........mi Mm..............-linmiir

AS SHOWN BY INSTANTANEOUS PHOTOGRAPHY

WITH A STUDY ON ANIMAL MECHANICS

FOUNDED ON ANATOMY AND THE REVELATIONS
OF THE CAMERA

IN WHICH IS DEMONSTRATED THE THEORY OF QUADRUPEDAL LOCOMOTION

By J. D. B. STILLMAN, A.M., M.D.

EXECUTED AND PUBLISHED UNDER THE AUSPICES OF

BOSTON
JAMES R. OSGOOD AND COMPANY

Copyright, 1881,
By Leland Stanford.

University Press :
John Wilson and Son, Cambridge.

I have for a long time entertained the opinion that the accepted
theory of the relative positions of the feet of horses in rapid motion
was erroneous. I also believed that the camera could be utilized to
demonstrate that fact, and by instantaneous pictures show the actual
position of the limbs at each instant of the stride. Under this con-
viction I employed Mr. Muybridge, a very skilful photographer, to
institute a series of experiments to that end. Beginning with one,
the number of cameras was afterwards increased to twenty-four, by
which means as many views were taken of the progressive move-
ments of the horse. The time occupied in taking each of these
views is calculated to be not more than the five-thousandth part
of a second. The method adopted is described in the Appendix
to this volume.

When these experiments were made it was not contemplated to
publish the results; but the facts revealed seemed so important that
I determined to have a careful analysis made of them. For this
purpose it was necessary to review the whole subject of the loco-
motive machinery of the horse. I employed Dr. J. D. B. Stillman,
whom I believed to be capable of the undertaking. The result has
been that much instructive information on the mechanism of the
horse has been revealed, which is believed to be new and of suffi-
cient importance to be preserved and published.

The Horse in Motion is the title chosen for the book; for the
reason that it was the interest felt in the action of that animal that led
to the experiments, the results of which are here published, though
the interest wakened led to similar investigations on the paces and
movements of other animals. It will be seen that the same law
governs the movements of most other quadrupeds, and it must be
determined by their anatomical structure.

The facts demonstrated cannot fail, it would seem, to modify the
opinions generally entertained by many, and, as they become more
generally known, to have their influence on art.

Palo Alto Farm, California,
1881.

Introductory .............

The Horse considered as a Machine. � Necessity of understanding its Construc-
tion.� General Physiological and Anatomical Facts. � Architectural Prin-
ciples involved in the Construction of the Skeleton.� Of the Joints. �The
Vertebra. �The Cartilages and Ligaments.�The Muscles, Voluntary and
Involuntary. �General Facts, Anatomical, Physiological, and Mechanical,
regarding the Muscles. �Articular Ligaments. �Tendons. � The Law of
Repair in Muscles and Tendons.�Relation of the Form of Organs to their
Functions.�Utility made to conform to Beauty in the Form of Organized
Beings........................ ₂₂

Special Anatomy.�Necessity of Technical Terms.� The lib spinalis. � Defi-
nition of Terms. � Psoas magnus. � Iliacus.�Tensor Vaginae Femoris.�
Sartorius.�Pectineus, Small Adductor, etc. � Great Gluteus. � Deep Glu-
teus. � Long Vastus. � Semi-tendinosus. � Semi-membranosus. � Great Ad-
ductor.� Gracilis.� The Adduction and Abduction of Muscles. � Triceps
Femoris. � Gastrocnemii. � Automatic Action in the Hind Leg. � The Per-
forans and Perforatus Muscles and their Tendons. � Suspensory Ligament.�
Difficulties in the Way of determining the Amount of Work done by Muscles.

� Elongation and Contraction of the Limbs. � Interference and Stifle Ac-
tion.� The Action of the Hock Joint to prevent Interference.�The Order

of Action in the Various Muscles of the Posterior Extremity in Locomotion . 35

The Comparison of the Anterior Extremity to the Spokes of a Wheel considered.

� Its Three Characters of Crutch, Passive Tool, and Active Automaton.�
The Great Serratus. �Its Double Character of Tendon and Muscle.�
Centre of Motion.�The Trapesius and Yellow Cord. � Levator Anguli

Scapulae. � Trachelo subscapularis, its Function hitherto unknown. � The
Great Dorsal and Pectoral as Propellers. � The Mastoido humeralis as an
Extensor. �The Muscles of the Shoulder-Blade.�The Pair of Muscles that
flex the Shoulder. � The Function of the Triceps in resisting the Fall of the
Body and in Locomotion. � Function of the Flexors of the Forearm. � High
Action. � Obstacles to a Full Understanding of the Functions of the Loco-
motive Muscles removed by the Camera. � Analysis of the Movements of the
Anterior Extremity. � Mechanical Points desirable in a Horse for Speed or
Strength. � Low Centres of Motion. � Long Levers. � Comparison between
the Anterior and Posterior Extremities. � Why Quadrupeds rise from Recum-
bent Positions with Difficulty. � Why Boxers and Others liable to be placed
suddenly on the Defence have their Limbs semi-flexed. � Elements of
Speed.........................60

Influence of Gravity constant. � Momentum accelerated.�The Law of Falling
Bodies and its Application to Locomotion. � The nearer the Trajectory of the
Centre of Gravity is to a Straight Line the more perfect the Locomotion. �
The Theory of Quadrupedal Locomotion stated. � Analysis of the Run.�
The same in all the Domestic Animals. � The Bound of the Deer.�Why the
Flexor Tendons of the Fore Legs are more liable to be injured in the Run. �
What is the Gallop? �Objections of Artists answered. � Truth must prevail
over Conventionalism. � The Canter..............83

The Leap not properly a Pace. � Action in the Leap described.�The Danger
to be apprehended in the Leap. � The Standing Leap. � Correspondence in
the Action of the Horse in the Leap and the Deer in the Bound. � Action in
the Trot. � Distinction between a Step and a Stride. � The Difficulty to be
encountered in increasing the Speed of Trotters. � Difference in the Action in
the Trot and the Run. � Difficulty in restraining a Horse from breaking into
a Run explained. � Fast Trotting cultivated in America in Thoroughbreds. �
Trotting not Hereditary, but a Habit. � Theory and Mechanical Action in the
Trot. � The Action in Ambling, or "Pacing." � Definition of the Walk appli-
cable to Bipeds, not to Quadrupeds. � The Action in the Walk. � The Action
in the Pace known as Single-Foot...............105

CHAPTER VII.
Illustrations of the Paces..................118

I. Arrangement of the Cameras for taking the Illustrations

of the Paces (Hcliotypi)........... Frontispiece

II. Skeleton of the Horse, Reference Plate........ ₂6

III. Superficial Locomotive Muscles Exposed......... 36

IV. Deep Locomotive Muscles Shown........... 38

V. The Haunch, with the Great Vastus Removed...... 40

VI. Internal View of the Muscles of the Haunch...... 42

VII. Internal View of the Muscles of the Haunch, with the Sar-

torius and Gracilis Removed............ 42

VIII. The Deepest Muscles of the Haunch Exposed ...... 44

IX. Posterior View of the Muscles of the Haunch...... 46

X. View of the Posterior Extremity, showing Automatic Action

of the Hock and Stifle Joints........... 48

XI. Internal View of the Anterior Extremity........ 63

XII. Skeleton of the Horse in Running Positions....... 74

XIII. "Mohammed" Running {Heliotype)........... 9⁸

XIV. "Hattie H." Running............... 9^S

XV. "Florence A." Running.............. 9⁸

XVI. "Phryne" Running................ 9⁸

XVII. "Florence A." Running.............. 9⁸

XVIII. Greyhound Running.............

XIX. Greyhound Running............

XX. Two Hounds Running at Unequal Rates........ 9⁸

XXI. Ox Running................... ⁹

XXII. Steer Running.................. 9⁸

Vlll LIST OF PLATES.

XXIII. Deer Bounding................ 98

XXIV. Deer Bounding................ 98

XXV. Conventional Positions of Horses in Motion...... 102

XXVI. Conventional Positions of Hog and Deer Running . . . 102

XXVII. "Mohammed" Cantering............. 104

XXVIII. "Frankie" Leaping a Hurdle........... 106

XXIX. "Frankie" Leaping a Hurdle........... 106

XXX. "Phryne" Leaping............... 106

XXXI. "Phryne" Leaping............... 106

XXXII. "Phryne" after Leaping............. 106

XXXIII. "Phryne" after Passing the Hurdle........ 106

XXXIV. Standing Leap................. .106

XXXV. Skeleton of a Horse in Leaping Positions...... 106

XXXVI. "Edgerton" Trotting {Heliotype).......... 112

XXXVII. "Elaine" Trotting............... 112

XXXVIII. "Edgerton" Trotting.............. 112

XXXIX. "Clay" Trotting................ 112

XL. "Occident" Trotting.............. 112

XLI. Walk changing to a Trot............. 112

XLII. A Four-Months' Colt breaking from a Trot to a Run . . 112

XLIII. Break from a Trot to a Run........... n₂

XLIV. "Phryne" Unsettled.............. 112

XLV. "Hattie H." Unsettled............. 112

XLVI. Ox Trotting................. 112

XLVII. Boar Trotting................. 112

XLVIII. Skeleton of the Horse in Trotting Positions..... 112

XLIX. Horse Pacing, or Ambling............ 114

L. "Sharon" Walking............... 114

LI. Ox Walking.................. 114

LII. Cow Walking irregularly, being Driven....... 114

LIU. Boar Walking. (See Plate XLVII.)......... n₄

LIV. Horse Hauling................ 114

LV. Irregular Hauling............... 114

LVI. "Sharon," Single-Foot.............. 114

LVII.-CV. Illustrations of the Paces............ 118

CVI. View of the Twenty-four Cameras in Position {Heliotype) . 123

CVII. View of the Background and Arrangement for measuring

the Strides (Heliotype)............. 124

THE HORSE IN MOTION.

The Horse, of all animals, holds the most important relations to
the human family. Though the earliest traces of his existence on the
globe are found as fossils in North America, as an historical char-
acter he is traced to Central Asia with the Caucasian race. There
was no representative of the race living in America at the time of
the discovery of the New World, but it was introduced by Columbus
and his followers, and its descendants became feral on the Prairies
of North and the Pampas of South America. They were undoubt-
edly of Arabian stock, through the Moors; small, active, and hardy.
Their descendants were very numerous in what were the northern
provinces of Mexico, previous to the invasion of Texas.

The genera were well represented in Africa and the deserts of
Arabia, but we have no evidence that the historic horse was known
in Africa before the time of Rameses the Great, in the Eighteenth
Dynasty, after the wars with the Persians. Nowhere in all the tem-
ples and tombs of Memphis, Sais, Abydos, of the First Empire, is
there a sculpture that could lead us to infer that the horse was
known to the Egyptians of that early age. There are no sculptures
in India older than the dawn of Buddh, or about five centuries
before our era. The oldest written account of the horse is found in
the book of Job, and that is a very spirited description of a war-horse;
and it is probable that that is the oldest of the sacred writings of
the Hebrews, though there is no clew to the date or origin of that
curious production.

RAN GEM T.HE CAMERAS

THE HORSE IN MOTION.

Though the relative importance of the horse as a factor in the
progress of civilization has been reduced by the introduction of steam
in our century, it cannot be forgotten that he has been the con-
stant companion of the Caucasian race in all its migrations, an in-
dispensable ally in all its conquests, and the most efficient agent of
its civilization. We have no history that is not interwoven with his;
and if by some sudden cataclysm he should be eliminated, we should
then be made to realize how indispensable he still is to our business
and pleasure. Whatever concerns him will never cease to interest
mankind.

The interest in the paces of the horse is not new: it had engaged
the attention of philosophers from ancient times. Aristotle, the
father of Philosophy, thought it not unworthy his investigation; but
with all other rational questions, it was lost to human thought dur-
ing the long reign of religious bigotry. When the intellects of men
were again set free, and Science woke from her slumber, Anatomy
was studied and taught in the schools, and attention became directed
to that of our subject; but even Borelli, who wrote about two hundred
years ago, and published the work on Animal Mechanics that most
later writers have drawn upon, thought it necessary that he should
not confound flesh and muscle. Vital force was as yet unknown,
and all treated the subject as a physical science, and deduced its
laws from the motions of the pendulum, and mathematically formu-
lated them.

Two brothers, named Weber, who are quoted much by the author of
"Animal Motion," in the "Encyclopaedia of Anatomy and Physiology,"
followed Borelli on the purely physical theory of Animal Motion.

Professor Marey has contributed the result of many laborious and
painstaking experiments on the slow paces, by means of apparatus
attached to the feet, and connected by elastic tubes with registers in
the hands of the rider. This apparatus would determine the force
of the footfalls and time of pressure, and by the system of notation
a chart could be made of the paces. But it failed to interpret the
paces correctly, or furnish the basis of a theory of quadrupedal loco-
motion. The importance of the subject had been fully appreciated by

1, Cervical Vertebra. 2,l)orsal do,with their spines. 3.Limibar do.4, Sacrum. 5,Crest of the ilium or hip.6,Shafl of die ilium. 7 Tuberosities

of the ischium.. 8,Hip joint .9. Great trochanter, 10, 33 I rochonler. IL, Inner trochanter .12 ,Feirmr oifhjtfh hone. 13,External condyle. 14Jnternal

do.l5,Patella.]6,Stif]ejomt.l7,AnU�^

bones. 24, Ph stern hones. 25, Cuniforni bones and pastern orfetloch joint . 26,2dpasterns.27, Coffin hones. 28, Scapula andits spine. 29,

Coracoid process of the scapula. 30. Sliouldei joint .31. Bicipital ridge.32.Iktenraltubercle. 33, Sternum or breast bone. 34-, Hum ems or

shoulder bone, with furrow of torsion. 35, Elbow ox olecranon process. 36, Bicipital tuberosity for the insertion of biceps flexor. 37,

Radius or arm .38, Pisiform, bone. 39, External tuberosity of thehumeris .40, Cartilages of the ribs .41. The coupling.

THE HORSE IN MOTION. II

him, as appears in the following quotation from his work on Animal
Mechanics: "There is scarcely any branch of animal mechanics
which has given rise to more labor and greater controversy than the
question of the paces of the horse. The subject is of great impor-
tance to a large number of persons engaged in special pursuits, but
its extreme complexity has caused interminable discussion. Any one
who proposed at the present time to write a treatise on the paces of
the horse would have to discuss many different opinions put forward
by a great number of authors."

Bishop, the author of the article on "Animal Motion" in the

^ncyclopaedia of Anatomy and Physiology," says: "The study of

, ° ^wnich the locomotive organs of animals is com-

., I , ,^1G ^aws ^bv which their progression is accomplished, and of
the vital force whirl-, 4-1 , .

_int . ^lcn ^tney expend in propelling the body from one

alik tl another with different velocities, serves to interest

cian ¹T_a^anat0miSt ^and ^the physiologist, the artist and the mechani-
deli" .^gn°^rance ^of ^these laws has been productive of grotesque
meations of the human figure as well as of the lower animals, when
represented in motion. We have abundant evidence of this in the

Pro uctions of painters and sculptors, both of the ancient and modern
world.

e difficulty in this, as in many controverted questions, is to
^etermme the facts; and the facts have been most difficult to obtain,
t seems to many unaccountable, that the horse, whose movements
re so open, should play such a l'eger-de-pied as to deceive all eyes,
and give rise to controversies as earnest as did the colors of the cha-
meleon in the fable. All attempts hitherto made to analyze these
movements have failed, for it is not possible for the eve to distinguish

">em; or rather, to state the case more accurately, the mind is unable
to distinguish the impressions conveyed to it through the eye.

Controversies were going on to the last as to which foot was ad-
vanced first in the trot; whether the toe or heel first touched the
ground; whether in a gallop the legs were stretched out fore and aft,
or the knees were flexed. All were dabbling in the shallow waters
of a sea whose depths there was no known method of exploring, and

THE HORSE IN MOTION.

artists of all degrees fell into the false and conventional manner of
representing animals in rapid motion, as untrue as were the Greek
conceptions on the subject thirty centuries ago. To understand how
little progress has been made in modern times, it is only necessary to
look at the productions of the best animal painters of our day.

Why is it that there have been such widely different interpre-
tations of these movements from the time of Aristotle down to the
present? These positions, as well as all others that have been rep-
resented, are proved by the unerring finger of light to be incorrect;
as mechanical anatomy, had it been properly consulted, would have
demonstrated to be impossible.

It is difficult at a glance to conceive how the eye could be so
deceived; but a little consideration of the physiology of that organ
will teach us that no dependence can be placed on it to interpret the
motion of an object moving irregularly, even at a comparatively slow
rate of speed.

It has been shown that the retina of the eye is capable of receiv-
ing a distinct image of an object in an almost inconceivably short
space of time, as that of the flash of an electric spark, or a millionth
part of a second, and that the impression remains for the space of a
third to a seventh of a second, according to the experiments of D'Arcy
and Plateau ; and the mind is incapable of distinguishing between
the first impression and the last made during that space of time, and
the images run together and are confused. A familiar illustration of
this phenomenon is furnished by the spokes of a wheel in motion; yet
these spokes will appear stationary, if, revolving in the dark, they are
suddenly illuminated by an electric flash; or if the end of a stick be
ignited, and moved rapidly, a continuous line of fire will appear. Here
there is a continuous line of impressions made upon the retina, and so
conveyed to the mind. The same is true of the auditory nerve; when
vibrations of air are too rapid, they are heard, but not distinguished.
The reader may ask why it is that the artists of all time, with the full
accord of all men, � and our own eyes confirm the tradition,� represent
the horse in galloping as extending his feet to the utmost, as seen in
all the pictures of horses racing. My answer is this: We now know

THE HORSE IN MOTION.

that it is not true that a horse ever did put himself in the position
portrayed by the best artists; and the explanation that I have to offer
is, that in the gallop the horse always moves his feet alternately, and
to the same extent; at the limit of extension there is a change of
direction given to them, and their image dwells longer upon the retina,
and the impressions are more lasting than of the intermediate and
more rapid movements which the mind is unable to distinguish any
more than the order in which they are made.

The ear has been relied upon to determine by the rhythm of the
footfalls the order in which the feet strike the ground; and bells have
been attached to the feet, each giving a different sound. Others have
studied the footprints, and the feet have been differently shod to dis-
tinguish the impression made by each foot upon the ground.

The study of the mechanical anatomy of the horse is a necessity in
order to a proper understanding of the forces employed and their
combined action. This necessity has now become more imperative,
as the action is better understood from the revelations of the camera.

All the systematic works on the anatomy of the horse have followed
the plan of those on human anatomy, and apparently for the same pur-
pose, namely, the intelligent treatment of the diseases and accidents to
which horses, as well as men, are liable, while the action and relation
of the machine, as such, have been treated as of secondary importance
or altogether neglected. It has not been possible to study the action
of the muscles singly without falling into errors ; the correlation of
all of them is necessary to the understanding of any one. It is to this
cause that so many errors and contradictions found in all authorities
that have been consulted are to be ascribed. Indeed, how was it pos-
sible that it should have been otherwise, so long as it was not known
what those actions were ?

The progressive motions of a quadruped, which must be considered
as a unit, are very complex; when so studied it will be found that all
the parts are mutually dependent, that the forces employed are com-
pound and often indirect, and that the compensation of one indirect
action may be found quite remote. When thus considered it will be
found that the horse in motion is as perfectly harmonious in the dis-

THE HORSE IN MOTION.

play of his forces and their balance as a steam hammer, which may be
adjusted to a force sufficient to forge a shaft for an ocean steamer or
to crack a nut.

It cannot be expected that many of those persons who are inter-
ested in the movements of the horse will be familiar with the anatomi-
cal terms necessary to be used in the description of the simplest
motion, and it cannot be made intelligible without them; much less
can it be expected that one will be able to comprehend a full stride
from any analysis that can be given without such knowledge.

The writer thinks himself warranted in the assertion that the correct
interpretation of the mechanical action of the horse cannot be obtained
from any existing work. It is very desirable that it should be under-
stood by every one who is interested in his achievements, and by artists
as well. To facilitate this study, technical terms will be omitted as far
as possible, and where they are employed they will be accompanied by
popular ones as far as they are known.

One of the sources of difficulty to the non-professional student is
the distinctive names given to different tissues whose mechanical
function is the same. Whether a muscle has its termination in facia
aponeurosis or at the bone on which it acts, either directly or in-
directly, may be important to the anatomist or surgeon; but to those
who desire to understand the mechanical action it is a matter of indif-
ference, very perplexing, and a fatal bar to the comprehension of the
subject; to such it is of little consequence whether the action is direct
by muscular attachments to bones, or indirect through facia or other
fibrous tissue. In all cases I shall use such terms as will most cor-
rectly give my meaning in the interpretation of their action.

Another source of confusion in the study of the muscles of mo-
tion in quadrupeds is the conflicting names given to them. When,
on the restoration of the cultivation of science, comparative anatomy
began to attract the attention of naturalists, human anatomy had
already received much attention, and names had been bestowed upon
all the principal organs. Some of them were purely fanciful; others
were -based on their resemblance to other objects. The muscles were
often named from their supposed function, or their correspondence to

THE HORSE IN MOTION.

muscles found in the human body. This last has been the most fruit-
ful source of confusion, and the mind of the student is constantly
biassed by this correspondence of names to muscles that do not have
corresponding functions. It may be taken for granted that organs
have the same diversity of form in man and animals as there is
diversity of function, and in each the organisms are just such as best
serve the offices which they were designed to perform. Some of the
later authorities have attempted a reform in the nomenclature of the
muscles, based on their supposed uses, and have only added to the pre-
vious confusion. Adductors and abductors have been so multiplied
that it would seem that a horse, like a crab, was made to go sidewise.

Anatomy will be treated no further than is necessary to demonstrate
locomotion; and those who would pursue it further, and those who
would be more minute in their knowledge of structure, must dissect
for themselves.

The writer has already had occasion to allude to design, and will
have frequent necessity for doing so in describing the complicated
mechanism by means of which locomotion in the higher orders of
animals is effected, and he wishes it understood that he uses that term
in its literal and highest signification. He does not shrink from the
use of terms that imply an intelligent Creator and all-pervading Spirit,
who, from the beginning, established the foundations of the earth, and
who, in incomprehensible wisdom and power, has fixed the laws which
govern the organic world from the beginning through all its changes.

In using the term " higher orders of animals," he follows custom. If
that distinction is founded on the complexity of his locomotive powers
or organization, then man could not justly claim the first rank; for if
his preservation had depended upon his speed in locomotion, he would,
in the long struggle for life through which he must have passed, have
taken his place in the earliest paleon-tological deposits.

It may seem presumptuous to compare objects, the lowest of which
are beyond our comprehension. The finite cannot comprehend the
infinite; there must be a limit, in the nature of things, to all inquiry
into the phenomena of life. If physical science could determine the
laws of that which is hyperphysical, then to its court we might

US ATSTD GRACILIS "MUSCLES REMOTED.

THE HORSE IN MOTION.

carry all cases involving ethical or aesthetical questions, and form
might be confounded with color. To this pons asinomm all the old
writers on animal mechanics came. They would test vital force by the
laws governing the motion of the pendulum or those of gravity. If
physical science could establish the laws and solve all the questions
that arise in the investigation of vital phenomena, and algebraic expres-
sions could represent the unknown quantities, the task would be easy.
We could calculate the force of the right arm of a warrior as we could
the weight of his sword; but when that arm descends, it falls with
more than the force of gravity. There is a power that must enter into
all our estimates of vital force, and that is the will. It cannot be
ignored in any calculation on animal motion ; and yet who can estimate
it, weigh it, and formulate it, as in the exact sciences?

Thomas Starr King used to tell a story of a countryman who
attracted the attention of a traveller by the fine physical development
he displayed, and of whom he inquired his weight. " Well, stran-
ger," said he, " ordinarily I weigh two hundred and thirty pounds, but
when I am mad I weigh a ton."

The progress that science has made in every department, and is
still making, is wonderful, and who can say where it will end ? But in
the knowledge of the laws which govern the origin of life, the vital
organs and their functions, of the nature of that force by which one
form becomes altered or modified by the altered conditions of its life,
it has made no progress since the days of Job.

The whole question of life and vital force is still a great mystery,
although it is receiving; at this time the concentrated attention of the
most intelligent naturalists of all nations. There are not many who
deny that organic forms may be modified within certain limits by arti-
ficial means. There are many who believe that all organic beings, of
whatever nature, had their origin in the most rudimentary element, as
a cell possessing certain inherent tendencies to develop by aggregation
into other and higher forms, unequally modified in various ways by
surrounding influences, with a tendency to variation by imperceptible
degrees in every direction, the useful variations favoring the existence
of the individuals possessing them. This idea has become familiar

E S : ;- . H E HAUNCH.

THE HORSE IH MOTION.

under the terms " natural selection" and " survival of the fittest." This
hypothesis does not presuppose design, and denies a Creator. Under
the name of " Darwinism" it has become popular and invaded all ranks.
It found the soil of Germany especially fitted for the propagation of a
theory of such an atheistic character, and it was proposed at a meeting
of the Society of Naturalists at Munich, a few years ago, to teach it in
the national schools. It has become so generally diffused in our own
scientific circles that a reference to a Supreme Being in an essay read
before a society of naturalists would be considered to be a poetic license,
if one had the courage to make it; and nature is usually personified to
meet the necessity. We have long been familiar with the reference to
the laws of nature, and we now begin to hear of the laws of evolution.
In all ages there has been a tendency on the part of the masses to
follow some leader whom they desired to do their thinking for them;
to pin their faith to his, or what they supposed to be his: it is no less
so in the scientific circles than in the religious. Dogmatism seems to
be leaving the latter to attach itself to the former; at all events, it is
inherent in the human mind; no person is utterly free from it; and to
appeal to the opinions of those whom we believe to be better informed,
rather than to examine the foundations of those opinions, has been
the vice of all ages.

It is well known that faculties and functions are strengthened
by use and weakened, or altogether lost, by disuse. We shall look
in vain for proofs of an organ changed in the mechanical principle
of its construction, or one evolved by imperceptible degrees where
none existed before; but we shall, on the other hand, find proofs
in anatomy that the changes could not have been gradual. Every
stable-boy knows that qualities are transmitted by heredity, and that
desirable ones may be bred by judicious crossing within certain lim-
its ; and he knows as much as any one of the force, or influence, by
means of which this is brought about. Speculation should not be con-
founded with science, as was said by Virchow, or science will lose its
claim to the respect of mankind; and this whole question of evolution
is speculative when carried beyond proof; and science, when it crosses
the vital boundary-line, is lost in speculation. We know that organic

E VIEW OF THE MUSCLES OF THE

l~hz.~H$>J.c±y_nePrinting Co,2UTrvmarU ..■

THE HORSE IN MOTION.

matter is subject to physical laws like other matter: it is attracted
by the earth, and will fall with a force as great as if it were inanimate,
and is equally subject to the law of falling bodies; it acquires mo-
mentum, and its momentum is equal to the weight multiplied by
the velocity, the same as that of a railway-car, or a cannon-shot;
and when vitality leaves it, it is resolved to its original elements,
oxygen, carbon, etc., which the chemist can prove by analysis. But
has the most skilful chemist ever been able by synthesis to restore
the lost element, the vital spark? Has he ever been able to imitate
the products of that vital laboratory the stomach, and form the
aliment that replenishes the blood?

With all the knowledge of physics ever acquired by man, can he
make a pump so perfect as the heart, � that organ that forces the
blood loaded with fresh sustenance to every part of the body ? And
what does he know of that power that has kept it in alternate action
and rest every instant since before the earliest memories of his child-
hood ?

He has been familiar with the laws of optics for centuries, and has
made instruments of glass and metal, in imperfect imitation of the eye
of an animal, to exalt the powers of his own vision; but what would
not an optician give to be able to construct a concentric achromatic
lens, with automatic power to adapt itself to the distance of objects,
such as the eye of the lowest of the vertebrates ?

Acoustics is another of the physical sciences of which man is a pro-
fessor, and he has just invented an instrument by means of which he
can communicate in ordinary vocal sounds to a person miles distant.
He has recently invented another, by which he can register and pre-
serve the intonations of his voice to be returned to him at will at any
future time; but that most wonderful instrument, the ear, he can only
wonder at and admire. Without it the world would be without music,
voice, or sound; the faculty of speech, our consciousness, memory,
imagination, affection � but it is needless to multiply this class of
facts. In nothing does man show himself to be the creation of an
intelligent power more than in his own creative faculty. How great
have been his achievements in mechanics! But what comparison does

THE HORSE IN MOTION.

the highest bear to the locomotive apparatus or machinery of the horse,
with its compound system of levers, pulleys, tendons, springs, and mus-
cular powers, and that marvellous ingenuity in arrangement to produce
results which man has not been able to understand until now, and all
set in motion through telegraphic communication distributed to every
muscular fibre, and the whole of this complicated system of organs
co-ordinated and controlled by one central will ? Another incompre-
hensible mystery of life is, that this complicated machine should pos-
sess the power, not only to preserve and protect itself through a long
life, but of reproducing from generation to generation indefinitely,
and transmitting to posterity its own peculiarities of form and mental
qualities !

Does the whole organic world furnish no proofs of intelligence and
design, that we must be told that all these marvellous manifestations of
both are but the inherent properties of matter,

" And that were true which nature never told " ?

If it were an " attainment and an aim " to escape moral responsibility
by getting rid of a creator, do we approach any nearer the solution
of the question of the origin of life by removing it farther off into the
mytho-geologic eras ? Or is the difficulty in any way diminished by
attributing to matter all the high intellectual functions that have been
by unschooled people in all ages ascribed to supernatural powers ?

Can the microscopist, when he discovers vibriones in a vegetable
infusion, or protoplasm in a drop of serum, be excusable for running
naked, like the philosopher of Syracuse, through the streets, shouting
" Eureka"? Can one who finds a shingle or a brick claim that he has
discovered the cause of a house ? Let him account for the origin of the
brick and the shingle /

Because a fossil skeleton of a four-toed horse, which failed to con-
nect his species with our time, has been found in the fossiliferous
deposits of the interior of this continent, does it follow, that our noble
soliped had an origin less remote and independent, or that he found
it necessary and practicable to concentrate his four toes into one, or
succumb to the altered conditions of his life ?

INTEHNAL VIEW OF THE ANTERIOR EX REMITS

THE HORSE IN MOTION.

All science, in whatever department of knowledge, is retarded much
by the ignorance and zeal of the multitude who follow on the heels of
genius. Medicine has its mountebanks, who are dragging a noble
science into public contempt; religion has its harlequins, and natural
science its buffoons, who, as itinerant lecturers, perambulate the towns
as representatives of learning they do not possess, and put forth as
proved truth the wildest speculations of enthusiasts, and call them sci-
ence. It is very common to hear of the origin of man from the ape,
as if the relation were a scientific truth, when in fact it is only a specu-
lation ; and all the evidence so far collected from fossil remains as early
as the tertiary deposits gives no confirmation to the speculation. As
far away as any trace of the prehistoric man has been found, he was as
perfectly developed as he is to-day, and as far removed from the ape.

Darwin is not responsible for what is known as Darwinism. He
is a model for a naturalist, collecting facts and placing them in their
relation, drawing his conclusions cautiously, and candidly admitting the
difficulty when a fact antagonizes the hypothesis he is framing. Not
so with his zealous disciples, who rush to their desired conclusions
over his facts, as the fanatical Christians of Alexandria did over the
last vestal altar of Greek philosophy.

Organic life is the result either of chance or design; there can be
no middle ground.* If the latter, the question of how it was brought
about will never be solved by man, nor is it important that it should be.
It is sufficient that a Supreme Intelligent Will is the author and sus-
tainer of all, � a beneficent Spirit, who

* Virchow, who will be recognized as one of the leaders in the new departure in science and
the cell theory of development, says : �

" This much is evident. If I do not choose to accept a theory of creation, if I refuse to be-
lieve that there was a special Creator who took the clod of earth and breathed into it the breath
of life, if I prefer to make for myself a verse after my own fashion, then I must make it in the
sense ofgeneratio equivoca (spontaneous generation). Tertiam non dalur. No alternative re-
mains when once we say, ' I do not accept creation, but I will have an explanation.' If that first
thesis is laid down, you must go on to the second thesis, and say, ' Ergo, I assume the generatio
equivoca.' But of this we do not possess any actual proof. No one has ever seen a generatio
equivoca really effected ; and whoever supposes he has is contradicted by the naturalist, and not
merely by the theologian." � Prof. Virchow, in a lecture delivered before the German Asso-
ciation of Naturalists and Physicians at Munich, 1877.

THE HORSE IN MOTION. ₂ _t

"Warms in the sun, refreshes in the breeze,
Glows in the stars, and blossoms in the trees,
Lives through all life, extends through all extent,
Spreads undivided, operates unspent " ;

who has endowed us with faculties to admire the beautiful, the good
and true, to know why so many things are as we see them, but none to
know how*

Having give,, _some of the reasons for his belief in the spiritual ori-
gin of the orgamc world, the writer claims his right, whenever he has
occasron m the following pages to do so, to speak, without danger o
berng m.sunderstood, of design or contrivauee in the same sense tha
he would when referring to similar manifestations of design i�_ahumanly constructed machine ^g ^a

tio^t^^r¹;;;;:': sr r^pression ^of ^the -^ - -

due time rest sailed ^ ** ** *»**«* ^ «* »

been ^^1^^!^^ ^^ ^^ * ^US ^th�Z^h ^a11 P^notnena, has
that, on the one hand s'h _a _Do ^eVentUa"^y *** *» ^to Actions. The certainty

�ion, and is bevon _m 1 ^? f""* ^ °* ^ °^th" ^^d '* nature transcends in J

beenp_ro_gress r^^S;;_B^ai;ⁿ''^S ^ ^^ Awards which intelligence has f_rom the first

« When th" k '^CER' ^FirH ^Prind^ ^2d "®*�> P- '08.

in mind Z! "* '" ^ ^^ "* ^^ "neously change is borne

the stranop , i � T wonderful contrivances of orchids, of mimicry, and

e strange complexity of certain instinctive actions, are considered, then the conviction forces

on many _minds that the organic world is the expression of an intelligence of some kind.

on the XoT "^atUre ^the" ^SPeakS ^dearly ^l0 ^many ^mindS °^f ^the ^aCti°ⁿ °^f ³ⁿ ^intelliS^ence resulting,
e vi e and in the main, in order, harmony, and beauty, vet of an intelligence the ways of
wmch are not as our ways." _ St. G. Mivart, F. R. S, in Genesis of S_Peeies, pp. 272, 273.

^ There is something in organic progress which mere natural selection among spontaneous
variations will not account for; this something is that organizing intelligence which guides the
action of the inorganic forces, and forms structures which neither natural selection nor any
other unintelligent agency could form." � Murphy, Habit and Intelligence, Vol. I. p. 348.

MO HAMMED,- RUNNING. STRIDE, 15 FT , 9 IN.

The Horse considered as a Machine. � Necessity or understanding its Con-
struction.� General Physiological and Anatomical Facts.� Architectural
Principles involved in the Construction of the Skeleton. � Of the Joints.
� The Vertebra. � The Cartilages and Ligaments. � The Muscles, Volun-
tary and Involuntary. � General Facts, Anatomical, Physiological, and
Mechanical, regarding the Muscles. � Articular Ligaments. � Tendons. �
The Law of Repair in Muscles and Tendons. � Relation of the Form of
Organs to their Functions. � Utility made to conform to Beauty in the
Form of Organized Beings.

It is proposed to present as concise a view of the locomotive
organs of the horse as may be consistent with a proper knowledge of
the parts, and the functions they perform in progressive motion.

There can be no just appreciation of the qualities of a complicated
machine without a comprehensive understanding of its construction,
and the manner in which each of its parts acts to produce the com-
pound movement for which it was designed. So, in order to under-
stand the paces of the horse, we must understand the action of all
the parts of the machinery by which they are produced. It need
not be said that it is very complex, and has never been understood,
for the reason that the motions themselves have been altogether mis-
interpreted.

This study of the mechanism of the horse is a necessity which will
become apparent to any one who undertakes to analyze these move-
ments by the aid of any manual of anatomy yet published. The dis-
tinction of muscles into adductors, abductors, extensors, and flexors
gives a very inadequate idea, and sometimes a very erroneous one, of
the action of the muscles to which those terms are applied, as well as
to their general agency in locomotion. In fact, these terms are used
to express the action abstractly with reference to the bones to which

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	CONTENTS.

		CHAPTER I.

			PAGE 9
Introductory .............


CHAPTER II. The Horse considered as a Machine. � Necessity of understanding its Construc- tion.� General Physiological and Anatomical Facts. � Architectural Prin- ciples involved in the Construction of the Skeleton.� Of the Joints. �The Vertebra. �The Cartilages and Ligaments.�The Muscles, Voluntary and Involuntary. �General Facts, Anatomical, Physiological, and Mechanical, regarding the Muscles. �Articular Ligaments. �Tendons. � The Law of Repair in Muscles and Tendons.�Relation of the Form of Organs to their Functions.�Utility made to conform to Beauty in the Form of Organized Beings........................ ₂₂ CHAPTER III. Special Anatomy.�Necessity of Technical Terms.� The lib spinalis. � Defi- nition of Terms. � Psoas magnus. � Iliacus.�Tensor Vaginae Femoris.� Sartorius.�Pectineus, Small Adductor, etc. � Great Gluteus. � Deep Glu- teus. � Long Vastus. � Semi-tendinosus. � Semi-membranosus. � Great Ad- ductor.� Gracilis.� The Adduction and Abduction of Muscles. � Triceps Femoris. � Gastrocnemii. � Automatic Action in the Hind Leg. � The Per- forans and Perforatus Muscles and their Tendons. � Suspensory Ligament.� Difficulties in the Way of determining the Amount of Work done by Muscles. � Elongation and Contraction of the Limbs. � Interference and Stifle Ac- tion.� The Action of the Hock Joint to prevent Interference.�The Order of Action in the Various Muscles of the Posterior Extremity in Locomotion . 35 CHAPTER IV. The Comparison of the Anterior Extremity to the Spokes of a Wheel considered. � Its Three Characters of Crutch, Passive Tool, and Active Automaton.� The Great Serratus. �Its Double Character of Tendon and Muscle.� Centre of Motion.�The Trapesius and Yellow Cord. � Levator Anguli



		PL ATI VI]

'^ERNAiVlEw OF THE
'^ERNAiVlEw OF THE

	US ATSTD GRACILIS "MUSCLES REMOTED.
	US ATSTD GRACILIS "MUSCLES REMOTED.



	THE HORSE IH MOTION.
	THE HORSE IH MOTION.	17
		17

under the terms " natural selection" and " survival of the fittest." This hypothesis does not presuppose design, and denies a Creator. Under the name of " Darwinism" it has become popular and invaded all ranks. It found the soil of Germany especially fitted for the propagation of a theory of such an atheistic character, and it was proposed at a meeting of the Society of Naturalists at Munich, a few years ago, to teach it in the national schools. It has become so generally diffused in our own scientific circles that a reference to a Supreme Being in an essay read before a society of naturalists would be considered to be a poetic license, if one had the courage to make it; and nature is usually personified to meet the necessity. We have long been familiar with the reference to the laws of nature, and we now begin to hear of the laws of evolution. In all ages there has been a tendency on the part of the masses to follow some leader whom they desired to do their thinking for them; to pin their faith to his, or what they supposed to be his: it is no less so in the scientific circles than in the religious. Dogmatism seems to be leaving the latter to attach itself to the former; at all events, it is inherent in the human mind; no person is utterly free from it; and to appeal to the opinions of those whom we believe to be better informed, rather than to examine the foundations of those opinions, has been the vice of all ages. It is well known that faculties and functions are strengthened by use and weakened, or altogether lost, by disuse. We shall look in vain for proofs of an organ changed in the mechanical principle of its construction, or one evolved by imperceptible degrees where none existed before; but we shall, on the other hand, find proofs in anatomy that the changes could not have been gradual. Every stable-boy knows that qualities are transmitted by heredity, and that desirable ones may be bred by judicious crossing within certain lim- its ; and he knows as much as any one of the force, or influence, by means of which this is brought about. Speculation should not be con- founded with science, as was said by Virchow, or science will lose its claim to the respect of mankind; and this whole question of evolution is speculative when carried beyond proof; and science, when it crosses the vital boundary-line, is lost in speculation. We know that organic 3



				PLATE JOV.

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			2* 2S 2C 27 ES 29 30 3> 28 �9 30 31 3i 33 34- :I3 »6
			2* 2S 2C 27 ES 29 30 3> 28 �9 30 31 3i 33 34- :I3 »6

		HA.TTIE H.EUNNING, STRIDE, 19 FT. 6 TKT.



			PLATE XVI.



	db4BgMg ^MhUBt a^\|w Jkd^mw j^Nfldl^^ jfl^jimiBir Vi^-j. ;^.?a i.\.\s '^ivVii.^ vSwWK V&wijifcw^ rfii?.v^.u.^v ^fcOTirs^i

-pff* ~jAr ^tAE nnkf jAT jAT "fctViiii.¹^ Viffv--Ui.>.^,,'^p- .ibiv^Uv '-/&4/JJL Jk* ittC- V//-^'. Av.i^; Vss^rxtx^ ^MMJsJIbP^ ^fMMljV^ ^g^JH^^ jJMl�rfBMnB M^¹ «^^JH^ «^BwrfHaBl^^'**

		PHRYNE L.� RUNNING,STRIDE, 19 FT, 9 IN.



			PREFACE.

		I have for a long time entertained the opinion that the accepted theory of the relative positions of the feet of horses in rapid motion was erroneous. I also believed that the camera could be utilized to demonstrate that fact, and by instantaneous pictures show the actual position of the limbs at each instant of the stride. Under this con- viction I employed Mr. Muybridge, a very skilful photographer, to institute a series of experiments to that end. Beginning with one, the number of cameras was afterwards increased to twenty-four, by which means as many views were taken of the progressive move- ments of the horse. The time occupied in taking each of these views is calculated to be not more than the five-thousandth part of a second. The method adopted is described in the Appendix to this volume. When these experiments were made it was not contemplated to publish the results; but the facts revealed seemed so important that I determined to have a careful analysis made of them. For this purpose it was necessary to review the whole subject of the loco- motive machinery of the horse. I employed Dr. J. D. B. Stillman, whom I believed to be capable of the undertaking. The result has been that much instructive information on the mechanism of the horse has been revealed, which is believed to be new and of suffi- cient importance to be preserved and published.



VI CONTENTS. PAGE Scapulae. � Trachelo subscapularis, its Function hitherto unknown. � The Great Dorsal and Pectoral as Propellers. � The Mastoido humeralis as an Extensor. �The Muscles of the Shoulder-Blade.�The Pair of Muscles that flex the Shoulder. � The Function of the Triceps in resisting the Fall of the Body and in Locomotion. � Function of the Flexors of the Forearm. � High Action. � Obstacles to a Full Understanding of the Functions of the Loco- motive Muscles removed by the Camera. � Analysis of the Movements of the Anterior Extremity. � Mechanical Points desirable in a Horse for Speed or Strength. � Low Centres of Motion. � Long Levers. � Comparison between the Anterior and Posterior Extremities. � Why Quadrupeds rise from Recum- bent Positions with Difficulty. � Why Boxers and Others liable to be placed suddenly on the Defence have their Limbs semi-flexed. � Elements of Speed.........................60 CHAPTER V. Influence of Gravity constant. � Momentum accelerated.�The Law of Falling Bodies and its Application to Locomotion. � The nearer the Trajectory of the Centre of Gravity is to a Straight Line the more perfect the Locomotion. � The Theory of Quadrupedal Locomotion stated. � Analysis of the Run.� The same in all the Domestic Animals. � The Bound of the Deer.�Why the Flexor Tendons of the Fore Legs are more liable to be injured in the Run. � What is the Gallop? �Objections of Artists answered. � Truth must prevail over Conventionalism. � The Canter..............83 CHAPTER VI. The Leap not properly a Pace. � Action in the Leap described.�The Danger to be apprehended in the Leap. � The Standing Leap. � Correspondence in the Action of the Horse in the Leap and the Deer in the Bound. � Action in the Trot. � Distinction between a Step and a Stride. � The Difficulty to be encountered in increasing the Speed of Trotters. � Difference in the Action in the Trot and the Run. � Difficulty in restraining a Horse from breaking into a Run explained. � Fast Trotting cultivated in America in Thoroughbreds. � Trotting not Hereditary, but a Habit. � Theory and Mechanical Action in the Trot. � The Action in Ambling, or "Pacing." � Definition of the Walk appli- cable to Bipeds, not to Quadrupeds. � The Action in the Walk. � The Action in the Pace known as Single-Foot...............105 CHAPTER VII. Illustrations of the Paces..................118

	Appendix
	Appendix	123
		123



			LIST OF PLATES.

		PAGE I. Arrangement of the Cameras for taking the Illustrations of the Paces (Hcliotypi)........... Frontispiece II. Skeleton of the Horse, Reference Plate........ ₂6 Colored ©raftings. III. Superficial Locomotive Muscles Exposed......... 36 IV. Deep Locomotive Muscles Shown........... 38 V. The Haunch, with the Great Vastus Removed...... 40 VI. Internal View of the Muscles of the Haunch...... 42 VII. Internal View of the Muscles of the Haunch, with the Sar- torius and Gracilis Removed............ 42 VIII. The Deepest Muscles of the Haunch Exposed ...... 44 IX. Posterior View of the Muscles of the Haunch...... 46 X. View of the Posterior Extremity, showing Automatic Action of the Hock and Stifle Joints........... 48 XI. Internal View of the Anterior Extremity........ 63 XII. Skeleton of the Horse in Running Positions....... 74 XIII. "Mohammed" Running {Heliotype)........... 9⁸ XIV. "Hattie H." Running............... 9^S XV. "Florence A." Running.............. 9⁸ XVI. "Phryne" Running................ 9⁸ XVII. "Florence A." Running.............. 9⁸ XVIII. Greyhound Running............. XIX. Greyhound Running............ XX. Two Hounds Running at Unequal Rates........ 9⁸ XXI. Ox Running................... ⁹ XXII. Steer Running.................. 9⁸



		Vlll LIST OF PLATES. PAGE XXIII. Deer Bounding................ 98 XXIV. Deer Bounding................ 98 XXV. Conventional Positions of Horses in Motion...... 102 XXVI. Conventional Positions of Hog and Deer Running . . . 102 XXVII. "Mohammed" Cantering............. 104 XXVIII. "Frankie" Leaping a Hurdle........... 106 XXIX. "Frankie" Leaping a Hurdle........... 106 XXX. "Phryne" Leaping............... 106 XXXI. "Phryne" Leaping............... 106 XXXII. "Phryne" after Leaping............. 106 XXXIII. "Phryne" after Passing the Hurdle........ 106 XXXIV. Standing Leap................. .106 XXXV. Skeleton of a Horse in Leaping Positions...... 106 XXXVI. "Edgerton" Trotting {Heliotype).......... 112 XXXVII. "Elaine" Trotting............... 112 XXXVIII. "Edgerton" Trotting.............. 112 XXXIX. "Clay" Trotting................ 112 XL. "Occident" Trotting.............. 112 XLI. Walk changing to a Trot............. 112 XLII. A Four-Months' Colt breaking from a Trot to a Run . . 112 XLIII. Break from a Trot to a Run........... n₂ XLIV. "Phryne" Unsettled.............. 112 XLV. "Hattie H." Unsettled............. 112 XLVI. Ox Trotting................. 112 XLVII. Boar Trotting................. 112 XLVIII. Skeleton of the Horse in Trotting Positions..... 112 XLIX. Horse Pacing, or Ambling............ 114 L. "Sharon" Walking............... 114 LI. Ox Walking.................. 114 LII. Cow Walking irregularly, being Driven....... 114 LIU. Boar Walking. (See Plate XLVII.)......... n₄ LIV. Horse Hauling................ 114 LV. Irregular Hauling............... 114 LVI. "Sharon," Single-Foot.............. 114 LVII.-CV. Illustrations of the Paces............ 118 CVI. View of the Twenty-four Cameras in Position {Heliotype) . 123 CVII. View of the Background and Arrangement for measuring the Strides (Heliotype)............. 124



			THE HORSE IN MOTION.

		CHAPTER I. INTRODUCTORY. The Horse, of all animals, holds the most important relations to the human family. Though the earliest traces of his existence on the globe are found as fossils in North America, as an historical char- acter he is traced to Central Asia with the Caucasian race. There was no representative of the race living in America at the time of the discovery of the New World, but it was introduced by Columbus and his followers, and its descendants became feral on the Prairies of North and the Pampas of South America. They were undoubt- edly of Arabian stock, through the Moors; small, active, and hardy. Their descendants were very numerous in what were the northern provinces of Mexico, previous to the invasion of Texas. The genera were well represented in Africa and the deserts of Arabia, but we have no evidence that the historic horse was known in Africa before the time of Rameses the Great, in the Eighteenth Dynasty, after the wars with the Persians. Nowhere in all the tem- ples and tombs of Memphis, Sais, Abydos, of the First Empire, is there a sculpture that could lead us to infer that the horse was known to the Egyptians of that early age. There are no sculptures in India older than the dawn of Buddh, or about five centuries before our era. The oldest written account of the horse is found in the book of Job, and that is a very spirited description of a war-horse; and it is probable that that is the oldest of the sacred writings of the Hebrews, though there is no clew to the date or origin of that curious production.



				PLATE II

		1, Cervical Vertebra. 2,l)orsal do,with their spines. 3.Limibar do.4, Sacrum. 5,Crest of the ilium or hip.6,Shafl of die ilium. 7 Tuberosities of the ischium.. 8,Hip joint .9. Great trochanter, 10, 33 I rochonler. IL, Inner trochanter .12 ,Feirmr oifhjtfh hone. 13,External condyle. 14Jnternal do.l5,Patella.]6,Stif]ejomt.l7,AnU�^ bones. 24, Ph stern hones. 25, Cuniforni bones and pastern orfetloch joint . 26,2dpasterns.27, Coffin hones. 28, Scapula andits spine. 29, Coracoid process of the scapula. 30. Sliouldei joint .31. Bicipital ridge.32.Iktenraltubercle. 33, Sternum or breast bone. 34-, Hum ems or shoulder bone, with furrow of torsion. 35, Elbow ox olecranon process. 36, Bicipital tuberosity for the insertion of biceps flexor. 37, Radius or arm .38, Pisiform, bone. 39, External tuberosity of thehumeris .40, Cartilages of the ribs .41. The coupling.



		THE HORSE IN MOTION. II him, as appears in the following quotation from his work on Animal Mechanics: "There is scarcely any branch of animal mechanics which has given rise to more labor and greater controversy than the question of the paces of the horse. The subject is of great impor- tance to a large number of persons engaged in special pursuits, but its extreme complexity has caused interminable discussion. Any one who proposed at the present time to write a treatise on the paces of the horse would have to discuss many different opinions put forward by a great number of authors." Bishop, the author of the article on "Animal Motion" in the ^ncyclopaedia of Anatomy and Physiology," says: "The study of , ° ^wnich the locomotive organs of animals is com- ., I , ,^1G ^aws ^bv which their progression is accomplished, and of the vital force whirl-, 4-1 , . _int . ^lcn ^tney expend in propelling the body from one alik tl another with different velocities, serves to interest cian ¹T_a^anat0miSt ^and ^the physiologist, the artist and the mechani- deli" .^gn°^rance ^of ^these laws has been productive of grotesque meations of the human figure as well as of the lower animals, when represented in motion. We have abundant evidence of this in the Pro uctions of painters and sculptors, both of the ancient and modern world. e difficulty in this, as in many controverted questions, is to ^etermme the facts; and the facts have been most difficult to obtain, t seems to many unaccountable, that the horse, whose movements re so open, should play such a l'eger-de-pied as to deceive all eyes, and give rise to controversies as earnest as did the colors of the cha- meleon in the fable. All attempts hitherto made to analyze these movements have failed, for it is not possible for the eve to distinguish fl ^J ">em; or rather, to state the case more accurately, the mind is unable to distinguish the impressions conveyed to it through the eye. Controversies were going on to the last as to which foot was ad- vanced first in the trot; whether the toe or heel first touched the ground; whether in a gallop the legs were stretched out fore and aft, or the knees were flexed. All were dabbling in the shallow waters of a sea whose depths there was no known method of exploring, and



			PLATE ix.

^p-°si_EEIC
^p-°si_EEIC	E VIEW OF THE MUSCLES OF THE
	E VIEW OF THE MUSCLES OF THE

		l~hz.~H$>J.c±y_nePrinting Co,2UTrvmarU ..■



		THE HORSE IN MOTION. ₂ _t "Warms in the sun, refreshes in the breeze, Glows in the stars, and blossoms in the trees, Lives through all life, extends through all extent, Spreads undivided, operates unspent " ; who has endowed us with faculties to admire the beautiful, the good and true, to know why so many things are as we see them, but none to know how* Having give,, _some of the reasons for his belief in the spiritual ori- gin of the orgamc world, the writer claims his right, whenever he has occasron m the following pages to do so, to speak, without danger o berng m.sunderstood, of design or contrivauee in the same sense tha he would when referring to similar manifestations of design i�_ahumanly constructed machine ^g ^a tio^t^^r¹;;;;:': sr r^pression *^of ^the -^ -* - due time rest sailed ^ ** »« ^ «* » been ^^1^^!^^ ^^ ^^ * ^US ^th�Z^h ^a11 P^notnena, has that, on the one hand s'h _a _Do ^eVentUa"^y *** » ^to Actions. The certainty �ion, and is bevon _m 1 ^? f"" ^ ° ^* °^th" ^^d '* nature transcends in J beenp_ro_gress r^^S;;_B^ai;ⁿ''^S ^ ^^ Awards which intelligence has f_rom the first « When th" k '^CER' ^FirH ^Prind^ ^2d "®�>* P- '08. in mind Z! "* '" ^ ^^ " ^^* "neously change is borne the stranop , i � T wonderful contrivances of orchids, of mimicry, and e strange complexity of certain instinctive actions, are considered, then the conviction forces on many _minds that the organic world is the expression of an intelligence of some kind. on the XoT "^atUre ^the" ^SPeakS ^dearly ^l0 ^many ^mindS °^f ^the ^aCti°ⁿ °^f ³ⁿ ^intelliS^ence resulting, e vi e and in the main, in order, harmony, and beauty, vet of an intelligence the ways of wmch are not as our ways." _ St. G. Mivart, F. R. S, in Genesis of S_Peeies, pp. 272, 273. ^ There is something in organic progress which mere natural selection among spontaneous variations will not account for; this something is that organizing intelligence which guides the action of the inorganic forces, and forms structures which neither natural selection nor any other unintelligent agency could form." � Murphy, Habit and Intelligence, Vol. I. p. 348.



			PLATE XIII.

		MO HAMMED,- RUNNING. STRIDE, 15 FT , 9 IN.



		PLA'

V

	RAN GEM T.HE CAMERAS See Chap. VII.



							PJLA'!


		-



		THE HORSE IN MOTION. they are attached, and not sufficient attention has been given to their actum m correlation to the others with which they are coworkers 1 he forces employed in each limb, considered alone, are very complex I he same muscle may be an extensor at one time and a flexor at an- other m the same stride, as we shall show further on relll °^rde-u ^enaWe ^thG ^rCader ^t0 ^understand the muscles and their vke ofⁿM^W W°ir ^t0°i^reat ' '^ °ⁿ ^the ^P°^Wers ^of ^abstraction' the -r- Tmost ^aHn'' ^D4sseldorfartist_s were secured to delineate skill can do r ^mUSdeS " ^thCy^ ^6XP°^Sed -dissection; but no of the deep 22" wVhTth ^ °[ " ^^* "^ complicated mechanism of the tor« f * ^ ^ description in such a manner a, M ? presented by written A perfect familiarity with _th'_s °^dlSpenSe ^with ^a ^tle close attention, the plan of the whole machine J/^ ^t0 ^Gnable °^ne ^t0 ^Can"^yaid of dissection. A kno M ^ °"^ly ^be ^attained ^by ^the ^is imperative im� ^ °^f ^the ^const�ction of the machine as necessary asTo °^n� ^W°^Uld ^C°^mprehend ^its *<>"� is engine With 1 I i **** ^t0 ^Understand the construction of his horse's strength 7a 1 ^ ^ * ^mde^* the elements of a source _oheda f ^^ * movements, and appreciate the ce the danger from injury in great trials of speed. facts well iff ^r6VleVV ^CGrtain ^Physi0l°g^ical and general anatomical cha ;_c l r;;°^generaiiy ^known'^as ^c°^uid ^be **** � -. _sive i ^e ^themSdVeS ^int° ^tW° ^daSSeS' ^the ^active and pas- are rh. ^PaSS1W ^PartS ^are ^thG ^b°^neS ^and laments ; the active parts e^the ^musdes in which dwells all the power. which ti^he ^bones ^[t ^may ^be ^said'ⁱⁿ ^general> ^that ^they^are ^the ^levers °ⁿ avaihbl T-°^]QS ^^ ^and ^by ^mCanS °^f ^WhiGh ^thdr P°^wer ^is ^made to serve ' wT ^f°^rm ^dependS ^UP°" ^thG ^USCS ^Which ^they ^are ^designed and ribbed lii^ei!,^intr^d:^d ** ^ °^f ^aCti°ⁿ' ^th* "" ^thin> ^anS^ular> as colum > shoulder-blade, or scapula. When they are to serve the utmost' ^^ ^ "* ^Cylindrical' ^and as there is always ^made hollow⁶?¹¹⁰-⁰¹⁷ "^ ^ ^ ^Creat°^r ^^ * ^iS ^nGeded' ^ ^are ^made, that ther°^r ^ ^ ^^^ � ^l0"^g ^ag° ^aS ^the ^6l"^St ^mammal was - was no loss of strength as a support in being so con-



			CHAPTER II.

		The Horse considered as a Machine. � Necessity or understanding its Con- struction.� General Physiological and Anatomical Facts.� Architectural Principles involved in the Construction of the Skeleton. � Of the Joints. � The Vertebra. � The Cartilages and Ligaments. � The Muscles, Volun- tary and Involuntary. � General Facts, Anatomical, Physiological, and Mechanical, regarding the Muscles. � Articular Ligaments. � Tendons. � The Law of Repair in Muscles and Tendons. � Relation of the Form of Organs to their Functions. � Utility made to conform to Beauty in the Form of Organized Beings. It is proposed to present as concise a view of the locomotive organs of the horse as may be consistent with a proper knowledge of the parts, and the functions they perform in progressive motion. There can be no just appreciation of the qualities of a complicated machine without a comprehensive understanding of its construction, and the manner in which each of its parts acts to produce the com- pound movement for which it was designed. So, in order to under- stand the paces of the horse, we must understand the action of all the parts of the machinery by which they are produced. It need not be said that it is very complex, and has never been understood, for the reason that the motions themselves have been altogether mis- interpreted. This study of the mechanism of the horse is a necessity which will become apparent to any one who undertakes to analyze these move- ments by the aid of any manual of anatomy yet published. The dis- tinction of muscles into adductors, abductors, extensors, and flexors gives a very inadequate idea, and sometimes a very erroneous one, of the action of the muscles to which those terms are applied, as well as to their general agency in locomotion. In fact, these terms are used to express the action abstractly with reference to the bones to which



		THE HORSE IN MOTION.
	24	THE HORSE IN MOTION.
	24

structed. It was long afterwards discovered by man, and the law was learned by him, that the lateral strengths of two cylindrical bones of equal weight and length, one being solid and the other hollow, are to each other as their diameters; and the spaces in the shafts of these bones, being needless for the purpose of support, are made depositories of fat or marrow for fuel, � literally, coal-bunkers, � as are all the angu- lar spaces not needed for more important uses throughout the body, by means of which heat is developed, which primarily is the source of all motion in the animate as well as the inanimate world. The extremities of these bony columns are spread out to give broader articulating surfaces ; at the same time the single hollow of the shaft is divided into innumerable small ones, so that greater strength is attained to resist the wrenching force to which they are liable, without increase of weight; roughened ridges, spines, and pro- tuberances * are formed to give greater surface for the attachment of muscles. For the purpose of still further increasing the surface for attachment of muscles, supplemental bones are added, as in the splint bones, � or, as they are called by anatomists, the little metacarpels, � which not only serve to widen the articulating surface, but, by a strong ligamentous membrane that connects them with the main pillar, give the necessary space for attachment of important muscles, and where the distance from the centre of motion renders the reduction of weight very important, as the rapidity with which these extremities move increases greatly with the distance from the centre of motion. The bones are composed of animal and earthy matter, in the proportion of about one of the former to two of the latter. If the proportion of the former is increased, they will bend under the force applied to * Atheists maintain that function makes the organ ; but how can we conceive of function without previous conception of the organ ? What conception can be formed of sight without the existence of the eye ? It is held by them that the roughened ridges and protuberances of bone are developed by traction of muscles upon the bony surfaces. If this is so, why is it that the surface of the bone above the acetabulum which receives the insertion of the rectus fcmo- ris is smooth ? It certainly is not because there is want of traction on the part of that muscle. On the other hand, the tensor vagina femoris and the superficial gluteus, whose insertions are low down on the femur for the necessary leverage, must find room between other muscles, and a rough protuberance is formed to give the most surface for attachment in the least space.



		THE HORSE IN MOTION. 25 them ; and if the proportion of the latter is increased, they are liable to break. Variation from the normal proportions is the result of disease, and is more common in the human family than among quadrupeds. The bones are covered with a compact, inelastic fibrous membrane, the periosteum, which adheres so closely to their surfaces that consider- able force is required to detach it. This membrane serves not only to nourish the bones through its blood-vessels, or vascular system, but to strengthen them and increase their elasticity. The Californian Indian adopts the same method, for the same purpose, in the construction of his bow. In studying the architecture of the skeleton, as a whole, it will be found that no element of strength is wanting, or principle of mechanics violated, in its structure. The bones are arched or bent when such forms give greater strength. They are connected to each other by a strong tissue, so flexible as to allow of the greatest free- dom of motion, but inextensible, and, under all ordinary use, too strong to be broken or detached from the bony levers whose motion it is designed to limit. It is, however, sometimes torn, either completely or partially, in dislocations or sprains; and the slightest injury to this tissue is a serious accident to an animal whose value depends on the soundness of his locomotive organs. The extremities of bones which move upon each other, as at the joints or articular surfaces, are covered with a peculiar formation known as cartilage. It is insensible in a state of health, and very elastic to pressure; thickest where most exposed to concussion, and covered with a membrane which secretes a glairy fluid adapted to lubricate the opposing surfaces and reduce friction. These joints are closed to the admission of atmospheric air and all foreign sub- > ances, for their admission would soon cause serious injury. e joints are divided by anatomists into several classes, according o their mechanical construction. Some are simple hinges, admit- ting of motion in one direction only, as those of the lower parts of provid ^rf^miheS' ^The ^heads ^of ^a11 ^the ^four columns of support are sock^ TV ^a ^k'^nd °^f ^°^Int ^knOW" ^t0 ^mechanics ^as ^the ^bal1 ^and direction � h^ ^0fm ^adm'^ts °^f ^the g'^reatest freedom of motion in every e motion is limited in extent by capsular ligaments



	26
		THE HORSE IN MOTION.


which surround the joints as a continuous collar, whose borders are attached to each of the bones so far from the opposing surfaces as not to intervene, and yet not so far that they may not limit the motion to its needs. These capsular ligaments serve another useful purpose. Being air-tight, when the limb is off the ground it is supported in its place by the pressure of the atmosphere, � estimated by Borelli to be equal, in the hip joint of a man, to a lifting force of twenty-six pounds. The force thus gained is set free to be employed in locomotion. Each joint constitutes by itself an interesting subject for study, as they all differ in some important particular, according to their uses. The construction of the hock joint is quite unique, and has no analogue in man; and that of the hock of the ox is quite different from that of the horse. The interlocking grooves are oblique, so that when the posterior extremity is brought forward to pass its fellow, fixed upon the ground, it is carried obliquely outward, independently of volition ; and when all danger of interference is passed, and the limb is again extended to reach the ground, the foot is carried obliquely inwards, to resume its place under the centre of gravity. This will be referred to more fully when considering the action of the posterior extremity. The construction of the joints at large would serve as a subject for a monograph of great interest; but to be fully understood it must be studied ensis in manu. A detailed description of the bones will not be attempted. They are proverbially a dry subject; but for the convenience of those who require it, a reference plate is presented, lithographed from a photograph; and it is hoped that it will, through the eye, give the necessary information to enable the reader to understand the mechan- ical movements without the study which abstract description would require. But the vertebra, or spinal column, as the keel or bed-plate connecting the various parts of the machinery, requires further attention. The term "spinal column," as applied to the skeleton of quadrupeds, is a misnomer, derived, like most anatomical names in comparative anatomy, from its analogue in man. The spine being horizontal in quadrupeds, and not vertical, as in man, the term " column"



			PLATE XVIII

	14 15 16 17
11 12 13 14 15 12 13 J4 15 J5 J6 27 18. **I" 18 19 20*** HOUND RUNNING	14 15 16 17

		23



	THE HORSE IN MOTION.
	THE HORSE IN MOTION.	2₇
		2₇

is inapplicable to them. The word " spine" is also objectionable, as it is derived from the processes which superficially mark its course. There seems to be no objection to the term " vertebra," as a collective noun applied to the whole or any number of its parts. As it is the keel and connection of the various parts of the animated engine, so it is the term from which has been derived the name for the whole division of animals to which quadrupeds belong, � Vertebrates. The vertebra of the horse is divided into five groups, differing ma- terially in their mechanical, even more than in their physiological rela- tions. These groups are the Cervical, the Dorsal, the Lumbar, the Sacral, and, lastly, the Caudal. The cervical vertebrae have an im- portant relation to locomotion, second to no other division. They are provided with spines along the median plane, as are all the vertebrae, and transverse projections or processes, which afford attachments to ligaments to maintain their relative positions; and with important muscles, as will be shown in a subsequent chapter. There is great freedom of motion of these bones upon each other, in comparison with those of the next two divisions, especially at the articulation with the head and the first vertebra of the trunk. This last is a ball and socket joint of a peculiar construction, to enable the animal to reach the ground, as in grazing and drinking. The second group is the dorsal, and it consists of those vertebrae that are articulated with the ribs. Like the cervical, these are pro- vided with transverse processes, which serve not only for muscular and ligamentous attachments, but as braces to the ribs. The spinous processes are longer than those of any of the other vertebra;, especially ^ ong the withers, where the suspending muscles of the anterior extrem- y originate. It will be apparent to the most superficial observer that e motion, either lateral or vertical, of the dorsal vertebrae upon each _]o "" ^1S.^very ^Clrcumscribed, being limited in a vertical direction by the , ' ^US P^r°cesses and their intermediate inelastic ligaments, and ^ir> a lateral direction 1 +u _ribg _T, ⁿ ^Dy ^tne transverse processes and their articulating of fn« 1 � ^C ^^ ^dlvision ^is ^th*t of the lumbar region, or the vertebra 01 the loin, with which tl grouo � � ^e ^are ^no connecting ribs. As the former 'ore intimately related to the thorax, so those of the lum-



									PLATE XIX.

	16 IT 18 19 20 17 18 19 20 21
				18 19 20 21 2 2
								20 21 22 23



					^t
							8 25 26 27 28 29

		22 23 24 25 23 24 25 26 26 24 25 26 27 28


						12 JL9 3 0 31 32 33
2.Q 27 28 29 30 27 28 29 30 31 2.8 29 30 31 32


			HOUND RUNNING-



	28
		THE HORSE IN MOTION.


bar are in the same relation with the abdomen. Their broad and long transverse processes afford a protecting roof to the abdominal viscera, and give attachment to important muscles of locomotion on the under surface. There is very little movement of these bones upon each other, even less than in the dorsal series, � so little that bony union takes place between them in old age; and the elastic cartilages that, at an earlier period of life, were interposed between each of the vertebra become degenerated into bony matter, and that condition obtains technically known as ankylosis. The next series, and fourth in order, is the Sacral. Though in the embryotic stage the sacrum is developed from several centres as dis- tinct vertebra, yet before birth they are united into one broad triangular bone, which, uniting with the iliac bones on each side, and the pubic bones in front, forms the ring known as the pelvis. It is in the lower or pubic portion of this pelvis that the cuplike cavities are formed into which the heads of the hip bones are lodged, and where the force of the levers of the posterior extremities is applied. The difficulty in locomotion that would be experienced from the want of flexibility of the spine, especially in old age, is obviated by the freedom of motion that is secured in the articulation of the last of the dorsal vertebra with the sacrum. This is what is known as the " coupling," as it unites the two distinct systems of locomotive organs, the anterior and posterior extremities. In the skeleton the connection seems very slight; but the ligamentous connections are very strong, and the long muscle of the back [longissimus dorsi or ilio spinalis), reaching out from its spinal attachments, lays hold of the hip bone (crest of the ilium) on each side as far as possible from the centre of motion at the coupling, the more effectually to limit the flexion at that point. The lasj: group of vertebral bones is known to anatomists as the coccyx, from its resemblance in man to the beak of the cuckoo; but as the resemblance totally fails in the Mammalia and all other vertebrates, we shall call them by the more general name of Caudal bones. They have no function in locomotion; but " thereby hangeth a tale." Between all the vertebral bones is interposed a layer of elastic carti- lage, of the same nature as that which covers the opposing surfaces



				PLATE XX

		7 8 9 10 11 IS 13 14. iQ n 12' 13 14 IS 16 17 '2 13 14 IS 16 IT 18 19 20 J3 14 IS ia IT 18 19 20

₅^^/^ .^^^r ,>^mfc^r , ~7( w^* 14 IS IS IT 18 19 20 21 _la _lt jg _IS 20 21 22 23 17 18 19 20 21 22 23 24 25 18 19 2D 21 » 23 24 SB 26

	21 It :3 2 4 25 26 2T 28 _aa j>₃ 24 25 26 27 28 23 24 25 26 27 28 29 30 31 24 SS 28 27 28 29 30 31 32

			TWO HOUNDS RUNNING AT DIFFERING RATES OF SPEED



	THE HORSE IN MOTION.
	THE HORSE IN MOTION.	29
		29

of the joints in the extremities. These cartilages by their elasticity admit of slight flexion of the vertebra, and they also deaden the force of the shock transmitted from the powerful impulses of the posterior limbs. As has been already stated, the flexion is limited by the liga- ments which bind them to each other. This restriction of motion is necessary for the protection of the vital organs of the thorax and abdomen, as well as the great nerve trunk transmitted through a continuous canal above the bodies of the vertebra, and which is dis- tributed thence to all parts of the body. While the three central divisions of the vertebra may be curved slightly, they cannot be shortened, even temporarily, as may be readily seen; and the apparent shortening that takes place when the animal's limbs are gathered under him is an illusion. The elasticity of the cartilages and ligaments is greatest in the young; as age advances, these tissues become stronger and less flexible, and resist the move- ments of the joints; they are said to become "stiff." Hence the importance of early training to give greater sweep and freedom of motion. This physiological principle is made the basis of gymnastic training by acrobats, being commenced at a very early age; and the same is not lost sight of in the exercises of colts. In contemplating the passive parts of the animated machine ab- stractly, we see the results of organic life ; they are without sensi- bility or power of spontaneous motion; we are familiar with the mechanical principles involved in their action, and are impressed by the perfect adaptation of means to ends ; we look upon them as we look upon the piston, connecting-rod, and crank of a steam-engine : but upon the muscles we look with far different thoughts; their action has no similitude in the inanimate world. The general appearance of muscle is too familiar to every one to need description ; its special vital property is contractility. The mus- cles are both voluntary and involuntary, but it is only the former that are concerned in locomotion. If we remove a fragment of muscle from an animal recently killed and examine it closely, we shall find it to be made up of longitudinal fibres of a red color bound together by gray fibres of a different tissue.



			THE HORSE IN MOTION.
	3°		THE HORSE IN MOTION.
	3°

If we lay this flake of muscle upon a plate and scrape it gently in the direction of its fibres with a dull knife, we shall find upon the edge of the knife a red pulp without apparent fibre or tenacity, and there will be left behind a bundle of strong cellular tissue. It is to the former that the tractile property belongs ; the latter has no more active power than other cellular tissue; yet this pulpy bundle of fibres, as muscle, contracts under the stimulus of the will with almost inconceivable power. Borelli estimated that the force exerted by the deltoid muscle of man in supporting a weight held horizontally in the hand was two hundred and nine times greater than the weight. Therefore a weight of sixty pounds held horizontally requires an expenditure of contractile force of the extensor muscles at the shoulder of more than six tons. He demonstrated that the force of the extensors emjaloyed by a porter in carrying a weight of one hundred and fifty pounds upon the shoul- der exceeds three tons.* It follows that this enormous power is exerted on the extensors of each leg alternately. The natural stimulant to the muscle is the will transmitted through the nerves; but the will is not necessary to muscular contraction, as it has no influence on the muscles of animal life or the vegetative func- tions of animals, and any of the voluntary muscles may be cut off from communication with the brain by severing its nervous connection; yet contraction may be excited in the muscle so cut off, and this may be continued indefinitely by further division to a microscopic degree ; still the fibres will be observed to contract upon the slightest touch, so closely are the nervous fibres interwoven with those of the muscle. Electricity when passed through the muscle in a broken current is a strong excitant to muscular contraction, overmastering the will, and will even cause contraction after life has left it; but if the current is continuous, it has no such power. The muscular fibres are paralyzed by certain poisons, and stimulated to violent contraction by others ; and in disease, as tetanus, they may be so violently stimulated as to be torn asunder. This subject, though very interesting, is leading away from the special inquiry to which we

		* Cyclopaedia of Anatomy and Physiology, art " Animal Motion."



		THE HORSE IN MOTION.
	3 ²	THE HORSE IN MOTION.
	3 ²

During the life of the animal the tenacity of the muscle is greater than that of its tendon, but when vitality no longer animates it it may be easily torn. While the articular ligaments are subject to extension and elonga- tion by early use and frequent tension, so that greater freedom of motion than is normal is acquired, it is otherwise with the muscular tissue and its tendons. By exercise within certain limits, at regular intervals, and with proper nutrition, the thickness and power of the muscles may be increased, and by neglect of these conditions they will become thin and pale, while contraction will be feeble and not well sustained ; but they will not become elongated under whatever violent and long-sustained exercise; they may increase in thickness, but not in length. But for this exception to the rule the whole plan on which animal mechanics was founded would have fallen to the ground with the animal himself. Were the muscles to become lengthened by use without corresponding increase in length of levers, the tension neces- sary to prompt action would be lost, and the effect would be similar to that upon the tiller ropes of a ship were they to become relaxed. What would be the effect upon the length of the bones in the period of time contemplated by some it is useless to inquire, but we know that the increase of muscular power by increase in the bulk of the muscle takes place in a short period, and in the lifetime of the indi- vidual. But while the muscles and their levers will retain their nor- mal relation of length during life in a healthy subject, that balance is sometimes lost as tlie result of injury. A child has been run over by a wagon; the wheel has passed over the muscles of the calf so as to disorganize the muscular tissue; in due time the injured part is re- stored to health, but the muscle does not develop fully; it is shortened, and a form of club foot is the result, in which the person cannot, while walking, reach the ground with the heel. The child has grown to manhood, but no amount of use and no length of time will elongate the muscle. Nature cannot elongate that muscle without anarchy. The Creator works by law, and to claim an exception is virtually an admission that we do not understand the law. But what He cannot do without anarchy his creature can; he slips a tenotomy knife

			%



				.PLATE mV.

			*-rr^-*

		8 9 10 11 8 9 lO 11 1Z 9 10 U 12 13 10 U 12 13

	*tl 12 13 14k* 12 13 14 15

15 1« IT 18 19 17 18 19 20 t& 19 ZO XI 19 ZO 21 ^22 DEER BOUEEDIN-G. STRIDE, 10 FT. 4r 111.



		THE HORSE IN MOTION. o o beneath the tendon, severs it with scarcely a visible external wound, nscrutall I "^ ** ^^ ^ ^and ^that "ver-p^ent, scrut_able po_Wr fills in the space left by the parted extremities of the t:«z Ly�:: ■ °^^is* *r°:^d* ^to ^proper ^iength'^and nmns of J! t ' °^U ^the °^ther ^hand> ^one ^of ^the ^b°y col- P wl aledTat ^"^ �^ the thigh, - the creative Lm:; _si: r_f ^soon;^ets ^at ^work ^to ^repair ^the ^da^ ^a *«»*** inelaltic ^^T xT^ ^ ^bl"°^ken "' "^ °^fdient, while the slower proc s^ of ^ ^P°^Siti°ⁿ " * ^P�"⁷ "** perfect bone is effected and th f "^ ^th°^r°^Ugh °^rS^anization ^of sequestrum is absorbed and carried "off T " ^"^ ^ ^ ^thethis change has been taking n] ^gH ^the ^drculation- While cal interference, in most cases b ^ ^"^ * ^W°^uld' ^With°^Ut ^SUISⁱ" contraction of the muscles on n " T^^ ^ °^VerlaPPⁱⁿS through the he that the same disaster ^ u °^f * ^The ^consecl^uence would where the muscles were si a ^encountered ^as ⁱⁿ ^the last case, law is observed The ^? i ^t0 ** ^el°ⁿS^ated ^from ^u«e ; but another «" proportion between theit i T^ "* ^S^ ^ ^Sh°^rten' ^and act ^on it is restored. ^ ^ ^the ^mUSdeS ^which It is said by Professor Marev that « ** - , machines and animate comparison between ordinary * ^ has shown titttr⁰¹;;⁶ ^powers ^wm ^not ^w ^been -^de - - and the charac tf � ^ " "' "^ « ^f°^rm °^f ^the °» ' by the ordu _a ' T^'' ** ^tHs �pondence is regu- lar and bo_nf_st \ f ^^ ^&° ^ ^whfin ^We ^See «* * the cha aTt _rs ^1C T'^G "° ^ � ^ ^ ^from ^th- >"» �■» �Z� :t°r^they ^possess-"^This ^statement'^wwch ^ma»y -uscles is I, _t ;^Ue' ^reqUir6S ^^ualifi-tion. The form of �ding orla t ,T * T ^^ ^and ^ °^f - ^is economic,! "!' 1 "'. ^ ^^ ^Where ^she ^can afford to be ^ -d es air _n^heI^e " ^ f * �^S - ^ in numerous Beauty of ^% ^ ^ ^a�gement of muscles. ^ and eveTll;".!⁰^ ^ °^f ^h ^the �truction of the ^maintain graceful i« "T °^f ^mechanical P�er are made to "nes, and that general contour of form that gave



			plate .xxv:

		*MHsEB3taSta_**

CONVENTIONAL POSITIONS OF QUADRUPEDS IN MOTION

	\



			34 THE HORSE IN MOTION.

		to him his matchless beauty, � beauty so great that to the eye of a superficial observer it is difficult to decide whether it is subordinate to strength or conversely. Both are developed in a perfect horse to such a degree that he has been a favorite theme of poets and painters since aesthetic culture has had a place in the history of our race. Numerous instances might be referred to where use has been sacri- ficed to economy of space and to beauty; but they cannot fail to occur to the mind of the anatomist; and it is premature to introduce them in this place for the general reader.



			CHAPTER III.

		Special Anatomy. � Necessity of Technical Terms.�The Ilio spinalis.�Defi- nition of Terms. � Psoas magnus. � Iliacus. � Tensor Vaginae Femoris. � Sar- torius. � Pectineus, Small Adductor, etc. � Great Gluteus. � Deep Gluteus. __Long Vastus. � Semi-tendinosus. � Semi-membranosus. � Great Adductor.� Gracilis.__The Adduction and Abduction of Muscles. � Triceps Femoris.� Gastrocnkmii. � Automatic Action in the Hind Leg. � The Perforans and Perforatus Muscles and their Tendons. � Suspensory Ligament. � Difficul- ties in the Way of determining the Amount of Work done by Muscles.� Elongation and Contraction of the Limbs. � Interference and Stifle Action. � The Action of the Hock Joint to prevent Interference. � The Order of Action in the Various Muscles of the Posterior Extremity in Locomotion. From the general observations of the last chapter we will proceed to a consideration of the special anatomy, and analyze the locomo- tive organs of the horse ; without this preparatory study it will be impossible for any one to analyze its movements. Those who have studied and suppose they understand this action must study again. Let no one be turned from this subject by tech- nical terms; they are indispensable in order to make one's self under- stood by those who have already made a study of anatomy, as well as to those who would follow the movements by which the various paces are performed, and speak of a horse in more intelligible terms than the slang of jockeys and the stables. I think I am warranted in the belief that we are on a new era in the history of our old friend and fellow-traveller; the increasing interest that is felt in America as well as Europe, and the impulse that is sure to be com- municated by the wonderful revelations of the camera, justify me in that opinion. I shall not follow the usual order of descriptive anatomists. It has already been stated that it is not the purpose of this essay to teach anatomy any further than is necessary to demonstrate the



	36
		THE HORSE IN MOTION.


mechanism of the locomotive organs, and the manner in which the muscles act upon their bony levers to produce the movements in progressive motion. The long muscle of the back holds the same relation to the loco- motive muscles that the vertebra does to the bones; it is a very com- plex muscle or system of muscles; it is called by Chauveau the ilio spinalis, so named from its attachments. It fills the angular space on each side of the spinous processes, giving roundness to the back. It is very broad and thick over the loins, and is attached to the whole anterior border of the ilium and strongly to its crest, or the hip bone, as seen in Plate III., q; it is attached anteriorly to all the spines of the vertebra, as far as the neck, and a strong mem- brane, tendon-like in its construction, that is firmly fastened to the same bones. This tendinous membrane, called aponeurosis, has not been mentioned thus far, but it is tissue very important in its relation to the muscles; it differs from fascia in several respects, but specially in thickness and strength. It covers nearly all the superficial muscles, and its strength is so great that the muscular fibres are attached to its inner face as to a bone, and it serves them often the same purpose as fixed attachments.* If one takes an elevated seat with the driver on a coach, and looks down upon the wheel horse nearest him, he can see the action of this muscle, and to the best advantage if the horse is trotting. It will be noticed that the spine is flexed in a serpentine manner as the diagonal legs move alternately. This movement is caused by the impulses given to the pelvis by the heads of the femurs alternately, which would seriously strain the articulation of the pel- vis with the lumbar vertebra called the coupling, but for the action of the ilio spinalis, which contracts simultaneously with the impulse communicated to the opposite side of the pelvis, acting as a brace checking the wrenching violence of the action and preventing injury to the coupling. This is the function of the iliac wings, as * A familiar example may be seen in a porter-house steak of beef. The part known as the tenderloin is a section of the psoas ; that above is a section of the ilio spinalis over- laid by its aponeurosis.



		THE HORSE IN MOTION. 37 referred to in Plate V., a, a, a. The great mass of the muscle which fills the angular spaces on each side the spines is called into action in rearing, or supporting, the anterior half of the body when not supported by one of the fore legs. The greater part of the ilio spinalis is concealed in the plate by the great glu- teus, c, c, c. The centres of motion between the vertebra are in the bodies of those bones which are most distant from the spines, and which form the rounded ridge of the backbone as seen in the great cavity of the trunk. In man they constitute the supporting column, ne _lho _spinahs _musde _Hes _who% _abQve _th._s ^ ^^ .^ _act._on abstractly would curve it downward; it can have no influence, there- ore i� _aid _to _support _& ^ ^ ^ ^^.^ ^.^ ^ �ong a�d powerful muscle is therefore, first, when they both act fixed I ,^SUPP°^rt ^thC ^anteH0r ^haIf °^f ^the ^ while the pelvis ten" ,^yf ^mUSdCS; ^and " ^the �1 P'-e, when they act the ho ^y' ° ,^C0UntC1'^aCt ^thC ^W1'^enchinS ^effect ^of the propulsion of the heads of the thigh bones. Before we proceed any further with the consideration of the mus- es ot locomotion, we must agree upon the signification of terms necessary to be employed. The words « flexor " and « extensor " may be proper enough in some ot their applications and express fully the action, but not in all. Some muscles act as flexors and extensors at the same time; others are exten- sors at one part of the stride and flexors at another; and some of the most powerful propellers in the whole machine are flexors, as we shall show in the course of this treatise. It will be seen that the actions o the muscular powers are sometimes quite too complicated to be expressed in one word. The term "extensor" is commonly applied to all muscles whose action is to enlarge the angles and by so doing elongate the limbs ; ^3u-t this extension may be forward when the foot is in the air, or back- ward when the foot is on the ground. There is no word in use by anatomists to express the fundamental idea, propulsion. The terms flexion " and " extension " will be used in the following pages to express the action of a muscle upon its attachments, without reference



	38
		THE HORSE IN MOTION.


to its functions in locomotion. The words " adductor " and " abduc- tor," meaning the function of drawing to or away from the vertical plane passing through the axis of the body, are well enough, but we must not be misled by the application of these names to muscles which may have such action to the extent only of five per cent of their work, and the rest, or eighty-five per cent, devoted to propulsion. I have already referred to the misnomers in muscles ; they mislead the mind no less with regard to their action than to their form and construction. What can be more inappropriate than the names semi- membranosus and semi-tendinosus, meaning half membrane and half tendon, when applied to the muscles so named in the horse ? They are well enough when applied to the corresponding muscles in man, but in the horse they are not at all membranous or tendinous. We should be glad to dispense with names altogether, and apply abstract or algebraic terms to avoid misconceptions, if practicable, but we must use such as are given, and, where there are synonymes, use such as are least liable to the objection referred to. There is a group of muscles whose action is to advance the whole posterior extremity after the act of propulsion is complete. They are all deep-seated, with two exceptions. The psoas magnus (Plates VI� VII., a, a) has its origin in the abdo- men, along the under surface of the lumbar vertebra; its fibres, which determine the course of its action, are directed backward and down- ward, and it terminates in a long tendon which is inserted into a rough ridge on the inner side of the femur, or thigh bone, just below the head of the bone ; another of this group is the iliacus (c, Plate VII.), which arises from the lower face of the ilium, or hip. The course of its fibres is similar to that of those of the psoas, but its origin being farther from the median plane, its direction is more inward to join the last-named muscle at the same point on the inner face of the femur. These two muscles are of delicate organization, and, though differing in form, unite in their function of flexing the femur upon the pelvis, and so carrying the whole leg forward. The iliacus, having its course more inward than the other, has the effect of carrying the free end of the femur out- ward, � the " stifle action," so important in the trotting horse.