puppy, or kitten; and the fact of such early maturity
in the formation of this animal, cannot fail to strike
us, when we consider its habits of life, as a beau-
tiful instance of the providence of Nature, whose
means are always so suitable and so adequate to Her
ends. Unlike the human female, or the beast of prey,
the mare, a graminivorous animal, cannot lay up a
store of food; although she is one that constantly
lacks it, and is, consequently, compelled to go in quest
of it, and take her offspring with her. Thus we find,
shortly afcer being dropped, the foal can not only stand,
but is able to follow its dam in pursuit of food ; indeed,
-ocr page 320-
Division of Bones.                          235
so much strength does it possess, that, while still but a
few days old, it will frisk and play around its anxious
mother, with all the powers, comparatively speaking, of
a child three or four years of age. What is the precise
stage of ossification in the foetus at birth, or what may-
be the periods at which particular bones take on this
change, and complete it, are questions we are not pre-
pared to answer: and though we are not aware that such
a knowledge would much benefit us in practice, still it is
what would gratify every one who feels a lively interest
in his profession. We are in the habit of regarding
horses as perfectly formed at five years old, as we would
a man who has attained the age of twenty-one; but
there are constant exceptions to these rules, depending
on constitution, species, mode of rearing, and perhaps
sex. Those bones which are not mainly employed in
sustaining the weight of the animal, but are only aux-
iliary props of support, appear to be the last to take on a
bony structure: for this reason, ossification of the coffin
bones precedes that of the navicular; and the pastern
bones become bony before the sesamoid. With regard
to the coffin bone, that portion of it which enters into the
composition of the coffin-joint, remains longest cartilagi-
nous : whereas, of the navicular, the surface forming part
of that joint, is soonest converted into bone.
Division of Bones.
Bones have been divided, according to their external
figure, into four classes : viz. cylindrical, flat, spherical,
and irregular. In the first class may be comprehended
all the long bones of the extremities—such as those of
the arm, thigh, and legs; in the second, those of the
head—the frontal, parietal and nasal bones, and the sea-
-ocr page 321-
286           Prominences and Cavities of Bones.
pulaj, and bones of the pelvis; in the third, the patella;,
and those of the knee and hock; in the fourth, such as
cannot be classed under either of the other heads—the
coffin bones, vertebrae, lower jaw, and navicular bones.
Prominences and Cavities of Bones.
In describing these parts, we shall have frequent occa-
sion to point out various projections, cavities, and holes,
all which we shall designate, as nearly as may be, by the
same terms as those used to denote similar appearances in
human anatomy. Thus, we shall give the name of ca-
put,
or head, to any round prominence upon the upper
pjirt of a bone, and that of cervix, or neck, to the part
immediately below it; tuberosity, to any unequal pro-
tuberance, and spine, if it terminates in a sharp ridge j
condyle to any flattened articular eminence ; coronoid, or
coracoid process, if it bears any resemblance to a bird's
beak; mastoid, when like a nipple, or teat; styloid, if it
is shaped like a pencil; and spinous, when sharp and
pointed like a thorn. Of the cavities—a shallow cavity
is called glenoid; a deep one, a fossa ; a long and nar-
row one, a furrow, or canal: beside these, there are
notches, sinuosities, sinuses, 8tc. Of the holes—if they
perforate the bone, they are called foramina; if not,
depressions, or pits.
-ocr page 322-
LECTURE XVII.
On the Skeleton.
The word skeleton, in anatomy, is applied to the bones
of an animal, divested of the flesh and other soft parts,
joined together in their natural order. A skeleton is said
to be natural, when the bones are connected by their own
ligaments; artificial, when by means of wire.
In taking a view of the skeleton of the horse, we find
that many parts of it have a close resemblance, in their
general outline, to correspondent ones of the living ani-
mal ; e.g. the head, the chest, and the legs below the
knees and hocks : on the contrary, the form of others is so
completely changed that we are unable to trace the slight-
est similitude ; e.g. the neck, loins, arms, and thighs.
It has been observed, that a horse in his general confi-
guration, when his parts are well proportioned, will, with
the exception of the head and neck, " come within the
square *;" a remark, in a general point of view, well worth
consideration, if it be borne in mind, that out of the nu-
* An 'Enquiry into the Structure and Animal (Economy of the Horse,
by Richard Lawrence, V. S.
-ocr page 323-
283                                     Spine.
merous deviations from this figure, many of them are at-
tended with peculiar advantages.
The skeleton may be divided into three pails :—head,
trunk, and extremities ; in describing which we shall ad-
here to the method commonly followed by teachers of
human anatomy, and begin with the trunk. This part
has been subdivided into the spine, ribs, and pelvis : first
let us consider the
Spine.
The spine, vulgarly called the back-bone, is that chain
of bones, which, in quadrupeds, extends in a more or less
horizontal direction from the occiput to the extremity of
the coccyx. In consequence of its great length, it con-
stitutes the bony fabric of the neck, back, loins, and tail.
Perhaps the best idea of its shape may be communi-
cated by saying, that it resembles that of the common S,
if we give to that letter an additional curve; e.g. )• Pro-
ceeding from the summit of the head with more or less
crest-like bend, the spine sinks into a concavity at the hind
part of the neck ; from which, in its course through the
back, it deviates but little from the horizontal line; in the
loins, however, an arch of great strength and regularity is
begun, which, more posteriorly, is completed by the de-
clivity of the tail.
From the centrical position of the spine, we find, on
examination of the skeleton, that it is sustaining the head,
neck, and trunk, and transmitting the weight of these se-
veral parts to the limbs: and such is the effect of this in-
termediate connexion, that, while all these parts are influ-
enced by its motions, in progression, its own movements
are regulated by those of the limbs. To this universal
concatenation of the bones to the spine, which is to be
-ocr page 324-
Spine.                                    289
regarded as the key-stone of the building, and to its pecu-
liar construction, are attributable the rapidity and ease
with which a horse performs his various actions;
The spine is made up of many small bones, called ver-
tebra ;
and these are connected together by cartilage and
ligaments of an elastic nature, so as to form numerous
joints : had it been constituted of only two or three bones,
with joints between them, material loss of resisting power,
as well as motion, must of necessity have resulted. Re-
ceiving it as an axiom, that joints are weak, insecure, and
liable to dislocation, in proportion as they possess exten-
sive motion, and taking it for granted, that the converse
of this is equally true, we shall discover that much wis-
dom is displayed in the formation of the vertebral chain,
and perceive that the objects sought after in its construc-
tion were extreme mobility, and great strength. The ac*.
complishment of the former is well seen in the several
motions of the neck and tail; and the completion of the
latter is equally well evinced by the immense weights the
spine is capable of supporting, and the almost unheard-of
accident of dislocation of its vertebra.
Seeing, then, that Nature has conbined in the construe*
tion of this part, such opposite mechanical properties, we
are induced to inquire by what inimitable mechanism
these objects have been attained. In the first place, the
vertebra are so dovetailed together, that their joints pos-
sess considerable strength, but exceedingly limited mo-
tion ; and had there been but two or three of these arti-
culations in the spine, but few of the motions it is now
capable of, could have been admitted. But instead of
having only two or three joints, we find that the spine is
constructed, including those of the tail, with upwards of
forty; so that if we admit the quantum of motion between
v
-ocr page 325-
290                             True Vertebra.
any two vertebra to amount (for the sake of illustration) to
the inclination of one-fourth of an inch in every direction,
the aggregate range in the extreme parts will be nearly
equal to a foot.
The bones of which the spine is composed have been
divided into true and false vertebrae: the first class com-
prehends all those that have the common characters of a
vertebra, and are moveable, one upon the other; the se-
cond, those that are either somewhere deficient in such
marks, or are immoveably united together. The true ver-
tebra; are distinguished into three kinds, named cervical,
dorsal,
and lumbar: of the first, there are seven; of the
second, eighteen ; and of the the third, five ; making alto-
gether thirty true vertebrae. The false vertebrae, accord-
ing to the usual mode of describing them, cease to be
called vertebra?; but are collectively considered as two
bones, by the names of sacrum, and os vel ossa coccygis.
The first is composed of five pieces, the coccyx of thir-
teen ; amounting together to eighteen bones, or, in fact,
false vertebra;; which, added to the thirty true, make forty-
eight, the total number of the bones of the spine.
True Vertebra.
The true vertebrae have a common resemblance, so
that a description of any one of them will apply to almost
all the others, so far as regard general characters; for
which reason, and to avoid repetition, we shall point out
the constituent parts cf one that differs least of all from
the majority of the others. Of this description we find
several of the posterior dorsal: suppose we select the
twelvth or thirteenth of this division.
We find that it is composed, first, of a round, solid
part inferiorly, called its body; of a spongy or porous
-ocr page 326-
Cervical Vertebra.
291
texture, convex upon its anterior, and concave upon its
posterior surface. Secondly, we observe a bouy arch ex-
tended transversely across the upper part of the body,
leaving a round hole of considerable size between them,
called the foramen spinalespinal, or medullary hole;
the use of which is to assist in forming an osseous canal
for the lodgment of the spinal marrow. From this bony
arch arise seven processes : four of them are short—two
jutting from its fore, two from its back part, in an oblique
direction—and these are denominated the articular, or
oblique processes; two others, longer than the former, ex-
tended from its sides, are called tranverse processes; the
seventh and longest arises from its upper part, and from
its pointed form takes the name of spinous process.
Having thus briefly described the common characters of
a true vertebra, we shall take notice of the diversities in
the external structure of the different classes, as well as
the peculiarities by which many of them of the same class
are distinguished from one another.
Cervical Vertebra.
The vertebra? of the neck are seven in number. They
are larger than those of either of the other classes, and
differ more in their external form from one another. They
are somewhat of a quadrangular figure. The body of a
cervical vertebra is of an oblong shape, presenting a
smooth round prominence anteriorly, and a cup-like ca-
vity posteriorly, which are fitted to a similar excavation
and rotundity upon the bodies of the opponent verte-
bra? : along its lower part runs a sharp ridge, which by
some has been described as an inferior spinous process.
The transverse processes, proceeding from the body as
well as from the bony arch, are bifid at their extremities,
u 2
-ocr page 327-
2Q2                          Cervical Vertebra.
and perforated in the centre, for the transmission of the
vertebral artery and vein. The articular processes are
large and broad : the anterior are directed obliquely up-
wards and forwards, and have surfaces of articulation
upon their superior parts, looking inwards ; the posterior
are pointed downwards and backwards, and possess articu-
lalory planes upon their inferior parts, facing outwards :
both the anterior and posterior articular processes form
joints with corresponding projections of the vertebra; si-
tuated before and behind them. The spinous processes
are short; but they vary somewhat in length. The spi-
nal foramen
is round, and of large dimensions.
The peculiarities of the cervical vertebras are as follow.
The first vertebra—erroneously in quadrupeds called the
at/as, for the head is rather suspended than supported by
it—differs in toto from any of the others : it cannot, in-
deed, be said to possess the common vertebral characters.
It is simply a ring of. bone with broad projecting sides.
It has no body ; the place being supplied by a process,
called the processus dentatus, of the second vertebra. Its
articular processes are directed horizontally forwards and
backwards: the anterior are scooped out internally, to
receive the condyloid processes of the os occipitis; the
posterior are slightly convex, to adapt themselves to the
anterior of the second vertebra. The transverse processes
are broader and stronger than those of any other bone
of the neck, not bifid, and are perforated by three pairs of
foramina. The spinous process is altogether wanting.
The spinal hole is larger than in any other vertebra;
but in the articulated spine is much reduced in size by
the vertebra dentata.
The second cervical vertebra, called, from a peculiar
projection upon the fore part of its body, the dentata, is
-ocr page 328-
Dorsal Vertebm.                          293
of a different form from the others. It is the largest cervi-
cal vertebra; exceeding the others however more in
length than in breadth. The processus dentatus, or
tooth-like projection, is round and smooth underneath,
where it forms a joint with that part of the atlas in which
the body of the latter is deficient; thereby in some mea-
sure supplying the defect. Upon the sides of this pro-
cess, near its root, are two oval surfaces of articulation,
which correspond to the anterior articulatory processes :
they are more extensive than the concavities upon the
posterior part of the atlas, with which they are joined,
thereby admitting of greater motion in the latter. The
transverse processes are smaller, and placed more back-
ward. Its spinous process is bifid posteriorly.
The third, fourth, and fifth have a general resemblance,
and bear the common marks of cervical vertebrae. The
sixth has no ridge along the under part of its body, or in-
ferior spinous process. The seventh is the smallest of
the cervical vertebra?, and approaches in its general figure
to that of the first dorsal. Its transverse processes are
short, round, and not bifid ; nor are they perforated by
any foramen. Its spine is more elevated, and sharper
than that of any other. At the back part of its body are
two small semilunar hollows; which, with similar de-
pressions upon the front of that of the first dorsal, form
sockets for the heads of the two first ribs.
Dorsal Vertebra,
The dorsal vertebrae, or bones of the back, are eigh-
teen in number*, and are smaller, generally speaking, than
either the cervical or the lumbar. They are remark-
* A spine in our possession has nineteen dorsal vertebra;.
-ocr page 329-
294                           Dorsal Vertebra.
able for the extreme length of their spinous, and the con-
trasted shortness of their transverse processes: the articu-
lator surfaces for the ribs form an additional character-
istic of them.
Each dorsal vertebra presents, upon the anterior part
of its body, a smooth round head, and upon the posterior,
a circular, but superficial cavity; by which means these
bones are nicely fitted to each other. Their articular
processes are short and oblique : the surfaces of the an-
terior face upwards; those of the posterior, downwards
and backwards. The transverse processes are short, ob-
tuse, and somewhat incurvated : the extremities of them
furnish articulatory surfaces for the tubercles of the ribs.
The spinous processes are long and flattened, and termi-
nate in rough blunted extremities : before they have sharp
edges, but behind are more or less grooved. Four sur_
faces for the articulation of the heads of the ribs are seen
upon the sides of the body. The spinal foramen is small
and round. At the roots of the spinous processes are
small excavations or notches ; which, in the articulated
spine, together form foramina, for the exit of the dorsal
nerves.
The first dorsal differs in some respects from the
others. In its general figure it approaches to that of a
cervical vertebra. The shape of its body, and the length
of its articular processes distinguish it from all the other
dorsal; the length of its spine, and the shortness of its
transverse processes, together with the surfaces of articu-
lation for the first ribs, specificate it from a cervical; the
peculiar shape of the spinous process is of itself a suffL
cient characteristic from both.
It is by no means difficult to arrange the others accord-
ing to their relative places in the skeleton, if we examine
-ocr page 330-
Lumbar Vertebra.
295
closely the form and comparative length of their different
spines. The second, independently of its longer spine, is
at once recognised by its anterior articular processes.
The third, fourth, fifth, sixth, and seventh, by the incli-
nation and greater length of their spinous processes.
The eighth, ninth, tenth, and eleventh, may be selected not
only by the progressive shortening of their spines, but by
their regular increase in breadth, so that they are of a dif-
ferent shape from those anterior to them. The twelvth,
thirteenth, fourteenth, fifteenth, and sixteenth spines re-
semble much in form those of the lumbar vertebra. The
eighteenth, and generally the seventeenth, have no arti-
cular surfaces upon their transverse processes, but whole
ones upon their bodies, for the reception of the heads of
the seventeenth and eighteenth ribs. The spinous pro-
cess of the fifth is generally the longest; forming that
part which is called the top or point of the withers.
Lumbar Vertebra,
The lumbar vertebra?, or bones of the loins, are five in
number. They are at first sight known from any others by
the remarkable length of their transverse processes. Their
bodies are somewhat larger than those of the dorsal, but
smaller than those of the cervical.
The body of each lumbar vertebra presents a smooth
convexity before of a heart-like shape, and a concavity
behind of corresponding figure and dimensions. The
anterior articular processes are hollowed out internally,
receiving between them the posterior articular of the ver-
tebra before ; the posterior, which are less distant from
each other, are round and smooth inferiorly, anoj are em-
braced by the anterior articular processes of the vertebra
-ocr page 331-
296                                Us Sacrum.
behind. Thus a kind of dovetailed union subsists between
these bones. The transverse processes are long, flattened
above and below, and stand out at right angles from the
body. The spinous processes are broad, flat, and nearly
of the same length with those of the four or five last dor-
sal. The foramen spinale is larger than in the dorsal,
and is somewhat of a triangular shape. There are grooves
upon the posterior part of the body of each vertebra,
which together form holes to give exit to the lumbar
nerves.
The first, second, and third lumbar vertebrae may be
known by their articular processes being nearer together,
and the greater breadth of their spines ; the fourth by its
possessing a surface for articulation with the fifth on its
transverse process, and the diminution in width of its
spinous ; the fifth from its general resemblance to the first
bone of the sacrum, from having four articulatory sur-
faces marked upon its transverse processes, and from the
extreme narrowness and peculiar incurvation of its spine.
Os Sacrum.
The sacrum in the colt consists of five pieces, but in
the adult horse these have become so united as to form
but one and the same bone; and as such we shall de-
scribe it. In its general figure it resembles the lumbar
vertebrae, from which it declines with a gentle curve—be-
ing convex externally, smooth and concave within, where
its surface is opposed to the pelvic viscera.
On the fore part of the body is an oval convex articu-
latory surface; corresponding to the concave one on the
body of the last lumbar, to which it is joined. The sa-
crum has only two articular processes, which, though
-ocr page 332-
Ossa Coccygis.                             297
wider apart, are similar in form to the anterior of the lum-
bar vertebrae. The transverse processes, thick, broad, and
strong, extend throughout the whole length of the bone :
each of them is marked in front by a smooth surface,
adapted to similar planes on the last lumbar vertebra.
The spinous processes differ from those of the loins both
in direction and shape : the latter lean forwards and dimi-
nish in breadth from the first to the last, these slope back-
wards and downwards and increase in breadth. The fo-
ramen spinale is triangular, and decreases in size.
There are eight pairs of foramina in this bone : four ex-
ternally, and four of larger size internally; through which
the sacral nerves take their course. Grooves are seen be-
tween the articular and transverse processes, which with
the last vertebra of the loins make complete foramina :
similar notches in the inferior extremity become foramina
when joined with the first bone of the coccyx.
Ossa Coccygis.
The coccyx or tail is composed of fifteen pieces, which
in their general character resemble so many little imper-
fectly formed vertebra?. The two, and sometimes three,
first pieces have transverse and spinous processes; the first
indeed frequently has two articular upon its fore part, by
which it is attached more firmly to the lower end of the
sacrum. The spinal canal is also generally perfect in
these bones. In the fourth piece we commonly lose all
appearance of transverse process, and the bony arch itself
is defective, as well as in the fifth, sixth, and sometimes
seventh; so that the spinal channel is here only in part
bony, being completed in the recent subject by ligament.
The remaining pieces can scarcely be said to retain the
vertebral form ; but merely consist of so many small cylin-
-ocr page 333-
2Q8                             Ossa Coccygis.
drical bones, which differ only from each other in regard
to their size.
The bodies of the vertebrae are united together by an
elastic substance, whose texture is of that peculiar kind
called cartilago-ligamentous: to its extreme flexibility
may be attributed that springiness of movement in the
animal's gait, which the experienced horseman alone can
properly estimate. Why young horses are more remark-
able for such a quality than old, arises from tbe circum-
stance of the intervertebral substance rarely being free in
the spines of the latter from osseous deposit. To shew
how extremely flexible and elastic this part is in horses
and asses, we would adduce, as a familiar illustration, the
declinations and incurvations of the spine that the latter
animal exhibits in writhing under the scourge of his merci-
less master, or in passing under a fence of inconsiderable
height: indeed were it not for this kind of union, a horse's
back must be broken every time he is said to sink under
oppressive burdens.
Between the articulatory processes of the spine are
joints, furnished with capsular ligaments, and a secretion
of synovia ; each of which in itself possesses but a very
limited degree of motion.
The cervical vertebrae are the most moveable : there
are indeed but few motions of the head in which they do
not participate. On the other hand, the dorsal are so
constructed and their intervertebral substances so much
thinner, that they are incapable of much motion ; had they
been equally moveable with the cervical, the functions of
the thoracic viscera, whose regular performance is so in-
timately connected with the support of life, must have
received much interruption, if not occasional suspension.
To compensate however for this comparative fixedness
*
-ocr page 334-
Ossa Coccygis.                             299
in the back, Nature appears to have centred the mobility
of the trunk in the vertebras of the loins, parts whose un-
restrained natural action is of the utmost consequence in
progression : only observe, as a proof of this, the gait of a
horse said to be broken-backed—whom the horse-dealers
call " a german"—and we shall be convinced that the trunk
owes its flexibility and adaptation to the motions of the
limbs in progression, very principally to the flexures of
the loins.
The cervical vertebras receive the weight of the head,
and transfer it to the trunk ; give attachment to a thick
mass of muscle; and by their spines afford firm connexion
to the strongest ligament in the body. Between the atlas
and dentata, there is a small space where the spinal mar-
row is unprotected by bone : this defect has given rise to
a mode of destroying an animal called " pithing;" which
consists in introducing a knife or other sharp-cutting in-
strument through the skin, for the purpose of dividing the
medulla at this part.
The dorsal vertebras constitute the superior part of the
trunk ; afford articulation to the ribs ; and serve for the at-
tachment of muscle and ligament.
The lumbar, from the length of their transverse pro-
cesses, defend those viscera unprotected by ribs ; and offer
a considerable surface for the attachment of some very
powerful muscles.
The sacrum appears to have no other mobility than
what is necessary to prevent concussion. The extent
and variety of the motions of the coccyx, are too well
known to require any remark in this place. On the de-
gree of incurvation which the sacrum and coccyx form with
the lumbar vertebrae, depends the position of the tail with
regard to the trunk : hence the common observations that
-ocr page 335-
300                     Diseases of the Spine.
a horse's tail is well or ill set on. Independently of the
symmetrical improvement which the high tail is allowed
to confer, it is attended with no inconsiderable advan-
tages in the construction of these parts : it affords more
space to the pelvic viscera, and gives more freedom, if not
power of action to the muscles attached to the sacrum and
coccyx.
Diseases of the Spine.
The spines of most old horses exhibit marks of dis-
ease, though we are not aware of any morbid change in
the generality of them during life : this probably may be
the reason why our authors on farriery have been so silent
with regard to this part of pathology. The most com-
mon, indeed we may say, almost the only diseases of the
spine to which horses are subject are
Fracture and Anchylosis.
In the phraseology of farriers and horse-dealers, these
cases are known by the names of broken~back, chinked-
back,
and german; stable terms simply denoting, that a
horse has received some injury in the back or loins by
which his action is impaired. Horses that are cast, now
and then have their backs broken ; i. e. the vertebrae are
either simply fractured, or fractured and displaced; (for
one cannot take place without the other;) in which latter
accident the horse is not unfrequently killed on the spot
from injury to the spinal marrow : or if the fractured por-
tiou of bone be merely partially driven out of its place
so as to occasion pressure to the marrow, palsy of the
hind quarters, or a convulsive or spasmodic action of them,
resembling slringhalt, will be the probable effect. Con-
trary to what we should expect in these cases, the accident
-ocr page 336-
Fracture and Anchylosis.                     301
seldom or never happens in the act of casting, but is the
sudden effect of some violent effort of the hind quarters
to disengage themselves while the animal is lying upon
his side : all at once his struggles, but now alarming and
resistless, cease, or become comparatively feeble; and
probably at the same instant a snap is heard in the back.
Several instances have occurred, however, in which the
operator lias known nothing of the accident until the
horse has been released, and found unable to rise—or if
able to get up, without the power of walking to the sta-
ble ; and we have been told of one where the animal re-
gained the stable before any symptoms had manifested
themselves : showing that the vertebra, though broken,
may remain in its place for some time afterwards. The
vertebra fractured is either one of the posterior dorsal, or
the anterior lumbar; and the substance of the spinal mar-
row is generally so contused, that its organization is whol-
ly or partially destroyed. Here is an example then, and
the only one at present known in the horse, of a bone
being broken by the force of muscular action; for this
is simply the explanation of an accident that has been re-
ferred, by those unacquainted with the nature of it, to
some mismanagement in casting. So far as our inquiries
have gone, it has always been judged expedient to put
the animal to death *.
With regard to anchylosis, the disease has its origin in
* We have been fortunate enough to have met with no accident
of this kind ; and this we account for by seldom having occasion
to cast horses, the subjects of operation. Surely both firing and
nicking are more conveniently performed standing—indeed with
the exception of castration and neurotomy, we—unless it be some
extraordinary case—forbid such a measure, not only as dangerous,
but quite unnecessary.
-ocr page 337-
302                    Fracture and Anchylosis.
an inflammation of the ligamentous structure connecting
the different vertebra ; and this may be brought on by
sprain, laceration, or other injury of it, as happens from
castitig horses, from overweighting them, or from violent
exertions in racing, leaping, suddenly turning or pulling
them up on the haunches, &c. The lumbar vertebrae are
commonly the parts affected, as might be anticipated from
what we have already stated respecting their motions.
The morbid alterations discovered in the spines of these
horses, if the disease have been of long duration, are well
known to knackers, who are in the habit of slaughtering
such subjects : they call them callus, a name by no means
inapplicable to their nature. The best description we
can cive of them is contained in the subjoined case of a
broken-backed horse, which we have lately dissected.
A brown horse the property R----------Esq. of Cam-
bridge, had been about two months the subject of disease
in the spine, which could not be traced to any hurt, or
other evident cause. The straddling gait, the difficulty
to turn round, the loss of general flexibility of the back
and loins, more particularly the latter, indicated the nature
of the case. As the malady was recent, as far as regard-
ed the presence of these symptoms, such treatment as we
think most appropriate in these cases was adopted: viz.
the repeated application of blisters—or other stimulants
to the spine, which were constantly kept discharging, com-
bined with the occasional administration of purgatives.
This was persevered in without the least benefit for the
space of a month, at the expiration of which time, the
horse was by consent of its owner destroyed.
On examining the spine, the disease was found to be
greatest in the loins, and to be included between the
twelfth dorsal and last lumbar vertebra. Several round
-ocr page 338-
Fracture and Anchylosis.                    303
bony knobs of different sizes projected from the arches
and bodies of the lumbar vertebra, and there were others
near them in part cartilaginous, and in part bony. Many
vertebrae were anchylosed, others still possessed a limited
degree of motion : also the transverse processes were in
some places joined by a similar substance. Within the
spinal canal there was a small bony eminence, which, no
doubt, had it undergone much accretion, (in event of the
animal being kept alive,) would have pressed sufficiently
upon the marrow to have occasioned a paralytic or con-
vulsive affection of the hind quarters.
The cervical vertebra;, though less frequently diseased,
are not altogether free from this affection. The atlas is
sometimes incrusted by bony deposit. We have specimens
before us of anchylosis between the dentata and third
cervical vertebra;; and between the sixth and seventh.
In the former instance a remarkable curvature is formed,
in such a manner that the marrow must have sustained
considerable pressure; indeed there can be little doubt
that suppuration had taken place in the theca, for below
we perceive an opening into the vertebral canal, through
which the matter discharged itself. In regard to them,
we may observe, though we are unacquainted with the
origin of these specimens, that the common excitants of
disease are external injuries—such as blows upon the
poll, and pressure and contusion of it from hanging back
in the halter, as young horses are apt to do—and that the
disease itself in its worst form is known by the name of
poll-evil; which rarely or never invades the bones with-
out being followed by necrosis and anchylosis.
The extent of anchylosis varies much, however, in dif-
ferent subjects, according to the severity and duration of
the disease. We have one spine in which all the bodies
-ocr page 339-
304                     Fracture and Anchylosis.
and transverse processes are completely fixed by ossifica-
tion, as far forward as the fourth dorsal vertebra : another,
in which in addition to extensive anchylosis, a bony tumor
of large dimensions projects downwards, at least four or
five inches, into the cavity of the chest: a third, in which
a long spicula of bone dips down from the sixteenth and
seventeenth dorsal. In all these preparations, the spinous
processes of the latter dorsal and those of the lumbar
partake more or less of disease.
The connexion between stringhalt and broken-back,
we suspect to be intimate : a reference to Lecture XII.
will disclose our theory of the former disease, and prevent
the necessity of any repetition in this place.
-ocr page 340-
LECTURE XVIII.
Pelvis.
J_HE Pelvis forms the posterior boundary of the trunk,
and is composed in the horse of three bones :—-the two
ossa innominata, and the 03 sacrum. Although the coc-
cyx in its dependent position may be said to enter in part
into the formation of the pelvis, it will be hardly so con-
sidered when erect; we have therefore chosen rather to
omit it altogether in our description of this part: and
having already described the os sacrum, we shall proceed
at once to a consideration of the
Ossa Innominata.
The ossa innominata, hip, or haunch bones, are two
of the largest bones in the skeleton. Each in the colt is
made up of two pieces : the larger is called the os ileum;
the smaller, in allusion to the human spine, has been sub-
divided into two portions, named the os ischium and os
pubis; ossific union, however, takes place so early in
horses, and all traces of any former separation become so
completely effaced, that we think it more proper to treat
of them but as one.
x
-ocr page 341-
Ossa Innominate/.
306
The os innominatum forms the lateral and inferior pa-
rietes of the pelvis ; the upper and back parts being bound-
ed by the os sacrum. It is broad above, contracted be-
low, thick and strong where it forms the socket for the
thigh bone. Along its upper part runs a waving rounded
margin, called the crista ; which is terminated at either
extremity by a rough projection : the one pointing for-
wards and outwards is denominated the anterior spinous
process ; the other directed backwards and inwards, the
posterior spinous process. Below the crista is a trian-
gular portion of bone, the external surface of which is
called the dorsum ; the internal, the venter. Projecting
from the inferior part of the bone is a fiat process, whose
extremity is rounded and roughened, to which the name
of tuberosity has been given. The acetabulum is that
bony cup intended for the reception of the os fenioris :
it is deep, surrounded by a prominent lip of bone inter-
rupted by a notch at the inferior part, and is marked with-
in by the insertion of the round ligament. The large
oval opening under this is the foramen magnum. The
symphysis is the place of union between the two ossa in-
nominata. The venter exhibits near its middle an oval
depression, which part rests upon, and is firmly attached
to, the transverse processes of the two first pieces of the
os sacrum ; the anterior spinous process of the latter be-
ing situated immediately between the posterior spinous
processes of this bone.
The two ossa innominata are firmly joined at the sym-
physis, by a substance partaking both of the nature of
cartilage and ligament, which in old horses is commonly
converted into bone. These bones are connected to the
trunk by cartilages, ligaments, and muscles; for which
-ocr page 342-
Sternmn.                                  307
last they present an extensive surface of attachment. The
foramen magnum is filled up with ligament in the recent
state; and the acetabulum is lined with cartilage.
The large circular opening between these bones—the
cavity of the pelvis, whose boundaries form what is called
the brim of the pelvis—is directed horizontally forwards
and backwards : it is larger in the mare than in the horse.
The posterior opening, over which the os coccygis hangs,
is called the outlet: it is comparatively of larger size in
quadrupeds than in the human subject, from which cir-
cumstance, and from the extreme mobility of the coccyx,
parturition in them is attended with much less pain and
danger.
We not unfrequently meet with pelves with incrusta-
tions of bone about the acetabulum, which would appear
to originate in disease of the hip-joint. We have one
pelvis in which the foramen magnum is much diminished
in dimensions.
Sternum.
The sternum, or breast-bone, is composed of seven
pieces, united together by intervening cartilages. They
are all nearly of the same size and figure, with the excep-
tion of the last, a piece wholly cartilaginous, which from
its shape has received the name of ensiform cartilage.
Protruding from the anterior extremity of the sternum,
is a portion of cartilage, in its figure not unlike the keel
of a ship : its fore part may be distinctly felt, and some-
times seen, in the living horse; its posterior end becomes
gradually narrower, and adheres firmly to the under part
of the bone. Each bone has indentations upon its sides,
marking the insertions of the cartilages of the ribs.
x2
-ocr page 343-
308
Cosl&.
The costa?, or ribs, together with the dorsal vertebrse
and sternum, constitute the osseous parts of the chest,
and protect the contained organs, upon whose uncon-
strained operation life itself depends. They are thirty-
six in number, eighteen on either side ; sometimes how-
ever there are thirty-eight, and occasionally forty; of
which we have specimens in the museum at this place.
In their general characters they resemble each other ;
though there are some few peculiarities among them, of
which we shall presently take notice.
The head is the superior part of the rib, and is received
into the cavity formed between the bodies of two dorsal
vertebrae; the contracted part below the head is called the
cervix, or neck; lower still is the tubercle, a small pro-
jection, articulated with the transverse process of the
vertebra.
The ribs are more or less contorted or twisted in their
figure, and are fixed in such a manner to the spine, as to
form so many bony arches upon the sides of the chest, the
convexities of which are turned outward. Their anterior
margins are thin and sharp; their posterior smooth and
round. Upon their lower extremities are oval depres-
sions, roughened by the attachment of the cartilages.
The first rib is shorter arid stronger than the others.
Its upper part is thicker and rounder, and its lower con-
siderably flatter and broader than those of any other; and
the concavity of its arch is turned forwards : in fact, once
seen it can never be confounded with the rest. The se-
cond is a remarkably straight rib, from which circum-
stance, and from its being longer than the first, we shall
have no difficulty in recognizing it. From the second the
-ocr page 344-
Costa.                                    309
ribs gradually increase in length, and somewhat in
breadth, to the seventh, which is the longest: from this
to the eighteenth they become shorter, narrower, and
rounder. The eighteenth (and sometimes the seven-
teenth) rib has no tubercle, consequently no articulation
with a transverse process.
The cartilages of the first seven ribs proceed and are
immediately attached to the sternum, from which circum-
stance they have been designated the true ribs ; the car-
tilages of the remaining eleven are only connected to one
other, hence are denominated false ribs ; they still parti-
cipate in the motions of the breast bone however, through
the medium of that of the last true rib. When the num-
ber of ribs exceeds thirty-six, the eighth and sometimes
the ninth are true—i. e. their cartilages are continued to
the sternum.
The chest is of a conical form, the apex of the cone
being turned forwards; a shape given to it in conse-
quence of the greater length and curvature of the pos-
terior ribs ; its area consequently is much greater behind
than before. The circumferent outline of the chest
differs but little in figure from that of a circle, at least in
wrell formed animals ; there are horses, however, in
which it approaches more to an elliptical shape, from
insufficient bow in the bodies of the ribs : such are
called flat-sided. But it does not of necessity follow, that
because a horse's chest is not round, it must be badlv
constructed ; for if there be great length from the withers
to the sternum, the deficiency in circularity is in a great
measure supplied by the depth. Speaking generally
however, that animal is best formed (more especially if it
be of a kind selected for food) whose chest exteriorly
presents the nearest outline to a circle: jt will preserve
-ocr page 345-
310           On the Bones of the Fore. Extremity.
its condition under less favorable circumstances, and
will, in fact, exist where one with an oppositely formed
thorax would probably starve. On the other hand, cir-
cularity of the chest is, and more particularly in horses,
always attended with a diminution of speed, in conse-
quence of removing the scapulas far apart, and giving
that conformation to the shoulders expressed by the
term, " thick-shouldered." Both these facts are strik-
ingly illustrated in the bull-dog and the greyhound : the
former, comparatively slow and aukward in progression,
but celebrated for strength, requires but little food to be
kept fat; the latter, the fleetest of the kind, by his lean
and delicate make shows himself unable to contend with
so robust an adversary. We shall enter more at large into
this subject in another part of the course.
The ribs are occasionally broken. We have not met
with a case of this kind; but should such an accident
occur, the principal part of the treatment would consist
in applying a broad roller around the chest, in order to
impede the motion of the fractured parts: we have se-
veral ribs now before us which exhibit traces of much
bungling in the management of these cases. Sometimes
from blows, hard round lumps, either callous, or bony,
make their appearance upon the ribs; which now and
then go on to suppurate, and produce troublesome ab-
scesses upon the side : in these cases, there is commonly
some pieces of dead bone to be cast off before the wound
be allowed to heal. In some instances we see the heads
of the ribs immoveably fixed within their vertebral
sockets by anchylosis.
On the Bones of the Fore Extremity.
Though this part corresponds to the upper extremity
-ocr page 346-
On the Bones of the Fore Extremity.          311
of the human subject, on which account the names of the
different bones composing it, have (like those of they
bones already described) been borrowed from the no-
menclature made use of by anatomists of the human
body; we are far from giving assent to such an unwar-
rantable liberty, or wishing to countenance such perver-
sion of language. At the same time, so averse are we
to the introduction of new names, that, with the exception
of one or two glaring misnomers, we shall faithfully ad-
here to the established veterinary vocabulary.
There are some bones of the fore extremity never
spoken of, even by professional men, but by the vulgar
(or farrier's) appellations—such are the pastern and cof-
fin bones; while others, remarkable enough, are seldom
or ever heard of but in Latin—as the scapula, os humeri,
and radius. Now there is much inconsistency in all this :
either let us have a Latin, or an English nomenclature;
a medley is not only degrading to the science, but casts a
slur upon the literary reputation of that individual who in
matters of professional importance makes use of it.
Stuebs considered (and properly enough too in order
to carry on a close comparison between the skeleton of a
man and that of a horse) the pastern and coffin bones as
phalanges ; veterinary science however, attaches far more
importance to them, than to regard them in so general a
way as human anatomy does these last mentioned parts:
indeed, they bear but little resemblance in structure, and
less in use, to the bones of which our fingers and toes
are composed.
Jn describing these parts, we always treat of them
singly; it is necessary therefore to have separate Latin
denominations for them. Those we have here adopted
-ocr page 347-
312                                  Scapula.
may be found in Latin authors on subjects relating to the
horse, and may serve—dum meliora proveniunt.
Scapula.
The scapula is a triangular bone obliquely placed
against the side of the chest; having its coracoid process
opposed to the sternal extremity of the I st rib, its posterior
angle to the curvature of the 7th, or 8th, and its superior
elevated somewhat above the transverse process of the 4th
or 5th dorsal vertebra *. The different parts of it worthy of
notice are very distinctly marked, and easily retained in me-
mory. It is broad and thin superiorly ; narrow, but thick
and strong, inferiorly. Its sides are called costae, prefixing
to each the epithet, superior, anterior, or posterior, ac-
cording to its relative position in the skeleton: the su-
perior costaiu the recent subject is tipped with cartilage.
Its angles are superior, posterior, and inferior; but the
latter appears as if it had been in part cut off, and
formed into an oval articular cavity, called the glenoid;
which is adapted to the reception of the round and
smooth head of the os humeri. From the fore and upper
part of this cavity, extends a strong, rough protuberance,
named the coracoid process. Its external surface—the
dorsum, is unequally divided into two concavities by a,
central ridge of bone, denominated the spine; the lesser
of them is placed anteriorly. Upon its internal part
the bone is smooth, somewhat excavated, and marked
by the attachment of muscles : to this the name of venter
* Stubbs, and many other delineators since his time, have repre-
sented the scapula out of its natural situation : they have placed it
too high, and have not attended to that slope, or obliquity, which
constitutes the beauty of this part in the living horse.
-ocr page 348-
Scapula,                                  313
is given. It is roughened about the glenoid cavity by the
insertion of the ligaments of the shoulder-joint.
The scapulae are attached to the trunk solely by means
of muscles—no joints intervene; so that the head, and
neck, and half the carcass, are in reality suspended by
the muscles which tie these bones to the sides of the ribs ;
for if they were cut through, those parts must necessa-
rily fall to the ground.
The scapula possesses a degree of rotatory motion, on
which the extent and facility of action of the fore limb
mainly depends; so that whatever lessens its sphere of
rotation, nearly in the same ratio limits the projection of
the anterior extremity. And if it be ascertained that its
motions are confined, for reasons we shall hereafter point
out, in proportion as it approaches (in situ) to a line pass-
ing perpendicularly through the middle of the fore leg, we
shall become practically acquainted with the mechanism
of the shoulder, and know as much as the experienced
horse-courser, who vainly piques himself in the posses-
sion of a knowledge, to a man of science he considers un-
attainable. When the scapulas are perpendicularly placed,
so that the superior costas are directed towards the spines
of the dorsal vertebras, horses are said to be " thick shoul-
dered," or more properly, "upright in their shoulders ;"
for, as we have already demonstrated, the thick shoulder
may arise from a very different conformation ; hence it is
as is well known, that such animals are bad goers, exceed-
ingly unpleasant to ride, not to say dangerous : the want
of adequate freedom in the projection of the fore
legs, destroys their concurrence of action with the
hind, confusion in progression follows, and stumbling,
if not falling, is the consequence. The scapula?, there-
fore, should be obliquely placed; though even then the
-ocr page 349-
Os Humeri.
314
shoulder may be thick ; still it does not arise from so
objectionable a disposition of parts, as what we have ju s
been describing : on the contrary, there are some horse-
men who prefer this kind of shoulder to a thin one.
The scapula sometimes exhibits morbid appearances
about its lower extremity. Earthy concretions are now
and then seen around its cervix, and ubon the coracoid
process ; more commonly however, the edges of the gle-
noid cavity are much thickened by incrustations of new
bone, and its articular surface presents that worm-eaten
appearance which shows the destructive effects of long
continued inflammation of the shoulder-joint.
Os Humeri.
It is somewhat remarkable that the os humeri of the
horse, as well as that of the human subject, and, we be-
lieve, most quadrupeds, should have the appearance of
having been twisted in its body. It is a short, but strong
bone; and its description, like that of others of the cy-
lindrical class, is much simplified by dividing it into a bo-
dy, and two extremities. The upper extremity is formed
principally by the head; a smooth, round, convex portion,
which we observed, when speaking of the scapula, was
received into the glenoid cavity; for which it is made
disproportionately large, in order to admit of extensive
motion. Anteriorly to the head are two projections, which
we may call, the greater and lesser tubercles: the former,
the outer one, terminates in a thick protuberant ridge.
The body of the os humeri is smaller, but rounder, smooth-
er, and more compact than the extremities. Its lower
end presents a pulley-like articulatory surface, formed of
three smooth eminences, with concavities between them,
which are fitted to corresponding depressions and pro-
-ocr page 350-
Radius el Ulna.
315
minences upon the head of the radius. Posteriorly, at this
part, there are two unequal projections, called condyles,
with a deep hollow between them for the reception of the
olecranon of the ulna; whereby the arm admits of being
carried backwards beyond the line of complete extension.
The motions of this bone are simultaneous and concur-
rent with those of the scapula: they are not confined to
simple flexion and extension, but are in some measure of a
rotatory kind, so that a horse has the power, to a certain
extent, of turning the toe in or out. Its chief movements
being downwards and forwards, they will be greater ac-
cording as it inclines to a right angle with the scapula:
here again then we perceive the advantage of having the
scapula in an oblique position.
The os humeri is seldom diseased but at its upper end;
its head often shews marks of caries, from disease of the
joint. It is sometimes seen encased with new bone, so
that its body is twice or thrice the natural size. We have
one preparation of fracture of it, in which union of the
broken ends has taken place without any material short-
ening : it is however by no means a specimen of good
surgery.
Radius et Ulna.
Though these bones are commonly treated of separate-
ly, in consequence of their union being of a cartilaginous
nature in the colt, we ought not to regard them as such
in the adult horse: we meet with but few instances in
which we can disunite them by maceration or boiling af-
ter five years old, in consequence of the conversion of the
original connecting cartilage into bone.
The radius may be said to be the os brachii of the
horse; indeed there would be no great impropriety in
-ocr page 351-
Radius et Ulna.
316
considering both the ulna and it under this name. It is
of a cylindrical shape, flattened and expanded at either ex-
tremity. Its head presents an articular surface, corres-
ponding to the pulley-like one of the condyles of the
humerus, upon which the latter have free hinge-like mo-
tion. The body of this bone is bent forwards, and so far
resembles that of the os femoris of the human subject :
it is convex and smooth upon its fore part, concave and
hollowed out posteriorly. At the lower extremity we
find three superficial depressions for articulation, the
external of which is the smallest, adapted to the upper
surfaces of the bones of the first row of the knee, upon
which the radius rests. In the recent subject, this bone
is invested with muscles, insomuch that no knowledge
of its exterior form can be obtained by examination of
the arm.
The ulna is chiefly remarkable for its protuberance
above the radius, which part is called the olecranon, in
conformity to a process of the same name extending from
this bone in the human subject, which forms the elbow :
and indeed, whimsically enough, this part in horses is de-
signated the elbow, though from it to the knee constitutes
the arm. The extremity of the olecranon gives insertion
to a powerful muscle of the shoulder, called the triceps
extensor brackii; a muscle that not only aids in pro-
gression, but one that is also employed in preserving the
standing posture : for these reasons, it is a point worth
attending to in the construction of this part, as connected
with speed and strength, that the elbow be long and pro-
jecting, and thereby afford a more powerful lever in the
extension of the arm. In front the olecranon is scooped
out and smooth, which part of it enters into the composi-
tion of the elbow-joint, by articulating with the os humeri.
-ocr page 352-
Radius et Ulna.
317
Its tapering lower extremity may commonly in the colt be
traced nearly to the knee, but in old horses its termina-
tion is indistinctly marked. Naturally, it is closely con-
nected throughout its extent to the back part of the radius
by cartilago-ligamentous substance, which, being elastic,
admits of sufficient yielding (we can scarcely call it mo-
tion) to prevent jar or concussion in violent efforts^as in
galloping and leaping. In dogs this bone is of equal
maguitude with the radius: in the deer, it approaches
more to that here described; in the antelope it bears a
still closer resemblance.
Both the radius and ulna are now and then deformed
by exostosis. We have two preparations in which caries
has destroyed their articulatory surfaces, and deeply and
extensively eroded their substance, the havock of malig-
nant disease in the elbow-joint: in both instances, the
surrounding parts of the bone are much thicker than in
the healthy state. In another diseased radius, there is an
exostosis as large as, and somewhat of the figure of a kid-
ney, upon the inner part of its upper extremity.
-ocr page 353-
LECTURE XIX.
Carpus.
XT is with a full conviction of the inapplicability of the
above term, that we commence our description of this
part of the skeleton : with the hope, however, of render-
ing a knowledge of the osteology of the horse easy of
attainment to the surgeon, we continue in the use of it,
and of some others equally inappropriate. With this re-
mark, which we trust will cast off the imputation of con-
sciously persevering in error, we proceed with our anato-
mical inquiries.
The carpus, wrist of the human subject, knee of the
horse, is composed of eight bones, arranged in two rows.
The upper row, beginning from the inside of the knee,
consists of the ossa scaphoides, lunare, cuneiforme, tra-
pezium*;
the second, of the ossa pisiforme, trapezoides,
magnum, unciforme.
* Willing as we are to observe a close adherence to the no-
menclature of human anatomy, in this instance, the incongruity
is such that we cannot proceed without some alteration. To name
a bone of the size and precise shape of a pea a trapezium, and ano-
ther of a quadrilateral figure pisiforme, when we have already
shrunk from calling the pastern and coffin bones phalanges, and
-ocr page 354-
319
Os Scaphoides.
The os scaphoides, situated on the inner side of the
knee, is the largest bone of the superior row. Above, it
articulates with the innermost depression upon the lower
end of the radius; below, with the ossa trapezoides et
magnum; laterally, with the os lunare. It supports a
greater proportion of the weight of the body than either
of its fellows in the upper tier.
Os Lunare,
Central bone of the first rank, is smaller than the
last described, and of a wedge-like shape. It articulates
above with the middle depression upon the radius; infe-
riorly with the ossa magnum et unciforme ; laterally and
internally, with the os scaphoides; laterally and exter-
nally, with?, the os cuneiforme.
Os Cuneiforme
Is the smallest bone of the upper tier, to the outer side
of which it is placed, a little more backward than the
others. It receives the innermost articulatory surface of
the radius superiorly; below, it is supported by the os un-
ciforme ; laterally, it is united to the os lunare ; and be-
hind, it is articulated with the os trapezium.
Os Trapezium,
According to STUBBsand his followers, os pisiforme
—is of quadrilateral figure, and is so placed at the back of
found that both of them differ in relative situation and use from
the bones of the same name in the human wrist, is to us perversion
of language to no useful end. To remedy the abuse with as little
innovation as possible, we have merely transposed these names.
-ocr page 355-
320                Os TrapezoidesOs Magnum.
the others as not to be visible from an anterior view of the
carpus. This bone, from its situation, does not partake
of the support of the body : it bears no more weight than
a spur affixed to our heel. It is articulated with the pos-
terior part of the os cuneiforme, to which, and to the os
lunare, it is connected by strong and short ligaments. Its
chief use is that of furnishing a lever, on which the flexor
muscles are enabled to act with considerably additional
force in bending the leg. It also serves for the attach-
ment of the posterior annular ligament of the knee.
Os Trapezoides
Is the smallest bone of the inferior row, situated at the
inner and back part of it. It is united above with the in-
ner part of the os scaphoides ; beneath, it articulates prin-
cipally with the internal metacarpal bone—only a small
portion of it pressing upon the large ; more anteriorly than
laterally, it is connected with the os magnum. What por-
tion of the weight this small bone sustains, it transmits al-
most wholly to the internal metacarpal bone : which fact
we shall have occasion to advert to at another time.
Os Magnum,
Properly so named from being the largest of these
bones, occupies the greater part of the articulatory sur-
face of the head of the os metacarpi magnum, upon which
it rests. Above, it supports the ossa scaphoides et lunare,
having the ossa trapezoides et unciforme at its sides. This
bone, though considerably broader, is not so thick as most
of the others.
Os Unciforme,
The outermost bone of the last row, is united firmly
-ocr page 356-
Os Puiforme.Bones of the Leg.             321
to the os magnum. Below, it is resting upon the os me-
tacarpi externum ; it is also in part supported by the os
metacarpi magnum. Superiorly its principal articulation
is with the os cuneiforme; it is however in part impress-
ed by the os lunare.
Os Pisiforme.
The true pea-shaped or orbicular bone. A little round
bone situated entirely out-of the line of force from above ;
being placed behind the os trapezoides, with which alone
it articulates. Its use is not very apparent.
The knee in the skeleton is somewhat arched, owing to
the broadest parts of the carpal bones being turned for-
wards. These bones are covered by cartilage, strongly
connected to each other by numerous ligameuts, and form
so many separate joints.
The knee, though not so common a seat of disease as
the hock, is more subject than it to external injury ; and
the worst cases of this description are those of open-joint.
We have lately had a case of punctured knee-joint, which,
from mal-treatment in the first instance, was followed by
death. On examination of the part, we found that many
of the small bones were rough and jagged upon their
surfaces, in consequence of having lost their articular
cartilages from ulceration ; and some bony accretions
around their edges had commenced anchylosis, a state in
which all such cases terminate.
Bones of the Leg.
These may be said to be the same, both in number
and kind, in the hind and fore extremities; the only ma-
terial difference between them is in their dimensions,
which of course vary according to the general confornia-
Y
-ocr page 357-
322                      Os Melacarpi Magnum.
tion of the limbs themselves. Indeed, in this respect,
these bones may be considered as somewhat dissimilar in
horses of different breeds : some, we know, have long can-
nons and pasterns ; others, on the contrary, are remarkable
for the shortness and (apparently) greater compactness of
these parts. That part of the leg commonly known as
the cannon, but which, according to our present nomen-
clature, is technically called the metacarpus, consists of
three bones :—the os metacarpj magnum, et ossa meta-
carpi parva.
Os Metacarpi Magnum.
The large metacarpal, cannon, or shank bone, is
placed between the knee and fetlock-joint. It is of a cy-
lindrical form, rounded before and somewhat flattened be-
hind. Its upper extremity, or head, is modelled to that
of the os magnum of the knee, which is resting upon it,
and covers nearly the whole of its articulatory surface.
There are two small depressions upon its outer part, one
before the other, for the articulation of a part of the os
unciforme ; another still smaller upon its inner and pos-
terior part, which receives an equally small portion of
the os trapezoides: they all form inclined planes towards
the small metacarpals, from which circumstance the
latter are receiving the principal part of the weight
transmitted by those bones. The large metacarpal is
a remarkably straight bone, very superficially placed in
the recent subject, being only in some places covered by
skin. Its lower extremity bears no resemblance to the
upper—it is shaped like a trochlea, or pulley, and ex-
hibits by its articulation with the next bone a good
instance of the hinge-like joint. It is formed into three
convexities, the central of which, the most prominent,
is divided from the others by two superficial, broad
-ocr page 358-
Ossa Metacarpi Parva.                      323
concavities : they are all adapted to correspondent rotun-
dities and excavations upon the upper end of the large pas-
tern-bone. By this kind of construction all lateral motion
is prevented, but flexion and extension freely admitted
of; had the structure of these parts been such as would
have given motion from side to side, a tendency to dislo-
cation must have resulted, and a considerable diminution
of actual strength. This joint is closed behind, and ren-
dered more secure, by the sesamoid bones, which are in
contact with the posterior and lower end of the cannon,
and much enlarge the surface of articulation ; whereby a
still greater range of motion is obtained.
Ossa Metacarpi Parva.
The ossa metacarpi parva, or splint-bones, two in
number, distinguished by the epithets internum et exter-
num, are
placed on either side of the os metacarpi mag-
num. A small portion of the upper part of each bone
is only visible from an anterior view : from inclination to
the back of the cannon, they are only seen, in full, from
behind. They vary somewhat in length in different horses,
but generally extend more than two-thirds of the large
bone downwards ; and the inner is frequently somewhat
longer than the outer. They are of a pyramidal figure.
The head is the largest part, and has upon it an articu-
latory surface; the lower end, which is tapering, is ter-
minated by a small rounded knob. The os metacarpi
externum supports, in part, the os uncifornie; the os
metacarpi internum, almost wholly, the os Irapezoides;
both however receive additional weight, in consequence of
the lateral articulatory planes upon the large metacarpal
bone being sloped towards them.
In order to convey a knowledge of the use of these
y 2
-ocr page 359-
224            Diseases of lite Metacarpal Bones.
bones, it will be proper to premise, that they are closely
and firmly connected, throughout their whole length, with
the large metacarpal bone by a cartilago-ligamentous sub-
stance—by an elastic material of the same texture as that
which attaches the ulna to the radius. Their situa-
tion in the skeleton demonstrates, that they in part sup-
port the weight of the body ; and their mode of connex-
ion leads us to believe, lhat they are in some small degree
depressed by it. The share of the burden they sustain is
received by the ligament connecting them, (for they arti-
culate with no bones below,) the fibres of which are put
on the stretch by its sudden impression; and this mo-
mentary extension is followed up by instantaneous con-
traction, the effect of the reaction of these elastic fibres.
That these bones move therefore, there can be little doubt;
but it seems to us, that the word descendis unhappily cho-
sen to express that which is the result of instantaneous
impulsion upon a body simply having sufficient elasticity
to counteract the effects of concussion. Before we pro-
ceed to a description of the boues below, it will be neces-
sary to consider the
Diseases of the Metacarpal Bones.
These bones are not unfrequently broken from a va-
riety of causes. Though we have seen accidents of this
nature, we have never had an opportunity of treating one :
we are informed however by Mr. Bass, a respectable
practitioner near Barnet, who has had many of these cases
under his care, that by the proper application of splints
and bandages, an union may be generally effected, with-
out slinging, or even narrowly confining the animal. The
only case of the kind we ever saw treated, was one that
occurred during our pupilage at the Veterinary College;
-ocr page 360-
Splint.                                325
and this had an unfortunate issue. The horse, we recol-
lect, was slung ; to which circumstance we now feel in-
clined to ascribe the failure.
We have two or three cannons whose bodies are so
completely encased in a layer of new bone, that the splint-
bones are altogether concealed in the adventitious mass.
Exostoses, sometimes of very large size, grow from the
cannon bone ; they are more common near its upper than
its lower extremity, and (with the exception of splints)
are rarely met with upon the middle of the leg; where,
we believe, they always originate from blows. The com-
mon and universally known disease of these parts, is
Splint.
A Splint—so called, says Bracken, because it
serves to strengthen the bone as thin pieces of wood would
—may be defined to be, an exostosis upon, generally the
inside of, the leg. Though this is the definition common-
ly given of a splint, it but little elucidates its nature—it
omits, what may be said to be, its essential character; for
unless the elastic substance joining the small to the large
metacarpal bone, partake of the disease, we, as profes-
sional men, should not call an exostosis, a splint; though,
to the common observer, it may appear to be in the pre-
cise site of one. A splint, in truth, is an ossification of
the cartilago-ligamentous substance uniting the small to
the large metacarpal bone. Inflammation is first excited
in it: in consequence of which, like other similar textures
in the horse, disposed to ossification, it becomes a nidus
for the deposition of bone ; into which it is soon convert-
ed, in the same manner as cartilage undergoes thatchange
in the young subject; so that there is no longer any na-
tural separation of these parts —the whole is consolidated,
k.
-ocr page 361-
326                                    Splint.
and forms but one and the same bone. If the disease
stopped here, (and indeed it sometimes does,) we should
never be able to detect a splint in the jiving horse;
more commonly, however, in consequence of diseased
action hi the periosteal vessels, a circumscribed callous
tumor is produced at the same time, which, like the callus
effused from the fractured ends of bones, is only the bed
for subsequent osseous deposition : and hence it is that
splints become perceptible externally. Though the ex-
ostosis, therefore, be the medium of our information as
to the condition of the parts underneath, it is by no
means essential to the existence of splint; for in old
horses, it not unfrequently happens that the whole of the
adventitiom deposit becomes absorbed; a fact which
farriers and grooms explain, by saying, " that their splints
ivear away." But we know, that these animals are no
more free from splints than they were before the tumors
disappeared ; for unless the original elastic texture of the
uniting material of the metacarpal bones be restored, a
process incompatible with the laws of the animal eco-
nomy, a splint is never eradicated :—a splint never was,
nor ever can be, radically cured—once a splint, always a
splint.
There are two universally admitted facts that serve to
point out the cause, as well as nature of this disease :
viz. first, that splints are seldom found upon the outside
of the leg; secondly, that horses throw them out soon
after they are domesticated, or broken in. One and the
same effect is produced in either of these cases—the pre-
ternatural extension of the uniting elastic medium we have
so lately alluded to : in consequence of which, it takes on
inflammation and ossification as before described. Why
the inner small metacarpal bone should be so constantly
-ocr page 362-
Splint.                                      527
its seat, happens from its more centrical situation in the
skeleton, where it receives a more forcible depression
than the outer : in addition to which, as another evident
reason, we may adduce the mechanism of the knee-joint;
the innermost bones of which, in the lower row, are so
arranged as to form independent joints with the inner me-
tacarpals. Why horses recently introduced into the ma-
nage
should more especially have them, is explained by
saying, that their limbs are supporting weights, and made
to perform divers rapid and unnatural actions, to which
they have never been accustomed, and to sustain shocks
too severe for their elastic powers to encounter at so tender
an age without injury.
When on the spine, we submitted, that the changes of
structure so frequently seen in it on dissection, must have
tended much to diminish its natural springiness of motion ;
although this effect is not sufficiently manifest in all cases
to lead us to suspect their existence during life. We
may, with equal truth, apply this remark to the disease
now before us ; it being one of those that deprives the
animal of its natural elasticity of movement, and, as
such, may, and probably does in process of time, give
rise to mischief in the joints in the vicinity, in conse-
quence of their being shaken by that concussion which
these parts, in their healthy condition, were designed to
ward of.
Recent splints are sometimes accompanied with lame-
ness ; and this has been accounted for in two different
ways : some referring it to interference with the motions of
the flexor tendons, or with those of the knee-joint; others
to preternatural extension of the periosteum. But splints
are very rarely of sufficient magnitude to produce lame-
ness from the first of these causes, and we are not much
-ocr page 363-
328                                  Splint.
inclined to place faith in the efficiency of the latter—one
that has its origin in a theory respecting the mode in which
pain is produced by nodes in the human subject; for the
cases are widely different. A node is not essentially a
bony tumor, but one that appears to have its origin
in the periosteum, and sometimes suppurates : its cause
is syphilitic, or probably mercurial; and the pain ac-
companying it is only occasional, and commonly noc-
turnal—but what has all this to do with splint ? With-
out entering again* into a controversy about what ap-
pears to us to be the upstart of false analogy, followed
by hasty conclusions, we would observe, that inflamma-
tion, especially if it be acute, in ligamentous structure, is
always productive of extreme pain in the human subject,
and that this, of itself, in our opinion, is at all times fully
adequate to the production of lameness, however severe,
in the horse. In support of this, we may offer, that the
lameness is not proportionate to the size of the splint, nor
to its rapidity of formation: on the contrary, the tender-
ness is often extreme, and the action as imperfect, when
the splint is of comparatively small size.
In regard to the treatment of splints, it is not necessary
to be prolix in what we have to offer, or to take up time
with an account of remedies of doubtful efficacy, when we
have one at our elbow that will fulfil our utmost wishes.
By the cure of a splint is vulgarly understood its removal;
but we should on most occasions content ourselves with
the subsidence of the lameness; and with this view, the
practice— old as it is !—of repeatedly blistering the part
is the best we know of:—rest, and a blister, or two, will
almost always succeed. But we are often called on to re-
* Vide Lecture XV. On Exostosis.
-ocr page 364-
Splint.                                   329
move splints ; and simply because they are deemed eye-
sores, though in reality they are seldom perceptible but
by the feel. When blisters are not active enough for this
purpose, wejire; but we seldom have occasion to do so.
Still, let it be remembered, that no splint, in truth, can be
cured—the parts converted cannot be restored to their
natural pristine condition ; so that its effects alone—pain
and tumor, come within the power of remedy. But as
the tumor itself is of no consideration, and lameness is
only an occasional symptom, many of these cases require
no treatment: and it is ever injudicious to meddle with
them unless they are accompanied with lameness.
To the operation of dividing the periosteum in splints,
we are not only theoretically, but practically adverse; in-
asmuch as we believe that the lameness can, in all cases,
be relieved by much simpler means. It is not enough
that a remedy be new ; it should have proved itself better
than the old, before the latter be relinquished.
As to the removal of splints by an operation, or the de-
struction of them by caustic, they are both troublesome
and dangerous modes of practice ; and as such have been
very properly discontinued in all ordinary cases of this
description*.
* Gibson, one of the best old authors on this subject, describes
a varicose condition of the veins, as an effect of splint: we do not
recollect to have seen a case of this kind. After shewing how the
cautery is to be used for this, the cure of which, he says, "is often
doubtful;" he adds, " nevertheless, I should, in the first place, pre-
fer mild blisters often repeated, as recommended in the cure of bone-
spavin, which I have found to answer beyond expectation, and
without the hazard of any ill accident, or any remarkable disfi-
gurement." Gibson's Treatise on the Diseases of Horses. Vol.11.
-ocr page 365-
LECTURE XX.
Os Suffraginis *.
XHEos suffraginis, or large pastern-bone, is situated
between the fetlock and pastern joints, and is somewhat
of a cylindrical figure. Its upper extremity, which is larg-
er than the lower, has three concavities—a central deep,
and two lateral superficial, adapted to the convexities upon
the lower end of the os metacarpi magnum. Posteriorly,
the head is hollowed out; to which part the ossa sesa-
moidea are firmly attached by ligament. Its body be-
comes smaller and rounder below, and terminates in a
somewhat expanded extremity, having two smooth rotun-
dities divided by a superficial hollow : these articulate
with the upper part of the small pastern-bone, and form
the pastern-joint. At the back part of the body of this
bone is a rough triangular surface, into which the short
ligament of the sesamoids is inserted.
The pastern-joint, like the fetlock, admits only of flexion
and extension.
* The Latin word suffrage is sometimes used for the hock, as well
as the pastern. We confine its signification here to the last: hav-
ing the word tarsus to denote the first.
-ocr page 366-
331
Ossa Sesamoidea.
The sesamoid bones, two in number, of a cuneiform or
wedge-like shape, are placed at the back of the fetlock-
joint, with their apices turned upwards, and their bases
downwards. Each has three sides, a base, and an apex.
They present triangular, excavated, articulatory faces
anteriorly, which enlarge considerably the surface of arti-
culation for the lower head of the large metacarpal bone.
Their inner edges, when united, form a groove for the re-
ception of the middle eminence of that bone. The pos-
terior parts are obtuse, and roughened by the attachment
of the suspensory ligament. Their bases afford insertion
to short and strong ligaments, which connect them to the
large pastern-bone. Posteriorly they are smooth, and
rather convex, and leave a hollow between them, when
joined together, which in the recent subject is lined with
cartilage, and receives the flexor tendons in their passage
to the foot. At this part is a large bursa mucosa, within
which these tendons play.
Here we have another instance of the weight being con-
veyed to bones, themselves without any bony support; au
admirable construction, not only to diminish force, but to
guard against the concussion which its sudden impression
upon the parts below, had they alone borne the burden—
without some diversion of this kind—must have been pro-
ductive of. That we may perfectly understand the mo-
tion of these bones, it will be necessary to state, that
they are chiefly retained in their situation at the back of
the pastern-joint by an elastic ligament, which connects
them to the large metacarpal bone, an.l that the flexor
tendons embrace them in their course down the leg, so
closely, that they also materially assist in their confine-
-ocr page 367-
332                           Ossa Sesamoidea.
ment. It is said, that " these bones descend at every step
the horse takes." This is not altogether correct; for
their inferior edges adhere so closely to the pastern-bone,
through the medium of short inelastic ligaments, that, as
far as regard these parts, they can have no such motion.
It is, in fact, by this mode of union, that the sesamoids
are so well adapted for the purpose for which they are
designed: had the lower as well as the upper parts of
them descended, then must the operation of this beautiful
piece of mechanism have been comparatively inefficient.
The inelastic connexions they have below, serve as a
hinge upon which they move; for every time they re-
ceive the impulsive force, the sesamoids spring backivurds
and downwards, in such a manner, that their apices
describe the segment of a circle, while the lower simply
turn upon their own axes*.
Their relative position, their
connexion, and the manner in which weight is imposed
upon them, all demonstrate to us, that such is the mo-
tion—can we correctly speaking call it descent?—that
these bones undergo. No sooner are the sesamoids set
at liberty again, which instantaneously follows their sud-
den and forcible depression, than by the combined re-
action of the suspensory ligament and flexor muscles,
they, with a resilient motion, regain their places. Thus
are the fetlocks of horses furnished with springs (if we
* Professor Coleman (page 24, vol. II. of his work on the foot)
expresses this as follows:—" In consequence of forming the back
part of the large pastern-joint, and articulating with the lower and
posterior part of the cannon; they contribute very essentially, by
always receding whenever the foot comes in contact rcith the ground,
to act as a spring to the animal, and to prevent concussion." And
the word recession is certainly preferable to descent; but by neither
is implied the modus agendi.
-ocr page 368-
Ossa Sesamoidea.
333
may so designate them) by means of which the machine
is transported from place to place, with grace, and ease,
and elasticity of movement. The operation of these parts
is extremely well seen, by observing the fetlocks of such
horses as are remarkable for graceful and elegant action:
such are the Arabian and Sicilian breeds, in which we
may not unfrequently perceive, that the tufts of hair
growing from the fetlocks, sweep the ground, at every
bound made in the canter, although they be elevated
several inches from it in the standing posture. From
what has been said, it will readily be seen, that the quantum
of weight thrown upon the sesamoids will be greater or
less, according as the angle formed between the cannon
and pastern is less or more obtuse: as it approaches to
the right angle, the seamoids being more under the cen-
tre of gravity, more impressed, so are their elastic con-
nexions put more on the stretch, and the spring is pro-
portionably the greater. Hence it is, that arabians, Si-
cilians, and our thorough-breds, whose pasterns are
oblique and long, (for these are inseparable properties,)
have an elasticity in their gait, which cart-horses and
heavy hacks, with short and upright pasterns, are not en-
dowed with : indeed, many of the latter, from the total
absence of such qualities, are knowingly called bone-
setters.
Why the fetlocks of different horses should vary
thus far in their construction, is a query not difficult of
solution, when we reflect on the uses of (what may be
called) these animal springs. If concussion be the effect of
the suddenness and rapidity of movement, with which the
machine is propelled, and these springs be set to ward it
off, how little can they be required in the pasterns of the
cart-horse, when compared with the arabian and racer ?
The gallop, or canter, which is nothing more than a sue-
-ocr page 369-
334                                Os Corona.
cession of leaps, is the pace in which those springy parts
are most called into action ; but it is one that the cart-
horse, and stiff and upright cob, appear never to have been
designed for.
Furthermore, it seems to us, that these elastic parts
assist in the elevation of the feet from the ground, in those
paces in which they are called into sudden and forcible ac-
tion. The suspensory ligament by its reaction, instantane-
ously after extension, we feel inclined to believe, aids the
flexor muscles in. bending the pastern-joints:
the astonishing
activity and expedition displayed in the movements of the
race-horse, at speed, seem to be referable, in part, to the
promptitude with which the suspensory ligament can act
before the flexor muscles are duly prepared; the latter,
we should say, catch, as it were, and then direct the limb,
first snatched from the ground by the powers of elas-
ticity.
Os Corona.
The os corona;, small pastern, or coronet-bone, though
of smaller dimensions than the large, bears much resem-
blance to it in appearance. It is not half the length of
the former, but of greater proportionate breadth, being
of a quadrangular shape. It has but two, and them su-
perficial concavities upon its upper part; which articulate
with the convexities upon the lower end of the large pas-
tern-bone. This joint, admitting only of limited flexion and
extension, is rendered somewhat more secure by a pro-
minent ridge around the articulatory surface of the os co-
ronae, and by little eminences in the centre, both before and
behind. The bone is somewhat contracted in its body,
and is smaller below than above : indeed the inferior ex-
tremity is nearly allied in appearance to the lower end of
the os suffraginis, but presents behind a more extensive
-ocr page 370-
Diseases of the Pastern-bones.                 335
articulatory surface, which part is opposed to the navicu-
lar bone.
Diseases of the Pastern-bones.
We have several specimens of fracture of these bones.
In one, the os suffraginis is broken directly across the ar-
ticulatory surface upon its upper part: others exhibit
fractures of the os corona?. These fractures however,
are all longitudinal or oblique ; there is no instance of a
transverse fracture in either the large or small pastern:
and the number of the latter broken, exceeds much that
of the former.
To point out the varieties of form and size which exos-
tosis acquires in these parts, would far exceed our present
limits; we shall, therefore, content ourselves with offering
such general observations as seem to apply to the more
common cases of this description. The soft parts about
the fetlock-joint not unfrequently take on ossification ; so
that the articular ends of the bones composing it, become
incrusted with a deposition of earthy matter, which may,
or may not, interfere with its motions : and to such an
extent does this bony change occasionally pervade the li-
gamentous and tendinous structures hereabout, that com-
plete anchylosis of the fetlock is the consequence ; of
which we have a beautiful preparation now upon the table.
By far the most common seats of this disease however,
are the pastern and coffin joints. From a minute in-
spection of about one hundred and fifty specimens of
anchylosis of these joints, now before us, we submit the
following summary detail:—
Five of complete anchylosis of the fetlock-joint.
Forty of complete anchylosis of the pastern-joint.
Eighteen of complete anchylosis of the coffin-joint; of
-ocr page 371-
336                                 Ringbone.
them there are only four in which the navicular joint does
not participate.
Seven of complete anchylosis both of the pastern and
coffin joints.
The others are all either simply incrusted, more espe-
cially their extremities, with layers of new bone, or vari-
ously deformed by exostoses of different shapes; many
of which are of very large size ; and several confined
to one side. Upon one of the large pasterns, a com-
plete bony ring is formed, in consequence of ossification
of the theca of the flexor tendons. In almost all, the dis-
ease appears to have spread from the pastern-joint; for
there are but few specimens in which some accretion is
not seen around the lower extremity of the os suffraginis,
and the upper one of the os corona?; and it is this kind of
deposition that gives rise to the disease called
Ringbone.
A ringbone may be said to be, an exostosis upon one,
or both, of the pastern-bones. We see it more commonly
in the hind than in the fore leg. It is asserted, that the
seat of ringbone is the middle of the os coronae: but
those who entertain such an opinion, would find it as
difficult to explain its origin, as to prove its existence in
such a situation, exclusive of any connexion with the
pastern, or coffin joint. We believe that ringbone, like
splint or spavin, is essentially a disease of ligamentous
structure ; and not of periosteal origin, as most old wri-
ters would lead us to conclude. Inflammation is first ex-
cited in the ligaments of the pastern-joint, which termi-
nates in the deposition of callus—afterwards bone—
around the edges of one, or both pastern-bones; and
this may, and frequently does, spread upon the body of
-ocr page 372-
Os Navicu/are.                            337
the os corona;, or upon that of the os suffraginis : still,
we contend, the disease has its origin in the ligaments of
the pastern-joint.
The causes of ringbone are acts of violence to these
parts :—overweighting the animal, or requiring exertions
of him his powers are unequal to; hence young horses
when first backed, are very liable to have them. Why
the disease should be more frequent in the hind legs than
in the fore, is simply owing to their vehement action in
progression : for we apprehend that ringbone is not so of-
ten the product of concussion, as the effect of severe
sprain, extension, or perhaps rupture, of ligamentous fi-
bre. Some say, that " blows produce ringbones :" un-
doubtedly a blow upon the os coronas would very pro-
bably, be followed by exostosis, and so would one upon
the head, or hip ; but the pastern is not a very likely part
to be often struck.
Ringbones may be accompanied by lameness, or not,
depending on the presence of inflammation, and the de-
gree of it, and on their size and situation, so far as they
may impede the motions of the joint: in the last case
the lameness is generally permanent.
If the horse be lame, and the cause of lameness be in-
flammation present, we first ought to make use of means
to abate this increased action; and could we take blood
from the part itself, none would prove of greater benefit.
After this, repeated blisters, or blisters kept open, are
alone to be depended on. Unless absorption of it be our
object, and then the actual cautery may promote it*.
Os Naviculare.
The navicular, sometimes called the shuttle-bone, is
* Vide Lecture XV. Treatment of Exostosis.
z
-ocr page 373-
338                            Os Naviculare.
somewhat of the figure of a half-moon: it is placed
obliquely at the back of the coffin-joint, with its convex
part downwards. Superiorly, it has an articulatory sur-
face divided by a small eminence into two parts ; where it
is opposed to the os coronae: anteriorly its edge is
smoothed off, where it lies in contact with the coffin-
bone ; and thus much of it enters into the composition of
the coffin-joint. Over the inferior part, where the bone
is smooth, and has a tubercle upon its centre, the tendon
of the flexor perforans passes, and entirely conceals it:
by an indentation upon its inner surface, the tendon ac-
commodates itself to the bone, and a large bursa is here
interposed.
The navicular is closely connected to the coffin and
small pastern bones by ligaments, which are short, strong,
and inelastic.
From the os naviculare being articulated in part with
the small pastern-bone, it will necessarily receive a
proportion of the weight; and this weight is transmit-
ted partly to its ligaments, and partly to the flexor ten-
don. The former being inelastic, cannot elongate; the
latter, though in itself inelastic, being attached to mus-
cle, will admit of extension. It is evident therefore,
that the os naviculare does not remain steadfast du-
ring the action of these parts; on the contrary, it is
moveable by the sudden impression of the os coronae.
It appears to us, that the edge opposed and connected
to the coffin-bone, is simply the axis upon which the
other part turns ; so that limited rotation, rather than
descent, conveys a correct idea of its motion *.
* In the lectures on the physiology of the different parts of the
foot, we shall draw attention to some points relative to the use
of this bone, which would seem to have escaped observation.
-ocr page 374-
339
Os Pedis*.
The os pedis, or coffin-bone, corresponds in shape to
the hoof of the animal from which it is taken, as is seen
by comparing those of the horse, ass, and ox together. We
shall divide it, for the sake of facilitating description, into
its body, and ala or ivings. The first comprehends the
broad, solid part of the bone ; the latter, its two sides, or
ends, which extend backwards, and are placed posteriorly
to its articulator surface. The body is of a conical form ;
but the apex of the cone appears to have been cut off;
at which part the bone is smooth, and excavated into two
superficial depressions, for the reception of two corre-
sponding eminences upon the lower part of the os coronae.
The inferior part of the os pedis is unequally divided into
two concavities : the anterior one, the larger of the two,
is very superficial, and in the recent subject is covered by
the sensible sole ; the posterior, situated between the two
alee, is deeper, and affords a surface of implantation for
the tendon of the musculus perforans. Above this hol-
low is a narrow art'culatory surface, extending between
the two alae, to which the os naviculare is fitted by one of
correspondent figure and dimensions. The alas proceed
from the upper and back parts of the bone, and terminate
in protuberant rough edges, to which the lateral cartilages
firmly adhere.
There are several foramina in the coffin-bone. One
through each ala gives passage to branches of the coffin
arteries to the front of the foot; and two in the posterior
concavity, through which the coffin arteries themselves
* Pes being the Latin word for the foot, not only of a man, but
of any other animal, we have adopted it here as the most signifi-
cant and familiar term we know of.
Z 2
-ocr page 375-
340 Diseases, of the Navicular and Coffin-bones.
run. Several large foramina, and innumerable smaller
ones, are seen in its front and sides, which transmit small
vessels and nerves to the laminae. There are generally
about thirteen holes, more distinct than the others, around
its lower ed<ie.
The coffin-bone is of a porous spongy composition,
and not possessed of much mechanical strength ; of itself
a strong argument to shew, that it was never intended,
in an insulated condition, to bear the superincumbent
weight. As we shall demonstrate in future lectures, this
bone is attached to the hoof by an elastic substance, of a
ligamentous nature, by which it is suspended in such a
manner, that the crust, or wall of the hoof, is actually the
part that sustains the weight of the carcass : were it not
for this beautiful piece of animal mechanism, the ossa pe-
dis must be fractured—nay, comminuted, the very first
plunge the animal made: as indeed occasionally happens
when disease has destroyed this much admired structure.
The front and sides of the os pedis, so much resembling
the wall of the hoof, present inclined planes of various
degrees of obliquity and depth, from the upper part to
the basis. Anteriorly the breadth of this part is much
increased by a semilunar bony eminence—the coronal pro-
cess—which adds much to the security of the coffin-joint,
and gives insertion to the tendon of the extensor muscle,
whose action it in some measure assists. The coffin-
joint, being of hinge-like construction, has no other mo-
tions than those of flexion and extension.
Diseases of the Navicular and Coffin-bones.
We have heard of several instances of fracture of the
os pedis; though none have hitherto come under ouf
immediate notice : and these cases, we believe, have been
-ocr page 376-
Diseases of the Navicular and Coffin-bones. 341
more frequent since the operation of neurotomy has been
practised. We should imagine, that this accident can
only happen to such horses as have had much previous
disease in the foot, from the continuance of which the
contained parts have been impaired in structure. We do
not recollect hearing of, much more seeing, a case of
fractured navicular bone. Perhaps no bone in the body
is more liable to disease than the os pedis; a fact
we are not to feel surprised at, when we consider i(s
intimate connexion with the hoof, and reflect on the
changes the latter is continually exposed to, from the
whims and caprices of those engaged in devising new and
ridiculous forms of horseshoes. Of about a^ hundred
morbid coffin-bones, we find, by far the greater numbet
to have bony accretions upon their sides, having the shape
and situation of the lateral cartilages: in upwards of
half of them, the laminae are, either partially or wholly,
converted into bony ridges ; twenty of them are morbidly
small and upright, in consequence of absorption of the
toe ; in six of them the wall is deficient, and nothing is
left but a small part of the sole, and the articulatory sur-
face; in two others, nought remains but the articulatory
surface—wall, sole, and aire, have all disappeared from the
destructive effects of mal-treated disease ; in thirty the
coronal process, as well as the edge on either side of it,
have received considerable increase from earthy incrus-
tion—the projection is, in several, many times its natural
size, and the coronary ligament appears to be wholly con-
verted into bone; in one or two the deformity is so great,
that we can scarcely trace the characters of the original
bone.
Where there is much disease of the coffin-bone, the na-
vicular seldom escapes: it is sometimes found, in cases
-ocr page 377-
342 Diseases of the Navicular and Coffin-bones.
of exostosis, so wedged in with the general mass of new-
formed bone, that we are unable to extract it even after
maceration. The lower articuiatory surface of this bone
not uncommonly appears as if it had been worm-eaten ;
which is nothing more than the effect of ulcerative action,
that has its beginning in the bursa, between it and the
tendon : the sequel of articular disease induced by pre-
cisely the same causes as give rise to it in other parts*.
* Vide Lecture XVI, on the Diseases qf Joints.
-ocr page 378-
LECTURE XXL
The Bones of the Hind Extremity.
These do not differ much in number, nor in general
arrangement, from the bones of the fore extremity : for
example, the quarter, like the shoulder, is composed of
two bones ; the thigh, like the arm, of two; and the
hock, corresponding to the knee, of many small ones.
With regard to the bones of the pastern and foot, so
great is their similarity in the hind and fore extremities,
that it is often difficult to say to which they belong : for
this reason one description suffices for both.
Os Femoris.
The os femoris is thejargest, thickest, and strongest
bone in the body. Though so called from being con-
formably situated in the skeleton to the bone of the same
name in that of the human subject, it is not, in reality,
the bone of the thigh in quadrupeds : in them it forms
what is called the haunch. Its upper extremity presents
a smooth, round head, turned inwards, and marked by a
small uneven depression upon its inner part, to which is
affixed the round ligament of the hip-joint. A strong,
-ocr page 379-
344                                Osl Femoris.
irregular protuberance of considerable size, juts out ex-
ternally to the head, called the trochanter major externus.
Below this projection is a smooth ridge of bone, inter-
rupted in its course about the centre by a small emi-
nence, whose extremity is crooked forwards : this is de-
nominated the trochanter minor externus. A little be-
low the head, but placed more backward than it, is a
rough lengthened process, named the trochanter internus.
The body of this bone is broad and flat above, round
and smooth about its middle, and polished upon its an-
terior surface : it expands below, and terminates in two
considerable prominences. Upon the fore part is a
broad smooth articulatory hollow, sometimes called the
trochlea, in which the patella is fitted, and plays with all
the advantages of a pulley. The two smooth rounded
eminences better seen posteriorly, named the condyles,
move in two superficial hollows upon the head of the.
tibia; and between them the bone is roughened and po-
rous, from the attachment of strong ligaments belonging
to the stifle-joint.
The hip-joint, independently of flexion, extension,
and some lateral motion, seems to possess, to a certain
extent, the power of rotation.
We have only two preparations of morbid ossa femo-
rum. In one, the condyles are encircled with a lip of
adventitious bone, and present evident marks of disease
having existed in the stifle-joint, in the asperity of their
articulatory surfaces. The other is an admirable speci-
men of the cancellated structure of newly deposited bone,
with which the whole of its body is thickly coated : in-
deed, from the softness and brittleness of its texture, it
would lead to the belief, that the accretion was going on
tU the time of the animal's death.
-ocr page 380-
345
Patella.
The patella, knee-pan of the human subject, stifle-
bone of the horse, is of a quadrangular figure; convex,
and exceedingly rough and porous, upon its exterior, into
which part the tendons of the extensor muscles of the
thigh are implanted ; but irregularly concave upon its
interior, where it presents two unequal articulatory sur-
faces, which fit it to the pulley-like convexities upon
the anterior and lower part of the os femoris. The su-
perior and lateral angles of this bone are more or less
acute ; the inferior, on the contrary, is obtuse and round-
ed off, and strongly marked by the attachment of the li-
gament of the patella,
which connects it to the tibia.
The patella of the horse has been seen dislocated upon
the outer condyle. Only one case of the kind has come
within our observation j but Mr. Charles Percivajll,
veterinary surgeon to the llth light dragoons, has met
with two instances of it. The lameness occasioned by
this accident is very considerable—the horse literally
drags the limb after him; for, in consequence of the ex-
tensor muscles having lost their action, the pastern-joints
are fixedly flexed to their utmost. In order to put the
bone again into its place, an assistant should carry the
limb forwards, so as to extend as much as possible the
stifle-joint, while the veterinary surgeon depresses with
the palm of his hand the outer angle of the patella: this
gives the extensor muscles the power of drawing the bone
into its proper situation, which they commonly do with a
sudden snap. The most troublesome part of the ma-
nagement of these ci.ses, is the prevention of another
dislocation; for this very readily happens. We may rest
the horse ; but it is difficult to confine ihe limb. In one
of the cases abovemeutioned, after repeated failures with
-ocr page 381-
346
Tibia et Fibula.
various contrivances, it was determined to fire the skin
around the stifle, with a view of obtaining a more com-
plete bandage than was possible by other means ; and the
expedient proved a very happy one.
Tibia et Fibula.
The tibia is the true os femoris of the quadruped. It
is a strong compact bone, extending from the stifle to the
hock, and is about the same length as the os femoris itself.
Its upper extremity exceeds much in magnitude the lower,
being broad and expanded : upon it are two articulatory
surfaces, upon which the condyles of the os femoris rest;
and these are separated from each other by a small irre-
gular eminence, to which the crucial ligaments of the
stifle-joint are firmly fixed. Posteriorly, at its upper part,
the bone is hollowed out: anteriorly we find the tubercle,
a projection serving for the attachment of the ligaments
of the patelh. The body of this bone is triangular in
form, but the angles become gradually less distinct as we
approach its lower end ; where it is flatter, and some-
what broader than above. Here the tibia presents two
deep fossa or oval-like hollows, whose course is not direct,
but oblique, from before backwards : they are separated
from each other, and bounded on either side, by oblong
eminences, roughened externally by the insertion of the li-
gaments of the hock-joint. The upper part of the as-
tragalus, supporting the tibia, is so shapen, that a pulley-
like articulation of great security and strength is formed
by their apposition ; and it is between these bones that
the chief motions of the hock are performed; which,
from the peculiar construction of the joint, are necessarily
limited, at all times, to flexion and extension—no lateral
movement whatever can take place. The principal ad-
vantages derivable from this dovetailed kind of union, are
-ocr page 382-
On the TarsusAstragalus.                   347
great strength, and the utter impossibility of such an ac-
cident as dislocation, unless preceded by fracture.
To the outer part of the head of the tibia is fixed, by
ligamentous and cartilaginous connexion, the fibula; a
slender bone extended, like the string of a bow, along its
body, and firmly attached again below its middle. In the
adult horse, it is commonly but an apophysis.
We have two morbid specimens of this bone, show-
ing the lower extremity somewhat enlarged from earthy
concretion of considerable firmness. As the exosto-
sis is chiefly confined to the inner side, we suppose
that it, or a part of it, comes under the denomination of
spavin.
On the Tarsus.
The tarsus—in human anatomy, the instep, in vete-
rinary, the hock—is composed of six bones : viz. astra-
galus, os calcis, os cuboides, ossa cuneiformia, externum,
medium, et internum.
Astragalus.
The astragalus, or knuckle-bone, is the strongest bone
of the hock ; being that upon which the tibia solely rests,
and moves so securely by means of those deep excava-
tions, or fossae, in its lower extremity, which we, when on
that bone, pointed out. The bold pulley-like eminences
received by them, are extended in a semicircular direc-
tion over its upper extremity ; and the smoothly scooped
out fossa in the middle, is well adapted to embrace the
central elevation at the lower end of the tibia : thus are
these parts so locked together, that the hock, while it is
admirably constructed to sustain great weight, and move
with facility under it, is most ingeniously contrived to
prevent all possibility of luxation. The astragalus infe-
riorly articulates with the os cuneiforme magnum, and
-ocr page 383-
348                                 Os Calcis.
posteriorly with the os calcis by three surfaces of adap
tation.
Os Calcis.
The os calcis—heel-bone, or hock-bone—is one that
is very conspicuously situated in the living horse : it con-
stitutes that part vulgarly called the point of the hock.
It js so placed with respect to the other bones of the
hock, that it receives but little of the superincumbent
weight. By a broad irregular concavity, upon which
there are three articulatory surfaces, it forms a like num-
ber of articulations with the posterior part of the astraga-
lus, luferiorly, it rests upon, and articulates with, the
os cuboides. A considerable portion of this bone is
made up of a projection extending backwards and up-
wards, called its tuberosity; the end of which is rough-
ened for the attachment of muscle.
That pressure is imparted by the astragalus to this
bone, appears to us indisputable, when we observe how
the astragalus itself is impressed by the tibia: had that
bone been placed perpendicularly, instead of obliquely,
with regard to the hock, then would all the weight have
been transmitted to the ossa ciineiformia ; but, seeing that
the direction of the force from the tibia is downwards, and
at the same time backwards, surely it cannot admit of a
doubt, that the os calcis receives a share of the superin-
cumbent burden. Another proof that Nature designed
this bone to assist in supporting the load imposed upon
the astragalus, is the circumstance of its resting (and it is
the only one that does) upon the os cuboides, which is
supported below both by the os metatarsi externum, and
by the os metatarsi magnum: so that if the os calcis
were a mere process—not a supporting substance, the
former of these bones could have no motion, conse-
-ocr page 384-
Os Cuboides.                              349
quently no effect in diminishing concussion ; nor would
the latter be but partially impressed by the other bones
of the hock ; indeed the three bones we have just named
would be comparatively useless. Notwithstanding these
facts, it is affirmed, that the os calcis does not receive any
portion of the superjacent load; "that it sustains no
more weight than the spur upon our heel;" and that its
whole and sole use is that of affording a lever for the ope-
ration of muscle. That it is a lever, and one of more or
less power according to its length, has been long argued,
and with much truth, by those who have reasoned analo-
gically—comparing it to the os calcis of the human sub-
ject ; hence we know, that broad and prominent hocks,
are regarded as fine points in the general configuration of
the animal. It must be remembered however, that these
bones, though somewhat alike in shape, and the same in
name, are very differently placed with regard to the limbs
of these animals ; and that the hock is a part which differs,
ill some essential points, in its construction from the in-
step. Considering these facts, it appears to us, that the
os calcis may also serve to counteract concussion; though
its operation will be very limited when compared with the
action of what we have in another place designated an
animal spring. Indeed, though the greater part of the
weight thrown upon the hock be transmitted to the main
bone of the leg, a certain proportion of it is expended in
its ligamentous connexions, and of those of the small me-
tatarsal bones. The uses of the os calcis, then, appear to
be three in number :—to serve as a lever for the action of
muscle; to bear a part of the incumbent weight; and to
assist in preserving these parts from the effects of con-
cussion.
Os Cuboides.
This bone is situated at the outer part of the hock,
-ocr page 385-
330                   Os Cuneiforme Medium.
and may be regarded as one of the small bones entering
into its composition. It forms, as it were, a firm pedes-
tal for the os calcis, to which it is firmly united above;
while inferiorly it is opposed in part to the os metatarsi
magnum, and by a smaller articulatory depression to the
os metatarsi externum. Posteriorly it articulates with
the ossa cuneiformia, magnum et medium. As the os
cuboides has no connexion whatever with the astragalus,
the weight transmitted to the outer part of the leg must
be received from the os calcis alone; a fact of itself,
as we had occasion just now to remark, that appears to
carry conviction with it, in regard to the last named
bone being a pillar of support to the parts above.
Os Cuneiforme Magnum.
That upon which the astragalus immediately rests ;
being wedged in, as its name implies, between it and the
bone underneath—the os cuneiforme medium. This
bone is somewhat concave above, and flat and smooth
underneath, nearly the whole of its surface being arti-
culatory. The under part shows three distinct articu-
lations :—a large one anteriorly for the os cuneiforme
medium; and two smaller posteriorly—one for the os
cuboides, the other for the os cuneiforme parvum.
Os Cuneiforme Medium.
This boue (which has received the epithet of medium
in regard to its size, and not its relative position) resem-
bles in form the last described : it is however altogether
smaller, and much narrower posteriorly. It articulates
above principally with the os cuneiforme magnum ; pos-
teriorly with the os cuboides, (in such a manner as to be
in some measure impressed by it,) and with the os cunei-
forme parvum: below it rests flatly upon the os metatarsi
-ocr page 386-
Diseases of the Bones of the Hock.            351
magnum, the greater part of whose upper surface it
covers.
Os Cuneiforme Parvum.
This is the smallest bone of the hock; upon the inner
and posterior part of which it is placed in such a manner
that a portion of it overlaps a little the back of the other
cuneiform bones. Superiorly it is articulated with a
part of the os cuneiforme magnum ; more posteriorly
with the cuneiforme medium : from the former it re-
ceives a part of the weight, but with the latter it is only
connected so as to be retained in its situation. Anteri-
orly it also articulates with the middle cuneiform. It is
supported chiefly by the os metatarsi internum; for
though a portion of it rests upon the head of the os me-
tatarsi magnum, that bone is comparatively but little im-
pressed by it.
Os Metatarsi Magnum.
This bone only differs from the os metacarpi magnum
in three particulars:—first, in being about one-sixth long-
er; secondly, in its body being much rounder; and lastly,
in the articulatory surface upon its head being such as
is adapted to the ossa cuneiformia.
The ossa suffraginis, coronas, pedis, et naviculare, bear
a close resemblance to each other, both in the fore and
hind extremities.
Diseases of the Bones of the Hock.
Few parts of the skeleton are more subject to disease
than the hock. It presents us with examples of such a
yast variety of exostosis, as well as anchylosis, that to at-
tempt to particularize them, would be quite an endless
task. Nor is this, indeed, a matter of surprise, when we
-ocr page 387-
352                                 On Spavin.
consider how much this joint, beyond all others, is exerted
during progression ; for it is very principally upon it, that
the strong muscles about the quarters, employed for that
purpose, exercise their powers in the propulsion of the
machine.
As most of these diseases affect the inner part of the
hock, where they appear iu the form of exostosis, we
shall describe them, according to established usage, un-
der the general head of spavin.
On Spavin.
The word spavin has been applied to several diseases
of parts about the hock-joint, not only distinct, but even
opposite in their nature, prefixing to it, by way of diag-
nostic, the epithet bog, blood, or bone, according to the
supposed nature of the malady. Nowadays, however, we
seldom use the term except to denote the last of these
affections : the two first having their origin in extremely
erroneous notions, are pretty generally discarded among
professional men. We would define a spavin, (called by
horse-dealers and grooms a jack,) to be an exostosis upon,
or near to, the inner and lower part of the hock. In its
origin and progress it is very similar to a splint; in-
deed, it may be, in reality, purely a splint; although
from its situation, we should denominate it a spavin.
To explain this, a spavin may, and commonly we be-
lieve does, arise from an inflammation of the cartilago-
ligamentous substance connecting the head of the in-
ner small metatarsal to that of the cannon bone, with-
out any accompanying disease of the bones of the hock ;
and this, terminating in ossification, may be a splint as to
its nature, but is a spavin as to its situation. If, however,
the inflammation extends from this cartilago-ligamentous
-ocr page 388-
On Spavin.                                 353
substance to the ligaments and bones of the hock, and ter-
minates there in the effusion of bony matter; or if the
exostosis of the inner metatarsal bone itself is so placed
as to disturb the motions of this joint, then does a spavin
differ essentially from a splint. To elucidate this point
still farther—if the exostosis, instead of making its ap-
pearance just beneath the hock, is seated about the
body, or lower extremity of the cannon, it constitutes
a splint of the hind leg: a disease however of but rare
occurrence, owing to the bony deposit commonly ap-
pearing at that part where inflammation is first excited.
Although a spavin at the commencement may be con-
fined to the metatarsal bones, it seldom happens that those
of the hock do not ultimately partake of the disease ; and
this will account for the various degrees of lameness and
stiffness observable in that joint: indeed, we have little
doubt but the internal parts—the vascular lining of the
joint—become eventually diseased ; so that the synovia
is unnatural either in quantity or quality, or perhaps both;
to which is chiefly referable the explanation of the fact of
spavined horses improving in their action during work. In
almost all cases of inveterate spavin, the cuneiform bones
are united together by a layer of ossific matter, extending
upwards from the inside of the large and inner small me-
tatarsals ; so that there is no longer any motion whatever
between the small bones of the hock and those of the leg:
very commonly also, the same sort of union renders the
os calcis as well as the os cuboides fixed in their places.
However much the exostosis increases in size after this,
it seldom invades the joint formed between the astragalus
and tibia ; so that, in fact, the chief motion of the hock is
still preserved; and in consequence of it, such horses
are able to go with very tolerable freedom. But when
2 a
-ocr page 389-
354                                On Spavin.
this joint, in which almost all the motion of the hock re-
sides, becomes diseased, the event is either partial or (if
the case be neglected) complete anchylosis : and now the
lameness is so excessive that the horse is either altogether
useless, or only fit for slow and moderate woTk. And
not unfrequently such horses derive benefit from well-re-
gulated exercise in harness, in consequence, probably, of
some absorption of the bony deposition, from the repeat-
ed pressure and friction it is exposed to, in the forcible
exertions of the hock during draught: hence it is that
ploughing, and other agricultural labor are esteemed pal-
liative
for horses that are cripples from this disease.
We have mentioned the inside of the hock as the seat of
disease, in our definition of a spavin; for were a similar
swelling to take place upon the outer, we are not quite
sure whether it would be so called or not. The truth is,
however, that such appearances are Exceedingly uncom-
mon, and for the same reason that splints are much more
frequent on the inside of the leg than the outside : viz.
the greater proximity of these parts to the centre of gra-
vity, and the position of the small bones of the hock with
regard to those of the leg. So that, from both these
causes, the inner metatarsal bones actually support more
weight than the outer; their elastic connexions, there-
fore, are more likely to be sprained, (as well as the liga-
ments of the inside of the hock,) and to take on inflamma-
tion, and ossification.
We have anticipated what may be said to link all the
causes of spavin to one as a principal: viz. any thing that
excites inflammation of the ligamentous parts in the si-
tuation of it; be it over-exerting, over-weighting, or other-
wise injuring them. Hunters are often spavined, because
they sprain their hocks in leaping and galloping upon
A
-ocr page 390-
On Spavin.                               3.55
heavy ground; military horses are often spavined, be-
cause they are made to use these parts with violence, and
in various unnatural movements ; young horses are often
spavined, because they are put to work before their limbs
have acquired due firmness and strength. Need we par-
ticularize further ?
In a work on the Diseases of Horses *, written more
than sixty years ago, we find the following pertinent re-
marks about the kinds of spavin : " that wliich begins at
the lower part of the hock is not so dangerous as that
which appears higher between the two round processes of
the leg bone. Likewise a spavin near the edge, is not so
bad as one that is more inward towards the middle, be-
cause it does not so much affect the bending of the hock.
It may also be observed, that a spavin that comes by any
common accident, as a kick or a blow, is at first no true
spavin, but a contusion ; amTtherefore not so dangerous."
—These practical conclusions, the truth of which is con-
firmed by every day's experience, admit of ready expla-
nation on the principles we have laid down.
In almost all systems of farriery, is met with a cure for
bone spavins. The remedies made use of for this purpose
are of three kinds : the first removes the tumor by a me-
chanical operation ; the second, by destroying its vitality,
and causing exfoliation ; the third, by exciting inflamma-
tion and absorption of it, on the principle of counter-irri-
tation. Though any of these may diminish lameness, or
take off the tumor, not one will eradicate the disease—a
disease that, like splint, essentially consists in the destruc-
tion of a part the original texture of which nothing we
* A New Treatise on tlte Diseases of Horses, <§'C by William
Gibson, Surgeon.
2 A 2
-ocr page 391-
356                                On Spavin.
can employ has the power to restore* Knowing that the
small metatarsal bones are of the same use in the hind as
the small metacarpal are in the fore extremities, it will at
once occur how preposterous it is even to suppose that
Nature should re-convert that whose composition she has
before changed, because its strength was insufficient to
sustain the force exerted on it. In truth, therefore, there
is no cure for a splint, or a spavin ; and though the lame-
ness caused by it may admit of removal, or palliation,
according to the circumstances of the case, it is equally
certain, that that horse in which it has once formed,
must perceive through life a degree of concussion, if not
inconvenience, in action he never experienced before.
Notwithstanding our confessed inability to cure this
disease, we are often called on to treat it; either for the
purpose of alleviating the accompanying lameness, or of
removing, what is regarded as, a troublesome and un-
seemly eye-sore.
With regard to operating on spavins, with a view to
remove them by means of a chisel, file, or saw, al-
though the practice is exceedingly commendable in cases
of common exostosis, it is not so well adapted to
this disease: those who employ such means, seldom fail
to leave the parts ultimately in a worse state than they
found them in. The reasons are obvious. So much
mechanical injury is inflicted, and unavoidably so, upon
the joint, that fresh inflammation, generally of a more ag-
gravated nature, is excited by the operation ; which, from
the texture of the parts it invades, commonly ends in spa-
vin or exostosis, if not so large, of a much worse de-
scription than that attempted to be taken off; inasmuch
as it extends more over the cavity of the joint, and inter-
feres so much the more with its motions. So that, at the
-ocr page 392-
On Spavin.                               357
best, this operation can only reduce the size, or promi-
nence of the tumor; but, at the same time, it will, almost
invariably, we believe, augment the osseous deposit in-
ternally, and increase the lameness. By farriers who
pretend to cure spavins in this way, the operation is so
bunglingly done, that the hock-joint is not unfrequently
opened; a circumstance now and then followed by the
animal's death : be it performed however ever so skil-
fully, the animal is subjected anew to pain, to be, with
but few exceptions, rendered lamer than he was before.
The practice of destroying spavins with caustic is ob-
jectionable for the same reasons: the remedy here, as in
the case above, is even worse than the disease it is in-
tended to relieve*.
Our most successful remedies, and those whose use is
attended with the least inconvenience, are such as come
under the denomination of counter-irritants. Stimulants of
various kinds have been from time to time recommend-
ed : the old favourite, and one that is now occasionally
employed, is the ol. origani; an essential oil well known
to farriers as an irritant when rubbed upon the skin ; com-
mon turpentine, liniments of various descriptions, and
mercurial ointment have been also, at one time or other,
made use of. Nothing, however, succeeds so well as
repeated blisters over the diseased part: let the hair be
closely shorn off the tumor; then spread thinly upon it
the unguentum lytta?, and repeat it every week, or fort-
night, according to the demands of the case. Should
* Speaking of caustics, disguised in blisters, Gibson says, " I
have seen many recipes of this kind that have been tried with va-
rious success, but for the most part they leave a continual baldness,
and often a remaining stiffness, which can never be removed.'' This,,
we apprehend, is partial anchylosis.
-ocr page 393-
358                             On Spavin.
this fail, (which it but seldom will,) firing may be had re-
course to; but not deep tiring, lest we slough beyond the
integument, and increase, instead of relieve the disease.
If the swelling be so recent that we can detect its exist-
ence in a state of callus—prior to ossification, (a disco-
very that we are not very likely to make,) we may take a
quart or two of blood from a superficial vein passing ob-
liquely over the anterior part of the hock, by puncturing
it a few inches higher up, and follow the venesection up
by the immediate application of a blister : no practice is
so beneficial as this, when there is much perceptible
heat and tenderness of the part.
Another mode of employing counter-irritation is by se-
ton. This remedy has been revived at the Veterinary
College, and the assistant professor informs us, with ma-
nifest advantage. Its success having shewn itself in two
or three cases which had resisted the ordinary treatment,
many others were operated on ; and the practice has so
far justified itself, as to be preferred to any other.
The operation is easily performed. Incisions through
the skin being made with a lancet, above and below the
spavin, insinuate a piece of tape between the integument
and the periosteum, with a blunt seton-needle. We may
excite more inflammation in the part afterwards by be-
smearing the seton with common turpentine, or other ir-
ritating application. We have no opinion of our own to
offer on this subject, not having as yet made sufficient
trial of the remedy : we leave the case therefore as it is,
and trust that those who are vigilant in the promotion of
the art, will not fail to inquire into the merits of it.
-ocr page 394-
LECTURE XXII.
Bones of the Head.
The bones of the head are divided into those of the
cranium, and those of the face : we shall first describe
the
Bones of the Cranium.
The cranium, skull, or brain-case of the horse, is but
small when compared to the bulk of his body : it forms
the upper part of the head ; is prominent and convex ex-
teriorly, and hollow and vaulted within, for the purpose
of lodging the brain and its appendages. The bones of
which it is composed vary much in the thickness of their
laminaa, and do so according to their situation ; those
being thickest and strongest whose exposure is greatest to
external injury. They are nine in number ; three pairs,
and three single bones : viz. ossa frontis, ossa parietalia,
ossa temporum, os occipitis, os sphenoides, os eth-
moides.
Prior to speaking of these bones separately, it will be
light to point out the different sutures by which tbey are
united. The sutures are those seams, or marks upon the
head, running in various directions, which define the li-
mits of each individual bone. One of the most conspi-
-ocr page 395-
360                              Ossa Frontis.
cuous is the frontal suture ; so called because it connects
the ossa frontis. A continuation of the frontal suture
upwards, between the ossa parietalia, seldom so well
marked as the frontal itself, forms the sagittal or parietal
suture:
it is often bifurcate below, and sometimes double
through its whole course. Occasionally it is altogether
wanting. The coronal suture is of a waving or serpen-
tine figure : it divides the ossa parietalia from the ossa
frontis. The lambdoidal suture separates the ossa pari-
etalia from the os occipitis : those parts of it which are
situated between these bones and the petrous portions of
the ossa temporum, receive the name of addimenta sutures
lambdoidalis.
The squamous sutures divide the squamous
portions of the temporal from the frontal and parietal bones.
Most of the sutures are subject to some variation in differ-
ent heads ; among the most uniform in their appearance
are the frontal and coronal. In order to have a correct
knowledge of them, we should procure a young head ;
for as the animal advances in years, many of them be-
come indistinct, and of some the traces are altogether ef-
faced. In the aged horse, ossific union of the bones has
so completely obliterated them that not a vestige of su-
ture remains : the sagittal suture soonest disappears; the
frontal remains the longest; though even it, we have re-
marked, has been scarcely visible in the skull of a horse
seven years old.
Ossa Frontis.
THE frontal bones, two in number, form that part of
the cranium which we distinguish as the fore-head, and
which, in the living horse, is commonly marked by a white
patch of hair, designated a star. Their external surface
is smooth and convex; prominent above, to give more
-ocr page 396-
Ossa Frontis.                              361
space to the brain; flat below, in the situation of the
frontal sinus. Projecting from its outer margin is a por-
tion of bone, of an arched figure, called the external or-
bitar process; so placed as to form the upper and ante-
rior part of the orbit. Below this, and behind it, is a thin
bony plate, named the internal orbitar process ; partially
divided from one of similar structure above by a consider-
able inlet, into which apart of the ethmoid bone is receiv-
ed. Thus, the orbitar processes of the os frontis contri-
bute a great share in the composition of this bony cavity,
called the orbit, designed for the lodgment of the organ of
vision. The inferior extremity of this bone, takes the
name of nasal process. The thin plate of bone above the
orbital, is the temporal process. Upon its interior, the
os frontis is divided by a vaulted piece of bone into two
unequal cavities: the superior contains the anterior lobe
of the brain, which is partly supported by this partition ;
the cavity below, known by the name of the frontal si-
nus,
is of less size than the cerebral, though its extent is
greater than, on a superficial view, it appears to be, in
consequence of its running for some way up in front of
the partition. One frontal sinus is separated from the
other by a septum, composed of a lamina from each
tone. There is but one hole (sometimes notch in the
dried bone) in the os frontis, and that at the root of the
orbitar process : it is called the foramen supra-orbita-
rium. The ossa frontis are connected above to the ossa
parietalia ; on either side to the ossa temporum, both by
their temporal and orbital processes; and to the ossa
sphenoides et ethmoides within the cavity of the orbit.
They are also joined to some of the bones of the face.
It is of some importance to carry in mind the precise
spot where the perforation should be made in the head
-ocr page 397-
Ossa Purietalia.
362
when it becomes necessary to open lite Jiv/tlal sinus.
First we feel (in the living horse) for the internal angle of
the orbit—the part pierced by the infra-orbitary foramen,
then drawing an imaginary line to the same point on the
opposite side, we may safely make an opening at any
point in the course of it, within half an inch, or an inch,
of the frontal suture : a puncture made one inch higher
would endanger the brain, and one an inch and a half
lower would enter the nasal sinus. For this operation a
well made spill-gimblet is as good an instrument as can
be used, A perforation through the anterior part of the
internal orbitar process, will also open into the frontal
sinus. These cavities communicate below with others
to be hereafter described.
Ossa Parietalia.
The parietal bones, two in number, constitute the up-
per and lateral parts of the cranium. They are of a square
figure: each somewhat resembles the shell of a crab. It
is smooth and regularly convex externally : but concave
and uneven internally ; being there marked by the convo-
lutions of the middle lobes of the brain, which it covers
and protects. The sides of these bones are jagged, and
extremely uneven ; and, with the exception of those over-
lapped by the squamous portions of the ossa temporum,
their edges are denticulated, so as to form true sutures
when united with those of other bones of the skull. They
are joined to each other in the centre. Their lower parts
are connected to the ossa frontis ; their sides to the ossa
temporum; and their upper borders to the os occipitis.
These bones have no remarkable foramen : though
some small holes are formed by their union with the tem-
poral bones.
-ocr page 398-
36§
Ossa Temporum.
The ossa temporum are, in truth, four in number ; for
those pieces which correspond to the squamous and pe-
trous portions in the human subject, are in the horse se-
parate bones, and remain so during life. They are situ-
ated on either side of the cranium, behind the orbital
cavities. The squamous portion is that which overlaps
the sides of the parietal bone, and forms a part of the
zygoma, or bony arch : the petrous, that to which the ear
is attached, and which contains the internal organ of
hearing. We shall first speak of the former.
Pars Squamosa,
Or squamous portion, consists chiefly of acircular plate
of bone, convex upon the outside, concave within, to adapt
itself to the middle lobe of the brain, from which are pro-
ceeding several projections. The most conspicuous is the
zygomatic process, which extends downwards hi a curved
direction to form a junction with the orbital processes of
the frontal and maln.r bones, and complete the upper and
outer boundary of the orbit, over which these three projec-
tions are extended in the form of an arch : hence the name
of zygomatic arch has been given to it. A thin portion of
bone is sent off from the root of the zygomatic process,
which may be denominated its occipital process; and be-
tween these two projections, a round prominence passes
downwards, which, from its resemblance to the mamma
or teat of an animal, is called the mammillary or mastoid
process. Anteriorly to the mastoid process is the glenoid
cavity; a superficial smooth hollow, ii.tended for the re-
ception of the condyle of the lower jaw. At the root of
the mastoid process is a small foramen, called the foramen
-ocr page 399-
Pars Petrosa.
364
mastoideum. The squamous portion is connected infe-
riorly to the os frontis ; posteriorly to the os sphenoides;
superiorly to the os occipitis, and pars petrosa ; and ante-
riorly to the ossa parietalia.
Pars Petrosa,
Or petrous portion, is united with the posterior and
upper part of the squamous : it is important from con-
taining the delicate parts of the internal ear. From its
lower end is sent off a thin, sharp process, called the sty-
loid. Every where this bone is extremely hard in its com-
position ; though internally it is hollow ; where are de-
posited, we repeat, those complicated little organs neces-
sary to the production of hearing. The passage leading
to this, is called the meatus auditorius : its bony begin-
ning, to which the external ear attaches itself, is marked
by a large foramen surrounded by a bony eminence, de-
nominated the auditory process. A slender portion of
this bone runs upwards and backwards, between the pars
squamosa and os occipitis ; which not unfrequently se-
parates by maceration. This bone has a slight connex-
ion to the os sphenoides.
Os Occipitis.
The occipital bone in the young subject is divisible
into two pieces ; but ossific union is completed between
them in the adult horse. The upper portion, by some
called the anterior occipital bone, is of considerable sub-
stance ; for being placed at the vertex, it is a part much
exposed to external violence : the summit of the head
generally receives the blow when a horse falls backwards
in rearing. It is somewhat arched in its shape; being
convex externally, and concave internally, to cover, and
\
-ocr page 400-
Os Occipitis.                                 365
shield from injury, the posterior lobes of the brain. The
upper protuberant part, forming the vertex, may be call-
ed its tubercle : into it is inserted the ligamentum michae.
This bone is connected with the ossa parietalia before ;
with the os occipitis posterius behind; and on each side
with the petrous portions of the ossa temporum.
The lower piece, or posterior occipital bone, is very
different in its general appearance from the anterior; and
exceeds in thickness, as well as strength, most of the
other bones of the cranium : it forms that part of the skull
which is articulated with the bones of the neck. Five
processes, and three foramina, are distinguished in this
bone. Through its middle is a large circular hole, called
the foramen magnum. By the sides of it are two round-
ed articulatory eminences, named the condyles or condy-
loid processes, which form joints with corresponding
concavities in the first cervical vertebra. Further remov-
ed outward from this foramen, project two others, called,
from their hooked figure, the coronoid processes : thev
are directed backwards, and tend much to prevent dis-
placement of these parts in the living animal. From the
lower part of this foramen exteuds forward a remarkably
strong rounded portion of bone, supposed to resemble a
wedge, hence its name of cuneiform process : it assists
in supporting the brain, and forms one of the strongest
barriers at the basis of the skull. The foramen magnum
lodges the origin of the spinal marrow. The two re-
maining perforations are those through the roots of the
condyloid processes, denominated the foramina condy-
loidea. This bone is joined above to the last described;
below to the os sphenoides, by means of its cuneiform
process; and laterally to the ossa temporum.
-ocr page 401-
366
Os Sphenoides.
The sphenoid bone is placed at the posterior part or
basis of the cranium. In shape it has been compared to
a bat with its legs and wings extended ; from which cir-
cumstance a division of its several parts has been made
into body, alae or wings, and crura or legs. The body, a
firm and solid piece of bone, is of a cylindrical form ;
convex and smooth upon its back part; irregularly con-
cave upon its fore or internal part, upon which lies a por-
tion of the brain. From the sides of the body are ex-
tended two broad and thin bony plates which correspond
to the wings, hence called its alas; whose extremities
are seen in the posterior parts of the orbits. They are
hollowed out and smooth internally, in order to enlarge
the cavity of the cranium, and assist in giving protection
and support to the brain. From the roots of the alae an-
teriorly proceed the crura or legs, two long slender pro-
cesses which embrace the sides of the os ethmoides : at
their junction with the alae are two foramina. The os
sphenoides is connected inferiorly to the os ethmoides ;
superiorly to the ossa temporum, et occipitis ; within the
orbits to the ossa frontis, temporum, et ethmoides.
Os Ethmoides.
The ethmoid bone, perhaps, more resembles a bat in
flight than the last described, if we suppose that the legs
have been taken away, and a head and neck added. It is
situated at the basis of the skull, before the os sphenoides ;
and is greatly concealed from our view by the vomer, the
broad part of which lies immediately upon it, in the form
of a crescent. Its body, unlike that of the sphenoid, is
hollow ; being composed of thin delicate plates of bone,
-ocr page 402-
Os Ethmoides.
367
so disposed as to form two small cavities, called the eth-
moidal sinuses :
these freely communicate, and discharge
their secretions by small apertures into numerous little
cavities called the ethmoidal cells, which open into the
chambers of the nose. From the upper and fore part of
the body runs a process which some have compared, in
the human subject, to the comb of a cock, and given it the
name of crista galli. Two thin expansions of bone from
its sides, more deserve the name of alaj than the process-
es so called of the sphenoid bone ; their terminations,
which are extremely thin and form a part of the posterior
boundaries of the orbits, have been denominated the ossa
plana. Around the crista galli is an exceedingly thin,
spongy portion of bone, which fills up two oval vacuities
left at this part, between this bone and the posterior por-
tions of the ossa frontis : this, from the peculiarity of its
structure, has been named the cribriform plate—through
its numerous perforations are transmitted the filaments of
the olfactory nerves to the membrane of the nose. At
the roots of the ala? are two round foramina, called the
optic, from giving passage to the optic nerves. The os
ethmoides is connected superiorly to the os sphenoides;
inferiorly to the vomer et ossa turbinata ; within the or-
bit to the ossa frontis, palati, et sphenoides.
-ocr page 403-
LECTURE XXIII.
Bones of the Face.
The bones of the face, like those of the cranium, are
united together by sutures, which have received differ-
ent names according to their situation : they all become
more or less indistinct, and many totally obliterated, in
the old horse's head. The only two we shall notice in
this place, are the transverse and nasal sutures. The
transverse suture runs from the inner angle of each orbit
across the forehead, and is continued within the orbits,
in a zigzag course, as far as the os sphenoides: it marks
the line of junction between the bones of the face and
those of the skull, The nasal suture, a continuation of
the frontal, unites the nasal bones : it is seldom effaced
in the oldest horses.
The bones of the face compose the upper and under
jaws : the upper jaw is separable into eight pairs, and
one single bone; the lower (formed in the foal of two) is
but one piece in the adult horse.
Ossa Nasi.
Two long slender bones, situated upon the fore part
of the face, immediately below the forehead ; where they
-ocr page 404-
369
Ossa Nasi.
form a vaulted roof to the cavity of the nose. Their up-
per edges are ragged and serrated, and make a zigzag su-
ture by their union with the ossa frontis: nearer to the
orbits, a less denticulated suture joins them to the ossa
malarum. Their sides are overlapped by the ossa max-
illaria superiora ; and in the centre they are united by the
nasal suture, to which part is firmly attached the septum
nasi. These bones, viewed either separately or articu-
lated together, are of a wedge-like shape, being broad
and expanded above, but thin and tapering below, where
they terminate in sharp pointed extremities ; parts con-
spicuous in the dried skull, in consequence of the nostrils
(which are supported by them in the recent subject) being
composed of soft materials. Upon their exterior the na-
sal bones are smooth, and irregularly arched ; so that the
internal part, by being hollow, increases the area of the
cavity of the nose. Opposite to the basis, is a cavity
that will contain about half an ounce of fluid, to which
the name of nasal sinus has been given. Below it, the
bone is scooped out, and divided by an irregular project-
ing ridge into two furrows, or canals ; the inner of which,
the larger, is the passage from the frontal and nasal si-
nuses to the chamber of the nose ; the outer is occupied
by the superior turbinated bone, whose ossifjc adhesion
to the central ridge between the grooves is so firm, that
it is not separable by maceration. In addition to the
connexions of the ossa nasi we have already described,
their edges are embraced on either side in part by the
ossa maxillaria inferiora ; between which and their apices
is a remarkable vacuity, tilled up in the living horse by
the different soft parts entering into the composition of
the nares externa;.
'I B
-ocr page 405-
370                Ossa Unguis.Ossa Malarum.
We would remark, in this place, that the frontal si-
nuses empty themselves in part into the nasal, but from
the latter there is no meatus or passage whatever; con-
sequently it is only when they overflow from the collec-
tion of secretion, or in certain positions of the head, that
discharge will trickle from them into the chambers of the
nose.
Ossa Unguis.
Two small bones placed below the orbits, to the out-
er side of those last described. Each os unguis may be
said to be composed of two plates, or laminae : a facial,
that portion which contributes to the upper and lateral
parts of the nose; and an orbitar, which assists in form-
ing the floor of the orbit. The latter is so thin as to be
transparent when held to the light, and is remarkable
from containing a bony canal, lined by membrane in the
recent subject, denominated the ductus ad nasum ; whose
use is to conduct the tears from the eye to the cavity of
the nose. The ossa unguis are joined above, both within
and without the orbits, to the ossa frontis; laterally, in
the same manner, to the ossa malarum; and inferiorly to
the ossa maxillaria superiora.
Ossa Malarum.
Two bones shaped like crescents; whose smooth
lunated borders form the outer boundaries of the orbits.
This is a bone of more than ordinary thickness, particu-
larly at its upper and outer part, where it is lengthened
out into a conical projection, called its zygomatic process ;
in consequence of its contributing to the formation of the
zygomatic arch, which it stands out to support after the
manner of a buttress. Its body rests upon the superior
i
-ocr page 406-
Ossa Maxillaria Superiora.                   371
maxillary bone. From its orbitar edge proceeds a smooth
excavated bony plate, let into the parietes of the orbit.
Its interior presents a rough laminated surface, firmly
dovetailed with the os unguis.
Ossa Maxillaria Superiora.
These are, with the exception of the lower jaw, the
largest bones of the face ; and constitute a very consider-
able part of the upper jaw. Though much thicker in
substance than those that complete the jaw below, (which
we shall next describe,) they are not of so firm a texture,
nor of such absolute strength. That part connected su-
periorly with the os malas, is denominated its malar pro-
cess. Behind it, is a rounded protuberance, near to the last
molar tooth, called the tuberosity. The projection from
its lower extremity, the dental process, is extensively con-
nected, along its upper edge, to the os maxillare inferius.
The posterior part of this bone, its alveolar process, is
composed of two bony plates, or laminae, intersected by
thin osseous partitions in such a manner that quadrangu-
lar cavities are formed between them, for the purpose of
containing and supporting the molar or grinding teeth :
these sockets, or alveolar cavities, vary in size and num-
ber according to the age of the animal. From the alve-
olar pass inwards the palatine processes; two vaulted
projections, which, by their union, form the roof of the
mouth, or bony palate. Upon their fore part, where their
laminae again unite, the maxillary bones become compara-
tively thin : along this (their anterior) edge, they are con-
nected to the ossa nasi; so that these bones constitute a
great share of the parietes of the nose, whose superficies
they extend by being excavated upon their interior. The
2 b 2
-ocr page 407-
372                   Oisa Maxillaria Anteriora.
nasal cavities are further enlarged by two capacious cham-
bers, called the maxillary sinuses, or antra maxillaria: not
however that they are, strictly speaking, situated within
these bones; for both the ossa unguis et malarum assist in
their formation ; indeed the orbitar plates of these bones
constitute the roof of the sinuses; so that in order to open
them, we should make perforations some little distance
below the inferior borders of the orbits. They commu-
nicate freely with the frontal sinuses, and empty them-
selves into the nose by the sides of the ossa turbinata.
Just below the site of this sinus externally is a hole of
large size, denominated the foramen infra-orbitarium,
through which passes a large branch of the fifth pair of
nerves. Between the palatine process and the os palati,
with which it is connected, is another hole of smaller size,
called the foramen palatinum. Besides the connexions
which have already been noticed, the ossa turbinata in-
feriora adhere to these bones, within the cavity of the
nose.
Ossa Maxillaria Anteriora.
Two bones remarkable for smoothness of surface, and
hardness of texture, composing that part of the upper
jaw to which the upper lip is attached : they do not exist
in the human subject; we have only two upper maxillary
bones, which, by forming a junction with each other in
the centre, called the symphysis, of themselves constitute
the upper jaw. Each of these bones may be divided into
a body and two projections: the body, the thickest and
lowest portion, is formed of two laminae or plates, be-
tween which are cavities for the incisor teeth, or nippers;
similar in construction, but not in shape, to the sockets
A
-ocr page 408-
Ossa Palati.                               375
that contain the grinders, and, like them, differing in size
and number in the young and adult animals. Below they
are united to each other, in the young subject by carti-
lage ; but in the old by osseous matter, so that they are
commonly inseparable by maceration : this part is known
as the symphysis of the upper jaw. From the body ex-
tends upwards a projection of considerable length,
which together with its fellow of the opposite side, frosn
which it diverges in course, leaves an oval-shaped open-
in<» of considerable size, througli which we can examine
the interior of the bony fabric of the nose ; the figure of
the oval is, however, broken in upon superiorly by the
tapering extremities of the ossa nasi. From the upper
and back parts of these bones are sent off two extremely
thin and transparent laminee, which fill up the space in
the roof of the mouth between the dental processes of
the superior maxillary bones. Beside the connexions
just mentioned, the anterior maxillary bones are joined
above to the ossa nasi. Through the centre of the sym-
physis is a perforation, called the foramen incisivum :
it affords passage to the extreme branches of the pala-
tine arteries, in their course to the upper lip.
Ossa Palati.
These bones are so named from composing a part of
the palate ; though they contribute to it very inconsider-
able portions, when compared to the broad arch formed
by the palatine processes of the superior maxillary bones.
They are firmly retained in their places at the top of the
bony palate by those bones; indeed, they are so securely-
locked in, that it is with no small difficulty their separa-
-ocr page 409-
374                Ossa Spongiosa vel Turbinata.
tion is effected in the macerated skull. Between the up-
per parts of the nose and mouth (for they enter into the
composition of both) the palate bones present a smooth
curvated edge, to which the velum palati or soft palate is
attached. Still higher they form a small share of the or-
bital cavities, at which part there is a foramen on each
side, called the foramen palatinum superius, leading to
the palato-maxillary canal: it gives passage to the pala-
tine artery. The lamella; of which this bone is composed,
having disunited, leave a smooth, oblong cavity between
them, which completes posteriorly, and something en-
larges, the maxillary sinus. Near to its lower end is a
notch continuous with a bony fissure: this is the termi-
nation of the palato-maxillary foramen. The ossa pa-
lati are connected with the ossa ethmoides, sphenoides,
et frontis above; centrically with the vomer; laterally
and inferiorly with the ossa maxillaria superiora.
Ossa Spongiosa vel Turbinata, Superiora et Inferiora.
The spongy or turbinated bones are four in number.
They are more delicate than any we have noticed, be-
ing composed of extremely thin, porous, flexible lami-
nae, the texture of which (when exposed to the light)
resembles that of crape, or muslin, perhaps, more than
any thing else we can compare it to, convoluted or rolled
up into a form not unlike a turban ; hence the epithet
turbinata. These bones, concealed from view, are si-
tuated within the interior of the nose, to the bony parietes
of which they closely adhere. We have, at another time,
described the superior turbinated bones (which are two in
number) as inseparably connected with the ossa nasi; it
therefore only remains for us to point out the attachments
-ocr page 410-
Vomer.Maxilla Inferior vel Posterior. 375
of the two iuferior. These are united superiorly to the
ethmoid cells, and so intimately, that by some they are
considered as part of that bone; they are also joined to
the sinuses of the frontal bones, with which they have
free communication ; but they are principally retained in
their situation by their connexions with the ossa nasi,
through the interposition of the anterior spongy bones.
The spongy bones materially augment the faculty of
smell, by affording a very extensive surface for the rami-
fication of the olfactory nerves upon the pituitary mem-
brane, in which they are enveloped. They are not un-
frequently in part destroyed by caries in the malignant
stages of glanders.
Vomer.
One of the single bones of the face. It bears some
resemblance to a ploughshare, whence it takes its name.
It is placed upon the arch of the bony palate, and in many
places becomes pretty firmly adherent to it by osseous
matter. This bone is constituted of two thin sides, with
a deep groove between them; into which the posterior
margin of the cartilaginous septum of the nostrils, is, in
the fresh head, nicely fitted. Above, the vomer is ex-
panded, and terminates in the form of a crescent; where
it is closely embraced, and retained in its situation, by the
ossa palati: the space within its lunated edge exposes to
view a small part of the os ethmoides, with which the vo-
mer is also connected.
Maxilla Inferior vel Posterior.
The inferior maxillary bone, more commonly called
the lower jaw, we shall divide, in our description of it,
i.
-ocr page 411-
376           Diseases of the Bones of the Head.
into body, sides, and branches. The body is that part
corresponding to the human chin, and has in its lower
end six alveolar cavities, for the incisor teeth, and in the
adult male two others in its sides for the tushes. The
sides consist of two broad firm pieces, flattened laterally,
rounded posteriorly, and hollowed out in front for the re-
ception of the molar teeth ; and the alveolar sockets in
them are formed by the separation of the plates of which
this bone is composed, partitioned by transverse osse-
ous septa. From the upper and back part of the bone pro-
ject forward the branches, which are thinner in substance,
but somewhat broader than the sides. Each branch
is surmounted by two processes : the anterior, from its
resemblance to the beak of a crow, may, with propriety,
be named the coronoid ; the posterior, which articulates
with the glenoid cavity of the temporal bone, the condy-
loid process or condyle. There are two foramina, one
in each side of this bone, which communicate, by a canal
that runs by the roots of the molar teeth, with two others
in the body : they may be called the superior and inferior
maxillary foramina.
Diseases of the Bones of the Head.
These parts are occasionally fractured from blows or
falls: both being aceidents, however, of but rare occur-
rence, and too variable a nature to admit of much practi-
cally useful description, or any denned method of treat-
ment, we shall leave them, with a solitary remark, to the
discretionary management of the practitioner :—replace-
ment and apposition of the fractured parts, and the pre-
vention of all motion between them, are the primary and
leading considerations.
-ocr page 412-
Diseases of the Bones of the Head.           377
Exostosis is not common about the head : we have
seen it oftenest upon the lower jaw ; indeed, this bone is
sometimes met with considerably augmented in thickness
from adventitious deposit upon its sides. We have but
one preparation of exostosis of the upper jaw: it is
about the size of an egg, grows from the orbitar process
of the os frontis, and is so placed as to intercept those
rays of light falling direct upon the eye.
FINIS.
-ocr page 413-
LONDON: PRINTED BY JOHN HILL, WATER LANE, BLACKFItlAKS.
-ocr page 414-
IN A STATE OF PREPARATION FOR THE PRESS.
OBSERVATIONS
ON
THE CONSTITUTION, ECONOMY, AND DEFECTS
OF THE
Vtttximv& Mtpaxtmmt
OF
GREAT BRITAIN:
ACCOMPANIED WITH
PLANS OF AMENDMENT.
.ADDRESSED,
With all due Submission and Respect,
to the
PRESIDENT, VICE-PRESIDENTS, SUBSCRIBERS, AND MEMBERS
OF THE
VETERINARY COLLEGE.
Among other topics, the Work will embrace.—The Rise
and Progress of the Veterinary Art.—The Veterinary College,
considered as a National Institution, and Public School:
The Professor, and the Assistant Professor.'—The Improve-
ment of the Art: Authors, Writers, Discoverers, and Pa-
tentees.—Present dormant state of the Art: Obstacles to
further Advancement.—Army Veterinary Establishment:
The Principal, and the Regimental Veterinary Surgeons;
Supply of Medicine; Veterinary Regulations.—Plans for
augmenting and extending the Utility of the Art, and for
ameliorating the Condition of its Members.
-ocr page 415-
THE
FOLLOWING IMPORTANT WORKS
WILL BE
PUBLISHED IN THE COURSE OF APRIL,
BY
LONGMAN, HURST, REES, ORME, and BROWN, LONDON.
FABLES for the HOLY ALLIANCE, with other Poems, &c.
By Thomas Brown, the Younger. In One Volume, 12mo.
The HISTORY of ENGLAND, during the Middle Ages. By
Sharon Turner, Esq. F.S.A. Vol. III. 4to. comprising the Reigns of Henry VI.
Edward IV. Edward V. Richard III. and Henry VII.
TRAVELS, comprising OBSERVATIONS made during a RESI-
DENCE in the TARENTANE and various Parts of the Grecian and Pennine Alps,
in Savoy, and in Switzerland and Auvergne, in the Years 1820, 1821, and 1822, with
Remarks on the present State of Society, Manners, Religion, Agriculture, Climate,
&c. of Countries hitherto little visited by English Travellers. In 8vo. illustrated
with Plates, &c. By Robert Bakewell, Esq.
MEMOIRS of a CAPTIVITY among the INDIANS of NORTH
AMERICA, from Childhood to the Ag-e of Nineteen, wim Anecdotes descriptive
of their Manners and Customs, and some Account of the Soil, Climate, &c. of the
Territory westward of the Mississippi. By John D. Hunter. In One Vol. 8vo,
A GEOGNOSTICAL ESSAY on the SUPERPOSITION of
ROCKS in both HEMISPHERES. By M. de Humboldt, and translated into
English under his immediate Inspection. In 8vo.
ALFRED ; a Romance in Rhyme. By Richard Payne Knight,
Esq. In 8vo.
" SYLVA FLORIFERA," the " SHRUBBERY;" containing an
Historical and Botanical Account of the Flowering Shrubs aud Trees, which now
ornament the Shrubbery, the Park, and Rural Scenes in general. By Henry
Phillips, F.H.S. Author of the " History of Fruits, known in Great Britain," and
the " History of Cultivated Vegetables." 2 Vols. 8vo.
SKETCHES of the LIVES of CORRBGGIO and PARME-
GIANO, with Notices of their principal Works; small 8vo. with a Portrait.
WINE and WALNUTS ; or, after Dinner Chit-Chat. By Ephraim
Hardcastle, Citizen and Dry-salter. In 2 Vols, small 8vo.
TRANSACTIONS of the LITERARY SOCIETY of BOMBAY.
Vol. III. 4to. with numerous Plates.
The KING of the PEAK, a Novel. By the Author of the
" Cavalier," &e. In Three Vols, 12mo.
RECOLLECTIONS of the PENINSULA, containing Sketches of
the Manners and Characters of the Spanish Nation. By the Author of " Sketches
of India." In One Vol. 8vo.
INTEGRITY: a Tale. By Mrs. Hoffland, Author of the "Son
of a Genius," " Tales of the Manor," &c. One Vol. 12mo.
MEMOIRS of the late MRS. CATHERINE CAPPE. Written
by Herself. The 2d Edition, in 8vo. with a Portrait.
The THREE PERILS of WOMAN. By James Hogg, Author
of the " Three Perils of Man." In 3 Vols. 12mo.
A NEW EDITION of the SAXON CHRONICLES, with an
English Translation and Notes, critical and explanatory. By the Rev. J. Ingram,
late Saxon Professor in the University of Oxford. With a short Grammar of the
Saxon Language, and Map of England during the Heptarchy. One Vol. 4to.
The JAMAICA PLANTER'S GUIDE, or a System for planting
and managing a Sugar Estate, or other Plantations in that Island, and throughout
the British West Indies in general. Illustrated with Interesting Anecdotes. By
Thomas Roughlby, nearly Twenty Years a Sugar Planter in Jamaica. One Vol. 8vo,
-ocr page 416-
April, 1823.
NEW AND IMPORTANT WORKS,
PUBLISHED BT
LONGMAN, HURST, REES, ORME, AND BROWN,
LONDON.
1.
THE LOVES OF THE ANGELS.
A POEM.
By THOMAS MOORE.
The 4th Edition, in 8vo. Price 9s. Bds.
Also, ILLUSTRATIONS to the POEM. From Designs by R. WESTALL, Esq. la
8vo. Price 5s.
2.
MEMOIRS OF MARY, QUEEN OF SCOTS,
With Anecdotes of the Court of Henhy the Second, during her Residence in France.
By MISS BENGER.
3.
ACCOUNT OF AN EXPEDITION FROM PITTSBURGH
TO THE ROCKY MOUNTAINS,
Performed in the Years 1819-20, by Order of the Hon. J. C. Calhoun, Secretary of War,
under the Command of Major S. H, Long, of the United States Topographical Engineers,
Compiled from the Notes of Major Long, Mr. T. Say, and other Gentlemen of the Party.
By EDWIN JAMES,
Botanist and Geologist for the Expedition.
In Three Volumes, Octavo, illustrated with Maps and Plates. Price 11. 16s. Bds.
4.
NARRATIVE OF A TOUR THROUGH THE MOREA,
Giving an Account of the present State of that Peninsula and its Inhabitants.
By SIR WILLIAM GELL.
In One Volume Octavo, illustrated by Plates, Wood Cuts, &c. Price 15s. Bds.
5.
MEMOIRS OF
THE LIFE OF CHARLES ALFRED STOTHARD, F.S.A.
Author of the Monumental Effigies of Great Britain.
Including several of his Original Letters, Papers, Journals, Kssays, &c. &c.
With some Account of a Journey in the Netherlands.
By MRS. CHARLES STOTHARD,
Author of Letters written during a Tour through Normandy, Britanny, and-,
other Parts of France, in 1818.
In 8yo. with a Portrait. Price 15s, Bds.
6.
. TRAVELS IN IRELAND, in the yea* 1822.
Exhibiting Sketches of the Moral, Physical, and Political State of the Country, with Re-
flections on the best Means of improving its Condition.
By THOMAS REID,
Member of the Royal College of Surgeons in London, and Surgeon in the Royal Navy.
In 1 Vol. 8vo. Price 12s. Bds.
7.
ADVICE TO YOUNG MOTHERS
ON THE PHYSICAL EDUCATION OF CHILDREN,.
By a GRANDMOTHER.
In 1 Vol. 12mo. Price 7s. 6d. Bds.
-ocr page 417-
Works printed for Longman, Hurst, Rees, Orme, and Brown. 3
8.
THE ENGLISH MASTER;
OR, STUDENT'S GUIDK TO REASONING AND COMPOSITION:
Exhibiting an Analytical View of the English Language, of the Human Mind, and of the
Principles of Fine Writing.
By WILLIAM BANKS,
Private Teacher of Composition, Intellectual Philosophy, &e.
In 1 Vol. 8vo. Price 10s. 6d. Bds.
9.
THE LINN^AN SYSTEM OF CONCHOLOGY,
Describing the Orders, Genera, and Species of Shells, arranged into Divisions and Fami-
lies : with a View to facilitate the Student's Attainment of the Science.
By JOHN MAWE,
A uthor of Travels in Brazil; Treatise on Diamonds and Precious Stones; Familiar Lessons
on Mineralogy and Geology, &c. &c.
With Thirty-seven Plates, comprising 234 Figures of Shells, in 8vo. Price 11. Is. plain;
or with the Plates beautifully coloured, Price 21.12s. 6d. Bds.
10.
BODY AMD SOUL*.
Consisting of a Series of lively and pathetic Stories, calculated to excite the Attention and
Interest of the Religious World.
In 12mo. Price 9s. the 2d Edit.
Contents.—The Town Rector—Philosophical Painter—Merchant's Family—Sick Penitent
.—Unitarian—Clerical Conference—Lunatic Asylum—Liturgy—Assizes—Athanasian Creed
—Sea Captain—Domiciliary Visits.
In the Press, and shortly will be published,
BODY AND SOUL. Volume the Second.
11.
FIFTEEN YEARS IN INDIA;
OR, SKETCHES OF A SOLDIER'S LIFE.
Being an Attempt to describe Persons and Things in various Parts of Hindostan.
From the Journal of an OFFICER in His Majesty's Service.
In Svo. the 2d Edit. Price 14s. Bds.
12.
A TREATISE ON MENTAL DERANGEMENT.
By FRANCIS WILLIS, M. D.
Fellow of the Royal College of Physicians.
In 1 Vol. 8vo. Price 7s. 6d. Bds.
13.
THE BRITISH CONSTITUTION,
OR AN EPITOME OF BLACKSTONE'S COMMENTARIES ON THE LAWS OF
ENGLAND,
FOB THE USE OF SCHOOLS.
By VINCENT WANOSTROCHT, L.L.D.
la One thick Vol. i2mo, 12s. Bds.
14.
THE FAMILY SHAESPEARE,
In which nothing is added to the original Text: but those Words and Expressions are omitted
which cannot with Propriety be read aloud in a Family.
By THOMAS BOWDLER, Esq. F.R.S. and S.A.
A new Edition, in 8 Vols. 8vo. large Type, 41.14s. 6d. Bds,
Also, in 10 Vols, royal 18mo. Price 31.3s. BOs.
-ocr page 418-
4 Wwlcs printed for Longman, Hurst, Rees, Orme, and Brown.
15.
AN ESSAY ON THE
HISTORY OF THE ENGLISH GOVERNMENT AND
CONSTITUTION,
FROM THE REIGN OF HENRY Til. TO THE PRESENT TIME.
By LORD JOHN RUSSELL.
In 8vo. tlie Second Edition, greatly enlarged, Price 14s. Bds.
16.
AN ENCYCLOPEDIA OF GARDENING;
Comprising the Theory and Practice of Horticulture, Floriculture, Arboriculture, and
Landscape-Gardening; including all the latest Improvements; a General
History of Gardening in all Countries;
And a Statistical View of its present State, with Suggestions for its future
Progress, in the British Isles.
By J. C. LONDON, F.L.S.H.S. &c.
Author of " A Treatise on forming and improving Country Residences.
Complete, in One large Volume 8yo. of 1500 Pages, closely printed, with Six Hundred
Engravings on Wood. Price 91. 10s.
17.
TRAVELS IN
GEORGIA, PERSIA, ARMENIA, ANCIENT BABYLONIA
&c. &c.
DURING THE YEARS 1817, 1818, 1819, 1820.
By SIR ROBERT KER PORTER, &c. &c.
Complete, in 2 Vols, 4to. With numerous Engravings of Portraits, Costumes,
Antiquities, &c. &c. Price 91. 9^ Boards.
18.
AN EASY COURSE OF DOMESTIC EDUCATION;
Comprising a Series of Elementary Treatises on the various Branches of Juvenile Instruc-
tion; together with Advice to Parents and Tutors for conducting the Education of
Children. Designed for the Use of Families and of Schools.
By WILLIAM JILLARD HORT,
Author of " The New Pantheon," &c.
In 22 Vols. 18mo. Sold together, hi a Case, Price 31. 13s. 6d. or separately.
19.
LECTURES ON THE ELEMENTS OF BOTANY,
Containing the Descriptive Anatomy of those Organs, on which the Growth and
Preservation of the Vegetable depend.
By ANTHONY TODD THOMSON, F.L.S.
Member of the Koyal College of Surgeons, &c. &c.
In 8vo. Price 11. 8s. Boards. Illustrated with Plates and numerous Wood-Cuts. Vol. I.
20.
THE SPEECHES OF
THE LATE RIGHT HONOURABLE HENRY GRATTAN.
Edited by his Son, HENRY GRATTAN, Esq.
In Four Volumes, Octavo. With a Portrait. Price 21. 8s. Boards.
21.
MISCELLANEOUS WORKS OF
THE RIGHT HONOURABLE HENRY GRATTAN.
In 8vo. Price 12s. Boards.