TABLE OF CONTEXTS.

ir^J

Introduction axd Spkeä.d of Mm, Cuolera sx the United States.......

Investigation of Swine Diseases................

Symptoms and Post-mortem Appeaiunces in Hog Cholera............

' .esions produced hy hoi/ cholera.......................

(a) Acute type.........................

(Ä) Chronic forms..............................

History an-igt; Adtopsy Notes of an Outbreak of Hog Cuoleka........

Disease in Healthy Pigs Caused by Material from this Epizootic! Brief Süjimary of the Important Features of this Epizootic........

Hemmorrhagic lesions.........................

LTloerative lesions....................................

Complications.................................

Lung lesions..........................

Bacteriological Observations...........................

The Causation or Etiology of Ihm Cholera...............

The bacillus of hog-cholera.........................

Staining of hog-cholera bacteria..........................

Biology of the hog-cholera bacillus.............................

(laquo;) Diagnostic characters.............................

('0 Other physiological characters

Tin-: Diagnosis of Hog Cholera by Means of Inoculation........

Vitality of Hog-Choleua Bacilli and their Resistance to various Destructive Agents..........................

Resistance of hog-cholera baot .na to beat in liqnid media...............

Vitality of hog-cholera bacteria in ordinary water....................

Resistance tocontinuom drying at ordinary temperatures................

Some Experiments on the length of time during which Hog Cholera Virus remains alive in the sou...............

A few Additional Observations as to the Vitality of Hog Cholera

Virus in the sou, at the Experiment .Station......................

The Effect of Some Disinfectants on the Virus of Hoc Cholera...

Mercuric chloride.......................................

Carbolic acid........................

Iodine water................................

Permanganate of potash.......................................

Mercuric iodide.....................

Sulphate of copper................................

Hydroohlorio acid...........................

Chloride of zinc.....................

Salphnric acid.........................

prude carbolic no id................

Pago.

54 54 r)S f.:{ 63 65 66 (it; 69 09

-#9632;ii

87 88 8-8 89 89 89 '.Kl 90 90 90 91

Ill U. Ml LUII .1 I

quot;^^^^^quot;

rape.

lt;)i:i)i.\Ai;v LniK as a Disinfectant: for Hog Cholera...................nbsp; nbsp; nbsp; nbsp; 93

Disinfection of the sun, with limk.......-------........................nbsp; nbsp; nbsp; nbsp; 99

Is there aw Resistant Spoke state in- the Life Histohy of the Bacillus of Hi Mi Cholera ..-............- ................... .........nbsp; nbsp; nbsp; l^fll

Ways in which Swine become Infected.................................nbsp; nbsp; nbsp; 1quot;5

By way of the digestive tract...........................................nbsp; nbsp; nbsp; 105

a. Feeding diseased viscera...........................................nbsp; nbsp; nbsp; 105

h. Feeding pure culture of ITog Cholera bacilli.......................nbsp; nbsp; nbsp; 107

Subcutaneous luoculation...............................................nbsp; nbsp; nbsp; I*¹''*

Intra-venous inoculation................................................nbsp; nbsp; nbsp; 1quot;

Infection by way of the lungs...........................................nbsp; nbsp; nbsp; U*

Some Observations on the Pathological Action of Hue Choleha Bac-

TERIA.....................................................................nbsp; nbsp; nbsp; nbsp;^11:!

Bacteriological Investigations of Hog Cholera in Nebraska, Illinois, and Maryland....................................................nbsp; nbsp; nbsp; '#9632;'#9632;quot;

Differential Chauacters of the Hog Cholera Bacillus..............nbsp; nbsp; nbsp; 119

Bacillus from Nebraska..................................................nbsp; nbsp; nbsp; ^1I'^J

Bacillus IViur. Illinois....................................................nbsp; nbsp; nbsp; nbsp;''#9632;

Bacillus from Maryland...............-..................................nbsp; nbsp; nbsp; ^l^⁰

Relation of Hog Cholera to the Pcblic Health......................nbsp; nbsp; nbsp; 120

Prevention of Hog Cholera.......................#9632;.....................nbsp; nbsp; nbsp; I²³

Isolation, Disinfection, and Cleanliness as Paeventive Measuresnbsp; nbsp; nbsp; nbsp;123

Tkeatmf.xt of Hog Cholera..............................................nbsp; nbsp; nbsp; nbsp;'#9632;'#9632;'

Experiments on the Prevention of Hog Cholera by Inoculation nbsp; nbsp; nbsp; 139

1. luoculation of small doses of strong virus in the form of liquid culture..nbsp; nbsp; nbsp; nbsp;139

II. The effect of feeding small (iiian titles of eulturos on immauitj.........nbsp; nbsp; nbsp; 151

III, Injection of sterilized call are liquid to produce immunity..............nbsp; nbsp; nbsp; nbsp;154

Tests with sterilized rah arcs on pigeons.............................nbsp; nbsp; nbsp; nbsp;'#9632;'#9632;^,

'iVsis with sterilizeil cultures on pigs ................................nbsp; nbsp; nbsp; loJ

Exteuiments on cue zVttenitation of the Hog Cholera Bacilli by Heatnbsp; nbsp; nbsp; 167

Hi.d Cholera ok Diseases closely Allied to it in other Countries..nbsp; nbsp; nbsp; 173

la Great Britain........................................................nbsp; nbsp; nbsp; nbsp; ''

In Sweden and 1 ten mark...............................................

, ,, .........nbsp; nbsp; nbsp; löG

la 1rauce............................................................

LLUSTRATIONS,

Page. Investigation of Hog Cholera:

Plates I, II, III, and IV. Illustrating necrosis and uleeration of (lie nm-

cosa of the large iutestiue, more particularly the cajcum.......nbsp; nbsp; nbsp; nbsp;i'.M

\^r. Showing ulcers in the ileuiu.................................nbsp; nbsp; nbsp; nbsp;1^lt;.)4

VI.nbsp; nbsp;Showing hemorrhagic kidney...............................nbsp; nbsp; nbsp; 194

VII.nbsp; Showing hemorrhagio lung................................nbsp; nbsp; nbsp; ]!i4

VIII.nbsp; nbsp;Showing hemorrhagio lieurt....................1..........nbsp; nbsp; nbsp; 194

IX.nbsp; nbsp;Collapse niul broncho-pneumonia............................nbsp; nbsp; nbsp; 194

X.nbsp; nbsp;Microscopic characters of hog cholera bacilli...... ..........nbsp; nbsp; nbsp; 194

XI.nbsp; XII. Growth of hoy; cholera bacilli in various culture media.-nbsp; nbsp; nbsp; 194

XIII.nbsp; nbsp;Spleen and liver of rabbit inoculated with hog cholera bacilli ..........................................................nbsp; nbsp; nbsp; nbsp;191

XIV,nbsp; XV, XVI. Photomicrographs of hog ehulera bacilli, showing variation due- to growth in different media.....................nbsp; nbsp; nbsp; 194

LETTER OF TRANSMITTAL.

WASHEsraiON, D. C, January IS, 1SS9.

Sir : T have the honor to submit herewith a report upon the history nature, ami treatment of the disease known in the United States as hoy cholera. Oar knowledge of this pest lias been (lev eloped almost entirely by the inquiries ami experimental investigations of the Bureau of Animal Industry; and while much of the iufortnation contained in tiiis volume has been published in the reports of the Department of Agriculture, a systematic and complete statement of the facts has never before been made in a connected manner.

It has been discovered in the course of these, investigations that there are two very different and distinct epizootic diseases of swine in this country which are widely prevalent, and which had previously been spoken of under-the one name of hog cholera or swine plague. These two names had, therefore, been used synonymously previous to 1S8G, when the differences between the diseases were pointed out in there-ports of this Bureau. It was then deemed best to apply the term hog cholera to that disease in which the intestines were found most affected, and in which the symptoms would come nearest to .justifying the appellation. The other malady appeared identical, not only in symptoms and lesions but in the microbe which caused it, with the disease recently described in Germany by both Loftier and Schütz under the name of tfc/HomeseMc/ie, or swine plague. For this reason it was considered best to call this affection swine plague in the reports, and thus preserve uniformity and prevent confusion of ideas in reference to the diseases of swine in different countries.

This volume treats exclusively of hog cholera, as it is the malady which has been longest under investigation ; but the material is on hand for an almost equally complete volume on swine plague, which we hope soon to submit for publication. There are, of course, many other diseases of swine, some of which are. communicable In a certain degree, but none of which are so widespread and fatal as the two that have been named. Some of these, especially the parasitic ones, are receiving attention, and may in the future be treated at length in the bulletins of this IJureau.

The greater part of the detailed study of the disease, the planning of experiments, and the bacteriological investigations have been carried

out by Dr. Theobald Smith, while tho couducting of the experimeuts, the care of the experimental animals, and the general management of the experiment station have been under the direction of Dr. F. L, Eilborne. I can only speak in the highest terms of tlie untiring industry and sldll displayed by both of these gentlemen.

The experiments in regard to prevention and medical treatment are being continued, but it is confidently believed that an understanding of the facts detailed in this volume will enable the owners of hogs to prevent or even arrest the great majority of outbreaks. It should be understood, however, that the measures indicated must be enforced promptly, energetically, and thoroughly.

J). E. 8ALMOF, Chief of the Bureau of Animal Industry.

Hon. Xorgt;ian J. COMCiN,

Commissioner of Agriculture.

THE INTRODUCTION AND SPREAD OF HOG CHOLERA IN THE

UNITED STATES.

la the early days of hog-raising in the United States these animals were comparatively free from disease, and wide-spread epizootic maladies among them appear to have been unknown. A circular letter of inquiry was recently sent from the Bureau of Animallndustry to the correspondents of the Department and to swine-breeders in all parts of the country, asking the date of the first appearance of hug cholera in the respondent's county, and a statement as to the health of swine previous to that time. More than a thousand replies have been received, many of them so carefully written as to be of much interest and value. Nearly all agree in stating that at one time the swine industry was not subject to the periodical losses from epizootics which now cause such discouraging losses. From the first appearance of this class of diseases the outbreaks became more numerous and more wide-spread until nearly-all parts of the country are now subject to frequent invasions.

The correspondence on this subject can only be briefly summarized in this bulletin. The first outbreak of disease supposed to be cholera that was referred to occurred in Ohio in 1833. It is reported from one county in South Carolina in 1837, and from one in Georgia as having existed in 1838. It existed in 1810 in one county in Alabama, one of Florida, one of Illinois, and one of Indiana. In 1813 it is reported from one county in North Carolina. In 1811 one county in New York reports being affected. Its presence in 1845 is only mentioned by one correspondent from Kentucky.

The thirteen years, from 1833 to 1S1.J, inclusive, form a period in which but ten outbreaks of swine disease, supposed by the writers to have been bog cholera, were mentioned in these replies. It is evident that during this period bogs were generally healthy throughout the country, and that the losses from disease were not sufficient to attract very much attention. The nature, of the disease referred to as existing so long ago may, of course, be questioned at this day, and we have no means of deciding whether or not any particular outbreak was cholera or some non-contagious malady due to local conditions. It is reasonable to conclude, however, that the correspondents are correct in their opinion in most cases, because since 1845 the outbreaks mentioned became more numerous year by year until we find nearly the whole

country involved. This rapid increase of the number of affected sections would seem to indicate that ;i contagious disease had been introduced and carried to widely separated sections of the country, from which it extended until, with a year favorable to its propagation, we find a sudden and alarming increase.

Turning again to the number of outbreaks reported, we und, in 1S-1G, that there were two in Xorth Carolina, one in Georgia, one in Illinois, one in Indiana, and one in Ohio, in 1847 four are given in Tennessee and one in Virginia. In 1848 we bear from it in one county in Illinois, two in Indiana, two in Kentucky, one in Forth Carolina, and one in Virginia. In 1849 it is mentioned as in one county in Indiana and in one county in Ohio. In 1850 we have accounts of three outbreaks in Georgia, one in Pennsylvania, one in Indiana, two in Kentucky, one in North Carolina one.iu Ohio, and two in Tennessee. In 1851 there were outbreaks in Illinois, Indiana, and Tennessee. In 1852 there were two reported in Illinois, two in Indiana, one in Missouri, and one in Ohio. In 1S53 it invaded two new counties in Illinois, two in Indiana, two in Kentucky, one in North Carolina, four in Ohio, two in Tennessee, one in Texas, and one in Virginia. In 1854 it appealed in one more county in Illinois, four in Indiana, five in Kentucky, two in North Carolina, two in Ohio, and one in Tennessee. In 1855 it is found m six counties in Illinois, five in Indiana, one in Kansas, four in Kentucky, one in Missouri, two in Tennessee, and one in Virginia.

The number of outbreaks mentioned by correspondents, it will be seen, is not less than ninety-three for the ten years from 1810 to 1855 inclusive. As compared with the ten outbreaks reported for the previous thirteen years this is an enormous increase. There can be little doubt that it was during the period from 1840 to ISÖ.l that hog cholera became scattered over the country and fairly began that work of destruction which has become so familiar to us in later years.

Below will be found a tabulated statement of the replies from nearly eight hundred and fifty of our correspondents. The figures show the number of original hog-cholera infectious reported for the different periods ironi the first recorded appearance of the disease in this country to 1SS7. Of course there have been many counties infected within that time which are not referred to in these communications, but the large number that were mentioned gives as perfect an idea as can now be obtained of the development and spread of this contagion. It is to be remembered that the outbreaks mentioned arenot secondary infections, but are the first outbreaks of the disease in the correspondent's local. ity, and in most cases the lirst which occurred in his county. In nearly all cases it is stated that previous to the outbreak referred to the health of hogs had always been good, and the losses from disease had been confined as a rule to a single animal at a time.

Number uml dales of original infections with hoy cholera and sioine plcujue. an cdiupiled

fium recent correspondence.


Staled.	t-i P i	*-1. aquot;* ^H 1	*'-i* 5,00	-' F 7 7	i ^:r- z. =gt; 5 6 1	a 4	T. -- *-jo* t.i i	s 1	quot;CO c *
			!

									i
								1 1 1! 1 1 13 26 :: i	1
			:			.......	........		1
						1 ! 4 8 11 5	....... :: 4 12
	i i i	5 14 19	13 41) IS	¹ 13 U 8 15 3	10 11 4 3
Georgia...................									1
Indiana...................
		1 15							6
	i								2
Looisiazia................. Af-.it.,. _ _____	i						1 1
			J	1			1 1	3 ²3 2 15 1 * 2 2 1 1 3	1 o
MnaaophnqAt.ta___________^:________ _______			J						1 o
							2 1 1 8		3
						1 S
			1 6 1	S	3 16 1
#9632;Missouri.................. Nebraska.................		L'	1 6 1	S	3 16 1				1 3
				1					1
	1 ¹			1	1 9				1
		......quot; V	1	10		3	4
		......quot; V	1	10		3	4
Ohio	i 1 ;	11 1 1 12	7 3 '.! IS	0 1 10	9	12 1	7 4		g
Pennsylvania............. Sou Hi Carolina............					9		7 4		1
					5				x
Texas					5	2 8	4 4 4	5 1 13	2
		1	1	6	3 4
		1

Whether the outbreak which occurred in Ohio in 1S;53 was the first introduction of Log' cholera in this country or not, can not now be de-teriuiued. It seems reasonably certain, however, that tbc contagion was imported from Europe with some of the animals that were brought from there to improve our breeds of swine. The investigations made in England and on the continent during the last year demonstrate that the swine fever of Great Britain is identical with our hog cholera, and that this disease is also widely scattered over the continent of Europe. This being the case, it would appear inucli more likely that the contagion was imported from there, as we know occurred with the contagion

of pknuopueumoiiia of cattle, than that it appeared spoutaneoosl; or was developed by the conditions of life in this country. Having been once introduced it spread gradually, following the lines of commerce and being for a long tinieconliued to them, until, extending step by step, it has at one time or another invaded every section of the country in which swine raising is a prominent industry. Dr. George Sutton of Aurora, Ind., in 1858, wrote as follows:

I bavc seen notices of this disease prevailing in tlie States of Illinois, Kentucky, Indiana, Ohio, New York, Massachusetts, I'eimsylvania, and Maryland. It has prevailed extremely in Indiana, particularly in Dearborn, Ohio, Ripley, Rush, Deeatur, Brown, Bartholomew, Shelby, .Johnson, Morgan, Marlon, Boone, I'osey, and Sullivan Couuties. It has also prevailed in Campbell, Kenton, Boone, Gallatin, Carroll, Breck-iuridge, Bullitt, Bath, Heory, Henderson, Nicholas, Livingston, Union, and Crittenden Conuties, Kentucky. It has also prevailed in Hamilton, Butler, Clinton, Fayette, and Cletmont Counties, Ohio. Also indifferent portions of Illinois, and very severely in Wayne, White, and Gallatin Counties. It has also prevailed in the State of New York. The Ohio Fanner for January ;i, 1857, quoting from the Buffalo Republic the extensive prevalence of the disease, says that quot;in western New York especially we learn it, has been very fatal, but is now over. In conversation with one of the most extensive dealers in the neighborhood, a day or two since, he informs us that about six weeks ago he lost about four hundred in a very short space of time. A distiller in Jordan, during the month of September, lost fourteen hundred, which cost, in addition, over sect;1,000 to have them buried, lu Rochester, at all the principal points, and even among the farmers, the mortality has exceeded anything ever before heard of. A butcher in this city not long since purchased SöOO worth of fat hogs, but they died so rapidly on his hands that he scarcely realized sect;75 on the investment.quot; The Worcester (Mass.) Spy reports that many fanners in that city and vicinitA are losing their swine by the mysterious and fatal disease known as the hog cholera. In the southeast part of the town it prevails in a greater or less extent upon nearly every farm.

In most cases the disease is traced to Western bogs that have been sold by the drivers the present season, and which seem to have communicated the contagion to the other inmates of the sties in which they have been kept. It is known that of many droves of Western shouts that have been sohl at Brighton this season, and peddled about the State, nearly all have died. The disease lias, no doubt, prevailed extensively in other part? of the country, of which I have seen no notice. In this section of the country it has been extremely fatal. Over portions of Dearborn County it spread from farm to farm, and some of our fanners lost from 70 to 80 out of 100 of their hogs. At the distilleries the mortality has been very severe. I received information that more than 11,000 died at the distillery in New Richmond, in the summer and fall of 1856. The owners of the distillery at Aurora inform mo that they have lost between 6,000 and 7,000. A gentleman informs me that he lost in 1856, at Ingra-ham's distillery, in Cincinnati, from the 1st of August up to the 2-lth of October, 1,235, losing 1,152 out of a lot of 2,408. Another gentleman informs me that at the distillery in Petersburgh, Ky., he lost from the 1st of June up to the 18th of October, 1850, 2,576. I have also received information from several other distilleries where the losses were large. *

According to Dr. Sutton, this disease first appeared in Dearborn County, Ind., in July, 1850.

* George Sutton, M. ])., Observations on the supposed relations between epizootics and epidemics, and experimental researches to ascertain the nature of the recent epizootic among the swine, and the effects which diseased meat may have on human health. The North American Medico-Chirnrgieal Review, May, 1858, pp. 483-504,

13 Dr. E. M. Snow writes that

Diiriny; the last live yours this disease has hc.en seen, from time to time, in portions of the more eastern States, sometimes, as in western New York in 185(3, proving qnite severe and fatal in comparatively limited localities, lint in the Eastern States it has, to a great extent, originated with and has generally heen confined to hogs imported from the West. I think that in no State east of Ohio has (he disease prevailed extensively, or attained the character of a wide-spread epidemic.

In the vicinity of Providence, R. I., it has prevailed to some extent, more particularly among large herds of swine daring each of the last live winters, but has been mostly eontined to hogs brought from the West, and has usually disappeared with the approach of warm weather. During the last winter it was more severe than in any preceding, and was not eontined to Western hogs. Neither did the disease, as heretofore, cease with cold weather, but it continued until August, having destroyed more than ')U0 hogs in Providence and in the, adjoining towns during the first seven montlisof the present, year, 1861. I havealso heard of its prevalence in various towns in Massachusetts during the same period.'

The losses from hosquot; cliolera in the United States have been enormous. Estimates Lave front time to time been made from carefully compiled data, and these have, so far as the writer is aware, never been less than $10,000,000, and have reached $25,000,000 annually. The inclusion of losses from other diseases is, however, unavoidable in such estimates, and consequently some allowance must be made for these. The recent identification of an epizootic pneumonia of hogs by the Bureau of Animal Industry, a disease which appears to be identical with the /Schweine-senche o£ German writers, shows that the varieties of swine diseases in this country are more numerous than has been supposed. The erysipelas of Europe (French, rouget; German, HotMauf), and charhon have not yet been identified as occurring in an epizootic or enzootic form among swine in the United States but the existence of these diseases is not impossible, as the investigations have not yet been sufficiently uu-nierous to reveal the nature of all such outbreaks. The diagnosis of such diseases has been very uncertain in the past, because the symptoms were not clearly defined, and not always sufficiently characteristic. The most reliable means of discrimination between these maladies at present is the isolation of the microbes which produce them. The characteristics of these organisms are now so well known that the bacteriologist has no difficulty in distinguishing between them.

Kdwln 11. Snow, M. D., Hog Cholera. Annual Report U. S. Department of Agriculture, 1861, p. 147.

THE INVESTIGATIONS OF SWINE DISEASES.

Among the first to investigate these diseases in the United States from a medical point of view was Dr. George Sutton, of Aurora, Dearborn County, Ind. In the extensive epizootics which prevailed in that county from 1850 to 1858 he had abundant material for study, and he noted tlie more salient features of the plague in a very clear and comprehensive manner. While it is extremely difficult at this day to decide whether the outbreaks studied by Dr. Sutton were bog cholera or Inbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;swine-plague, or a combination of the two, his observations are very in-

teresting and bring out many important facts. Of the symptoms, jposf mortem appearances, and nature of the malady, he says:

Tkis disease presents :i great variety of symptoms. In January, 1856, wlien tins epizootic was at its height in this section of country, I published a short notice of it in tlie C'iiicinniiti Gazette. The symptoms which I then described I have found upon a more extensive observation to be correct. Tie; hog first appears weak, his head droops, and sometimes in a few hours after these symptoms diarrhea commences. There is frequently vomiting. In sonny cases the discharges were serous and clay-colored, sometimes dark, also bloody, and mucus resembling those of dysentery. The urine al lirst was generally small in quantity and high colored, but as the animal recovered it became abundant and clear; this was one of the symptoms by which the men who were attending the hogs at the distillery ascertained that they were recovering.

[n a large number of cases the respiratory organs appeared to bo principally affected; there was coughing, wheezing, and difficult respiration. In some instances the animal lost the power of squealing, and the larynx was diseased. There was frequently swelling of the tongue and bleeding from the nose. In those cases where the respiratory organs were the principal seat of the disease there was generally no diarrbeaor dysentery. In many instances the disease appeared to he principally cou-iined to the skin ; sometimes the nose, the ear, or the side of the head were very much inflamed ; the ear swollen to twice its usual thickness. This inflammation would spread along the skin, sometimes over the eye, producing complete blindness. Sometimes one or more legs were inflamed and swollen, and the inflammation also extended along the body. The skin where w as inflamed was red and swollen. Somehad

! nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; large son's on their Hanks or sides from 3 to 0 inches in diameter. Xu one instance, at

the distillery, the inflammation extended along the fore leg, the foot became ulcerated and sloughed ott, and the animal recovered. Some appeared delirious, as if there was inflammation of the brain, I examined the blood of four hogswhich bad this disease well marked; they were stuck, and the blood, arterial and venous, was caught in a bowl. It was cupped and presented a well-marked buflfy coat. Death took place in from one to ten days after the attack. Sudden changes in the weather, particularly from warm to cold, appeared to increase the fatality of this disease. The average

mortality of hogs that were ia pastures or fed ou slop was from 33 to 45 percent., but it was frequently much more fatal if hogs were fVil on cimiin sortie instances ranging from seventy to eighty out of thu hundred, and in some instances even higher.

I found on opening the bodies of hogs that had died of this disease that they all presented evidences of a diffusive form of inflammation. From sixty-seven hogsthat I have examined I found it was not confined to any particular tissue. Sometimes this inflammation was confined to one organ; in other cases it attacked several at the same time. The shin frequently presented patches of inflammation, and often had a purple appearance. In cutting through parts that were the most inflamed, the skin was swollen and the cellular tissue was infiltrated with serum. Frequently, however, the skin was merely discolored, without any swelling whatever. The stomach was occasionally distended with food, and the mucous membrane in nearly every instance presented evidence of inflammation, sometimes extending over the whole stomach, at others only in patches. It was generally of a deep-red color, thickened, and frequently softened. Sometimes it was covered with a viscid mucus: in other instances there was an effusion of blood into the stomach. The mucous membrane of tho small or largo intestines, where there had been diarrhea or dysentery presented in all instances evidences of inflammation ; in patches it was red, thickened, sometimes softened, and occasionally ulcerated ; where there had been dysentery there was generally bloody mucus found in the large intestines. The bladder generally contained urine ; sometimes its mucous membrane was inflamed, and in one instance there was an eflnsion of blood into this organ. In a large number of cases I found evidences of peritoneal inflammation, such as redness of this membrane, effusion of turbid or bloody serum, adhesions between the intestines and between the intestines and sides of the body. In three instances blood was effused into the peritoneal cavityin one instance more than a quart; it appeared in this ease to come from the liver. The liver was occasionally the seat of this inflammation, not only in its investing membrane, but tho parenchyma; sometimes there were abscesses, and iu one instance portions of it were gangrenous. Tho lymphatic glands were generally of a dark-red color, frequently resembling clots of blood. This disease of the lymphatic glands was of common ocenrrence.

The lungs were frequently tho seat of this inflammation, portions of one or both presenting different appearances, from simple congestion to complete hepatization; .sometimes there was nleeration, and frequently there was a turbid or sero-purulent or bloody effusion into the pleural cavity; sometimes there were extensive adhesions between the lungs and pleura of tin- ribs. At first I was inclined to believe this malady to be a form of plenro-pneunionia, but after I became better acquainted with it I found that the inflammation was not uniformly confined to any organ. In a number of instances the mucous membrane of the bronchia, was deeply inflamed and the inflammation extended to the trachea and larynx. In several instance's the larynx was inflamed, resembling laryngitis. One animal that had groat difficulty in breathing and could make no noise I had knocked in the head, and on examination I found the mucous membrane of the larynx and epiglottis inflamed and swollen; also the tongue was swollen. There were evidences in several instances of pericarditis, which had produced adhesions between the heart and the pericardium. The brain, from the difficulty of opening the skull, was examined only in one instance; it- was found healthy, although I feel confident it was frequently the seat of tho disease.

From these examinations we see that it is a misnomer to call this malady cholera. It is a contagious inflammatory disease, the inflammation being confined to no particular tissue, sometimes attacking only one, at others several, in the same animal. Evidences of this inflammation were found iu the dermoid, the cellular, tho serous, the mucous, and glandular tissues. I consider it a diffusive form of inflammation from the manner in which I have witnessed it spread along tho skin. In one night I have seen it extend from the eye to tho earthe car becoming inflamed and swollen.

Although we have not liecu alile to show thiit. this is a cholera epizootic, still tlio facts elicited may be of interest and remove' doubts at some future period. Hut, then, if this malady does not resemble cholera, does it resemble any of the diseases to which the human system is snbject .' I think not. Like the specific eruptive diseases, it is highly contagious; the iufeotion has a period of incubation of from twelve to twenty days, and otto attack appears !igt; exempt the animal from a second. Hut, in this disease, although petecchiicand an eruption mayappear on the skin, its principal characteristic is a diffusive form of intiaiumatiou which may attack nearly every tissue and spread like an erysipulas. Bat t hen, again it differs from this disease, as it is well known that in erysipelas one attack does not exempt the system from a second; and although erysipelasmay be contagions, still it is doubtful whetherthe period before the eruption shows itself is so tmiforraas in this disease, and while erysipelas is generally confined to the skin this inflammation most frequently attacks the lungs and mucous membrane of the alimentary caual. This disease appears to be intermediate between the specific eruptive diseases and erysipelas, partaking of the nature of each and probably not having its exuel resemblance among the diseases to which t he human system is subject.'

Of his oxpei'inients ami observatious on the contagiousness of the disease and the maunerof its spread he writes:

When the disease made its appearance in this section of country, in the slimmer of 1850, and we saw it spreading from farm to farm, thoquestion was sufo-ested whether it did not spread by contagion, for it was not known at that time (July) that the malady was contagious, feeling mach interest in watching the progress of this disease, from the large numbers of animals that weredying, I suggested to the owners of the distillery at Aurora. Messrs. Grafts, that we should try a series of experiments to ascertain the nature of t he disease, a nd whether it was propagated by contagion. To this they readily assented, and as they were constantly receivinraquo; fresh lues there was a line opportunity to make any experiments we saw proper. 1 am in dein cd to Mr. .1. .1, Barkman, of Aurora, for seeing that the following experiments, with the exception of the last, were carefully made. The hogs on which t he experiments were made were known to be healthy:

(1) Six hogs that bad I.....n exposed tquot; the malady by being in contact with diseased hogs were put into a yard by themselves and fed on skip and corn ; on ! bo fourteenth day from the time they were exposed to the disease, they were all unwell : ;'. died within a week afterwards, the rest recovered.

(2) Ninety hogs were exp ised to the disease, then put into a yard by themselves and fed on corn and water (no slop given); in thirteen days disease made its appearance among them, and they coutinned to die until tut out of the 90 died.

(:gt;) Fifty hogs were put into a pen by themselves.and fed on slop; they had not been exposed to the disease : for six weeks they continued healthy.

(4) Oue hundred hogs that had not been exposed to the disease were put intoa yard by themselves, and fed on corn ami wider: for thirty days no symptoms of disease appeared among them. They wore then put into a pen with diseased hogs; on the thirteenth day they began to show symptoms of the malady, and the disease rapidly spread among them, until 40 died.

(,'gt;) Thirty-three hogs, out of alotof 263, were put into a pen by themselves ; for six weeks they coutinned healthy. The remaining -i'-M) were put into a pen adjoining in which were diseased hogs; In thirteen days disease made its appearance among them, and continued until one-half died.

((i) Four young and healthy hogs were put into a pen in which, four days previous, diseased hogs had been ; they were fed on corn and water. On the fourteenth dav they were all unwell: and one died on the fifteenth day, and in live days more they were all dead. This experiment shows that the infection may be retained in a pen several days.

* North American iledico-C'hirurgical Keview. 1858, II. 4'.((i.

(7) I inoculated, ou the 38tb of CTotober, five healthy hoga witli tlio blood taken from the inflamed tissaes of hogs that had died of this disease. On the fourteenth day (November It) they were all unwell, and all died with the esception of one. In three inflammation spread from the point where they wen; inoculated, along the

skin and down the legs, which became very much swollen. 1 can not say that this inflammation was caused by the iuoculatlou, for it did not appear until the fourteenth

day, and many hogs had this external form of disease.

From these experiments I think that we not only ascertained that this disease was infections,but that the infection had a latent period of from twelve to Qfteea days. Observations have since led me to consider the latent period as varyinj; from twelve to twenty days. These experiments also showed that the hogs in the pens were not dying from strychnine in the slop. A statement was going the rounds of the papers about this time that strychnine was used in making yeast at the distilleries, and was poisoning the hogs at these places in large numbers.

The manner in which this disease in many instances spread among hogs from farm to farm also showed most conclusively that it was infectious. Otic farmer had 75 hogs that he turned into a eorn-lield to fatten. These hogs had been exposed to the disease, had become sickly, and numbers had died. He bought '#9632;''gt;gt; more; these were all healthy : they were put into the same field with the diseased hogs ; in two weeks they were unwell, and numbers died. He bought tö more, all healthy, and put them in the same field; in two weeks they began to show symptoms of disease, and in a few days after a number died. Finding that be was likely to lose all his hogs, he sold 50 of the fattest that were left to the butchers in Cincinnati, at a reduced price, as diseased hogs. These hogs, it was said, were purchased for their fat, to he used in the manufacture of lard oil. Alter deducting the ;quot;gt;lt; he sold, he lost, out of the 156 all but 10.

A large number of facts could be given, if necessary, to show the contagiousness of the disease. Hogs thai had been once under the Influence of this malady appearnot to be susceptible to a second attack. Although placed in pens with diseased hogs they continue healthy and fatten, and not a single instance can I find of hogs having this disease twice. There is reason to believe that this malady occasionally prevails at the distilleries in a mild form, as the. old hogs at many of these places did not take the disease. Hut why it .should suddenly have assumed so malignant a character is as difficult to account for as that scarlatina, from being at one time the mildest of diseases, at another becomes one of the most malignant. On the farms the old and young hogs appear to be equally susceptible to the disease.

In 1SG1 Edwin M. Snow, M. D., of Providence, II. I., contributed a paper on hog ckolera to the Annual Report of the United States Dc-partment of Agriculture (pp. 147-154). The symptoms of the disease lie gives its follows:

The Symptoms, as described by persons uunccustomed to such observations, are extremely various. By combining the information obtained from others with results of our own observations the symptoms, as seen during the life of the animal, are nearly as follows :

(1) Refusal of food.This is the first symptom usually noticed by those who have the care of the animals, though, as will 1w seen hereafter, this sympton by no means indicates the beginning of the disease. The refusal of food, after it is first noticed, generally continues through the whole; sickness, and food of every description is mostly refused.

{2) Great thirst.This is constant, and large quantifies of cold water will be swallowed if it can be obtained. Even after the animal is unable to stand alone it will drink cold water with eagerness.

{'#9632;]) After a time, the length of which varies very much, the animal begins to show signs of weakness; reels, staggers, and. in attempting to walk, often falls down. 15012 h C-----3

(4)nbsp; In most cases there is a diarrliea, with copious fluid discbarges of dark, bilious, aud very offoasive matters. luafew cases there is no diarrhea, but evacuations of hard blackballs; bat in some of these eases the fluid offeusive matter is found in

the intestines after death.

(5)nbsp; In a few eases there is vomiting ; but this is not often severe, nor is it continuous for any length of time.

(6)nbsp; The external aijpeaianee of the animal is at first paler than usual, but towards the last of the sickness purple spots appear, (irst on the nose and sides of the head. These extend along- the sides of the belly and between the bind legs, after which the animal soon dies.

(7)nbsp; In many cases, perhaps a majority, ulcers are found on the dili'erent parts of the body. These were particularly noticed on the inside of the lips and gums, and on the feet, and were often quite deep and excavated. In some cases these ulcers were seen in the nostrils, and in one case there were extensive ulceratious in the back part of the mouth, on the tonsils.

(d) In some cases I lie legs are swelled, and the animal is lame ; sometimes the ears and sides of the head are swelled and red ; sometimes the eyes are sore and inflamed ; sometimes swellings like carbuncles are seep; and, generally,the glands near the surface seem to be enlarged.

{'J) In most cases the pulse is quickened, the breathing is harried ami difficult, and there is much cough. But insome genuine cases' there is no perceptible trouble with the lungs, and no important signs of disease are found in them after death.

(10) The duration of the disease in fatal cases, after the first symptoms are noticed, is extremely variable. We have seen some which have died within two or three hours; others have lived many days. It is difficult, however, to fix the time of the appearance of the first symptoms. The first noticed is usually the refusal of food; but it is probable, indeed it is certain, that the sickness is in progress for a considerable period before the animal refuses food. Cases like the following are sometimes seen: A hog refuses to cat: it soon grows weak; staggers in walking: turns purple on the sides and belly, and dies within two or three hours after the first symptom is noticed. But, on examination after death, extensive disease is found in the intestines, or in the lungs, or in both, at a stage of development which must have required many days to reach.

Tha gost-mortem appearances are then summarized in the following language:

Having described the symptoms, as seen while the animal is living, I will now give, briefly, the appearances found ou examination of the bodies after death :

In the course of our investigations, during the last winter and spring, the bodies of nine hogs were carefully examined by Drs. lt;;. L. Collins, J. \V. C. Ely, and E. T. Caswell, of Providence, in the presence of several other physicians. A iniunte account of eacli case was prepared by Dr. Collins, and published in the Transactions of the Ehodo Island Medical Society for 1861. It will be suliicient for theobjects ofthis paper to give a brief synopsis of the diseased appearances which were found in these examinations:

Lungs.In two cases the lungs were healthy. In the remaining seven cases one or both hingswere more or less inflamed, having a liver-like appearance, called hepatiza-tion. In some cases the inflammation was more advanced, and the substance of the lungs was breaking down into a mass of disease. In all cases where the lungs wore inflamed there was also pleurisy, and the inngs were adherent to the walls of the chest; the inflammation of the lungs and the pleurisy together constituting true plen-ro-pneumunia. In two cases there were tubercles, or consumption in the lungs; but this is not iincoinmou in hogs, and is not supposed to have any connection with the special disease we are considering.

Slomach.Thf stomach and the small intestines were generally healthy. Tho stomach was freqeatly distended with an offensive mixture of food, and in one case

the innei surface was alcerated to some extent. In two cases worms were found in

siiiall intestines, Imt this \v;is probably a merely accidental occurrence, and had do necessary connection with the disease.

Large inUslines.The inner coat of the huge intestines was generally inflamed and .softened with ulcerations to a greater or less extent, and they were frequently so tender as to be easily torn with the fingers. On account of their diseased condition their inner coat was frequently discolored. The inflammation and nlceration of these intestines are probably the principal cause of the diarrhea in this disease.

Kidneys,These organs were, in every case, mach mure pale and yellow than natural; this condition was well marked.

The /(Ver and MoWrr were generally healthy. In some eases water was found ill the cavity of the belly and of the chest, and in the membrane snrrounding the heart (heart-case). In two eases numerous minute purple spots were seen upon the membrane Uniug the walls of the belly. The urine was often changed from the healthy condition, containing albumen and other diseased products, not, however, noticeable to the eye. I'leers upon the feel and in the mouth were often found. The brain was not examined, as there were no symptoms observed which seemed to indicate disease! of this organ. It may be at times affected, hut is probably more rarely so than the other organs of the body.

Such are some of the most important appearances which are found on examination of the bodies of hogs which havedied with this disease. It will be noticed that three of the diseased conditions I have described are prominent, important, and such as would be readily recognized by the most ignorant observer.

These are, first, the pleurisy and inthnmnation of the lungs; second, the inflarama-tiou, nlceration, and softening of the inner coat of the large intestines: and, third, the pale and yellowish color of the kidneys. One or more of these diseased conditions will be found in every case, and in perhaps a majority of cases they will all be found in the same animal.

While Dr. Snow admitted the disease to be epizootic lie did not consider it to be contagious. Indeed, be neither considered epizooticnor epidemic diseases to be contagious, but, on the contrary, held thattboy were caused by (1) quot;an epidemic atmospherical poison,'quot; and (2) quot;the local conditions or circumstauces adapted to receive and propagate tlie poison existing' in the atmosphere.quot;

In 187.quot;) Prof. James Law contributed a paper to the report of tbo Department of Agriculture giving'his observations upon bog cholera, or ^u intestinal lever in swine,quot; in whicb lie so completely embraces tlie knowledge of our swine epizootics as it then existed that bis paper is here reproduced in fall. It is as follows:

Synonyms.Typhoid fever, enteric fever, typhus carbnncular fever, carbuncnlac gastro-eutoritis, carbuncular typhus, pig distemper, blue sickness, blue disease, purples, red soldier, anthrax fever, scarlatina, measles, diphtheria, erysipelas.

Definition.A specific, contagious fever of swine, characterized by congestion, exudation, ecchymosis, and ulceration of the mucous membrane of the intestines, and to a less extent of the stomach; by general heat and redness of the skin, efiaceable by pressure; by small red spots, complicated or not by elevations and blisters; by black spots and patches of estravasated blood on the integument, the snout, nose, eyes, month, and all other visible membranes, and on internal organs, ineffaceable by pressure and tending to sloaghing; usually by liquid and fetid diarrhea: and by a very high and early mortality.

The malady has been long known to pig-raisers and pork-factors in the Old World and the New-, but in veterinary works it has been mistakenly placed in the list of malignant anthrax affections, to which many of its lesions bear a striking resciu-

^quot;

bianco. Two EuglUb works, published within thelasrt year, repeat this time-honored fallacy. To tnaligaaut autlmcx it is allied by the altered coudition of the blood, by the solntiou of the blood-globules, by the imperfect ooagulatioa of the blood in many eases, by the occasional enlargement and congestion of the spltTen, Ijv the extravasation of the blood out of the vessels (petechiio) into the skin, mucous membranes, and internal organs, and by the dusky line of the eye, nose, ete. That it is essentially distinet is shown by Hie fact that its virus, so frightfully contagions and fatal to pigs, is not communicable to any other domestic animal. The contagion of malig-nant anthrax, on the other hand, is deadly to all domestic animals, and even to man himself.

The common American designation of hog cholera has only the diarrhea to support it, ami, aswe see outbreaks in which this feature is maiuly remarkable forita absence, the name comes to be an absolute misnomer. In many eases a gelatinifonu exudation takes place on the affected surface of the mucous mombrano of the intestines, windpipe, or bronchia, and the disease has accordingly been named diphtheria, lint as such an exudation is by no means constant, a name ton nded on this peculiarity would have no actual foundation in a large proportion of cases. Again, the exudation (see Post mortem No. 1) is mainly composed of cells and granules, with less of the ftbrinons yiatrix than is usual in diphtheria. Lastly, the intestinal fever of swine is most virulently contagious, whereas diphtheria is very slightly. If at all, infectious, and is confined rather to certain insalubrious localities or buildings.

From scarlatina and measles it is sufficiently distinguished by the constancy of the intestinal legions, though it resembles both in its cutaneous rash. With erysipelas it has no real connection, the one common feature, the redness of the skin, being due to a condition altogether different in nature, progress, and results.

The constancy of the congestion, specific deposit, and ulceratiou in the intestines in the lever of .swine, characterize it as perfectly as do the same lesions in typhoid fever in man. It further agrees with typhoid fever in having a higher evening than morning temperature and a rose-colored eruption on 1 lie skin. To this disease, indeed, it bears a closer resemblance than to any other disorder of man or beast, so that Dr. Budd and others with much plausibility call it the typhoid fever of pigs. But in spite of the similarity of the specific deposits and uleerations on the intestines, those, of the pig show- less tendency to attack the agminated glands (Peyer'a patches) and the solitary glands than is the case in man. They appear on all parts of the mucous membrane of the large and small intestines, yet the agminated and solitary glands rarely escape entirely, and sometimes (hey alone are the seats of ulceratiou and morbid deposit. The skin eruption, too, in the pig-fever is of ten distinctly raised, and even vesicular, whereas thai of typhoid (ever is a simple rash. and. like a blush, may bo completely though temporarily efl'aced by pressure. Finally, the contagion is incomparably more virulent and tenacious of life (hau that of typhoid fever, ami the mortality is greater and occurs earlier in the disease. On the whole, we must look on this affection of pigs as a disease sui generis, having close affinities with the typhoid fever of man, yet essentially distinct, and hence the term intestinal lever of swine is more applicable, its at once expressing its nature and avoiding confounding it with other and distinct affections.

Znoi/Jafioraquo;.The period of incubation has not been definitely settled. My experience in Scotland in 1864 would have led me to set it down at from seven to fourteen days. The infected pigs were four days on the journey from the English market by rail and seven days on the farm before the disease manifested Itself. Again, the home-bred swine, were sound until four weeks after the strange hogs came on the farm, and three weeks after the latter were generally sick. Pigs, though farrowed by sick dams, did not show any sign of disease for about a week, although nearly all eventually died.

In Dr. IJndd's cases, in April, 180.quot;., the first symptoms of illness were shown four or live days after the pigs were brought from Bristol market, where thoy may or may not have been infected.

Dr. Sattou'a oxpciiinuuts, made at Aurora, Ind., in September, October, and November, lft'48, deserve repetition in tbis coanectiou, (1) Six hogs, after contact with diseased animals, wore placed in ii Bound pen, and sickened on the tbnrteoutb day. (2) Of 90, similarly exposed aud then put in a sound yard, some sickened on the lliir-tcoutb day. (:i) One hundred, similarly exposed, contracted the disease on the tliirteentli day. (1) One hundred and thirty, placed in a yard adjoining one occupied by diseased lions, became ill on the thirteenth day. (5) Four young and healthy pigs, placed in a, pen oocapiedfour daylaquo; previously by diseased hogs, sickened on the fourteenth day. (6) Five healthy hogs, inoculated with the blood from the inflamed tissues of diseased swine, were unwell on tlio fourteenth day.

Further experiments were made by Professor Axe, of London, in April, May, Juno, and July, HT.quot;). (1) Two healthy pigs were, (in April) placed for forty-eight hours in the same house with a diseased one, contact being carefully avoided. One was dull and off its food on the sixth day and the other on the eighth. (-J) On May 15 a pig was inoculated with the liquid cutaneous exudation, which had been kept on dry ivory points for twenty-sis days. On the fifth day there was slight dullness and heat of skin, and on the sixth the malady was well developed. (3) On June 10 another pig was inoculated with the cutaneous exudation of the last, the operation being performed by another party and the pig kept apart to avoid all risk of indirect contagion. On the fifth day temporary redness was noticed on four teats, and on the sixth day the symptoms were fully developed. ( 1) Another pig broke into the pen occupied by the last-named subject and was left there for six days, when it was taken out seriously ill. In the hot summers of Illinois instances are met with in which symptoms of the disease are shown in a previously healthy herd under three days after the wind has blown from the direction of a sick lot half a mile distant. In analyzing this apparently somewhat discordant evidence we must bear in mind that the period dining which a poison will remain latent in the system will vary according to the amount taken in, the excited or febrile condition of the subject, and the mode of introduction into thesystem. Tims tin excess of any poison, animal or vegetable, will usually show its effects with remarkable rapidity. A feverish .state of the systcin. whether induced by intense heal, passion, or disease will rouse the poison into unusually early activity. Lastly, poisonsthat are inoculated usually actsooner than those introduced into the system by other channels. These considerations will serve to reconcile the prolonged latency of the poison in Dr.Suttou's cases, observed in cold weather, as compared with Dr. Budd's, Professor Axe's, and my own, in the English summer, and of these in their turn with the prompt development of the malady in the semi-tropical summer of Illinois.

iSi;jn_p/onilaquo;.The earliest symptoms are slight dullness, with sometimes wrinkling of the skin of the lace as if from headache; shivering or chilliness and a desire to hide under the litter are not uncommon. Some loathing of food, intense, thirst elevation of the temperature of the rectum to 104deg; Fahrenheit and increased heat audrednesa of the skin are usually the first observed symptoms, and ocoui one ortwo days later than premonitory signs above mentioned. The increased heatof theskiu is especially noticeable inside the elbow and thigh and along the belly. By the second day of illness tin; whole surface feeds hot. and in white nigs is suffused with a red blush, which may pass successively through the shades of purple and violet. It is usually more or less mottled at particular points, and a specific eruption appears as rose-colored spots of from 1 to :gt; lines in diameter, sometimes slightly raised so as to be perceptible to the touch, and cither pointed or more frequently rounded. The redness fades under the pressure of the linger, but only to re-appear immediately. The eruption is usually abundant on the breast, belly, and haunch, the inner side of the forearm and thighs, and the back of the ears. It stays out for two or three days, and may ho followed by one, two, or more successive crops of the same kind. The cuticle is sometimes raised in minute blisters, a feature which distinguishes this from the rash of typhoid fever, and the liquid of such blisters inoculated on other pigs

#9632;p-

communicates the disease. In addition to tlio rasli and siumltaueously with it, or soon after, there appear on tlit- sUin numerous spins of a dark-red or black color, varying in size from a line tigt; an inch in diameter, on the color of which pressure has no effect. These are due to the extravasation of Wood or of its coloring matter from the blood vessels into the tissues. :mil they dry up into I'aiu scabs or sloughs if the animal survives. Similar petecchial spots appeal'on the muzzle, in the nose, and on the eyes, and in some instances they are confined to these parts. The tongue is covered liy a brownish fnr.

From the fust the animal is sore to t lie tonch, but as the disease develops the handling of the animal is especially painful and causes granting and screaming. The pig lies on its belly, and, if compelled to rise and walk, moves stiffly, feebly, unsteadily, and with plaintive grunting, 'this weakness and prostration rapidly increases, and often ends in niter inability to rise or to support the body on the hind limbs. A watery discharge from the nose, followed b.\ a white muco-purnlent How. is not nncoin-innn. A hard, barking cough is frequently present from the first and continues to the last. .Sickness and vomiting may be present, but are far from constant. The, bowels are often confined at first, anil in certain cases, and even in nearly all the victims of iiarticnlar outbreaks, may remain so throughout, nothing whatever being passed, or only a few small black pellets covered by a film of mucus. These cases are qxdekiy fatal. More frequently, however, they become loose by the second or third day. and diarrhea increases at an alarming rate. The passages are first bilious and of a light or brownish yellow when not colored by ashes, charcoal, or the naturo of the foo :. lint soon they assume the darker shades of green and red, or become quite black and intolerably offensive. In such eases the elements of blood, inspissated lymph, and membranous pellicles, sloughed off from the ulcerated surfaces, are usually to be found in them.

The diarrhea becomes more profuse, watery, and fetid ; the pulse sinks so as to become almost imperceptible; the cough becomes more frequent, painful, and exhausting: the breathing is more hurried and labored; and the weakness increases until the patient can no longer rise on his hind limbs. At this period the petecchhe become far more abundant. Before death the animal is often sunk in complete stupor, with, it may be, mnscnlar jerking or trcaibling, or sudden starts into the sitting posture, anil loud screams, lu the last stages involuntary motions of the bowels are common.

Exceptionally swellings appear on the llank. with extreme lameness, and extensive sloughs of the skin of the ears or other parts. 1'alpitations of t lie heart also occasionally occur as precursors, attendants, or sequels of disease. If the disease should take a favorable turn, slight causes may make an early and perfect recovery, a complete convalescence being established in three or four weeks. A considerable proportion of the survivors, however, linger on in an unthrifty condition for months, evidently suffering from the persistent ulceration of the intestines or infiltration of the lungs. The mortality often reaches SO or 90 per cent, of all swine exposed, and in case of a certain number of the survivors recovery brings no profit to the owner.

Post-mortem appearances.The bine color of the skin becomes deeper and more universal a few hems after death. The fat beneath the skin is colored more or less deeply in points corresponding to the discoloration of the integument. The snout is usually of a deep blue, with ineffaceable black spots (petecchias). The membrane lining the eyelid, and to a less extent the skin, present similar black spots of extravasation.

The most constant changes are in the mucous membrane lining the alimentary canal, and especially that of the terminal portion of the small intestine (ileum) and the commencement of the large (cscoum, colon). The tongue is furred, but deep red, even eroded, at its base, and the pharynx and adjacent parts usually studded with petecchim. The cavity of the abdomen generally contains a few ounceraquo; of reddish serum, which coagulates on being heated. The stomach may show no more than a pink blush, but more commonly it is of a deep red. from congestion, especially to-

ward the pylorus, and its mncona membrane is often black thxongboat from tlio close aggregation of peteccbise. The small intestines are usually extensively congested, and of a deep red, in many cases approaching to Mack, as examined externally. Their mucous membrane in such parts is equally high colored, studded with petec-chiie, and in some cases lined by a linn, semi-flbrinous exudation. A more constant condition is the presence of minute sloughs or erosions in the seat of peteccbiea, and of equally small elevations, duo to excessive cell-growth, beneath the epithelium. These commonly have a whitish center, with a yellowish or red border. Such is the appearance in cases that prove fatal within two or three days. In those that have survived longer, extensive ulcers appear, of an inch and upward in diameter, evidently the sequel of the petecchite, and especially of the eruption.

These ulcers are often covered by black scabs or sloughs, have irregular projecting margins and a variously colored center, consisting of cells in process of disintegration. They are sometimes situated on Fever's patches, but show no very marked preference for those over other portions of the mucous membrane. The large intestines present a similar varying vascularity, discoloration, petecchise, deposit, softening, and ulcera-tion. The changes are especially marked in the caecum and colon and in the rectum close to the anus. The solitary glands are often large and open, but the ulcers show no particular preference for the points occupied by them. Extensive extravasations of blood into the coats of the bowels and among their contents are not infrequent, and in certain exceptional and advanced cases the peritoneum is inflamed and false membranes bind the bowels together or to oilier organs, or to the walls of the abdomen.

In the wind-pipe and air-passages within the lungs, the mucous membrane is usually mottled with black petecchise, or covered by a vise id mucous exudation. The anterior lobes of the lungs are of ten solidified by exudation, but remain bright, red, tough, and elastic (gplenisatiou). Limited hepatizatiou is also exceptionally met with, and oven false membranes on the pleura or pericardium.

Petecchise are commou over the various internal organson the lungs, pleura, heart, pericardium, diaphragm, peritoneum, liver, pancreas, kidneys, and bladder. The spleen is large and dark, as is usual in connection with blood poisons. Uoth sides of the heart contain clots of blood, extending from the auricles and ventricles into the great vessels. In the worst cases, the clot is black, soft, and somewhat diffluent; exceptionally it is firm, and shows a distinct bully coat. The blood-globules, as seen under the microscope, arc more or less puckered or crenated at their edges, and mixed with an excess of granular debris and even in some instances spores of a fungus (tnicrococous),

As illustrating tin! various lesions in different cases, I append from my notes of post-mortem examinations two that occurred with two years' interval, near Edinburgh and London, respectively:

I.No. 4. A three months' old, while Yorkshire x'ig in excellent condition. Examined a few hours after death, being still quite warm, rigor mortis had set in strongly. Along the whole lower surface of the body, from the mouth to the tail, arc spots of dark red or purple. On the right side of the head and left side of the chest the spots run into each olhcr. so much i bat they seem to form a single continuous blush. On the back the spots are smaller and less numerous. There are no spots nor petccchia! on the snout, but a glairy bloody lluid runs from the right nostril.

The membrane lining the eyelid is congested, having a dark hue, approaching purple, and a portion of the mucous membrane of the rectum, exposed by the relaxation of the sphincter, presents the same appearance. Dark red spots and petccchia! exist about the vulva. Under the belly is a subcutaneous layer of fat about an inch thick, and beneath the purple spots or. the skin this is discolored by blood throughout the entire thickness.

The abdominal cavity contains (1 ounces of a dark bloody lluid. The intestines have a deep florid line externally. The stomach ami the greater part of the rectum are pale and without any lesions of the mucous membrane. Close to the anus this

membrane is congested. The stomacli contains about two pounds of food (boiled potatoes, corn, ete.). Tbe siniill intestines Lave their mucous membrane thickened, soft, friable, and very red, the shades being lighter or deeper at different points. It presents at intervals spots of a much darker hue, approaching purple, and respectively from ouc to two lines in diameter. The large Foyer's patch on the ilenm seems Lypertrophied and of a deep red, especially close to the ileo-csecal valve, where it also shows small ulcers. The huge, intestines have their mucoas membrane of a very-bright red, soft, friable, and presenting at intervals small ulcers of about a line In diameter, and corresponding apparently to the solitary glands. Some of these ulcers are of a deep red, and appear on the peritoneal coat as dark spots ; others are of a dirty white in the center, witli raised red edges, and are not SO marked on the peritoneal surface. A small nodule felt through the outer coats is characteristic of both. The contents of the large intestines consist of dark semi-liquid feees, with a great amount of ashes.

The liver is variable in color and very friable. Though still warm, it presents small bubbles of gas at intervals under its capsule and throughout its substances. The gall-bladder is half full of a very light-colored yellow bile. The pancreas seem healthy. The kidneys, bladder, and uterus are normal.

The pleura and lungs appear healthy, excepting a portion of the anterior lobe of the left lung, which is in a state of splenisation. The bronchia contains bloody froth, especially in the left lung, and those of the solidified portion contain a white solid substance, completely filling them, and appearing to the naked eye like a fibri-nousclot,while under the microscope it is found to be mainly composed of small globules about the size of blood-cells. It is disintegrated and partly dissolved in a strong solution of potassa. The mucous membrane of the larynx and trachea is congested and the tube filled with a white frothy mucus of an exceedingly tenacious consistency.

II.No. 2. Three months'old female pig, large of its age. Dead twelve hours. liiyor mortis well marked. Skin almost universally of a livid hue, but purple along the abdomen. Hack, whirr. Profuse eruption overtho body, but especially abundant on the abdomen. The smallest, and evidently the most recent specimens of the eruption, arc indi vidually about aline in diameter, deep purple, and covered by a delicate, slaty-looking skin. The larger spots have a dark, hard, dead center, which appears to spread gradually to the whole of the patch : some appear as a large black scab of one-halt' to 1 inch in diameter.

Abdomen contains li ounces of serum, which forms a solid coagulum on being heated. False membranes bind the large intestine's to the lower wall of the belly, also the two horns of the uterus together and to the bladder, and both to the walls of the pelvis. The large intestines are the seat of an exudation half an inch thiek, from which a straw-colored fluid escapes on section. The stomach is considerably discolored on its great curvature externally, as if from extravasated blood. The mucous

membrane of the stomach presents nu.....ions petecchise and ramified redness along

the great curvature. The small intestines show slight branching redness on part of the ilenm,

Large inteiifines.Ciecum has its mucous membrane abnormally vascular; with abundant potecchiaj, and ulcers of considerable standing; these appear as white, raised masses, and have no manifest connection with the solitary glands. The blind-gut contains numerous ascarides. The mucous membrane of the colon repeats that of the ca;cuni, but at one point beneath its serous coat is a blood-clot measuring I inch by half an inch, and a quarter of an inch thick.

The, liver is healthy. Thedlaphragtn has abundance of petecchiai on Its posterior surface, especially on the cordilorni portion, and apparently leading in radiating lines from the center. Beyond the presence of petecchim the organs of the chest seem to be little affected.

Causes.Contagion is the maineanse of this disease. The introduction of diseased

lgt;igs into liealtliy herds; the placing of healthy pi^s in pens, cars, stoam-boats, markets, etc., where diseased swine are then or have formerly been exposed; aftesh breeze from t lie direction of a diseased herd, though half a inile distant; the passage of nieu or quadrupeds or birds from the diseased to the healthy ; the use of food, litter, or water that has been ia near proximity to the affected animals, have each served to transmit the fever.

The virus appears to be concentrated in the bowel-discharges and liquids of the eruption, but doubtless exists in all the liquids and tissues of the body, and is given oil'into the air from the skin and exposed macoas membraaes. Pigs are often born sick, and die in twenty-four hours. The feeding-troughs and water, contaminated by the lilthy feet and snouts, are particularly liable to convey the disease.

The malady prevails at all the periods of the year, but it has opportunities for the widest diffusion in dry seasons and countries, where the virulent matter may be dried up ami preserved unchanged for an indefinite period, and in this state may be carried by winds and otherwise. Wet weather contributes to the decomposition and destruction of this, as of any other animal poison, but cannot influence its propagation by the direct contact of healthy with diseased animals, nor aflect its preservation inside dry buildings.

Unwholesome conditions of life contribute largely to its diffusion, if not to its development de noi'O. The malady frequently appears in pigs that have been carried several days in succession in crowded boats or cars, among the accumulated tilth of tbeir own bodies and those of their predecessors, and subject to compulsory abstinence from food and water. Again, it will occur in fat hogs that have been driven a number of miles under a hot sun and then cooped up in a filthy, close, ill-ventilated pen, subjected to the reeking fumes of their own bodies and of long-accumulated Hastiness. Many think that dry-corn feeding and overcrowding on lilthy manure heaps are largely productive of the disease. But it is too much to assume that the poison is developed de noi'O in such conditions. .Similar unwholesome influences favor the development of all contagious diseases by loading the blood with effete and deleterious organic matter, and bringing about a feverish and susceptible state of the system. But, on the other hand, such abuse and maltreatnunt fail, in very many cases, to induce the affection, so that we are left in doubt in regard to those instances In which it appears as to whether the virus was not hidden away in the buildings, cars, etc., and roused into activity by the, presence of a fertile field for its growth in the bodies of the pigs, the blood of which was loaded with organic elements in pi'oc-ess of decoiupositiun. The important point is this: We know this as a contagions affection, to the propagation of which all probable insalubrious conditions contribute. So soon as we concentrate our attention on this point we have the key to its prevention, if not to its entire extinction. Jjuf, while admitting the influence of overcrowding, filth, starvation, and suffering in predisposing io this disease, it ought to be added that the very highest mortality is often reached among pigs kept in the best hygienic conditions, but among which the virus has been accidentally introduced, Again, some hogs, and even families, appear to be insusceptible, and resist the poison which is carrying off all around them. But similar instances of immunity are met with in all contagions affections.

Treatment.In a fatal contagions disease like that under consideration it is rarely good policy to .subject to treatment. The enormous increase of the poison in the bodies of the sick, and the exireine danger of its diffusion through the air, as well as on the feet of men and animals, render the preservation of the victims eminently unsafe and unprofitable. Yet, in the case of very valuable animals, and where seclusion, disinfection, and careful nursing can be secured, it may be resorted to.

A dry, airy, well-littered building maybe provided, abundantly sprinkled with a solution of carbolic acid or chloride of lime. Rugs steeped in a solution of one or other of these agents may be hung np at intervals, and sulphurous acid set free by burning a pinch or two of sulphur three or four times a day. The dung should be

saturated or tliickly sprinkled with finely powdered copperas. Any drains will re-(iniru disinfection in the same way. If the sick animals arc, kept iu the open air, Hio ground must bo freely sprinkled with disinfectants, above all where the dung has been deposited.

The diet should be well boiled grind of barley, rye, or Graham tlonr; or, If lever runs high and the temperature is raised by such food, corn-staroh made with boiling water or milk may be substituted. Fresh, cool, water should be freely supplied, either pure or slightly acidulated with sulphuric acid.

During the early stages, while constipation exists, the bowels may be gently opened by castor oil (2 ounces for a good six-monthsquot; pig) or rhubarb (1 dram), aided by injections of warm water. The heat of the skin must be counteracted by sponging with cool or tepid water, as may seem most agreeable to the patient. As the laxative operates, 20 grains of nitrate of potash and 10 grains of bisulphite of soda may be given twice a day in the drinking water. Charcoal may also be given to absorb and neutralize the deleterious products in the bowels. ()r the niter may be replaced by any other neutral salt and the bisulphite by another antiseptic agent. If the patient survives the Brsl few days and gives indications of nlceration, by tender abdomen, diarrhea, and the passage by the bowels of membranous sloughs, oil of turpentine, in doses of 15 or 20 drops, may be given, shaken up in milk or beaten in an egg ; or this may be replaced by similar doses of creosote or carbolic acid, or :5 to 5 grain doses of nitrate of silver. Ir may be necessary to give opium to check excessive purging, or stimulanta to sustain the failing strength and very prostrate condition. Infiltrations and intlanmiatiens of the lungs and bowels may demand applications of mustard and turpentine io the chest or abdomen. In short, any complication must be combated as it appears, and the soundest judgment will be wanted throughout to adapt the treatment to the various indications. Each case will demand as close attention and as careful an adaptation of remedial measures to its different stages and phases as would a case of typhoid fever in man. In case of recovery a course of tonics (gentian one-half dram, sulphate of iron 10 grains daily) will often be beneficial, ami the return to ordinary feeding should be brought about by slow degrees.

Prevention.A successful system of prevention can only be instituted when we duly appreciate the fact that almost all eases of this intestinal fever are due to contagion. And this is precisely what our hog breeders fail to realize. No mau iu his senses will affect to deny that the disease is contagions, but the natural tendency is to seek for other causes in the great majority of cases. As in the ease of all contagious affections that have attained a. wide prevalence, this presents a number of outbreaks which can not be traced to contagion from any diseased stock, and these are at once assumed to be spontaneous, and the cause of the. disease is sought in the peculiar treatment of the herd, and future prevention is attempted by the avoidance of these peculiarities. In illustration, 1 may quote from a letterof Jlr. I. F. Hatch, an intelligent. Illinois fanner, and former student of Cornell University :

In former years hog cholera has been local with us except when it first appeared, some ten or twelve years since. Then, as now, it was general, and swept everything. But since then it has been confined to a few farms or localities. Sometimes it appeared on a single farm, or perhaps on several farms, 1, 2, or :? miles apart, all others escaping. I hive a neighbor who has had it every second year since its first apppear-ance, losing more or less hogs each time, but his is the only case of which I have been informed laquo;here it, has been so regular and often.

This irregularity ami local appearance deluded us into the belief that we were preventing the disease by extra care and attention, and that salt, sulphur, and ashes

were a preventive ; but we have I.....n effectually undeceived this time, for bogs that

have been doctored thus fared no better than those that bad not.

There is one man here whose bogs have escaped the disease entirely, and bo has fed for a number of years once a week, or once in two weeks, corn boiled iu the ear with asheslyed corn, as they call itputting a peck of wood-asbes into a -JO-gallou kettle. He tells me he has had no cholera since he adopted this plan, and his bogs are certainly good subjects for cholerapoor, half-fed, and sleeping in a pile under the baru. lie says others have tried this plan and successfully warded off the disease.

He goes on to quote instances of aHegod pievention by feeding hoose-slops without corn, and by giving once a week a teed of the boiled Jowls and waste parts of the jiigs killed the year previous, and adds:

Generally diseased hogs run, sleep, and eat with the others, it being the general opinion that they'll all have it anyway, so no matter. I am of a different opinion. A few change the yards and sleeping places, but generally they stay in the same places throughout the disease. No attention is paid to disinfection.

These alleged preventives are doubtless somewhat beneficial by maintaiuing a free action of the bowels and kidneys, and favoring the elimination of the poison, as does diarrhea in the milder cases of the disease. ISut there need be as little donbt that, like the salt, sulphur, and ashes, they would all fail in the presence of a strong dose of the poison. Meanwhile, they are made to serve an evil purpose in diverting attention from the one eli'ect mil means of restrict ing the disease, the extinction of fhe poison. Jt must be fully recognized that neither contact: nor proximity is necessary to contagion. The poison may be carried a certain distance on a stream of water without losing its vitality. It may be blown a long way by a favorable wind, when dried np, on light objects. It may be carried on the boots, hands, etc., of men (dealers) passing from farm to farm and from district to district. Horses, cattle, sheep, dogs, fowls, pigeons, and wild animals of all kinds are liable to carry the virus on their feet and limbs, and to deal out death to the pigs at places widely separated from each other. It is, therefore, quite impossible to trace all new outbreaks to contagion. But to attribute them to spontaneous evolution of the disease is to beg the whole question.

It can be freely conceded that a certain number of eases probably originate spontaneously every year; but these are few and far between as compared with the enor-mons mortality caused by contagion. It can be equally conceded that certain seasons are far more favorable to the propagation and virulence of the disease than others, yet even in these the great majority of cases are infectious. It can be admitted even that a wholesome laxative diet is to some extent protective, as well as comfortable dwellings and antiseptic agents, like copperas, bisulphite of soda, charcoal, or carbolic acid. But all such protectives are comparatively limited in their operation, and, though they seem to have saved a few isolated herds, will fail disastrously if generally relied on. The epizootic inflaence, too, though apparently all-powerful in localities where the poison has already penetrated, fails to produce the disease in the neighboring States not previously infected. We can not give too much attention to secure the best sanitary conditions of life for the hogs, but if we allow a few of these so to engross our attention that our eyes are blinded to the most important of all the prevention of contagionwe shall only spread the poison and increase the destruction of our herds. On the other hand, the highest success must attend such measures as will slop the production of the poison and destroy and render innocuous what is already in existence.

Diseased pigs must be removed from the healthy, killed, and buried. A thorough disinfection of all buildings, yards, and mauure must be made. Chloride of lime or zinc, sulphate of iron, or carbolic acid may bo used for all solids, floors, troughs, walls, etc., and for drains: and sulphurous acid or chlorine for the atmosphere. The snlplinrous acid may be produced by burning sulphur, and fhe chlorine by adding oil of vitro] to common salt and a little black oxide of manganese. The surviving pigs must be carefully watched for the first signs of illness. Any unusual sluggishness, stiffness, or inappetence, or any disposition to leave the herd, demands a careful ex-aminat ion : and if there is heat or shivering, and, above all, if the thermometer introduced into the rectum indicates a temperature above 103deg; Fahrenheit, the animal should be at once separated from the herd, and destroyed as soon as unequivocal symptoms of the malady are shown. Cave should be taken to avoid the possibility of contamination by water which has passed infected hog-pens or fields. If the malady exists within a wide radius, the visits of dealers and others must be absolutely for-

bidden, and a similar prohibition should attach us far as possible to quadrupeds and

birds, wild and tame. Disinfectants may even be given to the sound animals that have been exposed to contagion. A table-spoonfnl of charcoal, animal or vegetable, may be given daily to each pig in its food. Twenty grains of bisulphite of soda, or ten drops of carbolic acid, or 10 grains of sulphate of iron may be used instead, and a tea-spoonful each of sulphur and gentian may be added with advantage. When a herd has been freed from I lie disease, a most exhaustive disinfection of the whole premises, manure, and other products is imperative, and it is usually- desirable to change the site of the hog-pen and run to obviate any future effects of this most virulent contagion. Old and rotten wood work should be burned.

In purchasing pigs, buyers will consnll their interests by avoiding markets, and going rather tu the breeders whose stock is known to be healthy,and by seeing personally to the thorough cleansing and disinfection of loading-banks, cars, boats, etc. which they must use in bringing them home. And after all such precautions, newly purchased swiae should invariably be placed In quarantine, at a safe distance from other hogs, and kept there for three weeks, with separate attendants, until they have been proved sound.

As in the ease of other fatal contagions, this could doubt less be kepi in check, or even completely extinguished, by a uniform system of destruction of the infected, and disinfection of their carcasses and all with which they have come in contact. Such a proceeding would imply an amount of governmental supervision and pecuniary outlay that would be profitable in the long run, though the past experience of the American people have scarcely prepared them to sanction it.

In 1877, a paper written by H. J. Detiners, V. S., giving his observations of tue disease generally called hog cholera, and Ins oonclusions as to its nature, was reprinted in the annual report of the Department of Agriculture. Dr. Detmcrs proposed to call the malady quot; epizootic iuflnenza of swine,'' and lie divided it into (1) quot;the catarrhal rheumatic form,quot; (2) quot;the gastric-rheumatic form,quot; (3) quot;the cerebro-rheu-matic form,quot; and (1) quot; the lymphatic-rheumatic form.quot; The causes of the disease lie divided into three classes, and he writes:

As belongingto the first class I look upon everything that will interrupt or disturb the perspiration: in the second class I place all such noxious influences and agencies as interfere directly with the process of respiration; llnally, in the third class, [put all such noxious agencies or injurious influences as tend to aggravate the disease if already existing, by aiding in making its character more typhoid, or which produce a special predisposition by weakening the constitution of the animal.

In regard to the contagiousness of the affection lie says: Still I think the epizootic character of the fearful spreading of (he disease can be satisfactorily explained without the existence of a contagion.

The above extracts show the most divergent views among physcians and veterinarians as to the cause and nature of the epizootics among swine. At the same time there were equally wide differences of opinion among swine-breeders and the contributors to the agricaltural press. In short, there was the greatest uncertainty and confusion of ideas not only as to the characters of the disease or diseases, but as to the most elementary principles to be applied for prevention.

It was Just at this period (1878) that Congress provided for the first investigation of swine diseases by making an appropriation of $10,000 for this purpose. The beginning of tliis investigation, which lias been

continued with short interruptions until tlio present time, marks a new era in our knowledge of swine epizootics and of contagious diseases iu general. It was just at the time when the biological researches of Pasteur in regard to fermentation were, attracting so much attention, and had already inspired Lister to make his discoveries in antiseptic surgery, and Koch to institute those researches which definitely connected the iadllus anthrads with the causation of charbou. The time was propitious, therefore, for the institution of a new line of researches, in a direction which even then promised much, and which since lias practically revolutionized the position ot medical science as to the nature of contagion and the methods most important for its control.

The writings of Drs. Sntton, Snow, and Law gave a very correct statement of the symptoms and postmortem appearances of the organs usually found in the swine epizootics of this country. They covered about all the points which can be decided by ordinary field observations, but they left many questions still unsolved which it was necessary to determine before measures of prevention could be formulated and made successful.

There were many who believed that these epizootics were due to the ravages of more than one disease, and there were also many who held that contagion and infection played no part in their extension. As to the nature of the agent or agents which caused the outbreaks, or the conditions which were required to prevent their destructive ravages, no results of value had been obtained, or indeed could be, without a more systematic and persistent investigation, with all the instruments, apparatus, and laboratory facilities which are required to work out the obscure problems of pathological science. As with other contagious diseases of men and animals, the instruments of the post-mortem case had been the moans by which a certain amount of information had been gained, but there were problems which they could not reveal, and for these the microscope, the culture apparatus, the biological and chemical laboratories were necessary, and without these a reliable solution could not be reached.

For the investigations of 1S7S nine men were appointed for a period of two months each, as follows : Dr. EI. J.Detmers, Illinois; Dr. James Law, New York; Dr. 1). W. Voyles, Indiana ; Dr. D. K.Salmon, Xorth Carolina; Dr. Albert Dunlap, Iowa; Dr. If. F. Dyer, Illinois; Dr. A. S. Payne, Virginia ; Dr. J. ZST. McNutt, Missouri; Dr. 0. M. Ilines, Kansas. The researches were to be made in the field in different sections of the country, and various remedies, suggested as applicable to the treatment of epizootic diseases, were to be tried. The result of this investigation may be summed up practically aa follows : (1) Swine diseases were found destructive in the most widely separated districts of the country. (2) The symptoms and lesions enumerated were similar to those formerly given by Drs. Sntton, Law, and Snow. (3) Xo evidence was discovered to show the existence of more than one disease which prevailed as an epizootic. (4) There was a preponderance of opinion that the outbreaks were duo to contagion and that the disease was com-

numiciible. (5) The remedies tested either prodnced no effect or were of doubtful value for the treatment of affected animals or for gnarding against the oontagion.

There were two points of more than usual interest raised in the investigation, lu the course of J)r. Law's investigations he made inoculation experiments with lalibits, rats, and sheep, which he thought demonstrated the communicability of the disease that he investigated. Dr. Detmers devoted more of his time to microscopical investigations, and asserted that he had discovered a specilie micro-organism, which he called the Bacillus suis, and that he had demonstrated its pathogenic connection with the disease.

Both of these conclusions must now be looked upon as premature and not supported by the direct and positive evidence which is necessary to establish such important points. That Dr. Law produced disease in the experimental animals which he inoculated is not to be doubted for a moment, hut that it was the same disease and caused by the same microbe which produced the swine epizootics of the country could only be definitely determined after the microbes of the swine diseases had been identified and their characters established. Very frequently in inoculating with the products of disease taken from dead animals, septic disorders are caused in the inoculated animals which are entirely different in nature from the malady which caused the deatli of the individual inoculated from. To determine, therefore, whether the disease induced is identical with the disease which we propose to propagate by inoculation it becomes'necessary to determine the microbe which causes the morbid changes in each case. At that time neither of the microbes which we have since identified and studied in swine epizootics in this country had been discovered, and consequently the line of evidence just indicated was impossible.

Dr. Detmers's culture experiments were too crude and primitive to be of any value, even in the condition in which bacteriological science was at that time; and his descriptions of the germ might be applied with equal accuracy to many different species of micro-organisms. For this reason no attempt will be made in this volume to give the details of either the culture or inoculation experiments which he made. While failing to obtain the evidence necessary to establish the connection of any microorganism with the production of this malady, this and subsequent reports of Dr. Detmers had some effect in directing the attention of investigators in this country to bacteriological researches as a promising field in which to search for the hidden mysteries connected with this class of diseases.*

* It is dne to justice to state iathia conaeotion that, whereas the appointments llm-itod the work of those selected tor the investigations of IST.-i to a ])eiio(l of two months, Drs. Detmers and Law were subsequently given an opportunity to continue their iu-vestigations for a much longer period. It i.s also proper to stale that several months before the investigations of 1Ö78 began, Dr. Klein, of JLondon, had published investigations which lie believed established the fact that the swine epizootics of Great Britain were caused by a baciihis. See Quarterly Journal of Microscopical Suienee, April, 1878.

The investigations of the Department of Agriculture were continued in 1879 by Dr.s. Law and Detiners; in 1880 by Drs. Law, Detiuers, and Salmon, ami in 188I-'82 by Drs. Detiners and Salmon. The efforts of Dr. Law were largely directed to obtaining a modified virus for preventive inoculation, a doubly difficult and discouraging task before the microbes of the diseases had been discovered and studied. While his results were more or less encouraging, no conclusions of practical value as to a method of preventive inoculation were established.

Dr. Detmers continued bis microscopic observations and modified his first descriptions of the microbe so far as to speak of it in later reports as a micrococcus. The author devoted the greater part of his time during these years to an investigation of southern cattle fever and fowl cholera, but incidentally investigated a number of outbreaks of swine diseases. He found micrococci in the liquids of the affected animals, which he cultivated and inoculated into other animals, but his results were not sufficiently positive to demonstrate their connection with the disease.

There was here a period of about four years when the investigations of swine diseases gave no very decided advance in our knowledge of the subject. The reason for this was that the investigation had been carried about as far as was possible by the methods then employed.. To get a better insight into the nature of the epizootics and the peculiarities of the contagion, it was essential that the pathogenic microbes should be discovered and accurately studied. The investigators saw this and were working in the proper direction, but at that time bacteriological science was young and the methods of research had not been clearly worked out. Another and equal difficulty was the fact that the investigators were working without proper laboratory facilities and apparatus for such researches, without assistants, and some of them were devoting much of their time to other duties. Under such conditions it is next to impossible to reach successful results in such a difficult field of study. These difficulties were not fully appreciated either by the officials of the Department of Agriculture or by the stock-owners of the country, for the reason that such investigations were new to them and their requirements but imperfectly understood. It was not expected that a chemist would go into a sorghum field and discover the proportion of cane sugar in the sorghum cane without apparatus or laboratory facilities, but, it was expected that the veterinarian would make much more difficult and delicate investigations than these with no other aids than an ax, a butcher knife, a scalpel, and a microscope.

The author saw that more facilities must be provided for these investigations, and the work systematized and properly divided, or the final result would be disappointment and failure. It was through his urgent representations that a beginning was made in 18S;3, by securing an unoccupied room under the roof of the Department building, which was fitted up as a laboratory, and by obtaining permission to rent a small place in the suburbs of Washington ou which to keep experimental animals.

The year 1883, however, was one in which tlic necessity of investigating the prevalence of the lung plague or plenropneunionia of cattle became too urgent to admit of delay. There were frequent outbreaks which it was the duty of the chief of the veterinary division to visit and give assistance to the State authorities as to their diagnosis and eradication. This precluded any systematic investigations of swine diseases. The spring of 1881 hiought the extensive, outbreaks of ergotism in Kansas, Missouri, and Illinois, which alarmed the whole country, and which demanded instant attention; and these unfortunately were followed, in the suiiimer, by the outbreaks of pleuro-pneumonia in Ohio, Illinois, and Kentucky, which required the constant attention of the chief veterinarian and prevented scientific researches for several months.

The investigations (luring the years 188.'} and 1881 were, therefore, too much interrupted to allow the number of experiments and the thorough working our of details which was desirable. The time was not entirely barren of results, however, in the investigation of swine diseases. The laboratory was fitted up and suitable microscopic and bacteriological apparatus obtained. Able assistants were selected and placed in charge of the different branches of the work. The lines of research were marked out and such arrangements made as would permit of the intelligent prosecution of the work, even in the absence of the chief of the bureau.

This systematization of the investigations, with the employment of a proper number of-persons to keep the different lines of study advancing uniformly, was followed almost immediately by the most important developments. In 1SS5 a motile bacillus was discovered to be the cause of bog cholera, and its leading characteristics were accurately described. In 188Ü the production of immunity by chemical products was demonstrated, the effect of disiufeetants on the hog cholera contagion was thoroughly studied, and the presence of swine plague, a second epizootic disease of swine, was discovered. These discoveries solve the most important problems connected with swine epizootics and give a secure scientific basis from which to work in future. In fact these diseases are now much better understood than are most of the contagions diseases of people, and the measures applicable, in the present condition of science, to their prevention are equally as apparent as are those which are applied to the plagues of mankind.

In the sections of this work which follow the details of the investigations of hog cholera made since 1884 are given as fully as are considered necessary to an understanding of the different phases of the subject. The account of the experiments in regard to swine plague are reserved for publication in a separate volume, which it is hoped will appear within a few months.

SYMPTOMS AND POST-MORTEM APPEARANCES IN HOG CHOLERA.

The symptoms arc uot entirely characteristic, owing to the many forms wirich tlie disease may assume. It is moreover quite troublesome to make careful thermometric and other clinical observations on swiue, which enhances the difficulty of exactly determining the course of the malady. In general we may regard the disease as manifesting itself in an acute and a chronic or mild form.

Of the acute form very little need be said. The animals die very suddenly, without having been sick for more than a few hours to a day. The chronic disease may last from three weeks to several months. The animals grow stupid and dull, they refuse to eat, and are apt to separate themselves from the rest of the herd. They grow weak, and their movements become slightly tottering. A common symptom is diarrhea, which may appear very soon after the animal becomes sick and last until it dies. In protracted cases the liver may become aflected secondarily through the impaired condition of the large intestine.

The following symptoms, as noted for three or four years by Dr. Kil-borne at the experiment station of the Bureau, will show how little there is upon which we can depend for a diagnosis during life.

The temperature of healthy pigs ranges between 101deg; and 104A⁰ P. With sick animals it may rise from 1deg; to ;!⁰ above the temperature observed in health. Frequently this elevation is absent. During an outbreak elevation of temperature may be considered diagnostic, but absence of such elevation proves nothing, since an animal may die without having shown any rise of temperature during the disease. There is rarely any cold or shivering stage. The sick animals are (lumpish, spiritless, and lie quietly in a corner or huddle together, hiding the head under the litter. They refuse to move even when disturbed, and are more or less oblivious to surroundings.

There is more or less loss of appetite. They usually continue to eat a little, however, and often the appetite is scarcely impaii'ed during the whole course of the disease. Acute cases may be seen feeding before they are found dead an hour or so later. In most cases the stomach is well filled after death.

The bowels may be costive at the outset or continue apparently normal for some time, or they soon become costive, and remain so in some cases throughout the disease. In the later stages diarrhea of a 15612 H C------3nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; 33

liquid, fetid character appears in many cases. The color of the discharges laquo;lepeiuls largely upon the teed. In slop or garbage fed pigs they are usually of a dirty black color. In those fed with grain they are light yellowish. The diarrhea persists until death. Vomiting is absent.

Respiration is only occasionally quickened and labored in the later stages. The pulse is more, rapid than in health, but its determination unsatisfactory, owing to the struggle of the animals when held. Cough is infrequent, and then only heard when the animals are aroused, as a single effort or in paroxysms.

The skin is frequently found reddened on the nose, abdomen, inside of limbs, the ears, and over the pubic region. The redness is diffuse, varying from a slight blush to a deep bluish red or purple. It increases as death approaches, and is usually found at the autopsy. A skin eruption appears occasionally, which is followed by crusts or scabs of varying size. Reddening of the skin is a sympton comuion to the other swine diseasesrouget and swine plague.

The eyes are apt to be watery. This is frequently the first outward sign. Later the discharge becomes thick, yellowish, often gumming the lids together.

Towards the end of the disease the animals have a gaunt appearance, with arched hack anil staving coat. Emaciation is very rapid. The weakness manifests itself in a staggering, uncertain gait, as if the animal were about to fall. Death ensues quietly. Rarely convulsive kicking is observed. The mortality is very high, usually from 80 to 90 per cent, of those attacked die.

These symptoms vary in intensity, and only n certain number are seen in one animal at the same time. In very chronic cases only the autopsy enabled us to make a diagnosis.

LESIONS PKOD1 CED BY HOG CHOLEEA.POST MORTEM APPEARANCES.

(See Plates 1-VIII inclnsive.J

a. The acute type.This might with equal propriety be called the hemorrhagic type,inasmuch as thechief and perhaps the only changes are hemorrhagic in character, and these lesions arc seen most clearly when an animal is examined immediately after death. The spleen is variably enlarged, soft, gorged with blood. Sometimes it is twice as long as the normal spleen (the other dimensions being proportionately iucreased), and it may extend across the median line to the right side. Next to the spleen the lymphatic glands and serous membranes are most severely involved. The cortex shows, on section, as a hemorrhagic line or hand, according to the amount of extravasatcd blood, or the entire gland maybe infiltrated with it. Among the glands most commonly hemorrhagic are those of the meso-colou (large intestine),

those at the root of tue lungs (bioncliial), and on the. posterior thoracic aorta. Besides these, the retro-peritoneal and gastric gland? (lesser omentam) may be involved. Most rarely the meseutric glands show extravasations to a slight extent. Hemorrhages are also quite frequent beneath the serous surfaces of abdomen and thorax. They are most abundant under the serosa of the large and small intestines as petec-chiae and larger patches. They are occasionally found under the peritoneum near the kidneys, the diaphragm, the costal pleura as extravasations nearly an inch across.

The lungs, in a small percentage of cases, show subpleural ecchy-moses in large numbers, and on section small hemorrhagic foci are observed throughout the lung tissue. In a few eases severe hemorrhages, involving one or more lobes, have been observed. The kidneys are occasionally the seat of extensive hemorrhagic changes. The glomeruli appear as blood red points; larger extravasations occur in the medullary substance, and blood may collect around the apices of riic papil-Ige. The subcutaneous tissue over the ventral surface of the body may be dotted with petecchise and occasionally collections of blood (loemato-mata) are found in the superficial muscular tissue. The brain and spinal cord have not been examined for want of time. In one case, however, in which they were laid bare, peteechia' were seen on the cerebellum.

The digestive tract usually is the seat of extensive lesions. The fun-dus of the stomach is as a rule deeply reddened ; there may be more or less hemorrhage on the surface, giving rise to patches or larger sheets of blood clots. The small intestine in some cases has subniucous ecchy-moses throughout its entire length, hraquo; the large intestine the ecehy-moses may be so numerous as to give the membrane a dark red appearance. The food is now and then found incased in sheets of blood clot due to hemorrhage on the surface.

b. The chronic form is perhaps the most common, at least in those epizootics which we have studied. The acute hemorrhagic cases usually die in the beginning of an outbreak and are apt to be overlooked. Following these are the more protracted, milder cases. In these animals the disease is apt to be limited in its severe manifestations to the large intestine. The other organs, however, are not exempt from degenerative changes, owing in part to the impairment of the functions of the large intestine, consequent fermentations and the absorption of poisons thereby produced, in part to the presence of the specific bacteria in the spleen and presumably in other organs where they exercise their poisonous activity.

The lesions of the large intestines are necroticand uleerative in character. The ulcers may be isolated and appear as circular, slightly-projecting masses stained yellowish or blackish or both in alternate rings. Or they may be slightly depressed and somewhat ragged in outline.

When the superficial slough is scraped away many ulcers show a grayish or white bottom. A vertical .section reveals a rather linn neoplastic growth, extending usually to the inner muscular coat. When sections of such an ulcer arestained with aniline dyes and exannned under the microscope we notice the submucous tissue very much thickened, infiltrated with round cells, and containing a large number of dilated vessels. Besting upon this thickened subniucosa is aline of very deeply-stained amorphous matter, and upon this is situated the Jiecrotic mass which fails to retain the coloring matter and is penetrated by an immense number of bacteria of various kinds. Frequently ova of triehooepJialus are imbedded in the slough.

The extent of the submucous infiltration, depends upon the age of the ulcer. In old ulcers it contains many newly-formed capillaries, and evidences of the formation of connective tissue aro present. The capillaries may extend to the very edge of the border where the slough begins. The latter may have been partly shed, leaving a smooth line bounding the cicatricial tissue. The submucous infiltration gradually disappears as we leave the center of the ulcer, and somewhat outside of the ulcer no inflammation of the membrane is observable. Giant cells may be seen in some cases in the intertubular tissue at the edge of the ulcer. In very young ulcers it is frequently possible to observe the fundi of the tubules intact, while the inner or free half is converted into an amorphous mass. The depth to which the infiltration extends is not always limited to the submucosa: it may extend into the muscular coats and cause inflammatory thickening there and inflammation and the formation of new vessels in the subjacent serosa.

In some cases the necrosis, instead of appearing in circumscribed ulcers from one-sixteenth to one half inch or more across, involves the whole surface of the mucosa, giving it, the appearance of a so-called diphtheritic membrane. In such cases the walls of the intestine are very much thickened and so friable as to be easily torn with the forceps in handling. Such necrosis is rare in spontaneous cases, but it quite invariably appears in animals which have been fed with pure cultures of hog cholera bacilli.

The distribution of the ulcers varies but slightly. They appear most frequently in the csecum and on the ileo-cseeal valve, as well as in the upper half of the colon. The lower half is implicated in severe cases only, and then less extensively. The rectum is only very rarely ulcerated. The lower portion of the ileum is ulcerated in a small percentage of animals, especially when they have been fed with bog cholera viscera or cultures. The stomach is occasionally the seat of slight ulcera-tion. The lymphatic glands of the affected intestine are usually much enlarged, pale, tough, whitish on section. The spleen is rarely enlarged; the liver shows degenerative changes (softening of the parenchyma. Increase of connective tissue). Heart and lungs are usually normal. The lobular pneumonia frequently found in young pigs in the winter

months must be ascribed primarily to exposure rather than to the disease, as will be shown subsequently.

In some outbreaks the acute and the chronic types of the disease are not so clearly distinct as given in the foregoing pages. Frequently re. cent hemorrhagic lesions seem to be grafted upon cases presenting extensive nlcerations, which certainly are much older than the extravasations. It may be that the latter are the result of asecondary invasion of the hog¹ cholera virus, either from the ulcers in the intestine or from tnbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;without.

HISTORY AND AITTOPSV NOTES OF AN OUTBIIEAK OP HOG CHOLERA.

There is perhaps no better way to illustrate this disease than by giving briefly the history of an outbreak in a single isolated herd. In the following pages are recorded the autopsy notes and the bacteriological examination of such an outbreak- near the city of Washington during the months of November and December, 1887. A study of this outbreak was taken up to ascertain more especially the condition of the lungs in hog cholera. As it is the fifth or sixth which has been observed during the past three years less attention was paid to careful bacteriological observations. At the same time this phase was by no means neglected, as the notes will show. The history of the outbreak as far as could be ascertained was briefly as follows: On October 28, there were in all one hundred and nineteen swine, chiefly young pigs, weighing from 50 to 100 pounds. Most of these bad been purchased in the city markets. At this same time some twenty boar pigs were castrated. Within two weeks these began to die, and soon after the others took sick, dying at the rate of three to four a day. Less than three weeks after the first deaths only sixty-seven remained out of the one hundred and nineteen. At the end of the year only about a dozen were alive out of the entire herd. These may have acquired immunity.

The animals were kept in pens on the top of a hillock sheltered from the weather by large boxes. They were swill-fed, and this may account for their feeble resistance to the disease. In most of them there was a cirrhosis of the liver, with softening of the parenchyma, which was probably induced by the feeding. The origin of the epizootic could not be traced, as the animalshad come from various quarters. The city markets had proved themselves in the past the source of disease in several purchases of pigs for experimental purposes.

The autopsy and bacteriological notes will be given in the order in which the animals were examined, any general remarks being reserved for the end. The rapidity with which the animals succumbed to the disease made any very thorough examination quite impossible, since it seemed more desirable to utilize all the material by examining those organs most always diseased in hog cholera. Most attention was paid jnbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;to the lungs and the digestive tract, while the lungs and the spleen

wore tlie only organs examined bacteriologically. These notes will serve to supplement the autopsy notes in the reports for 1885aud 1880.

In making cultures from the spleen the following method was usually adopted. At the autopsy the abdomen was carefully laid open by first removing the skin and then cutting through the abdominal muscles with flamed instruments. The Haps laid back, brought into view the spleen not touched as yet by any instrument. It was then drawn out with flamed forceps, severed from its attachments with flamed scissors and placed in a large bottle plugged with cotton wool which had been previously subjected to a temperature of 15ü^o-l(!0^o 0. for two hours. In this way it was taken to the laboratory and either immediately examined or kept in the refrigerator below 55deg; F. over night. In making cultures the spleen was placed on a sterile glass support and the surface thoroughly charred with a red-hot platinum spatula. This was always done, although seemingly unnecessary when we consider the momentary exposure to the air in transferring the spleen from the abdomen to the sterile bottle. It may, however, destroy any bacteria which have entered the peritoneal cavity through ulcers. Through this charred area an incision or rent was made and a platinum wire introduced, and then a tube of gelatine or beef infusion inoculated with it. When roll cultures were made a minute bit of spleen pulp was torn away from beneath the charred portion and stirred about in the liqaefied gelatine. From this usually a second tube was prepared. Experience of past years had shown that frequently this is not sufficient to insure the fertility of the cultures, in chronic cases with the spleen but moderately enlarged, hog cholera bacteria are found in very small numbers. In such cases bits of spleen are cut out from the charred area with flamed scissors and transferred to tubes of gelatine or beef infusion with or without peptone. Hueii cultures rarely fail. It might be supposed that the chances ol accidental contamination are very great in this process. Hal a long experience with spleens of healthy animals and with organs in the study of other diseases has demonstrated the entire safety of this procedure. Salmon culture tubes with bits of organs in the bottom covered by nutrient liquids have remained sterile for months in the, laboratory. At present the Esmarch tube or roll culture is indispensable in such cases.

In nearly all the cases examined both liquid and gelatine cultures were made. The former permit a diagnosis on the following day, while the latter require at least two days, usually three or four, before a reliable diagnosis can be made. The cultures were always examined unstained in a hanging drop, as the bacteria in this way are not deprived of their power of motility, which is one of the important diagnostic characters. Staining cultures was also resorted to, but it adds little information to that gained by a careful examination of the hanging drop. When gelatine cultures were examined the bacteria were always mixed with some sterile beef infusion to bring out their motility.

In a number of cases rabbits were inoculated directly trom lung tissue. A small bit, about one half centimeter cube, was torn up with flamed forceps in a flamed watch glass containing some sterile beef infusion, and the turbid fluid injected beneath theskin of the thigh. The syringe used was an ordinary hypodermic syringe, carefully disinfected by 5 per cent, carbolic acid above and below the piston for one-half hour both after and before use, and each time thoroughly rinsed in boiling water. As hog cholera bacteria are, destroyed by a 1 per cent, solution of carbolic acid in less than ten minutes, and by a momentary

contact with water near the boiling point the. disinfection was certainly all that could be desired. This method was regarded as less open to criticism than the insertion of hits of tissue under the skin. We still stand in need of a syringe which can be disinfected without much trouble, as the above method is extremely tedious. The syringes devised by Koch are both unsatisfactory. The joints formed by the glass barrel and tbe metal cap in the syringe in which the propelling force is air were fouiul to leak in üve out of six samples. From the fluid injected into rabbits either plate or roll cultures were made in order to get an idea of the approximate number and the kind of organisms present. In every case the portion of lung tissue from which the inoculations were made was transferred to sterilized bottles and protected from accidental contamination as carefully as possible. Unless otherwise indicated, the methods just given were employed throughout the investigation.

November 16.Pig No. 1, just died and brought to experimental station. Is'o skin lesions; heart and lungs normal with exception of a few collapsed lobnles in principal lobe of one lung.* In abdomen omentum injected so as to appear bright red. Spleen enlarged, soft, dark. Some lymphatics have the cortex hemorrhagic. Stomach and small intestines normal. In caecntn near valve several large superficial yellowish ulcers and a number of smaller ones, an eighth of an inch in diameter. Two bits of spleen were cnt out and dropped into a tube of gelatine, and one of beef infusion. The gelatine culture remains sterile. The liquid culture contains the motile hog cholera bacteria and a large butyric bacillus growing only in the bottom of the liquid.

No. 2 died last night. Buzzards have eaten into the thorax and penetrated the coats of the stomach. Only the small ventral lobe of right lung diseased. Bright red, mottled with pale yellow dots. (See Plate IX, fig. 2.) The smallest bronchi occluded by cylindrical plugs. Alveoli likewise occluded. The plugs consist chiefly of cells and arc so dry and firm that they may be removed as small ramifications or branchings when the lung tissue is torn away. Bronchial glands enlarged, hemorrhagic. Spleen enormously enlarged, liver in advanced stage of cirrhosis. Glands at portal fissure chronically enlarged. Tn Cfecnm four superficial ulcers one-half inch across, slough stained yellow. In upper colon four similar to these and a large number of small ones about one-eighth inch across with yellowish slough.

A moderate number of bacteria found in cover-glass preparations of spleen. A gelatine tube culture contained, after three days about, seventy-five to one hundred colonies of the motile hog cholera bacteria iu

* In order to understand the description of the lung lesions, the. following brici! outline of the anatomy of the lung and of the terms used may be of service:

The right lang is made np of fonr lobes; the left has only three. (In text-books on anatomy The left lung is considered as being made np of only two.)

In both there, is a large principal lobe resting npon the diaphragm and against the adjacent thoracic wall. Thislobe forms the major part of each long. The remainder, occupying the anterior (or cephalic) portion of the. cavity, is made np of two small lobes, one extending ventnilly (or downward in the standing position of the animal) and in the expanded state covering the heart laterally, the other extending towards the head and overlapping the, base of the beart. These small iobes may he denominated the ventral and cephalic lobes, respectively. The right cephalic lobe is longer and more distinct, from the ventral lobe than the corresponding left cephalic. Wedged in bet ween the two principal lobes and resting on the diaphragm is a small lobe, pyramidal, belonging to the right hmg (azygos lobe). This lobe rests on the left against the mcdiastinal membrane, and on the right it is separated from, the right principal lobe by a fold of the pleura passing from the ventral abdominal wall to inclose the inferior vena cava. This small lobe is almost completely shntoff, therefore, from the other lobes by folds of the pleura.

each needle track. A liquid culture inoculated simply with the platinum wire thrust into the .spleen pulp contained hog cholera bacteria only. A rabbit was inoculated from huig tissue as above described; about one-fourth of a cubic centimeter of the suspension injected. Dead on the seventh day. Slight (ibrinous exudate on coils of intestines. Spleen very large, soft, dark. Beginning coagulation-necrosis in liver. Bacteria very uunierous in spleen; both gelatine and liquid cultures contain only the motile hog cholera bacteria. The plate from lung tissue with which rabbit was inoculated contains a very large number of identical colonies, made up of motile hog cholera bacteria.

November 17.Hb. 3, male, died yesterday. Buzzards have consumed pectoral muscles and pierced into thorax and abdomen. Ecchymoses on costal pleura and entire epieardi um, a few under pulmonary pleura. Left lung hypostatic, slight amount of whitish foam in trachea. Lung tissue otherwise entirely normal, neither hepatization nor collapse anywhere to be seen. Bronchial ghuidsand those along posterior aorta with hem-orrhagic cortex. Ecchymoses in the subcutaneous fatty tissue over entire ventral aspect of body, about one-eighth inch across, beneath peritoneum of abdominal muscles and of the entire length of small intestine, from size of pin's head to one-eighth inch. Congestion in patches in large intestine, no nlceration. Stomach and intestines contain a yellow liquid resembling the yolk of eggs. iSplecn hut slightly enlarged. Ecchymoses under serosa of liver. Cirrhosis moderate. A bit of spleen tissue dropped into a tube of beef infusion gave rise to a culture of hog cholera bacteria. In each needle track of a gelatine culture countless colonies of the motile bacteria appear.

November 18.No. i, medium sized male, died this morning. Superficial inguinal glands enlarged, cortex slightly hemorrhagic. Some fibrils on coils of intestine. Petecehiae under serosa of small intestine; extensive hemorrhage between mucous and muscular coat of stomach along fundus, forming a clot about one-half inch thick. Spleen very large, friable, blackish, extends beyond median line into right side. Petecchiae on liver, which is considerably cirrhosed; mucosa of stomach along fundus blackish: closely set petecchhe under mucosa of small intestine; contents liquid, bloodstained, A dark hemorrhagic patch near valve in large intestine. Colon studded with petecchim, no nlceration. Small number of petecchhe on surface and throughout cortex of kidneys. No bacteria seen on a cover-glass preparation of spleen tissue. Beef infusion inoculated with a wire thrust into spleen remains sterile. A bit of spleen dropped into a tube of gelatine gives rise to about a dozen colonies of hog cholera bacteria.

November 18.Fo. 5, male, 75 pounds, three to four months old, died last night. Inguinal glands enlarged, pale. Left cephalic, ventral, and about one-third of principal, right cephalic and ventral lobes of lungs soliditied, bright red, mottled with minute yellowish dots, i. e., same as Xo. 2. (Jostal pleura covered with a very thin whitish exudate. Soliditied portion of principal lobe adherent. On epicardium a very delicate papery deposit. Spleen much congested. Inflammatory adhesion of liver to diaphragm. Mesenteric glands nearly as large as hen's eggs, mottled, pale red. About twelve ulcers one-quarter to one-half inch across in lower ileuia; base depressed and covered with a thin yellow layer; outline irregular; not connected with Peyei's patches. Valve thickened and ulcerated. Several ulcers in caecum; a large projecting slough attached to one of them. A gelatine and a liquid culture from the spleen contain hog cholera bacteria only. A liquid culture from the pleura remains sterile.

A rabbit inoculated from the bepatizecl lunji^- tissue died on the eighth day. Slight libriuous exudate on intestines, diffuse coagulation necrosis in liver, spleen nuich congested, lininense number of hog cholera bacteria in spleen and liver. Cultures pure. A plate made from the same bit of (pig's) luug tissue contains about fifty colonies resembling Log cholera.

Ko. (5, large black male, died last night. Extensive sero-tibrinous inliltratiou of subcutis from axilla to pubis and over right, thigh. The subcutis has a gelatinous aspect. Spleen much congested. Lungs normal. In cover glass preparations from spleen large bacilli, with ends square. Cultures in gelatineand beef infusion remain sterile. Animal probably died of malignant OBdema.

NovetHber21,No. 7, mediam sized male, died yesterday. Tempera-tare of air varying from 20deg; to 50deg; P. Omentuiu deeply reddened. Spleen enlarged, soft; small hemorrhages under capsule one-eighth inch across. Liver imparts a Sensation of grittiness when cut. Cortex of kidneys dotted with hemorrhagic points. The patch of mucous crypts about valve in ca'cum dark, pigmented; no ulceration. Mucosa of stomach hemorrhagic in fundus. Thorax half full of blood-stained serum and some fibrin stretching i'roin lung surface to walls; small quantity of fibrin in pericardial cavity. Lung tissue infiltrated with blood (pulmonary hemorrhage). Two ventral lobes collapsed; subpleu-ral hemorrhagic patches. A cover-glass preparation from spleen contains numerous hog cholera bacteria. In each needle track of a gelatine culture, countless colonies. A liquid culture from a bit of spleen tissue contains hog cholera bacteria only.

No. 8, small female, died yesterday. Patches of skin on ventral aspect of limbs and groin reddened. Minute petecchia! under serosa of ventral abdominal walls. Spleen very large, congested. Some delicate librils stretched over coils of intestine. Liver cirrhosed. Clauds of mesentery and inesocolon enlarged; cortex hemorrhagic. Fuudns of stomach moderately congested. Jn csecum are black pigment spots resembling former hemorrhage, chiefly on the summit of folds. In upper colon ulcers about three to a .square inch, each one-fourth inch in diameter, and covered by a convex, projecting yellowish slough. Ulcers found down to rectum. Small quantity of clear serum and a few fibrils in pleural cavities and pericardium. Left ventral and tip of right cephalic lobe collapsed. A gelatine and a liquid culture, made from a bit of spleen tissue contain hog cholera bacteria and a butyric bacillus which slowly liquefies the gelatine.

No.!), small male. Diffuse reddening of ventral aspect of body especially marked on limbs. Spleen, lymphatics, and kidneys normal. A small abscess in pelvis attached to bladder, probably caused by castration. Venous congestion of vessels of meso-colon. The transverse folds of mucosa of colon covered by very thin yellowish patches of necrosis. Feces hard, distending the large intestine. Cephalic and ventral lobes of left lung solid, plainly mottled. The bronchioles and alveoli filled with consistent plugs of cellular exudate. llemainder of lungs normal. Owing to small size of spleen, two liquid cultures were made, each with a bit of spleen tissue. Jn both, hog cholera bacteria alone appeared. A rabbit inoculated with hepatized lung tissue remains well for weeks after. A plate culture therefrom is liquefied iu two days.

No. 10, small castrated male, died yesterday. Has been sick for sometime according to overseer of farm. Spleen not enlarged. 1 nthuninatory changes in pelvis due to castration. Stomach slightly reddened and

bile stained. One large ulcer on ileo caecal valve one-lmlf iucL across, black, with yellowish margin. A few very superficial ulcers in cieemn. Lungs normal, left somewhat hypostatic. Two cultures made with bits of spleen contain both hog cholera bacteria and butyric bacilli.

Xo. 11, dying, killed by being^- bled from brachial vessels. Lungs normal. Spleen small. Liver slightly cirrhosed. Two nlceres in csecum; slight superficial necrosis in colon. A liquid culture made from a bit of spleen contains bog cholera bacteria on following- day.

Noremher L'3.No. 12, small white male, died yesterday. Median lino of ventral aspect of body much reddened, limbs slightly so; extravasation under skin and into muscular tissue over sternum. Much bloodstained serum in peritoneal cavity; spleen very large, dark. In kidneys, cortex and base of pyramids deeply reddened. In ca'cuiu, slight traces of superficial necrosis. Anterior and cephalic lobes of both lungs collapsed. Blood-stained serum in pericardium. Numerous hog' cholera bacteria on cover-glass preparations of spleen pulp. In a gelatine culture from the spleen countless colonies appear in each needle track. A liquid culture made with platinum wire contains hog-cholera bacteria on following day. A rabbit inoculated from the collapsed lung- tissue died on the tenth day. Spleen engorged ; numerous foci of coagulation necrosis in liver, involving each one or more acini; extensive necrosis along border of left lobe. Ecchymosis of pyloric valve and duodenum; hemorrhagic foci in lungs, about fifteen in each lung, one-eighth inch to three-.sixteenths inch in diameter. Examination of the spleen shows numerous hog-cholera bacteria. A gelatine culture contains countless colonies in each needle track.

Number 13, small female, died yesterday. Skin on ventral aspect of limbs and over pubis reddened. Spleen greatly enlarged, congested. Lungs normal. A few lobules in ventral and right cephalic lobe collapsed. Liver slightly cirrhosed. Stomach distended with (bod. Large patch of niucosa in fuudus reddened. (Ja^cum and colon contain numerous ragged depressed ulcerations. Valve entirely encircled by nlceration. Contents of intestine liquid, yellow. A gelatine and a liquid culture inoculated with a platinum wire thrust into spleen remain sterile. ZS'o bacteria seen in cover-glass preparations.

No. 11, small female, weight about 50 pounds. Considerable reddening of theskin over ventral aspect of body and limbs: especially marked along median line. Superficial inguiuals enlarged, of a mot lied pale and deep red on section. Spleen very large. 12 inches long, 2 inches broad, and five-eighths to three-fourths inch thick at hilus; gorged with blood, friable. A small number of punctiform hemorrhages in cortical portion of kidneys. Clauds of mesentery and of colon en larged and congested. Deep reddening of several square inches of mucosa in fnndus of stomach. Large intestine contains a semi-liquid mass, chiefly earth. Four large ulcers in caecum, one of them at least 1 inch across, covered by a yellowish slough; the peritoneum covering it is thickened and inflamed. In upper colon there is considerable necrosis, involving the epithelinm in patches. Lungs normal, excepting the right ventral lobe, which is solid. Bronchi and air cells of this lobe completely occluded by plugs as with No. 2; surface bright red, mottled with yellowish pointsthe ultimate air cells filled with the cellular ex-udate. Subplearal ecchymoses over both lungs. From the spleen a liquid and a gelatine culture contained only hog-cholera bacteria. They were very nnmerous in cover-glass preparations from this organ,

A rabbit, inoculated from the consolidated lung- tissue died on the seventh day. At the point of inoculation a pasty mass extends to ab-

dornen, only suhcntis involved. Spleen engorged. Single acini and groups in the liver are completely necrosed, yellowish white, in both orgatis, hog-cholera bacteria. Cultures from spleen pure.

November 25.Xo. 15, black and white male, died Yesterday morning. Redness of skin of abdomen, throat, and limbs. Superficial in-guinals bemorrhagic. Spleen very large, gorged with blood. Lungs normal, excepting a few lobules at the caudal border of principal lobes, which are red, collapsed, and contain lung worms. Pericardium contains deep-colored serum and coagula; left auricle dotted with petecchise. Bronchial lymphatics hemorrhagic. Liver .slightly cirrhosed. Cyst in right kidney one-half inch in diameter. Fundus of stomach intensely congested, similarly the caecum and colon ; no ulcers. Lymphatics of meso-colon hemorrhagic. A beef-infnsiou culture from a bit of spleen contains the motile hog-cholera bacteria only. A gelatine culture became liquefied by the heat of the. laboratory; no bacteria seen on a cover-glass preparation of spleen.

ISo. 16, black and white female, died last night. Skin and spleen as in previous case. The small ventral lobe of both lungs collapsed, lungs otherwise normal. Liver in advanced stage of sclerosis; stasis of portal circulation. Lymphatics of abdomen as in No. 15. Fundus of stomach slightly reddened; one nicer three fourths inch across. Extensive necrosis of mucous membrane in colon and rectum, slight in caecum; wherever the membrane is free from a slough it is deeply congested. Numerous hog-cholera bacteriaand some large (butyric) bacilli in spleen. A beef infusion and a gelatine culture contain them. From a bit of collapsed lung tissue a plate culture is made and a rabbit inoculated. The plate contains in two days about six to seven liquefying and a large number of non liquefying colonies, the latter made up of motile hog-cholera bacteria; the rabbit died on the seventh day. Spleen very large, friable; contains large numbers of hog cholera bacteria. On left lobe of liver an area of necrosis one-fourth inch by three-fourths and one-sixteenth inch deep. On the right lobe only three or four acini necrosed. Pylorus and duodenum covered with hemorrhagic laquo;lots and patches. Culture from spleen pure.

Wovember 26.No. 17, female of medium size; died suddenly this morning without previous illness. Subcutaneous fat abundant. Spleen moderately congested. Petecchiae in cortical portion of kidneys. Fundus of stomach slightly reddened. In lower ileum patches of congestion. Scattered petecchise in mucosa of large intestine; contents normal. Glands of mesentery and meso-colon with cortex hemorrhagic. Large quantity of blood-stained serum in thorax. Fibrinous deposit on pleura; lungs partly expanded ; cephalic half of right lung solid, blackish; air-

tubes and alveoli filled with extravasated blood. Interlobular tissue

distended with blood-stained serum (pulmonary hemorrhage). Left lung m the same condition. Trachea lull of reddish foam, Bloodand fibrin-ous coagula in pericardia! cavity. Beef infusion, into which a bit of spleen was placed, remains sterile; also a tube of gelatine inoculated from the spleen with platinum needle. In a cover-glass preparation of the spleen large (butyric') bacilli.

No. 18, small female, died last night. Buzzards have consumed thigh muscles. .Diffuse reddening along median line of abdomen. Hemorrhagic spots one-eighth to one-fourth inch across, subepidermal, chiefly on ventral aspect of limbs; subcutaneous and snbperitoneal ecchymoses. All abdominal lymphatics with cortex infiltrated with blood. Serosa \nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; of large intestines as if sprinkled with fresh blood; several subserous

'nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; hemorrhagic spots one-half inch across on diaphragm, along inferior

j I

vena cava, common bile duct, and gall bladder; also, under mucosa of the whole length of small intestine, throughout cortical portion and between pelvis and medullary portion of kidneys. Fundus of stomach one mass of peteccbise and larger extravasations. One ulcer in etecum, old, with indurated base. Valve and the patch of mucous crypts at its base ulcerated ; depth of ulcer indurated, consisting- of a tough, pale tissue. Small old ulcers in apper colon. Lungs dotted with small hemorrhages, chiefly snbpleural. Three or four hemorrbagic patches under costal pleura of each side. Lung- tissue normal, excepting the base of right ventral and the tip of left ventral lobe, wbicli are collapsed, ilemor-rhages under epicardium over entire heart; left auricle one mass of ec-chymoses. Goagnla of fibriu in auriculo-ventricular groove.

Through an oversight the cultures from this animal and the one following wore both numbered the same, so that it was impossible to identity them. A liquid culture from each was made by adding a bit of spleen tissue. A gelatine culture from each was made simply with platinum wire. One tube of infusion contains hog cholera and butyric bacteria; one tube of gelatine contains immense numbers of hog-cholera colonies. The other two tubes remain sterile. A rabbit inoculated from the collapsed lung tissue remained well for a month after. A plate culture from the same contained about six: colonies, evidently of hog-cholera bacteria.

No. 1!.), small male, died last night. Diffuse reddening on abdomen along median line. Superficial ingniuals very large, pale, cedematous; peritonitis; feeble adhesion of coils of intestine to ventral wall and of lobes of liver to one another. Slight tibrinous deposit on intestines. Liver sclerosed. Lymphatics hemorrbagic. Cortex of kidneys dotted with extravasations. Macosa of large intestines of a dark shite color; it is dotted with closely-set conical elevations, tough, whitish, about one-eighth inch high and one sixth across. When scraped away a depressed pale pink, sharply-outlined spot remains. Microscopic examination of the intestine showed that these elevations correspond to amorphous masses, which failed to become colored on applying the ordinary staiu-ing agents. They covered portions of the mucosa which werequot; either wholly or partially necrosed and incapable of being stained. In some places the outline of the tubules could still be discerned. On applying Weigert's fibrin stain, long meshes of fibrin corresponding in general to the outline and position of the destroyed tubules appeared. Valve thickened and completely covered by ulc'eration. Cephalic half of both lungs airless, affected with broncho-pneumonia; catarrhal exudate filled alveoli and air tubes. Epicardium dotted with hemorrbagic points. Slight, feeble, pleura! adhesions.

For cultures from spleen, see Xo. 18. A rabbit inoculated with lung tissue died on the fifth day. Spleen slightly enlarged; contains many hog-cholera bacteria. Gelatine culture contains very many colonies of the same.

No. 20, a large female. No skin lesions; a few strings of coagnla over coils of intestine; spleen small; base of pyramids quot;of kidneys much reddened; ileum dotted with subperitoneal hemorrbagic points and patches; mucosa not affected; mesenteric glands with cortex hemor-ihagic. Large intestine empty, scattered ulcers one-eighth to one-fourth inch across. Liver sclerosed.

A beef-infusion culture inoculated with a bit of spleen tissue contains bog-cholera bacteria and butyric bacilli. A gelatine tube culture contains a few hog-cholera colonies.

November 29.No. 21, small Jersey red, female, died last night. Skin

deeply reddened along median line of abdomen. Large quantity of blood-stained serum in peritoneal cavity. Serosa of ileuni and the mesentery completely covered with hemorrbagic points and patches. Lymphatics of abdomen bemorrhagic throughout their substance. Pe-tecchiic in cortex of kidneys. Mucosa infandusof stomach hemorrhagic. Macosa of lower ileum a confluent layer of necrosed tissue. Numerous round ulcers in ca'cum and colon ; slouch projects slightly. Lungs hypo-static, interlobular spaces distended with coagulated blood, most marked in dependent lobes. Simple collapse, of both ventral lobes and of the right principal near the root. Ventricles of heart dotted with petecchise, auricles black, covered with clotted extravasated blood. Hog cholera bacteria present in cover-glass preparations from spleen and in both gelatine and liquid cultures.

No. 2_^,, male, Jersey red, died last night. Glands of abdomen with cortex infiltrated with blood. Spleen engorged. A few hemorrhagic patches in fnndus of stomach. In caäcum and colon ulcers abontthree-eighths inch across ; very thin, adherent, yellowish slough. About one ulcer to i square inches of surface. Considerable blood-stained serum in piemal cavities, hemorrhage in anterior half of left lung, which is solid, blackish on section. Clots and reddish foam in trachea and bronchi; hemorrhage seems somewhat older than in Xo. 21. ' Pleura of right lung roughened and parts adherent to chest wall. Ventral lobe solid, bronchioles (irmly plugged with dry catarrhal secretion. Hog cholera bacteria, on cover-glass from spleen pulp and in a gelatine and liquid culture made therefrom ; only five to ten colonies in each track of the platinum wire. A rabbit was inoculated from a bit of the solidified lung tissue and a plate culture made. The latter develops numerous colonies of hog cholera bacteria. The rabbitdied on the thirteenth day. Xnmerous hog cholera bacteria in both organs. A gelatine culture from the spleen contains the same organisms.

No. 23, small black male. Buzzards had removed pectorals of one side. Lymphatics congested, not hemorrhagic Crowded peteccbiicin subcutis and beneath peritoneum of ventral abdominal wall. Spleen very large, congested. Four or live small hemorrhages on diaphragm. Mucosa of ca'cum and upper colon ulcerated in large patches. In lower colon the ulcers are small, yellowish, depressed areas embedded in a very dark mucosa dotted with numerous punctiform ecchymoses. At root of left lung there is some collapse, extending slightly into all lobes. Of right lung the ventral and cephalic lobes are collapsed, with occasional euiphysematous lobules interspersed. Langs otherwise normal. Extensive hemorrhage of both auricles in the form of diffuse patches and petecchise. A gelatine and a liquid culture from the spleen remain sterile. A plate culture made, from a bit of collapsed lung tissue con-tainsa considerable number of colonies, which are made up of bacteriare-sembling those of hog cholera, but differing from them in their manner of growth on gelatine, in beef infusion, and in the absence of motility. A rabbit inoculated from the same bit of lung tissue remains weil. A plate culture from a bit of normal tissue from the same lung contains but one colony.

No. 24 died yesterday; medium-sized female. Spleen very large, extends beyond median line. Lungs normal, excepting collapse of a small portion of the right ventral lobe. Lymphatic glands in general with hemorrhagic cortex. Osecnm and colon very much congested, ul-ceration superficial and slight. Entire fnndus of stomach of a uniform deep wine color. A gelatine and a liquid culture from the spleen contain only motile hog cholera bacteria. In the former the colonies are

I 6

very mimerons. The bacteria are demonstrated in (-over-glass preparations from spleen pulp.

No. 25, medium sized black male, died yesterday. Spleen very large. Subperitoueal tissue full of petecchise. Lymphatics with hemorrhagic cortex. Ilemonliages under serosa of duodenum and common bile duct. Valve completely ulcerated. Intestine otherwise normal and feces dry. Lungs contain a large number of snbpleural hemorrhages, tissue normal, epicardium hemorrbagic. Kidneys contain a specimen of kidney-worm [sclerostomapinguicola), A. gelatine and a beef iufnsion culture from the spleen became confused with those of another pig (Xo. 435), to be described later on. One set of cultures remained sterile; the other contained hog cholera bacteria. In all probability the sterile cultures belonged to this animal.

December 2.Xo. 2(), medium-sized female, died last night. Considerable redness of skiu over the ventral aspect of limbs and along median line of abdomen. Spleen very large, blackish. Several strong fibrous adhesions betweeen costal and pulmonary pleura. Lung tissue normal. Lett kidney contains a small cyst. Large number of round depressed ulcers stained yellow, most numerous in csBCum. One ulcer is one-half incli across, the inflammation extendiugto serosa. Stomach very dark, pigmented along fnmlns. On a cover-glass preparation from spleen numerous lai'ge bacilli (probably butyric). They did not develop in the liquid and gelatine culture, which latter contained only hog cholera bactera colonies, very numerous in each needle trad-;.

Xo. 27, small black male. Superticial inguinals enlarged,pale,cedem-atous. Superficial nlceration and hemorrhagic changes in csecam. Lungs normal, rout mortem changes too advanced for cultures.

Xo. 28, small female, died last night. Superficial inguinals with cortex hemorrhagic. Spleen slightly enlarged. Minute hiematomata on its surface. Slight sclerosis of liver. Left kidney contains six cysts one-half inch diameter. raquo;Stomach in fundus somewhat congested. In large intestine, ulcers one-quarter to three-eighths inch diameter, with adherent yellowish, projecting slough, most numerous in ea;cum. About one-third of the ventral lobe of each lung and a few lobules of the right principal lobe collapsed. Lungs otherwise normal. In a beef infusion culture from the spleen both hog cholera and butyric bacteria were present. A gelatine culture contained but two colonies. From a bit of collapsed lung tissue a plate culture was made and a rabbit inoculated. On the plate about fifteen colonies of hog cholera bacteria appeared. The rabbit died on the fifteenth day. Bare indications of necrosis in liver. Spleen very large. Loth organs contain a moderate number of hog cholera bacteria. A roll culture from the spleen is pure.

Xo. 29, large black male, died about thirty-six hours ago. Temperature below freezing point. Skin deeply reddened over entire ventral aspect of body. Superficial inguinals enlarged, slightly congested. Spleen very large (about 11 inches long), very sott and friable. Slight sclerosis of liver and old perihepatitis. Eetro-peritoneal glands with cortex hemorrhagic. Cyst in right kidney. Slight eechymoses in fundus of stomach. Valve and patch of mucous glands in csecum very dark with pigment. Slight superficial nlceration in ca-cum and upper colon. Lungs and heart normal. Loth gelatine and beef infusion cultures contain bog cholera bacteria. In the former the colonies are very numerous.

Xo. 30, small black male; died thirty-sis hours ago. Xo reddening of skin. Superficial inguinals and spleen but slightly enlarged. Peritonitislaquo; Petecchiffi under serosa of small and large intestines andblad-

der. Moderate amouut of ftbrinoas exadate. Valve completely ulcerated, ulcer deep. One near valve has caused thickeniug of serosa of intestinal wall. In cseeam an extensive patch of ulueratiou; in colon a few ulcers and numeions panctifonn hemorrhages. Right lang completely adherent tocostal pleura by means of fibrous tissue. A small ventral portion of principal lobe of left lung is airless, pale red, mottled with yellowish points. Air tubes ami vesicular portion occluded with dry cylindrical pings. A culture in gelatiue from the spleen develops numerous colonies in each track of the wire. A liquid culture contains the butyric bacillus also, A bit of the solidified Inug tissue was used for a plate culture and to inoculate a rabbit. The plate developed countless colonies of hog cholera bacteria as tested by other cultures. The rabbit died on the tenth day. The spleen was enlarged, the liver full of centers of advanced necrosis, involving one to three acini; hog cholera bacteria very numerous in both organs.

December'S.No. 31, small black and white female, died yesterday. Well-marked odor of decomposition. No skin discoloration. Spleen but slightly enlarged. Lymphatics in general with hemorrhagic cortex. Liver in .state of advanced sclerosis. Stomach normal. A few large old ulcers and a considerable number of small ones throughout ca'cmn and colon. Mncosa itself pigmented with patches of fresh congestion. Lungs normal. A liquid culture from the spleen contains only butyric bacilli.

Xo. 32, small black and white female. No skin discoloration. Lymphatics, including inguinal, bronchial, and peritoneal with more or less hemorrhagic cortex. Spleen engorged. Liver solerosed. Kidneys with numerous petecchise throughout cortical portion. Stomach pale. raquo;Several large old ulcers in upper colon. Caecum and colon pigmented. Lungs normal with exception of a few collapsed lobules in ventral lobes. Loth a gelatine and a beet infusion culture contain hog cholera bacteria. Colonies very few.

2s^To. ;gt;;gt;. large black and white male; said to have died last night. Advanced post mortem changes. No examination made, excepting to see the condition of lungs, which were healthy.

2gt;o. 34, medium-sized white, died last night. Considerable reddening over ventral aspect of body. Inguinals reddened on section. Small quantity of dark-colored serum and numerons yellowish flaky coagula attached to abdominal organs. Spleen very large, dark, friable. Liver cirrhosed. Kidneys with cortical portion thickly dotted with petecchise, hemorrhage into pelvis. Lymphatics in abdomen with cortex more or less hemorrhagic. Extensive and deep nlceration in huge intestines ; in caecum and upper colon as large patches, in lower colon as small ulcers. The mucosa which is not destroyed is deeply congested. Stomach along fundus deeply reddened. Extensive, fibrous adhesions of left lung to walls of thorax. Collapse involves ventral, cephalic, and portions of principal lobe of right lung, and small portion of principal and ventral lobe of left lung. Extensive muco-purulent secretion in trachea, bronchi, and subdivisions throughout both lungs. Bronchial glands with cortex hemorrhagic. A beef infusion culture from the spleen contains hog cholera and butyric bacteria. In the gelatine culture each track of the wire contains countless colonies of what are shown under the microscope to be motile hog cholera bacteria. Erom a bit of collapsed lung tissue a plate culture was made and a rabbit inoculated. The plate develops countless nou lupiefying colonies. The rabbit died on the eighth day. Spleen enlarged. Liver infested with coccidia. A

slight amount of coagulation-necrosis. Tlo£- cholera bacteria in both organs and in cultures from the spleen (both gelatine and liquid).

Jkcvmber 5.No. 35, small black ami white female, died yesterday. Eedoess of skin over abdomen and inside of limbs. Spleen enlarged, slightly congested. Lymphatics with cortex infiltrated with blood. Large quantity of blood-stained serum in abdomen. Liver sclerosed. A few scattered petecchise in cortical portion of kidneys. Mucosa of colon pigmented ; a few small ulcers present. Lungs normal, with exception of a few collapsed lobules in ventral lobe of each lung. Dark-colored serum in pericardial cavity. The spleen contains large numbers of butyric bacilli. A liquid culture contains both hog cholera and butyric bacilli. A gelatine culture remains sterile. ^ No. .:gt;G, huge black and white female, died yesterday. Lungs normal. Spleen very large, dark, friable. Liver sclerosed ; lymphatics generally with cortex congested or hemoniiagic. Large number of ulcers in ciccum and colon; mucosa deeply congested. From spleen countless colonies of hog cholera bacteria in a gelatine tube culture. In a liquid culture the butyric bacilli are also found.

No. o7, medium Jersey red and the last of ^ lot of seven, dead forty-eight hours. This animal has been sick for some time; the spleen was very large, gorged with blood. Lymphatics pale. Large number of old ulcers, from one sixteenth to 1 h inches across in ca'cum and colon ; mucous membrane generally pale. Of the lungs, both ventral and a small portion of cephalic lobes with smaller bronchi and alveoli plugged with dry catarrhal products. A liquid culture from the spleen contains bog cholera and butyric bacilli. A gelatine culture contains countless colonies. The spleen pnlp on coverglass preparations shows many. From the diseased lung tissue a rabbit was inoculated and a plate culture made. The latter develops a huge number of colonies of hog cholera bacteria. The rabbit died on the eighth day. Spleen enlarged and friable, contains many hog-cholera bacteria. Slight coagulation-necrosis in liver, which is infested with coccidia Cultures from blood and spleen pure.

December 7.No. 38, small white female, died last night. Much emaciated. Subcutaneous and subperitoneal tissue contains uumerous extravasations. Lymphatics in general with liemorrhagic cortex. Spleen moderately congested. Lung tissue normal. Numerous subpleural and epicardial hemorrhages. Kidneys with cortical portion dotted with numerous punctlform extravasations. Mucosa of small intestine contains numerous petecchise. One ulcer, one half inch across, in lower ileum. Lxtensiveand deep ulceration throughout whole length of large intestine. Some of the ulcers over 2 inches across; surface coal-black; the inflammation extending through the intestinal walls to serosa, which is dotted with scattered extravasations. A gelatine tube culture from spleen pulp contains countless colonies in each needle tract, consisting, as seen .under the miscroscope, of motile hog cholera bacteria. A liquid culture contains also streptococci and butyric bacilli.

No. ','A), black and white female, jw.sf mortew changes under way. No examination made beyond ascertaining that lungs are normal, lymphatics with cortex infiltrated with blood, and spleen enlarged and congested.

December 8.No. 40, small black female, died this morning. Superficial ingninalsenlarged but paie. .Moderate quantity of stra'w-collored serum in abdominal cavity. Spleen enlarged, deeply congested. In CiBcum and upper colon a large number of deep broad ulcers; in some the inflammation extends through intestinal wall to serosa. lu lower

üi

colon, ulcers small and mucosa deeply congested, Nnmeroas hog

cholera bacteria in spleen as shown by a gelatine culture. A liquid culture contains also butyric; bacilli.

No. 11, small black and white t'emale, died yesterday. Post mortem changes under way. Large qnantityof bload-stained semin in abdomen. Plastic peritonitis matting together the various organs; spleen enlarged and congested. Numerous old ulcers in csecum and colon, with adherent slough. Adhesive pleuritis, with large quantity of blood-stained serum in thorax. Lungs normal, excepting areas of collapse in ventral and cephalic lobes. A liquid culture from spleen contains both hog cholera and butyric bacilli. A gelatine tube culture develops a large. number of colonies in each needle track.

.December 10.No. 42, small black and white male, died yesterday morning. ISo discoloration of skin. Spleen very large, congested. Lymphatics with cortex slightly reddened. Livercirrhosed. A fewex-travasations in pyramids of kidneys. Mucosaof csecum and upper colon covered with ulcers, the adherent slough dirty yellowish. Fully onebalf the area of membrane thus involved, the remainder is pale. Lungs normal. From the spleen, hog cholera as well as butyric bacilli appeared in a beef infusion culture. In a tube of gelatine the colonies wen? very numerous.

Deccmher 12.Xo. 43, small black and white male, died December 10. No discoloration of skin. Spleen very large, friable, gorged with blood. lugiiiiials and lymphatics at lesser curvature of stomach hemorrhagic throughout. Those; of mesentery and meso-colon less so. A few petecchhe on surface of kidneys. Liver slightly cirrhosed. Mucosaof csecum pale, of colon considerably congested. A few small ulcers with hemorrhagic border. Mucosa in fundns of stomach deeply congested. raquo;Slight bemorrkage in principal lobe of each lung, otherwise both normal. Bronchial glands hemorrhagic. Hog cholera bacteria quite abundant iu spleen, as shown by cover glass preparations and cultures.

December 15.No. 44, medium-sized white female, died yesterday morning. Slight reddening of skin along median line of abdomen, limbs, and throat. Spleen enlarged and engorged. Ingninal, bronchial, retro-peritoneal and mesocolic glands with cortex hemorrhagic. Liver badly cirrhosed. In csecum one ulcer an inch across, involving entire thickness of wall, and few smaller ones. A few in upper colon. Lungs cedematous. At least one-hall' of each lung (most dependent portion) airless, of a red flesh color. Sprinkled through it in some places more densely than in others are grayish-yellow areas one-half to two millimeters in diameter. Trachea full of foam. Bronchi contain a thick mucous secretion, most abundant in the diseased region. A roll culture from the spleen contains numerous colonies of hog cholera bacteria. From a bit of lung tissue a rabbit was inoculated; a plate culture from the same shows a very large number of colonies, probably bog cholera. The rablnt died on the.seventh day. Spleen enlarged. Coagulation necrosis in liver, which also contains coccidia. Hog cholera bacteria numerous in spleen, as shown by cover-glass preparations ami roll cultures.

No. 45, large black-and-white female, died December 13. Slight reddening of skin. Spleen large, congested. Lymphatics in general with cortex hemorrhagic. Liver badly cirrhosed ; surface dotted with hemorrhagic points. Kidneys on surface and on section, as well as mucosa of csecum and upper colon, dotted with numerous petecchite. No ulcer-ation. Large quantity of blood-stained serum and coagnla in pleura! sacs, chiefly in the right. Lungs not collapsed, infiltrated With a rod-15612 HC------4

dish seram ; left hypostatic. Abundant mucous secretion in bronchi and smaller air tubes stained with blood. Fo bepatization. Roll culture from a bit of spleen contains a large number of colonies of hog cholera bacteria. Tlic same may be seen in cover-glass preparations from rhe spleen itself.

So. 40. Large black-and-white male, died December 13. Spleen enlarged and congested. Abdominal lymphatics with cortex more or less congested. Liver slightly eirrliosed. One largo ulcer on valve about 1 inch across; several half as large in the middle of colon. Mucosa deeply congested in cfecum and colon ; much pale serum in pleural sacs. Lungs slightly oedematoas. Of right lung the principal near root, ventral and tip of cephalic airless, collapsed. One lobule on ventral (diaphramatic) surface of principal lobe airless, with faint oatarrhal injection of bronchioles and alveoli ; of left lung a small portion of the principal collapsed; the ventral and cepbalic emphysematous. The trachea, bronchi, and branches contain a large quantity of a translucent viscid mucus; no lung worms present. Bronchial glands enlarged, pale; those on posterior aorta with cortex iieinorrhagic, Extravasations beneath epicardium. A plate culture from a bit of lung tissue develops about seventy-five colonies of hog cholera bacteria. A rabbit inoculated from the same bit remains well. A roll culture from the pig's spleen contains about fifty colonies alike; one examined is made up of motile hog cholera bacteria.

December 17.No. 17, small female, died yesterday. Superficial in-guinals entirely hemorrbagic. Mesenteric glands slightly congested. Spleen barely congested. Mucosa of lower ileuni completely ulcerated. Similarly that of caecum and upper colon, but more severely so as to make the intestinal wall very friable. In lower colon the ulcers are isolated. Lungs and heart normal. In a roll culture from a bit of spleen tissue about one hundred colonies of hog cholera bacteria appeared.

No. 48, medium-sized black-and-white female, died last night. Superficial ingninals enlarged, pale. Abdominal lymphatics in general with cortex hemorrbagic. Spleen congested; surface covered with numerous elevated bloodied points. Liver extensively eirrliosed. Mucosa of ileuni dotted with petecchiae. It contains about fifteen ulcers, not limited to IVyer's patches, with longer diameter transverse, in some cases encircling the tube. The ulcer is covered by a thin yellow slough. One ulcer, one-half inch across, in ca'cnm, and two in colon. About one-half pint of straw-colored serum and a mass of semi-gelatinous pale coagulum the size of a list in each pleural sac. Lungs but partly collapsed, pleura slightly roughened. Jnterlobular tissue of dependent lobes distended with serum, parenchyma oedematous, so as to sink in water. Bronchi contain a slight amount of reddish fluid. In a roll culture from a bit of spleen pulp about two hundred colonies of hog cholera bacteria appear,

Deceniher '2i.Xo. 49, large, black and white. Spleen gorged with blood. Lymphatics generally pale; liver eirrliosed. Ca-cumand colon with walls thickened and very friable; mucosa entirely ulcerated. One ulcer in rectum. A roll culture from the spleen melted, but found to contain on examination only hog cholera bacteria.

DISEASE IN IIEALTIIV PIGS CAUSED BY MATERIAL FROM THIS EPIZOOTIC.

Jfovember 21.Two pigs (Nos. 434, 435), about two months old, fed #9632;with spleens from several of the preceding eases. Two days later a few

more spleens were given then). Both beeaine sick a few days later and died November 28, about twelve hours apart.

No. 434. Spleen slightly enlarged, full of blood. All gloinemli of kidneys show ashemorrhagic points: lymphatics inorteratcly congested. Stomach along entire lundns deeply congested. Superficial small ulcers in Ciecum and colon; in the caecum they are covered by a projecting slough. Wight ventral and cephalic lobes collapsed, theformer developed into broncho pneumonia (catarrhal injection of small air tubes and alveoli). A few lobules of left principal lobe in the same condition. Hog cholera bacteria in the spleen as determined by a- gelatine and a liquid culture. A rabbit was inoculated with a bit of lung tissue and a plate culture made. This developed countless colonies, non-liquefying, alike, shown to be motile hog cholera bacteria. Rabbit dies on sixth day. Spleen moderately congested; contains many hog cholera bacteria. In liver, minute loci of necrosis. A gelatine culture from the spleen contains numerous colonies of hog cholera bacteria.

No. 435. Spleen enlarged, covered with hemorrhagic elevations. Kidneys bemorrhagic as in No. 4.')4. Stomach near pylorus deeply congested. Ofecnm and entire colon covered with a dirty yellowish and blackish sloagh. Right and left ventral lobes, a small portion of right principal and left cephalic affected with broncho-pneumonia. Cultures from the spleen of this animal were confused with those of another pig (No. 25), but one set remained sterile; the other contained bog cholera bacteria, and it is highly probable that the fertile cultures belonged to this animal.

A few additional cases are cited to show the infectious nature of this outbreak.

No. 436 and No. 437 were placed, November 27, in the infected pen containing the two preceding animals. They were also fed portions of hog cholera viscera later on. No. 436 was found dead December 27. Red blotches on skin of ventral aspect of body. Superficial inguiuals hemorrhagic. Other lymphatics enlarged but pale. Spleen slightly congested. Mucosa of ca-cum and colon deeply congested and dotted with considerable number of small ulcers. A roll culture from the spleen melted, but contains only hog cholera bacteria according to microscopic examination. No. 437 did not take the disease.

No. 41!) and No. 4Ö2, placed in the same pen December 17, but not fed with infectious matter, died December 21). The lesions were somewhat different from those, usually found, and are briefly as follows:

No. 452. Spleen and lymphatics not enlarged. Large quantity of serum and fibrinous coagula in abdomen. Viscera generally agglutinated. ^; gt;nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; Lungs glued to chest wall by a recent exudate. Pericardium distended

with serum and coagula. Lung tissue not affected. Kidneys deeply reddened. Mncosa of caecum and colon entirely covered with a thin layer of diphtheritic exudate; when scraped away a deeply reddened surface is exposed. Numerous small, deep ulcers present. A roll culture of spleen, also melted from the heat of laboratory, contains only hog cholera bacteria. In No. 449 the lesions were the same, excepting the pericarditis. The ulceration of large intestine less extensive.

Two very instructive cases of hog cholera were caused by simply exposing pigs on an infected asphalt floor in a pen adjoining cases of the disease.

No. 464 and No. 466, about three and one-half months old, exposed with six others January 4. No. 464 died January 11. Superficial inguinals

.):

Dormal. Those in abcloiueu much tutnettetl and heuiorrhagic throughout. Spleen enlarged, friable, with Leiuorrhagicpoiuts, Several patches of mucosa in fuudns nt' storaacl] one-fourth to one-half inch across, covered with hluod clots. In large intestine only a few scattered petec-cliia' on uineons membrane. Some subpleuralhemorrhages in lungs; lung tissue normal. Scattered petecchise on epicardium of auricles and ventricles. On cover glass preparations from spleen pulp a moderate number of bacteria were present. In several roll cultures only colonies of hoy; cholera bacteria appeared.

No. 4(gt;(; died January 13. Skin of ears, throat, nose, limbs, and belly deeply reddened. Spleen as in No. 404. A fewpetecchiaj on epicardium, Ividueysas in No. 404. Urine contains blood. The mucosaoflarge intestine in general deeply congested and studded with about fifty ulcers one-fourth inch across. Meso-colic and retro-peritoneal lymphatics with cortex hemorrhagic. Stomachasin No. 464. Lungs normal, excepting collapse of two-thirds of ventral lobes. Roll cultures from u bit el'spleen pulp gave the same result as m preceding ease.

BRIEF Sr:OIARY OP IHK CMPORTAICT FEATURES OF THIS EPIZOOTIC.

The high percentage of mortality in epizootics of hog cholera like the foregoing is the first thing to claim our attention. Out of 119 animals not less than 100 perished within the brief space of two months, or over SO per cent. As no disinfection was resorted to, no isolation of the healthy attempted, it is difficult to say what number could have been saved. At any rate, the above Hgures indicate the mortality of this disease when left to itself, ami it shows that, nearly all young animals, such as weigh between 50 and 100 pounds, are susceptible to this disease.

.Most of the animals died rather unexpectedly. Only a comparatively small number were visibly diseased some time before death. Since in many there was more or less ulceration in the large intestine, it indicates that animals may be in a very had condition and become a source of infection for others without necessarily showing it.

The swill feeding has already been mentioned as a probable cause of the cirrhosis of the liver observed in so many of these animals. This organ was tough and imparted a gritty sensation to the hand when cut. The parenchyma was softened and degenerated. It seems reasonable to suppose thai this chronic malady may have made the herd more susceptible to the disease.

Hemorrhagic leisioHS. At least one-third of tiie cases examined showed lesions of a hemorrhagic character. The most common was an infiltration of the cortical portion of lymphatic glands with blood: sometimes the entiie glandappeared hemorrhagic on section. As regards the relative frequency of this condition, the bronchial, posterior mediastinal (aortic), and inguinal glands stood first : next, the retro-peritoneal, meso-colic glands and those in the lesser curvature of the stomach. The mesenteric glands were rarely allected. Accompanying this condition of the lymphatics was a very large spleen, its great size being simply due to an engorgement with blood.

Next in frequency were the hemorrbagic lesions of .serous meinbranes, in the form of panctifomi extravasations, larger eccbymoses, and very rarely of collections of blood infiltrating the muscular layers beneath the serous nieinbrane. These extravasations were most frequent on the auricles and ventricles of the heart, under the serosa of the large and small mlraquo; Minis, beneath the pulmonary pleura, and in the subentane ons tissue. In the severest eases blotches appeared on the diaphragm-and costal pleura. In about 10 per cent, the kidneys were heuior-rbagic. The glomeruli then appeared as minute blood-red points. To this may be added bemonhagea in the pyramids and extravasations collecting around the papillae.

The mucous membrane of the stomach in hemorrbagic cases was deeply reddened in tbefandus; in some eases there was hemorrhage into the moinbraue, more rarely on the surface. The mucosa of the small inlestine was usually intact, but that of the large intestine in the acute form of the disease was in the same condition as the stomach. In older cases, when not covered with ulcers, it was either pigraented or dark red, chronically congested. This outbreak was characterized by hemorrbagic lesions more than any other which we have examined. Our experience has been that the early cases are hemorrbagic and are succeeded by those, in which ulceration, cellular Infiltration of the lymphatics and signs of weakness, such as serous effusions, predominate.

In some of the animals in this outbreak there, were most extensive hninorrbages, In one the mucous membrane of the stomach was separated from the muscular coat by an extensive clot one half inch thick. In live cases (10 per cent.) the lungs were the seat of extensive lietnor-rbages, which literally converted the most dependent, lobes into a blood clot and tilled the pienral sacs with bloodstained serum. In a considerable number both peritoneal and thoraciccavities contained much bloodstained serum.

Vlcerntive lesions.Ulcers of the large intestine were present in 3G out of V.) cases, or 7b per cent. They varied from very slight to very severe and extensive lesions, involving in a small number nearly the whole mucous membrane of the ciecum and colon. The rectum was quite invariably free, from disease. The age of the ulcers can not be determined, as the process of necrosis and subsequent ulceration seems to vary much in rapidity. In a few cases it was not limited to the mucous membrane, but extended into the muscular wall, producing considerable local inflammation and thickening of the serous membrane. In rare cases the necrosis and cellular infiltration had made the intestinal wall so friable that it broke when handled. When the ulceration was slight it was frequently confined to the ileo-csecal valve and adjacent membrane, which consists of a large patch of lymph follicles and some mucous glands. The ulceration in this situation was accompanied by an extensive neoplastic thickening of the valve beneath the ulcer, indicating that the ulcer was old. In .Teases (10 percent.) the

lower ileuui was ulcerated (tfos. 5, 21, 38, 47, 48); the ulcers seemed to have no relation to IVyer's patches.

Complications.Peritouitis, pleuritis, and pericarditis were not uu-comuion complications usually accompanying- old alceratlou.

Lntiff lesions.This epizootic was studied mainly for the porposeof detcriiiiiiin.i;'the condition of the luugs in hog cholera. Swine plague is essentially a disease of the luugs, secondarily of the digestive tract. It may be possible to lind some cases of swine plague in which the largo intestines are primarily diseased. Thus far they have not eome to our notice. From the facts obtained from this epizootic we may safely assume that hog cholera produces no lesions which may not be found in the lungs of apparently healthy animals of the same age. and which may be due to the debility caused by the infectious disease. We must accept, however, the hemorrhages found in a small percentage of cases. Such are coexistent with hemorrhages in most other organs, and are not specilic lung lesions. (See Nos. 7, 17, 21, 22, 43, of autopsy notes.) The lesions found on post-mortem examination were eil her simple collapse or lobular broncho pneumonia following it.

Simple collapse usually involved the two ventral dependenl lobelaquo;, more rarely portions of the small cephalic and the principal lobes. The collapsed lobes, or groupsof lobules interspersed among emphysematuus lobules, appcared slightly, it at all, depressed. The color approached thatof red flosli. In only a few instances could plugs he found occlud-ing the brouclii. Sections made from lobules in this condition show a number of interesting features. The alveolar walls are crowded together in sonic places till they almost touch one another. Besides the flbrin, there may or may not be one or several large cells, rouud, with much protoplasm inclosing a vesicular nucleus. The bronchi are all open; the epithelium intact. The alveolar walls are not changed, nor is there any rouud cell infiltration to be seen. In circumscribed areas the capillary net-work is distended with blood corpuscles, while all the larger vessels are similarly filled witli these elements. In the alveolar duct there is now and then considerable librillar fibrin well brought out by Weigert's slain.

in about 15 per cent, of the animals examined one of the smaller ventral lobes was airless throughout and moderately enlarged. Viewed from the surface, the diseased lobe is blight red, dotted with minute, pale grayish or yellowish points of a diffuse hazy outline, each not more than 1 mülhneter (^ inebi in diameter. They are usually arranged in groups of four, and represent the ultimate air-tubes filled with cellular exudate. The larger bronchi are also occluded. The exudate is yellowish white, so firm thai it is possible to tear away the lung tissue with needles without necessarily breaking up the inclosed exudate. It may thus be teased out in flic form of branching cylinders,becoming smaller, and finally dwindling down to the size of a coarse hair.

In microscopic sections the alveolar walls arc found beset with dis-

tended capillaries. The alveoli are filled up with cellular masses, fibrin appearing very rarely. In most alveoli the cells are large, round, with vesicular nucleus, evKlontly derived from the alveolar epithelium. In some alveoli aud in the smallest air-tubes the cell mass is so dense that iiuliviilual elements can only be seen with dilliculty, but they appear to he identical with the cells just described. The process seems to be accompanied with very little inllammation. The desquamatiou and proliferation goes on in the alveoli and smallest air-tubes until they are occluded by the casts described. Of the 49 animals of the same herd, 17 were found with collapse (Nos. 1, 7, 8,12, 13, IG, IS, 21,23,24, 28, 32, 34,35, 41, 44, 4(5), and eight with lobular bionchopneumonia (Xos. 2, 5, 9, 14,19,22,30,37; see also Xos. 434 and 435). More than one half, therefore, had some defect of the lungs.

it might be questioned whether such lesions as those of broncho-pneu-monii?. are not due to swine plague bacteria, since they closely resemble the appearance found in many swine plague lungs. This question is eÜ'octualiy disposed of by the inoculation of lung tissue into rabbits. From 10 lungs 10 rabbits were inoculated. Of these lungs 8 were involved in simple collapse; laquo;Sin broncho pneumonia. Of tlie 10. rabbits 4 survived (Xos. 9, IS, 23,46); the remainder died of hog cholera (Xos. 2, 5, 12, 14, Hi, 22, 28, 30, 34, 37, 14, 434). . (The notes on these rabbits will bo found in the autopsy notes of the swine as numbered.) Of the 4 survivors .'gt; had been inoculated from collapsed lung tissue, I from a bronclio-pneumonia. It is interesting to note that of these rabbits 1 died in six days, 4 in seven days, 3 in eight days, 2 in ten days, 1 in thirteen days, and 1 in flfteeu days after iiioenlation. Plate cultures from the corresponding bits of lung tissue showed a vari-

i able number of colonies almost invariably non-liquefying, and in many cases identified as hog cholera bacteria. These facts lead to the inference that in hog cholera the specific bacteria will find their way to any diseased portion of lung tissue, and there multiply to a certain extent. In one case a plate culture from a bit of normal lung tissue showed but one or two colonies, while a bit of \nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;collapsed tissue from the same lung showed a large number. There is

\nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;no doubt that the slight exudatc and feeble circulation in collapse and

the abundant partly cellular, partly mucus or librinous exudatc into the air spaces in broncho-pneumonia furnish a. favorable nidus for pathogenic bacteria. These may have been carried there by the blood or they may have been introduced from without, if the latter supposition prove true, and there are no valid objections to it, diseased lungs in hog cholera may not only become the means of disseminating the disease through the mucus and expired air, but they may become the channel, the weak spot, througb which the virus enters the organism.

To elucidate this question, if possible, the following instructive experiment was made:

Two pigs (Xos. 4(jO and 4(il), about ten weeks old, received each into

the right iuiiji-, December21,3 cubic ceutimetersof a bcef-infasionpep-tone cultaro two laquo;liiys old, iaocalatcd from a single colony growing in a roll culture. This bad been made from a bit of spleen tissue from No. 40 of the outbreak described in the preceding pages. There were about fifty colonies in the tube, all alike. To test the culture, a rabbit received at the same timeone-nintb cubic centimeter subcutaneously in the thigh. It died in live clays. The spleen was much enlarged, blackish, friable, and contained hog cholera bacteria. A roll culture contained nuiiierons colonies after two days. The liver contained no centers of coagulation necrosis, as the animal had .succumbed too quickly.

Xo. 400 became very weak in its hind limbs in less than a week; respirations sliort and quick; bo weis relaxed, it was found dead on the ninth day. raquo;Superficial inguinal glands nornuil. Petecchia-in tbesligbt deposit of fatty tissue beneath peritoneum of abdominal muscles. Spleen about 1'2 inches long, 1.] inches wide, and three-fourths inch thick at the liilus, blackish, friable. A few peteechhe on cortex of left kidney. One cyst, the size of a large pea, in medulla. A large number of small hemorrhages in connective tissue around pelvis of right kidney; live small urinary cysts not showing on surface. (Hands in lesser omentuin enlarged, bemorrhagic throughout. In ca;cum and colon an almost continuous yellow sheet of superficial necrosis, about 1 miUimeter thick,covering themucosa. In lower colon it breaks up into

isolated patches, simulating uh

In microscopic sections this layer

is found to consist of necrosed epithelium intermixed with some round cells. (Jn Peyer's patches in lower ileum a yellow, soft deposit rests which is not adherent, and might be mistaken for chyle. Lobes of right lung glued together and to pericardium. Pleura thickened generally ; serum very slight in amount, blood stained. On lobes of left lung, which are also glued together, and on right lung, there is a very slight deposit, about one-half millimeter thick, in tho form of a net work. The pleuritis and exudute is most marked on the most dependent portions of the lungs. Cavity of pericardium normal. Lung tissue not hepatized anywhere; trachea and bronchi contain a small quantity of reddish fluid. Bronchial glands and those along posterior aorta, hem-orrhagic throughout. Cultures from pleural cavities, as well as those from spleen, contain only hog cholera bacteria. As shown in roll cultures they were very numerous in the latter organ.

While Iso. 4C0 presented such a well-marked case, Eo. 401, although presenting at first the same symptoms, slowly recovered. The difference may have been due to the fact that with No. 400 a (J-incli needle was used, while with Xo. 401 one only .'5 inches long, i a the latter case the chances for the passage of bacteria into the lung tissue and I hence into the intestines were much poorer.

On July 31, over seven months after inocnlatiou, No. 461 was fonbd dead. It had continued well and thrifty, and no more attention had been paid to it. Only the lungs and the liver were brought to the lab-

oratory, since all the other organs, incladiag tbe digestive tract, wore reported normal, excepting tbe kidneys, whieli were said tobe highly congested.

Lungs, luit slightly collapsed, dark red. Cephalic and ventral lobes of botli lungs and the azygos lobe solid to the touch, f a grayish red color, witli tortuous injected vessels under the pleura. On section, the tissue cats like cold meat. Color grayish to dark red. The cut ends of bronchi show plugs of a glairy mucus. The marginal portion of the lobe is grayish, homogeneous, very dense. Towards the center of the lobes the tissue, is more reddish, inflltration not so dense, ami speckled with small masses (one-half millimeter across) of a yellowish-white, Loinogeneous, cheesy matter. On the border of the right cephalic lobe, an encysted mass, cheesy, yellowish, gritty to the knife, evidently the result of the inoculationquot;. There were reported adhesions of the diseased lobes to chest wall, indicative of plenritis.

Bronchial glands slightly larger than walnuts, of a uniform gnnish dense texture. Trachea and bronchi occluded with a blood clot of very recent origin. In the extremities of the large bronchi lung-worms embedded in the chit.

Heart of normal size, rather flabby. Both auricles and the attached vessels filled with tarry semi coagulated blood. In left auricle a white clot also present. Left ventricle firmly contracted.

Liver small; surface roughened with adherent Hakes of tissue, indicating old perihepatitis. Parenchyma tough, resembling in texture very soft rubber. Acini with dark center and pale bloodless periphery.

The immediate cause of death was pulmonary hemorrhage; the remote cause, the broncho-pueumonia caused by the inoculation. The lung worms aggravated the lesions already present. What is most interesting in this connection is the fact that hog cholera bacteria wore still present in the lung tissue, as the following- will show :

Three roll cultures made from bits of lung tissue; the developing colonies all alike and resembling those of hog cholera bacteria; no liquefying colonies in any tube. Beef infusion cultures from the individual colonies demonstrate the identity of the bacteria with those of hog cholera. A rabbit inoculated with sterile beef infusion, in which a bit of lung tissue had been torn up, remained alive, while another rabbit, inoculated from the pure culture made of the colonies of the roll culture, died in six days with enlarged spleen, coagulation necrosis in *nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;liver, extravasation in lower large intestine, and many hog cholera bac-

teria in spleen. Cultures from blood and spleen pure.

The, lung disease in this animal could not have been more than three months old, and was very likely duo to the injury to lungs resulting in adhesion to chest wall and the inflammation around the encysted mass.

This experiment shows (1) that hog cholera bacteria, when introduced into the lungs, do not produce a specific parenchymatons inllam-mation of themselves j (2) that they may pass from the lungs by way of the pharynx Into the digestive tract and there produce their characteristic effect.

Bacteriological observatiom.The preceding experiments oil rabbits and the intrathoracic inoculation in case of the pigs are sufficient of

themselves to establish the fact that the bacteria described in the reports of the Bureau for the years 1885 and 1886, and again found in this epizootic, are the cause of hog cholera. It may be added, however, that out of fifty-six cases (here reported) hog cholera bacteria were found in the spleen of all but six. Even in these the cultures made were too few to make the negative evidence of any value.

In many cases the hoy cholera bacteria were associated with a.rather large bacillus, which, lor the sake of convenience, we will call butyric bacillus.* This organism was only detected when a bit of spleen was ' dropped into beef infusion, with or without peptone. The culture, kept at about 303 c., contained ou the second and third days a cloudy mass limited to the bottom of the tube. The cloud was made up of bacilli, rather large, with a spore in one extremity of the rod strongly refracting the light. The rod was not enlarged at this end in the fresh .state. AN hen dried and stained, the shruukeu protoplasm gave the spore bearing end a swollen appearance, remindiug one of the tailed bacteria of older writers. In the few tubes in which (his bacillus alone was present the liquid itself remained perfectly clear: when hog cholera bacteria were present, it became uniformly but faintly clouded. In liquid cultures, without the bit of spleen, the bacilli did not develop. This was evidently necessary as food material. In gclatinc-tul e and roll cultures the bacilli did not grow. They are very likely anaerobic organisms, abundant in the alimentary tract, and absorbed from ulcers or lesions of blood-vessels into the circulation before death, in the spore state, and their development kept in check until that occurs, it is also probable that they are important factors in the rapid changes which

may take place after death. They arc quite constantly fo.....I in the

liver of different animals when post mortem changes have begun to develop.

In some half dozen cases decomposition was so far advanced that no thorough examination was made. At first it was thought that theani-mals had been dead several days, hut the person in charge of the herd asserted that they had died during the night. Although the temperature had fallen below 30deg; Fahrenheit (1deg; 0.), decomposition was far advanced. It may be that the live animals crowded upon the dead and thus kept the bodies warm. Vet this supposition is not capable of accounting for therapid changes. Tliehemorrhagic lesions may have enabled various bacteria to become distributed throughout the body. The heat disengaged by them during multiplication, aided by thebody heat of the animals still alive, may have been sufficient to keep up the process of decomposition. This post raquo;worte?raquo; growth may also account for the large number of hog cholera bacteria found in many spleens,

* Wliotlier tliis bacillus is identical with the bacillns of malignant oedema, iis lias been asserted by some, 1 do not know, as no experiments were made to test its pathogenic power.

!laquo;

although the temperature of the air was far below the point where mnl-

tiplicatiou may take place.

In the foregoiug epizootic, as well as in those studied in 1885, and 1880, there was no difficulty whatever in demonstrating the presence of the hog cholera bacillus in the spleen. The herd referred to in the preceding pages was swill-fed, and the animals were very likely crowding each other more or less, not being compelled to hunt for food. Heuce each one was exposed to a large quantity of vims. The same may be said of the penned pigs at the Experiment [Station. The diseased animals found in dillerent localities weie brought to the station and penned with healthy ones. A severe epizootic; was quite invariably the result, owing to the unusually good opportunity tor infection in the peus and the saturation of the floors and soil of the pens with virus.

quot;When swine roam over a considerable extent of territory in search of food, the virus is more widely distributed but less concentrated. Less virus is therefore taken np by individual animals, and although the disease is equally fatal in the end, the course may be somewhat different and the lesions less extensive. At the same time the bacteria may elude observation. They may remain more or less localized, owing to the reactive power of the organism, which destroys those that have entered the internal organs. To those who would give up the search for hog cholera bacilli after a few nnsuccessful attempts to find them, we would reccommemi the perusal of the following three eases, after having reviewed the epizootic just described :

Hog cholera prevailed more or less iu Montgomery County, Mary-laud, during the latter weeks of September and the early part of October, 1888. October 17 Mr. II-------- lost about 22 out of a herd of 55

to lt;gt;(gt; swine during the past four weeks. Of those now scattered in a large field 2 appear ill; 1, a small black shoat, is lulled by cutting its throat and examined. The superficial inguinal glands are very much enlarged, the surface mottled, dark red. The spleen large, but pale and rather firm. The liver shows signs of invasion of thu sclerosioma pinguicola. The lymphatic glands at lesser curvature of stomach are very large; cortex completely hemorrhagic.

The left lung normal; the principal lobe of the right lung has in it a mass of tissue involved in broncho pneumonia, extending obliquely from the free border to near the dorsal region, about 1 inch thick; the lymphatics along the dorsal aorta are likewise hemorrhagic; the stomach filled with food ; small intestines contain a number of attached eehinorhyneM] the large intestines distended with semi-solid fecal matter ; the mucosa in general is normal, but in the ca'cum are two ulcers about three-eighths inch across, round, slightly elevated, with center black and periphery yellow; beneath the superficial slough is a whitish, firm, new growth, extending to the nmscular coat in the center of the ulcer.

The spleen and the right lung were taken to the laboratory. From the former cultures were made on a^ffr, in gelatine and beef infusion, by adding bits of spleen tissue as large as peas. In no tube did any development take place.' A rabbit inoculated by tearing np a piece of liepatized lung tissue in sterile beef infusion and injecting the turbid liquid siibcutaneonsly remained well.

Several miles from the first farm wo came tiprm a herd of jonng pigraquo; which were just showiug sinus of disease, although none had been lost. One of them, with unsteady gait, whicb liid in the litter under a shed and returned to it when driven away, was killed by bleeding from the vessels of the neck. The lungs were without a sign of disease. Spleen enormously enlarged and gorged with blood. The lymphatic glands of groin and about stomach very large but rather pale, and OBdematous on section. Stomach filled with food. Large intestines overdisteuded with very dry, bard feces, somewhat softer near csecuui; in the latter only one ulcer and this on the valve, about one-fourth incb across and of the same nature as the one found in the preceding ease.

A portion of the spleen of this animal was taken to the laboratory and cultures made, as in the previous ease, with bits of spleen. All cultures remained permanently sterjle.

Several miles from the latter place we found the disease on a farm situated on a bill. The swine were allowed to go a considerable distance down the slope to a niarsliy stream. The owner had lost G or 8 out of a herd of 20to25 within six weeks. A few were evidently ill, but none were killed, as a dead one was found, li had probably died during the night. The buz/aids had consuraed nearly all the intestines through a small hole near Hie pubis. Putrefaction bad already set in. Spleen enlarged, slightly congested. In the small portion of the large intestine, which still remained, an nicer was found three-eighths inch across. The glands of lesser oinentniu with hemoiThagic cortex. The stomach contains a small quantity of bile stained lluid. Both lungs glued to chest wall by coagulated fibrin from blood extravasation. Left lung contains about ten to Qfteen hemorrhagic foci, visible under pleura, one-fourth to one-half inch across. The principal lobe of right lung solid, graunlar, involved in broncho-pneuinonia. The bepatized lobe was discolored by recent and extensive blood extravasation. A gelatinous deposit luuler steinum testing on pericardium. The semi-decomposed condition of the animal prevented a morj careful examination. Portions of the spleen and bepatized lung tissue wert'. taken for examination.

While the spleen of the two preceding cases showed no indications of bacterial life on cover-glass preparations, the spleen of this case contained a considerable number of bacteria resembling hog cholera bacilli very closely. On gelatine they grew differently from the latter, and the cultures emitted a slightly offensive odor. In liquids they were actively motile. They were putrefactive bacteria, without effect upon two rabbits inoculated with large quantities of the cultures. A rabbit inoculated with the diseased lung tissue remained well. The latter on closer examination had a texture as granular as the roe of fishes, the granules being inspissated cell masses in the alveoli and air tubes. At least four different kinds of bacteria were presenl in large numbers.

The absence of bacteria from the spleens of Kos. 1 and 2 is in bar-mony with the results obtained in other infections maladies when animals are killed in the early stages or during the height of the disease. It is only in the last stages that the bacteria become most numerous and appear insufficient numbers iti the internal organs tobe easily detected. In the third case, death was very likely brought on by pulmonary hemorrhage not infrequently found in bog cholera. The specific bacilli produced at first the ulcers, and were either working their way slowly into tiic internal organs or else were being destroyed in the nicer itself.

The hitter termiuation would signify recovery; the former death. These ulcers might be aptly compared to the malignant pustule in man, in which the virus remains at first localized but may spread throughout the system after a time. The presence of numerous ulcers in swine in the first epizootic is to be regarded as a multiple infection, while in the three cases just cited the infection was limited to a few foci or but one. The ulcers would no doubt have revealed the vims, but our previous experience with spleens of diseased swine made it seem unnecessary to study the ulcer itself. As regards the lung disease of the third case, nothing positive can be said. It resembles most closely cluonic swine plague. The germ of this disease was not present, however, as shown by the rabbit inoculation.

Buzzards may carry the disease from one place to another. When the, dead animals are at all exposed to view they are immediately attacked. Whether hoy; cholera bacteria are entirely destroyed in the digestive tract of the birds can nor be said, but there is nothing in the range of our knowledge of bacteria which will exclude the probability that the bacteria are not all destroyed dining the process of digestion, and that they may be distributed by these birds from place to place in (he discharges.

THE CAUSATION OR ETIOLOGY Ob¹ HOG CHOLERA.

The suspicion entertained by those engaged in the study of diseases of man and the lower animals that iul'ectious or commuuicable diseases are due to living organisms ot the lowest order, capable of rapid inulti-plication by the process of fission and spore-forinatiou, has been transformed into conviction during the past ten years. A considerable iiiini-ber of the most common, most dreaded diseases have been proved to be caused by exceedingly minute, plant like organisms known under the general name of bacteria. Among animals the micro-organisms causing anthrax, black quarter, tuberculosis, glanders, strangles, infectious pneumonia in horses ami swine, and rouget in swine have been very thoroughly demonstrated. The opinion has been steadily gaining ground that in order to control infectious diseases we must learn their causes and the life history of the pathogenic bacterium found in each disease. These will suggest to us the measures that are most likely to prove successful in combating such maladies. Moreover, it is pretty well accepted today that the prevention of infectious diseases is the main thing to be arrived at in our studies, and that their treatment when they have oncoobtained a footbold is at best tentative and rarely successful. This is especially true, of the lower animals. They cannot be treated with the same care which is accorded to human heings attacked by infectious diseases. They are (in some diseases at least) always scattering the living virus and thereby endangering those still free from disease.

In the investigation of swine epizootics these facts have been carefully borne in mind, so that most attention has been paid, first, to the life history or biology of the micro-organism ; second, to disinfectants as destroyers of the specific bacteria; and third, to the various methods of preventive inoculation.

THE BA.CILLÜS* OF HOG CHOLERA.

During the past three years the number of swine affected with this disease which have been examined is about 500. About three-fourths

'The term bacterium, implying ;i form fjeiuis between raicrococcus and bacillus, has been almost wholly given up by bacteriologists, a,ncl all those, forms classed under bacteria have been thrown together under the genns bacillus. This cliango is gt;m-fortnnate for several reasons, inasmuch as many species were best elassed under the genns bacterium. This latter term, which was applied to hog cholera microbes in the reports of 1835-'camp;=-'sect;7| is now relnctmitly given up for the sake of uniformity.

G-,5

of this number dietl at tbe experimental statiou of the bureau. Tbe remaiuder came from outbreaks of tbe disease within 2 or 3 miles of tbe Statiou Besides tbese, a small uumbei- of animals were examined m some of the Westen. States. From perhaps 400 the same microbe was obtained, tbere being practically uo difference between the pathogenic _Uliciobes obtained from all the outbreaks thus far investigated.

Of tbe internal organs tbe spleen coutains the largest number ot bacteria, and in acute bemorrhagic eases they are sufficiently numerous to be detected on cover-glass preparations. A minute bit of spleen ulp is rubbed on a cover -lass, dried and heated according to the accented methods, and then stained fur a few minutes in an aqueous so-_lation ₀f methyl violet. The bacteria then appear as elougated ovals or short rods wltb rounded ends, chiefly in pairs. When the staining Ins been very brief onlv the periphery of the rod is deeply stained, the _c;_utl._a1 p_0l.tion being pale ami simulating the appearance ol an endo-spore. When the period of staining is prolonged to half hour or more, the rod may become uniformly stained.

Bacteria thus dried on a coverglass and mounted in balsam measure iVon, 1 2 to 1 5 occasionally l.S micro-millimeters (.OOO05-.0OÜ00 inch) in l_cntb, and about .0 mien.millimeter (.0ÜU02-1 im-h) in breadth.

[u sections of the spleen from acute bemorrbagic cases the bacilb _mav be round in considerable numbers. Sort ions were hardened in alcohol cut dry, ami subsequently stained with aniline water methyl violet. They were in some cases decolorized in 1 per cent, acetic acid. The bacilli then appear as short, plump rods, Avitb ends rounded off; sometimes they are short enough to deserve the name ol ovals. 1 ne raquo;eripbery is more deeply stained than the central body o the rod. Thev measure on the average 1.5 uiicro-millimetcrs. in such sec ions the'bacteria appear in small masses ill the capillary spaces of the spleen-pulp, rarely among the cells of the malpighian corpuscles fPlate X lbgt;- 2). The masses appear more or less star-shaped. 1 ho \_M;,_üh _;11,. ^owded together in the enter ; bom this, linear groups radiate iuio the capillary network. Such masses may be b to 10 micro-nnllimcters in diameter. Tbey are fairly numerous m spleens from _acute cases That the size of these colonies is not due to po,I mortem multiplication is shown by the tact that the largest and most numerous eolouies wer., (band in the spleen of an acute case which was examined within two hours after death, in the mouth ol November.

[ sections of ..leers hog cholera bacilli have been searched for, but the examination of a largo number of ulcers showed that, no positive results could be obtained. Different ulcers showed different bacteria, sometimes large colonies of micrococci, sometimes groups ot large ba-₍.illi, following tbe course of the blood-vessels in the embryonic tissue under the slough. These no doubt found their way in from the super-tidal slougbwbicb seemed to be made up almost entirely of bactena. Moreover.'hog cholera bacilli closely resemble many putrefactive forma,

(J5

.so tbat even if they could be readily .seen nothing but a good differential stain would enable us to recögnüse them. Tbat they are present, however, may be demonstrated by inoculating mice or rabbits with bits of the ulcer. A small nuiiilierof mice maysuccumb to malignant Gedema. The rest: will die of bog cholera. In rabbits the local effect of such inoculation is usually quite severe, owing to the putrefactive bacteria introduced at the same time.

Staining of hog cholera bacteria......On cover-glass preparations they are

easily bronght into view by a few minutes' contact with watery solutions of the ordinary aniline colors, such as methyl violet, fnchsiu and methyleue blue. Decolorizing agents, such as acetic acid, one-half to 1 per cent, must be used carefully lest the color disappear from the bacilli also. When stronger dyes, such as alkaline methyleue blue orani-line water fuchsin, arc employed, the bacilli are decolorized with greater difficulty. Watery solutions should therefore be employed only for cover-glass preparations where decolorizing is unnecessary. Forsectious it is well to harden tissues in alcohol. The sections may be stained with Löffler's alkaline methyleue blue or with aniline water methyl violet or fuchsin for from one-half to one hour. After a a few seconds' contact with a 1 per cent, solution of acetic acid they are washed in water, then passed through alcohol, turpentine, or xylol or cedaroil, and mounted in xylol balsam. Xo stain which differentiates these bacilli very sharply from others has been found. They are decolorized when tinraquo; method of Gram is employed.

Distribution of bacteria in the body.This can be best determined by the delicate method of cultivation. In acute cases the spleen contains the largest number. In covei'glass preparations of spleen pulp there may bo four or five in every field of the microscope, lu general, the liver contains almost as many bacteria as the spleen. The lungs, lymphatic glands, and kidneys may also contain them in moderate number. They are fewest in Mood from the heart (right ventricle). In slow, chronic cases, characterized by slight nlceratioh of the large intestine, the number of bacteria in the internal organs is very small. From the spleen of such cases cultures are made fertile only by using hits of tissue as large as split peas.

When it is of importance to make a diagnosis from a chronic case it might be well to adopt the method suggested by Friinkel and Simmonds for typhoid fever. They wrapped the spleen in cloths wet with a solution of mercuric chloride and placed it in a warm room for twenty-four hours. The bacilli of typhoid, capable of multiplying in the organs after death when the temperature is not too low, became sufficiently numerous to be readily detected in sections. The same may be said of hog cholera bacilli. It must, however, be borne in mind that in chronic cases other bacteria may have gained entrance into the body and appear in the spleen. These, multiplying at the same time, may give rise to erroneous interpretations. .15lt;llli n c------~gt;

When the destruction of tbe luucons membrane in the huge intestine is extensive, bacteria of various kinds may be found in the peritoneal cavity The serum collected often contains several varieties oi organ-isms and when sections are made of the walls of the peritoneal cavity micrococci and bacilli are seen resting iu a thin layer upon the pento-cum. Sometimes the pleural flnid, and still more rarely the per.car-.lial fluid, may give rise to cultures of micrococci. These resemble the micrococci, causing suppuration iu man {staphylocooci) in their appear-auce and mode of growth in gelatine. The presence of anaerobic bacüli iu spleen and liver has already been dwelt upon. The presence ot bacteria in the peritoneal cavity is easily explained by their passage through the ulcers iu the intestines. It is a fact worthy of note that only very rarely bacteria other than those causing the disease were encountered in the spleen and the circulation. IVrlmps those causes or agents which destroy bacteria are less active in the serous cavities than in the blood uid spleen The various complications of chronic ulceration already mentioned, such as peritonitis, pleuritis, and pericarditis, are without doubt due to this secondary invasion of bacteria, which have the power to produce inflammation of serous membranes. It need not be said that in the earlier investigations, when little was known of bacterial diseases, the explanation of the presence of these microbes was very perplexing and misleading.

Biology of the hog cholera badllus.-The cultivation ot bacteria m nutrient media outside of the animal body serves two distinct purposes: (I) The diagnosis of specific forms so that they may be easily recognized, and (2) the study of their biology or life history.

a Diagnostic characters.-Jiog choter* bacilli are not readily distinguished from a large number of other bacteria found in surface waters and in the superficial layers of the soil, either in their tonn or iu their manner of growth in culture lubes. The more minor dilleren-tial characters we can therefore obtain, the more certain our diagnosis will be. For this end the hog cholera bacillus was cultivated m as many media as were available.nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; , , . , ,

If a bit of spleen pulp from swine which hare succumbed to hog cholera be thoroughly shaken up in a 10 per cent, beef infusion peptone -elatine, liquefied by a gentle, heat, and the whole poured upon a sterile glass plate protected from the dust by a bell-glass and allowed to congeal, colonies of hog cholera bacilli will appear within forty-eight hours as mere specks to the naked eye. Examined under a low power they are spherical, with sharply defined border. The disk of the sphere is homogeneous without any concentric markings, and of * brownish color. This description applies to colonies beneath the surface of the gelatine layer. Colonies which grow on the surface soon spread out fnto thin pearly layers several times the size of the deep colonies, and roundish or irregularly polygonal in outline.

Besides the deep spherical and the flat surface colonies there is oc-casually a third form present. This is a very taint cloud like colony

growing between the glass plate and the gelatine, spreading as a very thin layer laterally and attaining the dimensions of a surface colony. Many such colonies have spherical prolongations upwards into the gelatine layer so as to assume the form of a lid with a knob like handle attached to its center. It is very probable that the colony begins as a

äl

here in the gelatine layer near its lower surface. As soon as it ehes the glass, by virtue of its enlargement, spherically, it spreads t into tiie attenuated, clouddike layer. Such colonies are rare, ex

cepting in so-called line cultures made by drawing a platinum wire across the, gelatine layer before it has congealed.

Perhaps the best device for studying the growth of such colonies is the Esmarch roll culture.* The gelatine, coating the inside of the test tube, is protected from contamination and desiccation For a long time. The colonies have thus the opportunity of expanding to their utmost capacity. In a roll culture ten days old, for example, the deep colonies were about one half millimeter in diameter, perfectly spherical, the disk homogeneous, yellowish white, when viewed with a hand lens. Under a 1-inch objective it appeared reddish brown, with no markings. The surface colonies in the same tube; were about eight times as large, i. e., t millimeters across. They presented centrally an opaque white patch or nucleus, outside of this a more translucent zone, beyond this another opaque /.one, and lastly a limiting translucent bolder. The colonies were irregularly polygoiml in outline. The alternation of thin and thick /ones was very likely due to the variation in temperature to which gelatine cultures were exposed in a badly heat'd laboratory, for they are by no means always present. (Plate XI, fig. 2.)

Tube cultures, made by piercing the gelatine in a test tube with a platinum wire previously forced into the spleen, show minute yellowish-white spheres in the track of the wire in forty-eight hours. These rarely exceed one half millimeter even after several weeks. The, surface growth spreads from the place of inoculation as a thin pearly layer of variable thickness, eventually becoming 4 to 6 millimeters in diameter ; under especially favorable conditions of temperature, etc., it may become still larger. When the inoculated bacteria are verynumeious the growth beneath the surface appears as a solid yellowish-white track, in which the colonies have become fused together. The gelatine is at no time liquefied. The bacilli grow somewhat larger in gelatine than in the body of diseased animals. Occasionally filaments of considerable length are, met with, and in general irregular, involution forms are not

' These roll cultures are made as follows: The gelatioo, liquefied by gentle heat in

I lie rn He m willen it was siennzeil, is inoeuia ieu wiui 1 lie \ issue, oiooii, urine, pi' any liquid coiitaiiiing bacteria, and carefttlly stirred up. A second culture may be made from the, iirst by transferring from it with a platinuni loop some of the liquid gelatine. This is done when the niimber of bacteria in the, Iirst tube may be too nuiner-ous. A rubber cap is lifted over the month of the tube after replacing ami trimming the cotton-wool plug, and the tube placed horizontally in ice water and rolled about its long axis until the inside of the tube is coated with a uniform layer of congealed gelatine. The tube may also be rolled on a smooth block of ice, a method which I Iirst saw iiithc Pathological Laboratory of Johns Hopkins university, and which is very useful when rubber caps arc wanting, or when it is desirable to keep the plug free from srelatiue.

uncotmnou. V\ heu n bit of spleen tissue is rubbed upon an iuclinod surface of agaragarin a culture tube, isolated colonies make their appearance witMn twenty-four hours as circular, grayisb-white, semi-fcranslucent, very flat cones 1 to 2 millimeters across. When tbe bacilli are very numerous a slight prick of the spleen pulp witb a platinum wire is sufficient. Otberwise tbe too numerous colonies will coalesce into a grayisb, sbiuing, semi-opaque layer of scarcely perceptible thickness. Its appearance on agarciLn not be distinguished from the growth of typhoid bacilli and a number of saprophytic bacteria. On blood serum the growth appears as a very thin, grayish, translucent layer. In bouillon, either with or without peptone, the bacilli grow rapidly enough at80deg; to95deg; F. to produce a slight opalesceucc within twenty-four hours. This docs not increase in density subsequently. There is no membrane formed on the surface of the liquid. When standiug undisturbed for one or two weeks, a white ring-like deposit of bacteria frequently forms around the tube at thesurfaceof tbe culture liquid. There is only a very slight deposit formed, showing that multiplicatiou in liquid media comes to an end within a few days.

The length of the bacilli in bouillon is about .9 inicromillimeter,their width .4 to .'gt; mieroinilliraeter, therefore somewbal smaller than in the spleen. When examined in a drop of bouillon suspended from the under surface of a cover-glass in a quot;cell,quot; the bacteria are seen to be motile. Taken front cult ores one or two days old they execute very active spontaneous movements. Their movement is one of rotation as well as translation. They quite invariably occur in pairs, and the movement of rotation is about their point of union as an axis. The pairs

oot across the field have thus an oscillating motion

of bacilli as they

at the same time. The bacilli do not come forest at all. but swarm about very rapidly until the liquid is dried up.

Though' this motility is most marked in recent cultures, it may still be seen at, the end of one or two weeks in most liquid cultures.

The same active motion is observed in bacilli taken directly from the animal, such as the spleen of rabbits, which have succumbed to inoculation.' If a bit of spleen tissue be rubbed in a drop of sterile water on a cover-glass and the whole examined as a hanging drop, in one or two minutes the bacilli become as active as in cultures.

Growth on boiled potato, when at 95deg; F., appears as a faint straw-colored deposit within twenty-four hours after inoclution. At L't^ to 25deg; C, it appears one or two days later. It slowly spreads in all directions as a layer of perceptible thickness. The color changes to a dark brick red, or may remain whitish. In general the growth is darker the more rapidly the potato dries up.

The growth is also restricted by drying. In some sulturcs it has covered almost the entire cut surface of the potato. In others it remained as a broad band over the line of inoculation. The bacilli multiply very abundantly in milh without producing any alteration visible to tbe naked eye.

The diagnosis of hog cholera bacilli may tbereforo be made by taking together the following morphological smd biological characters: (!) Short bacilli with rounded ends, or orals, readily stained in aqueous solutions of anilinedyes. (2) Growth at GiPtoSlP F., on gelatine, without producing liquefaction. (3) A ratherfeeble growth in beef infusion coupled with active spontaneous movements. (4) Growth on tlie cut surface of boiled potato nt ordinary temperature as well as in the incubator. (5) Active innltfplication in milk without any macroscopic changes. (6) Growth ilaquo; vaouo. (7) A.bseuce of any odor arising from the cultures. (8) Fatal effect on rabbits, guinea-pigs, and mien when inocnlated. This will be discussed later on.

These characters are emphasized, since we have several times found bacteria in the internal organs of swine which may have many points in coiiiinim with hog cholera bacilli; especially as regards their form, motility, and growth in gelatine. In fact in was quite impossible to decide until inoculations upon animals were made. The absence of pathogenic power was thus made the chief criterion.

(/lt;) Other physiological characters. Though alkaline media are as a rule most favorable for bacterial multiplication, yet there is a slight, development in media containing a small amount of acid, such as Liobig's meat extract.

A feeble development was observed in sterilized hay infusion.

The temperature range of the active multiplication of hog cholera bacteria lies between 00deg; and 104deg; F., being most favorable between 85deg; and 100deg; P.

Hog cholera bacilli, though they seem to develop best in presence of oxygen, are capable of growing in what is practically a vacuum, i. e.. they are facultative anaerobic organisms. Comparative experiments made with such obligatory aerobic organisms as bacillus snbtilis determined that while the latter shows no trace of growth in tubes from which the air has been removed, hog cholera bacilli grow quite as freely as in presence of air. When the latter are shaken up in liquid gelatine in test tubes and the gelatine rapidly congealed the colonies that appear throughout the gelatine show no difference in size, whether near the surface where air can penetrate or near the bottom of the tube.

TUB DIAGNOSIS OF IKHi CHOLERA BY MEANS OF IXoClLATK )\.

The inoculation of small animals in the study of infectious diseases has been of the utmost importance from a diagnostic stand-point. Pre-quently bacteria which are nearly identical in form, size, and many biological characters, can only be distinguished from one another by Üieir effect upon smaller animals. This is especially true of hog cholera, since tiie specific bacillus closely resembles many forms found in decomposing liquids. Fn the following pages, therefore, a careful exposition of hog cholera as manifested in small animals will be made to facilitate the diagnosis of this disease. During the course of these in-

vestigatious rabbits have been found best for this purpose, a though ordinary house- .ni.r and guinea-pigs will answer almost as well.

If a bit of spleen tissue from a case of hog cholera be inserted under the skin of the thigh, or simply rubbed upon a slight abrasion made on the inner surfoce of the ear, or if the bacilli from pure cultures be used the disease will be imbued. The rabbit will succumb within a erio'd after inoculation varying Iron, live to fourteen days (very rarclv longer), depending upou the number of bacteria introduced. The neriod of incubation, during which the animal shows no symptoms, varies from three to five days before death. At this time the temperature vises from the nprmal (102.50-103.5deg; F., according to the age ol the animal), to 107O _or 108deg; F.. and remains at that point untd shortly before death, when, if examine.! in time, a fall is observed, the height of the fever is accompauicd by loss of appetite and a tendency to sit

perfectly quiet.nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; . , .nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;-

The disease thus induces in the rabbit a typical continuous fever invariably ending in death. By way of illustration, the temperatures ol a few cases are here reproduced :

Rabbit inoculated June 18, with i cubic centimeter culture liquid; weight, 2i pounds; temperature, 102.5deg; F.; at end of lirsl day, iraquo;i'.. : of second day, 104.C; of third day, 105; of fourth day. 108; ol fifth day, IfltJ.-l: dead on sixth day.

Babbit inoculated .lane litraquo;, with infected soil, one and one-half months old; temperature on fifth day, 103.4; on seventh day, 103.8; on eighth day, 103.8; on tenth day, 107.0; on eleventh day, 10,.4 ; dead

on twelfth day.nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;.

Babbit inoculated June 28, with J cubic centimeter ol culture liquid ; weight, 2-Ä pounds; temperature, 103.7O F.; end of first day, 103.3;

of second 'day. 105.5; of fourth day. 107.8; found dead on seventh

The lesions produced are very constant and characteristic. At the point of inoculation there is a slight infiltration of the suhcutis and fascia and occasionally a slight superficial necrosis of the muscular tissue The spleen is very large, perhaps three to five times its normal size. The liver presents on its surface yellowish white patches winch correspond to one or more lobules which have undergone coagulation necrosis These patches vary greatly in number but are randy absent, provided the animal lived long enough to permit their formation, i. e., not less than seven to eight days after inoculation.

This necrosis appears chiefly in lobules near the surface, although oceasioiiallv the entire tissue is involved. In some livers the necrosis ScomiSfso far as the lobule is concerned. In others u _1S restneted S the peripheral or portal zone of the lobule, ,n which case a arge patch of lobules usually undergo the same change. Ehere can he no doubt that they represent different stages in the process which seems to begin in the portal area. When sections are examined under tlie mi-crosco ' thelivcr-cells show as unstained masses without nuclei. There

is a remarkable abseuce of leucocyte iufiltratioti around the necrosed tissue. The bacilli are very well brought oat in such tissues after thorough hardeDiog in alcohol, by staining over night in aniline water methyl violet (tubercle stain), and decolorizing slightly in J, to 1 per cent.' of acetic acid. The deep blue bacilli appear in dense masses, chiefly in the. capillaries along the edge of the necrosed area. The necrosis is most probably due to the plugging of the different vessels, thus cutting off the blood supply.

The enlargement of the spleen and the necrosis in the liver are'the tvvo important characters of the inoculation disease. In a moderate number the intestinal tract is found diseased. The snbmucosa of the duodenum near the pylorus is dotted with ecchymoses, which may fuse into a single hemorrhagic patch. Besides this the snbmucosa of the large intestine 2 to o inches from the rectum, i.e., the straight portion merging into the rectum, may bein the same condition. Sometimes the nmcosa is beset with minute bulging hamiatomata. These intestinal lesious arc due to the discharge of bacilli from the necrotic foci in the liverinto the bile ducts and thence into the duodenuni. The lesions in the large intestines may be influenced by the more or less prolonged stay of the feces before linal discharge.

In some cases when the disease has lasted from ten to thirteen days there is a peculiar exudate in the large intestine, which may be drawn out of the anus in the form of hands or cylindrical masses 1 or 2 feel long, consisting of a translucent, clastic, whitish material, finely fibril-lated -when examined under a high power. The duodenum may be distended with a straw-colored semi-gelatinous mass. Hemorrhagic lesions may also be present. It seems very probable that the exudate is the result of a fibrinousor croupous inflammation of the large intestine due to the presence of hog cholera bacilli.

The lungs are occasionally the seat of hemorrhages. The kidneys contain more blood than usual, but liemorrhages are absent. Hog cholera lacilli are obtained by cultivation from nearly all the internal organs. Tliey are usually so abundant in spleen and liver as to be detected readily in cover-glass preparations.

The following experiment shows bow few bacteria are required to produce the disease:

K-.ihhU No.

18..........

19..........

Inoonlatt-a with culture liquid.

Doatl nil sixili day. Dead on ninth day. Dead on eigbteentli day. Dead on eiglith day.

The beef-infusion culture was diluted so that one-quarter of a cubic centimeter of the liquid contained the equivalent given in the table. It s probable that No. 10 took the disease from No. 20, penned with it. The latter had ecchymoses in the duodenum, indicating that the bacilli

had escaped into the intestinal cauul and were belüg discharged with the t'eces. The time of death of NO. lu suggests tliis view.

A very small nmnber of bacilli, therefore, are snl'iicienl to produce in rabbits an infectious fever, or septicaemia.

The characteristic action of hog cholera bacteria on the mucous mciii-brane i.s well illustrated by feeding cultures to rabbits:

September 11, 1888.Two rabbits were starved for one, day and then fed hog cholera bacilli from an agar culture on clover. This was readily consumed.

One rabbit was found dead on the sixth day. Agglutiuation of bladder to csecntn ; serosa of stomach reddened. Ileniu about (3 inches from valve invuginated for 2 to 3 inches. Spleen congested, slightly enlarged. Liver and kidneys engorged. Large numbers of hog cholera bacilli in spleen, as tested by the microscope and cultivation on gelatine. The other rabbit died in thirteen days. Spleen very large, congested; coagulation necrosis in liver. Lungs contained several dark-red hepatized areas. Severe lesions were found in rlie large intestine. The mucous membrane of lower colon and rectum were, dotted with small bulging hemorrhages, and the tube contained a cylindrical mass of a material resembling colorless gelatine, partially softened in water and very elastic (fibrin?), The duodenum was distended with a pale yellowish translucent semi-gelatinous mass. Hog cholera bacilli as above.

At the same time two other rabbits were starved for a day and then 5 cubic centimeters of a liquid culture was added to 20 cubic centimeters water and given them to drink. One rabbit died in ten days. The lesions were the same as those in the rabbit just described, with this exception, that there was no coagulation necrosis in the liver. The other rabbit did not take the disease. It is quite likely that it may not have taken much of the water.

When rabbits are not easily procurable the ordinary house mice may be used. They usually appear quite well and active, after inoculation until some morning they arc found dead. The period of the disease is the same, as that for rabbits. The spleen is very la igt.'; the liver contains many centers of necrosis. .'Mice have been frequently fed both with pure liquid cultures and with spleen pulp containing hog cholera bacilli. They invariably take the disease and die, within seven or eight days after the first feeding, with lesions the same as those observed in mice inoculated subcutaneously. Two mice were peculiarly affected the day after eating some spleen pulp. They were scarcely able to move. Their limbs sprawled, and on being taken out of the.jars they remained in this position unable to escape. They died subsequently of true infection. The symtoms recorded were due very likely to the absorption of the ptomaine produced by the bacteria in the digestive tract.

There is a reuiarkable regularity in the length of the, disease in mice. Those inoculated at the same time and with approximately the same dose, usually die not more than a half a day apart; they appear lively up to the night during which they die. in one case four mice, inoculated at the same time, all died in the night of the seventh day, though they appeared well the day previous.

The following experimeuf is worthy of record as iudicating tbe effect oi' hog cholera virus on muie that survived iufection :

October 28, 1888.Two mice wore fed with bits of liver and kidney tissue from mice wliich had succumbed to inoculation with hog cholera cultures. The material fed had been kept in the refrigerator for nearly four weeks in salt solution. Before feeding it was thoroughly mixed with bread crumbs and placed in the mouse cage. Uoth mice survived the feeding and were active December 1, over one month after feeding. One was thereupon killed with chloroform and examined. The spleen was very much enlarged, not congested abnormally. On the ventral aspect of the liver a whitish patch where diaphragm was adherent. Under the patch a large abscess. This was without doubt the .site of extensive coagulation necrosis, which was now broken down.

The second mouse was killed December 19, over seven weeks after being fed. The spleen was likewise very large, the liver intact, but there were live abscesses in the left kidney, with adhesion^ to surrounding structures. Un section one abscess was wedge-shaped, the apex being at the pelvis; the whole only partly softened. These also were the result of coagulation necrosis. We have here a striking illustration of the mainly mechanical injury done by hog cholera bacilli.

The effect of hog cholera bacilli an guinea-pigs differs but little from¹that exerted on rabbits and mice. The duratiou of the disease and the lesions are, the same. There seems to be a somewhat greater tolerance in guinea-pigs, although the small number used docs not Justify any decided statement.

Pigeons arc also susceptible to this disease, but by no means to the degree witnessed in the animals Just mentioned. It requires about three-fourths of a cubic ceutimeter of an ordinary beef infusion peptone culture to produce a fatal result (t. e., about 150,000 to 3,000,000 times the dose necessary to destroy rabbits). The birds frequently died within twenty lour hours after the injection, which was usually made under the skin over the pectorals on one or both sides. The pectoral after death is partly or wholly discolored, and has a parboiled appearance. The injected bacteria are present in the heart's blood and in other organs, notably the liver. If the dose is smaller than three-fourths of a cubic centimeter, the bird may survive after a week or two of pronounced illness. A large sequestrum forms in the pectoral muscle, which is gradually absorbed. Occasionally the birds will die after a week of illness manifested by diarrhea, ruffling of the feathers, and a qitiet, somnolent attitude in a corner of the cage, ilog cholera bacilli are also present in the internal organs in such cases. Feeding' cultures has no effect.

Fowls have been freqiiontly inoculated and fed with cultures without showing any signs of susceptibility. Among other animals inoculated were several white rats, one gray rat, one sheep, and a calf. In none did the disease appear. In the sheep and calf a small abscess was found at the place of inoculation.

VITALITY OF HOG CHOLERA BACILLI, AND THEIR RESISTAKCE TO VARIOUS DESTRUCTIVE AGENTS.

The vitality of Log cliolera bacilli in cultures remains for moutbs mi-cbanged. The followiug is perhaps an extreme illnstratiou :

A tube of beefs blood sniuii, coagulated by heat, was inoculated with hog cholera bacilli November 28, 1885. The platiuum wire penetrated the blood serum and the bacteria grew as a slender plug in the needle-track and as a thin film on the surface. In July, 1887, more than one and one half years later, a tube of beef infusion inoculated from the blood serum culture became promptly turbid, and contained the hog cholera bacilli only. Two mice inoculated subcutaneously with a few drops August 2, died Augusts and 9, respectively, with lesions characteristic of the disease and with the bacilli present in spleen and liver. The germs had not therefore lost their virulence. The blood serum had contracted but slightly from loss of water, there being very little evaporation from the culture tubes used.

Resistance of hog cholera haderia to heal in KgHlaquo;?laquo;.A knowledge of the degree of heat necessary to destroy hog cholera bacteria is of considerable importance, not only in its bearing upon the application of heat as a disinfectant, but also upon the various processes that are used in the preparation of pork for consumption.

Culture tubes containing about 10 cubic centimeters of beef infusion were inoculated from a culture of a certain age and then placed in a water-bath kept at the desired temperature. They were exposed for different periods of time and then removed to an incubator at 95deg; P. When the tubes remained clear it was inferred that the bacteria had been destroyed. A control tube was inoculated in every experiment to make sure of the vitality of the culture used.

A momentary exposure to boiling water will destroy them, When tbe temperature of the surrounding water is 158deg; F. (70deg; C). the inoculated tubes remain sterile after an exposure of four to five miimtes. As it takes about four minutes for tbe temperature of the culture liquid to reach 70deg; C, it is probable that a two minutes'exposure to 70deg; C. would be sufficient.

An exposure to IJtP to 13S³ V. (580-59deg; C), is sufficient to destroy hog cholera bacteria in tifteen minutes. The same is true for bacteria taken directly from the spleen. An exposure to 130deg; F. (54.5deg; 0.) will destroy them in one hour. Tubes exposed for one-quarter of an hour become turbid within twenty-four hours. Those exposed for one-half

and tliieciiiiartors of an hour become liirbid wirliin forty-eight hours. This shows that most of the bacteria Lave been destroyed by such prolonged exposure. Tubes heated for one hour remain clear.

When the temperature is still more reduced, to 120deg; F. (49deg; ('.), exposure for a period as long as two hours is insufficient to destroy them, although their growth may be slightly retarded.

It must be remembered that these results mean that the bacteria must be actually exposed to these temperatures for the length of time indicated. Jn the culture tubes employed it takes about five minutes to bring the temperature of the liquid up to 70deg; C, and less for lower temperatures. If, therefore, it takes longer than this for the beat to penetrate into meat or lard containing these bacteria, their destruction can not be regarded as certain within the time indicated above, and the exposure to the required temperature must be correspondingly lengthened.

Uos cholera bacteria iu 10 culm- centimeters bauillou placeil in a watcrbatli ;il-- I '¹quot;,quot;¹ 'quot; ^wl;icli

¹nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;(lestroyeu.

ICOraquo;0.(212deg; F.)......................................................................nbsp; nbsp; tmmdllatelj-.

70deg; C. (158deg; F.).......................................................................nbsp; nbsp;i minutes.

68deg; C. (138deg; F.).......................................................................nbsp; nbsp; 15minutes.

54.5= C. (130deg; F.).....................................................................nbsp; nbsp;1 I,hi.

492C. (l;u F.).......................................................................nbsp; nbsp; Sot in 2 hours.

Bacteria do not so readily succumb to beat when dried and then exposed to dry Lot air. It was found that dry heat at 8(1deg; O. (176deg; K.) is sufficient to destiny the bacteria when exposed in a dry state for fifteen minutes.

In these experiments bacteria from cultures were rubbed on the inner side of plugged and sterilized test tubes. Gelatine was added after they had been exposed to the beat and roll cultures made. Absence of growth indicated the death of the contained bacteria.

Resistance to freezing is well illustrated in the experiments reported in the section on the vitality of hog cholera bacilli in the soil during winter.

Vitality of hay cholera bacteria in ordinary water.The hardiness of this microbe is well illustrated by its capacity for multiplication in ordinary drinking water. To determine this, the following experiment was made :

September 8, a culture tube containing very clear Potomac drinking Water* which had been sterilized several weeks previous by a temperature above 1 M)⁰ 0., was inoculated with a platinum loop from a pure liquid culture of the bacillus. By mixing a given quantity of this water immediately after inoculation with gelatine, and making a plate culture of the same, it was found that the water contained about 26,240

* Whoa drawn this trater iliil not coutain more than lOe to 200 bacteria to the cubic centimeter.

bacteria in 1 cubic centimeter. The water was kept iu the laboratory, in which the temperature corresponded closely witb that prevailing oat-doors. It was examined from time to time on gelatine plates, and the

nuniber calculated for 1 cubic centimeter. The following figures give the results obtained :

September 8, 26,240 in 1 cubic centimeter (immediately after inoculation).

September 9, 201,000 in I cubic centimeter.

.September 10, 1,290,000 in 1 cubic centimeter.

September 11, too numerous on plate to be counted.

September 13, 2,008,200 in 1 cubic- centimeter.

September 15, 1,010,5(10 Lu l cubic centimeter.

September 17. 1,300,308 in 1 cubic' centimeter.

September 20, 83,700 in 1 cubic centimeter.

October 12, 10,125 in 1 cubic centimeter.

October 21, 10,880 in 1 cubic centimeter.

November 18, 225 in 1 cubic centimeter.

December 0, a few bacteria still present, as determined bj^T liquid cultures.

January t, 17 in 1 cubic centimeter.

January 11, no growth on plates.

According to another experiment the vitality lasted about two months.

.(uiie 13, ISS8,10 cubic centimeters, Potomac drinking water, sterilized in a Salmon culture tnlgt;e. was inoculated with a platinum wire to which a minute bit from the surface growth of an agar-agar culture adhered. Plate cultures prepared immediately after thoroughly shaking the tube, indicated that each cubic centimeter of the water contained from

1,000,000 to 2,()0o.ooo germs Plate culture of June 14 shows in

cubic centimeter of water a very

large nuniber of colonies. Roll cultures; made June 22, July 3, and July 16 contain a smaller number.

A roll culture of August 4 contains about 200 colonies (/. e., about (1,000 in 1 cubic centimeter).

A roll culture of August 25 remains sterile. A tube of beef infusion to which about 1 cubic centimeter of the water had been added September 15 contained a large coccus live days later; no hog cholera, genus.

These cultures show that the bacilli perished in about two months. The difference in the results obtained in this and the last experiment may have been due, to the season of the year.

That the bacilli can be kept alive in clear river water for from two to four months and perhaps longer is a fact very significant in itself. When we consider, moreover, that the added bacteria in the fust experiment multiplied so that each individual was represented by ten at the end of five days, the hardiness of the bacillus is very evident. The danger from infected streams into which feces from sick animals find their way is thus proved beyond a doubt. Stagnant streams and pools are more dangerous, since the water is but slowly renewed, while in rapidly flowing streams the bacteria are speedily carried away. On the other band, the latter may spread an epidemic from one place to another.

Resistance to contimwiis drying at ordinary tenyperatwre{amp;P to 8(1deg; F. A number of experhuents were made to determine this point. Some of them are reported in full in preceding Annual Eeportsof the Bureau, and are therefore simply summarized in this place.

(1)nbsp; A .series of corer-glasses, upon each of which a drop from a liquid culture bad been dried, were placed in bouillon at different times. Xo growtb in bouillon after they had been dried from seven to nine days.

(2)nbsp; .Minute bits of spieen' tissue from a pig which bail succumbed to hog cholera were dried on cover-glasses. These were capable of infect ing bouillon np to the twenty-third day.

(3)nbsp; Spleen tissue dried on four cover-glasses gave rise to pure cnlt-ures of hog cholera bacilli after forty-nine days.

(t) lloj;- cholera bacteria from a liquid culture one week old. dried on silk threads, were placed on a gelatine plate from time to time to observe any growth. They were still capableof development after twenty-one davs, when the stock of threads was exhausted.

^5) threads steeped in a liquid culture one day old and dried were placed on gelatine plates, as described in series 1. No colonies appeared on the twenty-seventh and twenty-eighth days. A few appeared later on, showing that even after thirty days a few still survived.

lu these series of experiments the vitality of the bacilli was not exhausted after forty-nine days in one series; in another it was destroyed in less than ten days.

The following series of experiments, made during the present year, show how very varied is the length ol time during which the bacilli remain alive when dried:

Jane 15.Minute bits of spleen tissue, from a rabbil which bad died of hog cholera after inoculation with a pure culture, were nibbed on sterile cover-glasses and kept under a flamed funnel, plugged with cottonwool.

On July 3, 6, and '.raquo; two cultures were made by dropping into each tube of beef infusion a cover glass. All six tubes remained clear. The bacilli bad thus perished within three weeks.

In the following experiment hog cholera bacilli reniaired alive for more than four mouths:

June S.From an agaragar culture, three days old, some of the abundant surface growth was placed upon sterile cover-glasses each receiving about as much as the point of a platinuin wire could bohl. These were placed on a flamed glass support under a flamed and plugged glass funnel, and kept in the laboratory, the air of which was moderately

dry.nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; . ,,_ ,.

Two cover glasses dropped into beef infusion peptone June -gt;. Une culture remains clear, the other clouded in one day ; contained only motile hog cholera bacilli.nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;, #9632; nbsp; nbsp; nbsp; nbsp;, , ,

Two covers were added to beef infusion June 29, July 9, and July IG. All six cultures became clouded and contained only hog cholera

bacilli.nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; , - i i

Of two cultures made July 23 only one becomes clouded, and ISraquo; pure culture of hog cholera bacilli. Of two cultures made Aiigust2, both become clouded with Log cholera bacilli only.

Four cultures, imule ou August 1), 22, 30, and September 14, became clouded with the same microbes, and these alone. A tube into which a cover-glass had been dropped September 21 remained sterile. A tube inoculated in the same way September 20, became turbid on the second day, and contained hog cholera bacilli only. A tube inoculated on October 8 was still fertile. The stock of cover glasses had become exhausted.

it will be seen from the above results that some ofthe germs were dead in oue and a half and three and a half montlis; all the rest were capable of multiplication for four months. The prolonged vitality was no doubt, due, to the massing together of the germs from the agar culture, for on those cover glasses which failed 1o inoculate cultures, or in which the appearance of growth was retarded, the quantity of growth was smallest. The interesting question here arises whether it is the oxygen of the air which gradually' destroys the bacilli, since this is more or less kept away when they are massed together, and since all previous experiments with bacilli suspended in liquids have shown that the period of their vitality may average not more than two months when in a dry condition.

On August 30, after having been dried for two months and twenty-two days,two mice were inoculated with a liquid culture obtained from one of the cover-glasses. Both died of hog cholera on September 14 and 15, respectively.

The vitality of hog cholera bacilli during oontinuous desiccation may thus last from two weeks to more than four months.

In the soil, and in nature generally, bacteria are rarely subjected to continuous drying, but to alternate wetting and drying. In order to observe the effect of such alternatiou, some of the same agar-agar culture used in the preceding experiment was placed in the bottom of a sterile watch glass under a funnel June 8.

June lö.About one-third cubic centimeter of sterilized distilled water added to the watch-glass, so as to cover the dried film completely. The water was evaporated entirely next day.

Tnne 22.Sterile water added again ; dried up next day.

/?(/.;/3.Water added again and two cultures made; both remain sterile.

iuhj 0.A liquid culture made by adding some sterile water to the dried culture mass, stirring it up and transferring the water with a sterile pipette to a tube of beef iufusiou. This also remained clear.

Thus bacilli from the same culture which resisted continuous drying for at least four months were destroyed in less than a month when a moist and a dry state alternated. This fact, so striking and important, needed confirmation.

September 10.A considerable quantity of the surface growth from an agar-agar culture two days old was rubbed on the bottom of a sterile watch-glass covered by a plugged funnel as before. Thoroughly dry next day.

/September 18.A small quantity of sterile distilled water added. This was dried up next, day; the genus had spread out into a thin layer.

i^quot;quot;

Septemher 21.Sterile water added agaiu ami a tube of beef iufnsion peptone inoculated with a loop from the liquid .stirred up. Tube turbid with lio^' elioleia bacilli next day.

September 2$.Sterile water added again. The tube of beef inlusiou peptone inoculated at the same time. Pure culture next day.

October 1.The same process repeated ; culture contains hog cholera bacteria.

Ocioamp;er 8.-Dried bacilli wetted again with sterile water. The culture made from them becomes turbid; only bog cholera bacilli present.

October 15.The same process repeated; the inoculated tube becomes turbid after forty-eight hours.

Octoher 22.After wetting the dried growth again, it was thoroughly stirred up and several drops added to a liquid culture. This tube remained permanently clear.

This experiment therefore confirms the other in showing that hog cholera virus is far more quickly destroyed when it is alternately moistened and dried than when it remains continuously dry. In both tests the germs died in one-third the time required to destroy dried virus.

SOME EXPERIMENTS ON THE LENGTH OF TIMI-: DURING WHICH HOG CHOLERA VHMS REMAINS ALIVE IN THE SOIL.

The virus of hog cholera is quite tenacious of life in spito of the fact that no spores are formed. During the past year some preliminary experiments were made conccrniug the vitality of hog cholera bacteria in the soil. This becomes infected during epizootics of this disease by the discharges of the siH; |ioibnps more thoroughly than anything else in the surroundings of the animals. Moreover, it is the most difficult to disinfect, as we have no knowledge of the depths to which the living virus may be carried by water. If it can be shown that the life of such virus in the soil is speedily destroyed, the precautions to be taken would be quite different from those needed if it exists for a long period of time.

Experiment I. A small Howerpot contaiuiug soil was sterilized by moist beat at 110deg; to 118deg; C, and protected from drying and dust by a large bell Jar. On its surface about 100 cubic centimeters of a bouillon peptone culture of hog cholera bacteria was poured and the whole maintained moist and at the laboratory temperature. The soil used was a very line loam from t lie grounds of the Department of Agriculture. The bulk of the soil consisted of grains not larger than _T,'_l; milliineter (#9632;._:\,_igt; inch). Boll cultures from the soil after a felaquo; days demonstrated the presence of immense numbers of bacteria, From this soil rabbits were inoculated from time to time by stirring up a little soil in some sterile beef infusion and injecting the clear sapernatant liquid hypodermically. The soil was infected September 17, 1887. The appended table gives the inoculations into rabbits to test the virulence of the soil. The rabbits which succumbed died of hog cholera, as indicated by the lesions and the bacteriological examination.

I Date of No.; inocn-

rectiou of soil

Died.

Remarks.

lutiun.

Mot. Days. 1 Oct. 10nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; 23nbsp; nbsp; nbsp; nbsp; nbsp;Oct. 17

Enlargemont of sploen; Goagaiation*neci'oaifi in

liver; hemorrlia^ic lesions in damUninn anil rectum, in Iiinj;,s and heart; mimerouH iiog cholera bacteria in spleen and liver. i Spleen and liver and liinf;s as in Xo. 1. Spleen, liver, ilnodemnn, and rectum as in No. 1, Spleen large, pale; coagulation-necrosis in liver Bliebt; no other lesions j hog cholera bacteria us in No. 1.

2nbsp; nbsp; nbsp;Oct 18

3nbsp; nbsp; nbsp;Nov. I

4nbsp; nbsp; nbsp;Dec. 12

31nbsp; nbsp; nbsp; nbsp; nbsp;Oct. 24 .

40nbsp; nbsp; nbsp; nbsp; nbsp;Kov, 12

23nbsp; nbsp; nbsp; nbsp; nbsp;Dec. 2a.

5 Jan. u 0 Jan. 23

3 23 Remaias well.

3 23nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;.. do.........

The infectious quality of this soil when a mouth old was tested on two pigs, by feeding each directly with a tablespoonfal of the soil. One showed no disease; the second, a young pig, became very sick and was killed on the eighteenth day. being unable to rise.

A utopsy.Animal about eight weeks old, very thin. Xo skin lesions. Lungs normal, excepting the cephalic and ventral lobes of left lung, the ventral and the root of principal lobe of right lung. These are airless, bright red, mottled with yellowish points, indicating broncho-pneumonia. The spleen was small. The lymphatic glands of large intestine very large, tough, whitisb. The wails of C9ecam and colon ever one-eighth inch thick; do not collapse when slit open. The mucos;i is everywhere covered by a firmly adherent yellowish-white slough, extending as far as rectum. The ilenm for about 2 feet from lower end has the inucosa likewise involved in superficial necrosis, but only on the suniinit of the longitudinal folds. In the stomach a portion of the fundus is covered by a friable deposit made up chiefly of large granular cells with single nucleus. Gelatine and liquid cultures from heart's blood and spleen contain only hog cholera bacteria. The gelatine cultures indicate only a moderate number of colonies. The bacteria had also penetrated into the diseased lung tissue. They were obtained on plate cultures, ami a rabbit inoculated subcutaneousiy with sonic beef infusion in which a bit of hing tissue had been torn up died in eleven days with coagulation necrosis in livtr, enlarged spleen, and numerous hog cholera bacteria in both organs. The broncho-pneumonia may have been due to the aspiration of some of the soil during the forced feeding.

It has thus been shown that moist soil, nor allowed to dry out and ke[it in a summer temperature ranging from 00deg; to '.raquo;.quot;P F., retained its virulence for rabbits from two to three months. At the end of this time fungi and other bacteria had found their way into the pot of soil, as shown in roll cultures. This and other reasons drawn from observations of this germ lead to the conclusion that its life becomes extinguished with its pathogenic effect on rabbits. This phase of the question is not to be overlooked, for even if a germ should no longer prove pathogenic, but remain alive, it is not improbable that it. may regain its original virulence under certain unknown circunistances. 10012 it 0------0

The severe disease caused in the yoaug pig with soil which had been infected one month ago shows the great susceptibility of young animals to this disease. Since rabbits are, most susceptible of any animals to Log cholera virus, it was not thought necessary to experiment on pigs after the former failed to take the disease.

It may be argued that the conditions of this experiment were abnormal, in that the bacteria were not exposed to the various meteorological conditions, such as rain and drought, freezing and thawing, and the compotition with other bacteria in the soil. This is true. The conditions just enumerated are opposed to such a long life in the soil. A condition favoring it, on the other hand, is the low temperature in winter, which may act as a means of preserving the life of bacteria.

These objections were partially removed by the following experiments:

Experiment 2.A small pot, about 5 inches across the top, tilled with soil, is placed in another pot of twice the diameter, also tilled with soil in such way that the rims of both are on the same level. In this position they were sterilized for three and one-half hours, at a temperature of about 110deg; 0., in a steam sterilizer. The outer pot was to protect the inner one to some extent from coining in direct contact with the garden soil in which it was subsequently placed. About 1200 cubic centimeters of a beef infusion culture of hog cholera bacteria three days old was ultimately mixed with the soil of the inner pot by removing the upper layers and pouring the culture liquid upon the deep layers and then upon the surface, after replacing the superficial layers. The pots were then placed in the grounds of the Agricultural Department so that the top was level with the surrounding soil. Nothing was placed over the surface to protect them from contamination with ordinary bacteria.

The infected soil was placed in the grounds December IG, 1S87 During the remainder of December the out door temperature oscillated slightly above and below the freezing point, remaining for several days below this point at the end of the month. The soil in the pot was saturated with water during part of the winter and the surface covered with it. It had probably become tightly packed, and hence impervious after the culture liquid had been poured upon it.

The appended table indicates the persistence in virulence of the infected soil as tested upon rabbits. The soil was taken from the surface of the pot, or from near the bottom as indicated, and the inoculations made as in the preceding experiments:

[Soil infected Deoembec 1*gt;, IHST

Date of =_nii _t-f,. Nnmlier ol days Ko. inoonla- ,#9632;'. ,nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; quot;ft''¹' infection Rabbit die!

tlon.nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; iromnbsp; nbsp; nbsp; nbsp; nbsp; nbsp; r suil.

Bemarks.

1 Jan. 5 Surta.'

#9632;JUdavs .

January 16 ! Om¹ lube of liver involved in coaff-iilatlon*necrosis; bacilii of hoy übolera present.

2 Feb. 1 ___do

L montb 13 days .. February 1ft .. Spleen very largo. Hark; cuayulii-

lion-lieelesis in liver: inuueroud hog cholera bacilli in both organ-raquo;. ;; Fell. T Depth ...... lmontU19days..................: Killed February 27; i.....liscascd.

4 Feb. 2:j Surfaco..... 2 months 7 days .. March 5...... Spleen and liver as in KTo. 2; hem.

orrliagio lesions in dnodenum #9632;mil rectum ; hog cholera bacilli

present.

5nbsp; nbsp; nbsp;Mar. .quot;) .. do..... 2 months IS days Romains well

6nbsp; i Mar. 21 ..do....... 3 months 5 days......ibraquo;.........

Rabbit No. 3 was inoculated with soil from beneatb the. surface. This was obtained by removing the inner pot, thrnsting u small metallic cork-borer previously flamed througli the hole in the bottom of the pot upwards, about half-way to the surface. The. soil brought down in the inside of the borer was used for inoculation. In this way it was obtained unmixed with soil from the superficial layer. The rabbit re mained well for twenty days after inoculation. This is longer than any period of incubation which we have thus far observed. Owing to extensive disease of the external ear caused by psoroptes (lice), it was killed on the twentieth day. There were no indications of hog cholera. The deeper layers of the soil had thus rid themselves of the infectious material sooner than the surface. Roll cultures showed the presence of a large number of pearly colonies spreading rapidly and made up of non-motile bacilli.

Rabbit Xo. 2 lived seventeen days after inoculation. Was this long-period of incubation due to an attenuation of the virus, or to the scarcity of the surviving bacterial The lesions were practically identical with those usually found. In order to learn whether attenuation had actually taken place, a rabbit was inoculated subcutaneously with three to four drops of a beef infusion culture prepared from the blood of No. li. It died in five days with extensive coagulation-necrosis in liver; spleen very much tumefied and petecchiie in rectum. There was no attenuation, therefore, so far as the second rabbit is concerned. There still remains the possibility that the bacteria, attenuated when inoculated into the first rabbit, grew in virulence during the long period of incubation until they had attained their original pathogenic power, when the rabbit died.

Experiment','). February 20, two pots of soil, one within the other, were sterilized as in the preceding experiments. The soil of the inner pod was saturated from below up with 100 cubic centimeters of a beef infusion culture one day old, of hog cholera bacteria. The whole was buried in the garden on a level with the soil and not protected in any way. Rabbits were inoculated with the soil as previously indicated.

(Snil infected February 20.1

Date ni' ,- #9632;, , ,1. , N'umber of So. inocula- ^S^¹* quot; rtaysalter tion.nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;quot;^om-nbsp; nbsp; nbsp; nbsp; nbsp;iuoeulatiun.

Koraarks.

I liar. 10 Surface

18 days

.. Rabbit laquo;lies on eleventh day. Spleen very large j coagula*

turn necrosis in liver; !iquot;,t: cholera bacilli present

.. K.iMiil died on eighth liity ; lesions as in Xu. !. .. Rabbit remains nlivc.

2nbsp; nbsp; nbsp;Mar. 29 Depth...... 38 ilays

3nbsp; i.. do---- Surface........lt;Lgt; ..

Soon afler the last inoculation the ])ot of soil was accidentally removed by laborers working in the garden, so that the experiment came to a premature close. It shows, however, that t lie bacteria in the depths of tin soil were alive thirty-eight days after iuoculatiou, while at this same time they were dead in the surface layers.

Experiment I.Soil prepared, sterilized, and infected precisely as in the preceding experiment, was buried in the garden April 4, 1888. The soil soon became packed hard and dry on ilie surface to a depth of one-half to 1 inch. The following table gives the inoculations:

[Soil infected April*.]

Date of

%\h ll:-: l-la- A ': T^C 1 iii'-Jl i : 11

tion.

Soil taken from

Remarks

1 Apr. -ii I -1 ilays........

Surface . ... Dies April 3Ü; enlarged si'lccn. Slight necrosis in

liver.

Depth...... Dics'May2. Same lesions as in Xo. 1.

:; M;iy I-' 1 month - day 4 ...do ... ....do........

Sn: face..... Homains alive.

Deplh..... Dies May 21. Same as No. 1. besides hemorrliagic

lesions in reel um.

5nbsp; nbsp; nbsp;May 29 1 month 25 days .. Surface... Renminsalive.

6nbsp; nbsp;...do......dt)............ O'-pili...... DiesJuneC. Same lesions as in Ko. 1.

7nbsp; nbsp; nbsp;June 15 2 months 11 days......do....... DiesJuue29; spleen and liver lesions as in No. 4.

S ...do....]....do...............do....... Eemainswell.

9 July II 3 months lOdays.....do.......nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;Do.

10 .. do.....do...............do......nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; Do.

The presence of hog cholera bacteria was demonstrated by cultivation from spleen and heart's blood in all the animals that died.

Experiment ö.Soil sterilized and infected with hog cholera bacteria as in preceding experiments. Placed in the department grounds May IS. June :.'(). surface layer dry and very hard : boring necessary to get sonn- of it out. Two rabbits inoculated from surface and deep soil. The result of these and subsequent inoculations is given in the follow-in quot;#9632; table :

[Soi] infected May 18.|

Date Lcngtli of tiun-Xo. ofiuoca- after soil iBfcc-lation.nbsp; nbsp; nbsp; nbsp; nbsp;tion.

lull taken from -

Remarks.

1 Juno 20 33tlays........... Surface. ... Dead July 4 (ling cliolora).

lt;iquot;........do............| Depth......I Gcmaius well.

July 'J^t 2 months 2 days... Su:!';!! . do.......do............. Deptl

Do. Do.

Experiment G.Inly 14 a pot of soil was sterilized and infected throughout with 100 cubic centimeters of a culture of hog cholera bacilli as before and placed in the Department grounds.

Date of Length of time No. inooulalaquo; after soil infec. tion.nbsp; nbsp; nbsp; nbsp; nbsp; tion.

s.iil taken (Vorn

Remarks.

1nbsp; nbsp; nbsp;Aug. 10 27 days...........| Surface------#9632; Dies Augusi 23; spl-fn very largo. Necrosis in

liver; hogcholeia bacilli in snlecu; intestines diseased.

2nbsp; ! Any. 10 ----i!igt;............. Dvptli....... Hied Auausi 11 : sj.lcen and liver as in N'o. 1.

:i I Anir.--! 1 tnoiith 10 days .. Surface.....' Krmains well.

4 AoS-Sl .-(id........... Deptli ..- inbsp; nbsp; nbsp; nbsp; nbsp; Do.

These various experiments extended over the coldest as well astho liot-test in'iiod of the year, and may therefore lay claim to more or less com-pleteuess. They may all be brought together in the following table:

I).! IO Of

Rabbits failed (o take the disease when inoculated

With surface soil alternbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;With deeper soil aftei

1nbsp; nbsp; nbsp;Sept 1?nbsp; nbsp; :! months 23 days

2nbsp; nbsp; nbsp;1gt;i e. 10nbsp; nbsp; 2 months 7 days

::nbsp; nbsp; nbsp;Feb. 20nbsp; nbsp; 1 mouth 7 days ..

Inbsp; nbsp; nbsp;Apr. 1nbsp; nbsp; 1 month 23 days .

Snbsp; nbsp; nbsp;-May 18nbsp; nbsp; nbsp;2 .....nlhs #9632;_'days

0nbsp; nbsp; July Unbsp; nbsp; nbsp;1 month Id days -

I m^liih 1!' days. Not completed. '#9632;'#9632; months 10 days.

1 month 10 .lavs.

[fc may be said in general that hog-cholera germs will perish in the soil in from two to lour months, depending on the season, moisture, and depth from the surface. In what direction these three (actorsinflueuce their vitality the experiments are not complete euougli to show, We may, however, safely assume that frost has no rapidly destructive effect upon them, while drying (experiments 5 and G) seems much more destructive. Attention lias already been called to the destructire effect of alternate wetting and drying. So far as the above results go, a period of at least four inontlis should be allowed for the natural destruction of bog cholera virus in the superficial layer of the soil, #9632;'. e., in a layer extending about 2 or .quot;gt; inches below the surface.

,_r

A PEW ADDITIONAL OBSERVATIONS AS TO THE VITALITY OF HOG CHOLERA VllUS I.\ THE SOU. AT THE EXPERIMENTAL STATION.

(1)nbsp; nbsp;A pen has a concrete floor, with a gentle slope towards the back. From January to December, 18SC, at least 70 pigs died in this pen from hog ebolera. During this time all the liquid in the pen drained into the field back of it. During February and March of 1887 a number of pigs in this pen died of swine plague. Two survivors from the disease were removed September 15, leaving the pen empty. In December, 1.SS7. the infected ground behind the pen was inclosed, making a yard (1 feet deep and 10 feet longand communicating willi tlie pen. December 1 ö. 1887, quot;gt; pigs about two months old were placed in the concrete pen and allowed to run in the yard behind it. All three continued well. To make sure that there were no ulcerations escaping observation one of the pigs was killed one and a half months after their transfer to this pen. There were no lesions indicative of hog cholera ; cultures from the spleen remained sterile. The two remaining pigs were well three and a half months later.

These observations show that ground thoroughly infected for more than ;i year was free from infectious properties eight months after the death of the last case.

(2)nbsp; nbsp;Upon a plot of ground of one-fourth to one-third acre about 100 Pigs which had died of cholera during 1880 were buried, being covered with li to 2 feet of soil. Dining ISS7 no animals were buried here, but many had been interred within 3 to S roils of this plot during the latter half of the present year. A triangular yard Hi feet on each side was fenced off upon the old ground, with a movable pen in one corner for shelrer.

December 15, I8S7, ',; pigs were penned in this yard. They remained well : one and a half months later I was killed and found healthy. The two remaining ones were well after three and a half months.

This experiment shows that ground containing the bodies of numerous animals which had died of hog cholera was not infectious after one year.

(.')) The following notes arc valuable in illustrating how rapidly the ground may lie treed of infectious matter:

A yard (! by l*¹ feel was enclosed by a fence and made to communicate with a double pen having concrete floors. This pen had been infected by pigs from the outbreak described on page .'gt;7. The soil rgt;f the yard is a clay loam.

November 27.Nos. 434, 435 now occupy the [raquo;en and Nos. 430, 137 added today.

November 28.Nos. 434, t,').quot;) both die of hog cholera. These had been infected by feeding (see p. 50 for notes on these and other animals in this pen).

Ihrcmln'r 10.Viscera fiom Xo. 42 fed to Nos. 436, 437.

December 12.Viscera from No. 43 scattered over the soil of the yard.

readily eaten by ÜTos. 436,437; later in the day Sfos. 439,440, and 443 added.

December 17.Viscera from No. -17 and No. 48 scattered over the ground, and STos. 448 to 4015 iuclosive placed in the yard.

December 21.No. 443 dies of cholera.

December 28.No. 448 dies of acute cholera.

December 29. -Nos. 430, 43!), 440, 14!raquo;, and 4513 all die of acute cholera. The pen may now be said to be tliorougliiy infected.

iTanuary 1,1SSS.No. 437 found dead.

Jnnuarij 3.Nos. 450, 451, and 453 removed.

January 10.After the yard and pen have been vacant for a week and simply brushed out but not disinfected nor cleaned thoroughly two healthy-pigs (Nos. 470, 480) are placed in it to determine whether the, ground is still capable of giving the disease.

l)^ll#9632;illg#9632; the greater part of January the ground was frozen over, but during February and March there are frequent, prolonged thaws.

March 29.Nos. 470, 480 have remained well since January 10. They are now removed. The yard itself is now converted into a genuine mad-hole.

March 30.Two fresh pigs are transferred to this yard.

July 24.They have remained well for nearly four months.

This virus was in the lirst place either destroyed or made harmless by the prolonged frosts in January, so that the pen and yard were thoroughly disinfected by natural agencies and perfectly safe two months later. The disease did not re-appear in the following midsummer. It may also be seen from the notes that the two pigs placed in the infected pen but one week after tiie removal of diseased and infected animals did not take the disease, perhaps because the infectious matter was frozen up and slowly killed in this condition before they could get at it.

THE EFFECT OF SOME DISINFECTANTS ON TIIE VIRUS OF IXOir

CHOLEEA.

In the report for 1880 there are given in extenso a series of experiments to test the destructive power of the more reliable disinfectants on hog cholera bacilli from liquid cultures usually from one to two days old. The results, owing to tbeir practical importance, are also summarized here.

The method employed needs a few comments. A few drops of culture liquid were added to the disinfectant solution in a sterilized watch glass under a bell glass. After certain regular intervals of time platinum loops holding about j,^,, cubic centimeter were used to transfer this liquid to tubes of beef infusion. These were placed into a thermostat and watched for a number of days. The loop of disinfectant carried over into 10 cubic centimeters of sterile beef infusion is diluted to such an extent (about 1,000 times) as to be practically of no account whatever. This method is more sensitive than the method originally employed by Koch, lie used bits of silk thread impregnated with the specific organism to be tested and placed them upon plates of gelatine to develop.

It has been suggested that lioji- cholera bacteria may survive in the brine from sailed meats long enough to be exported to other countries and comuiunicate the disease. It need not be -said that this is impossible, for the attenuating action of a concentrated salt solution would be in itself safficieut to speedily destroy the pathogenic power of the bacilli, even if their life were not destroyed. The following experiment shows, however, that they are absolutely killed within four weeks:

Ten cubic centimeters of a saturated solution of common salt was added to each of three culture tubes. These were then sterilized and 1 cubic centimeter of a fresh bouillon culture of Log cholera bacilli mixed with the contents of each tube. Small quantities of liquid from one of these tubes were introduced into sterile bouillon everv two or three days. Up to the twenty-first day the bouillon became'clouded, indicating that the bacilli were still alive in the brine. After the twenty-ninth day the bouillon remained clear. The two remaining tubes of brine hitherto antouched were also found sterile when examined by means of cultivation a day or two later.

Mercuric chloride was found destructive to the bacillus when diluted in the proportion of 1 : 7500(1 (.OOl.'j per cent.).

Several drops of a culture were mixed with abonl 1 cubic centimeter of a .1 per cent, solution, and lubes inoculated from this at the end of two, four, six, eight, and ten minutes. Tubes remain sterile. To show that the antiseptic effect of the liquid transferred with the platinum loop was ju7, one of these tubes was inoculated again from another culture. This tube was turbid on I be following day.

Five tubes treated in the same way with .05 per cent, solution. All remain sterile.

Five tubes inocidated with bacteria exposed for the same periods of time to a.01 per cent, solution. All remain clear.

Five tubes treated as before, using a .005 percent, solution. Permanently clear.

Five tubes treated as before, using a .002 per cent, solution. All tubes clear, excepting tin-one inoculated after six minutes'exposure.

Five tubes inoculated al the end of live, ten, Üfteen,twenty, twenty-five, anil thirty minutes after exposure to a .001 percent. (1:100000). Tubes inoculated after five and ten rainutesturbid next day. On the second day all but the one inoculated alter thirty minutes 'turbid and containing pure cultures of the bacterium.

The limit of disinfection for this period of time must therefore lie between I :500000 and 1:100000; bend' live lubes were inoculated as above, using a solution of 1: 75000 al the end of seven, ten, fifteen, twenty, twenty live, and thirty minutes. All tubes remained clear.

Carbolic acid destroys the bacillus in solutions containing from I to 1 { per cent, of the acid by weight.

Five tubes inoculated alter treating bacilli from a liquid culture with a 1 per cent, solution for five, ten, fifteen, twenty,and twenty-live minutes. All turbid (in the following day. The two last tubes were also examined on gelatine plates and the cultures found pure.

With a 2 per cent, solution five tubes inoculated after ten, fifteen, twenty, twenty-five, and thirty minutes remained sterile. The sann' result with a U per cent, solution. With a !| per cent, tubes inoculated at the end of seven, ten, fifteen, twenty, twenty-five, and thirty minutes remained clear,excepting the first, which contained hacillm sxibUlu.

8!)

Passing to aone-balf percent, solution, tubes iiiotmlated at the same intervals became turbid with the ßacterinm sown. Willi a threetbnrtbs per cent, .solution tlie resnll was the same.

Passing back to a 1 per cent, sölution, tubes iuoculntcd ai tbc same intervals remained sterile.

There seems to bean incompatibility between the first ami last series. II \veexamine the others, however,we mnst conclude that tbc limit of disinfection lies between 1 and ]\ percent.

Iodine water was prepared by shaking up somu iodine in distilled water, which assumed an amber tint. This solution destroyed the bacillus in fifteen minutes, as the following experiment shows:

Six tubes were inoculated with bacilli alter they had been exposed to the action of the iodine water for seven, ten, ßfteen, twenty, twenty-six, and thirty-one minutes. On the following day the first tube became turbid; on the second the ten minute tube was turbid and found to be a pure culture of the^ bacilli sown. The other tubes remained sterile. One of the tubes, inoculated later, showed its capacitv for sustaining growth by becoming promptly turbid.

Permanganate of potash. A series of experiments with this substance, conducted in the manner described above, showed that the bacillus is killed by fifteen minutes' exposure to .02 per cent, solution (I :5000).

In order to obtain this result: a ö per cent, solution was tried first, lubes inoculated after an exposure of the virus for seven, ten, fifteen, twenty, twenty-live, and thirty-oue minutes remained permanently clear. One of these tubes, subsequently inoculated with the unaffected virus, was turbrl next day. Two and a half per cent,, 1 per cent., one-half per cent., one-fourth per cent., one-tenth per cent., ami one-twentieth per cent, solutions were, tried in the same way. The six tubes used for each solution remained sterile. Finally, a one-fiftieth per cent. (1:5000) was used. Tubes were inoculated after an exposure of the virus for two, four, six, ten, fifteen, twenty, twenty-five, and thirty minutes. On the following day the four tirst tubes were turbid; the fifth and seventh remained sterile; the sixth and eighth contaiueda Hue bacillus. These two tubes, as was found later, belonged to a lot which, through some carelessness, had not been properly sterilized, and the majority became tuibm before use.

Mercuric iodide was found to destroy the bacillus in solution of 1:1000000 in ten raiuntes.

Two grams of potassium iodide and I gram of mercuric iodide were dissolved in 10;) cubic centimeters of distilled water, making a 1 percent solution of the disinfectant in a l' per cent solution of potassium iodide

This solution, diluted with sterile distilled water so as to make .1 per cent., killed the bacillus of hog cholera taken from liquid cultures in less than five min ates; .01 percent. (1 :10000), .003 per cent (quot;#9632; 100000) .001 per cent. (1: 100000), and .0005 per cent. (5 :1000000) destroyed the germ within two minutes.

When the.solution was diluted so as to make.OtfOL'jHT cent f2-1000000) and .0001 per cent. (1 : 1000000), it was found that with both solutions tubes inoculated with bacilli, after an exposaro of two ami live minutes, were opalescent, the bacilli introduced baviug mult iplied, while the remaining tubes (ten to thirty minutes) were sterile. These two solutions, therefore, were still powerful eiioutjTi to kill the germ in ten

inimites. The dilation had been carried so far as to make them practically equivalent in disinfecting power.

Sulphate of cupper.This disiufectaut, which seems to be more effective than most other metallic salts, was tried in solutioas containing 2 per cent., one-half per cent., one-tenth per cent. Both the - per cent, and the one-half per cent, solutions destroyed the germ within five minntos. Tubes inoculated with bacilli after an exposure to the one-tenth per cent, solution for five, ten. and fifteen minutes, became tar-hid; those inoculated aller an exposure of twenty, twenty-five, and thirty minutes remained clear.

The disinfectant power for short periods of time maybe said to lie between one-half and one tenth per cent. In this, as in other tests, one or two drops of the culture were added to 5cubic centimeters of the disinfectant. A slight flocculent precipitate formed each time.

Oi hydrochloric acid a .'2 per cent, solution of the acid, made by adding 4.2 cubic centimeters of chemically pare acid (containing about. 40 per cent. 11C1) to 95.8 cubic centimeters of water, destroyed the germ in less than live niiimles.

Chloride of zinc.A 10 per cent, solution of this salt failed to destroy thevitalityof the bacilli in ten minutes; 20 cubic centimeters of (Squibbs) chloride of zinc, containing 50 per cent, of the salt, were added to 80 cubic centimeters of sterile distilled water, to make a Itraquo; per cent, solution. A drop from a culture five days old was mixed with 0 cubic centimeters of this solution, from which mixture tubes were inoculated at the end of live, ten, fifteen, twenty-five, and thirty minutes. The two first tubes became clouded.

Sulphuric acid.A .05 percent, solution (I : 2000) was fatal to the bacilli, of hog cholera in less than ten minutes.

Without going into detail, it is sufficient to say thai the results weie reached as indicated above. Tubes containing sterile beef broth were inoculated at the end of live. ten. fifteen, twenty.twenty-live, and thirty minutea with bacteria exposed to one-half percent, and one fourth per cent, üfo development. Those inoculated with one-fortieth per cent. became clouded, each being a pure culture of the bacillus inoculated. When one twentieth per cent.-was tried only the five-minute tube became, clouded. The solution (by weight) was made from sulphuric acid containing '.'(i per cent, of the acid (specific gravity 1.838).

It must be remembered that the foregoing tests were made, upon bacteria in an active, vegetative state. It is probable that in the dried condition il would have taken solutions of the same strength somewhat longer time to destroy their vitality. To briefly summarize the results, placing the least effective substance first, we obtain the following table:

Chloride of zinc in a 10 per cent, solution destroyed the bacilli in liquid cultures in fifteen minutes.

Carbolic acid. 1 to 1 [ percent. (1:100), in live minutes. .Iodine water, in fifteen minutes.

Hydrochloric acid, one-fifth per cent. (1:500), in less than five minutes. (Only a .2 per cent, solution of this acid tried.)

Sulphate of copper, one-tenth per cent. (1:1000), in fifteen to twenty minutes.

Sulphuric acid, one-twentieth per cent, (1:2000), in less than ten min utes.

Permanganate of potash, one-fiftieth per cent. (1:5000), in fifteen minutes.

Mercuric chloride, one seven hundred and fiftieth per cent. (1:75000), less than five inimUes.

Mercuric iodide in one ten-tlumsamltli per cent. (1:1000000), in ten minutes.

The above, table would without doubt be very materially altered if the test had been made with virus mixed with considerable organic matter. This is very well illustrated by the experiments on lime, crude carbolic acid, and additional experiments on sulphuric acid, given in fall in the following pages. Mercuric chloride, for instance, often fails completely in albuminous liquids, although it is one of the best destructive agents of bacteria suspended in water. So permanganate of potash, which would have little or no disinfectant power in liquids highly charged with organic matter, has a very high power in this direction in the experiments detailed above.

The only substances in the above list, which, in our estimation, would be useful for purposes of disinfection, are mercuric chloride and carbolic acid. Of the former, more will lie said in discussing the subject of prevention. Carbolic acid as it nsnally appears in the market is too expensive to be used on a large scale.

CBUDE CAEBOLIC ACID.

Laplace {DeittsheMeä. Wochenschrift, 1888, 121), found that the so-called crude carbolic- acid, which will not dissolve in water, is capable of solution when mixed with an equal volume of commercial sulphuric acid. A 1 per cent, solution in water of this mixture was sufficient to kill anthrax spores within forty-eight hours, and a '2 per cent, solution destroyed them within seventy-two hours. Pure carbolic acid in a 2 per cent, solution has no effect on anthrax spores. The crude material contains about 25 per cent, of carbolic acid. Experiments were made to test the germicide effect on hog cholera bacilli. The crude carbolic acid used was a very dark, reddish, thick liquid, smelling strongly of tar, and not translucent even in a layer one-half inch deep. When a drop of this liquid was added to water it broke up into a few globules, which settled to the bottom without undergoing solution. When an equal volume of commercial sulphuric acid was added and the mixture thoroughly shaken, a few drops added to water caused a faint turbidity, but none remained in a globular condition. When more was added the water assumed a grayish, opalescent appearance, similar to water in which a small quantity of soap is dissolved.

To test this mixture, a culture liquid was prepared like that used in testing the disinfecting power of slaked and unslaked lime. (See p. 96.) Beef infusion (to which the white of an egg was added in the proportion of one egg to 000 cubic centimeters of the infusion) was neutralized and sterilized without previous filtration at 110deg; C. in Erlenmeyer flasks, containing each about 150 cubic centimeters. This turbid liquid, with its large quantity of Hocculent material, was inoculated with hog

cholera bacilli and allowed to .stand Tor a week. Bacb llask then received a certain quantity of the mixture and was thoroughly shaken up. After certain intervals of time a platiumn loop of liquid was withdrawn from each llask, mixed with gelatine, and a roll culture made to indicate the number of surviving bacilli. To make sure of the vitality of the bacilli in the culture a control culture was made from one of the flasks before adding the disinfectant.

Flasks with ISO cubic ceutimetors cnUiire-Iiqaul.to whioL wasnMcil of the ruixtaro of carliolic and sulphuric acids

N umber of colonies in roll cultnivs at the end of

3 cubic centimeter A per cent, (vol)........

\\ cubic centiiueters3 per ecu 1............

2i cubic centimetois--U percent...........

3 cubic centimeters 2 per cent.

(Inr lieiu'.nbsp; nbsp; nbsp; nbsp;I-'.iur Isiuus.

Nquot;onc.......nbsp; nbsp; None.

... do....... He.

....,1quot;.......nbsp; nbsp; nbsp; nbsp; nbsp; Hu.

Check

tube.............................................................. Countless.

The table shows that a one-half per cent, solution by volume is sufficient to destroy the bacilli within one hour. What share the sulphuric acid has in deterraiuing this result can not be inferred unless tried by itself under precisely the same conditions. This is what has been done in the followiug experiment:

Five Krlenmeycr tlaaks, coutaiuiug each about 150 cubic centimeters of a culture fluid prepared precisely like that in the preceding experiment were inoculated with hog cholera bacilli and allowed to stand at a temperature of 70deg; to SO⁰ F., for iounlays. At the end of this period each drop of the culuire mciliimi. as ascertained by roll cultures, contained countless baeteriii. Commercial sulphuric acid was added from a sterilized burette to the tiasks in defiiiite proportions by volume and roll-cultures made at the cud of one. two and n half, twenty-four hours, and four days by transferring a minute quantity of the agitated culture on a platinum loop.

The accompanying table indicates the result obtained, the specific gravity of the acid being I.S ,

Number of colonies in roll eultiiros ;it the i lid of

/. - - .

I'd cent.

hv weight.

riicek.

Two anil

Twi nl v-four

Four days.

One hour.

.#9632;Jtnbsp; nbsp; Cnantleaa

.48 ....do.....

1.11 ........

2.04 ............

3.0nbsp; nbsp; nbsp;............

C.muiless... Countless .. 100nbsp; nbsp; None.

30 10 None.......nbsp; nbsp; nbsp; nbsp; Do

None....... 3 .. do.....nbsp; nbsp; nbsp; nbsp; Do

.. do....... None..........lo......nbsp; nbsp; nbsp; nbsp; Do

....do..........do.........do .. ..nbsp; nbsp; nbsp; nbsp; Do

One half per eeut, of sulpluinc acid (Ivy weight) is thus sufficient to sterilize a richly albumiuous liquid in tlirue tlt;gt; four Lours. Uemeniber-iug that in the cnule carbolic acitl mixture the per cent, of sulphuric acid (by weight) coutaineJ in the one half per ceut. solution (which was capable of steriliziug a similar liquid in one hour) was .30, wo must conclude thai there can be no great difference between the exude carbolic acid mixture and the sulphuric acid in regard to disinfecting power. We shall, however, recommend the former in disinfection, since it may last, longer in the .soil in which sulphuric acid soon forms sulphates and thereby loses its germicide properties. According to experiments given on page 90, .05 per cent, sulphuric acid was sufficient to destroy hog cholera, bacilli in ten minutes when no organic matter was present. In the above experiment, in which the liquid contained much organic matter, about ton times as much Mas necessary.

ORDINAEY LIME As A DISINFECTANT FOR HOG CHOLERA.

Recent experiments made with ordinary lime (CaO) by Liborius {Zeitschrift/. Eygiene 11, 1887, p. 15) have shown that water containing but .007-1 per cent, of lime is capable of destroying typhoid bacilli in the course of a few hours. Cholera spirilla arc destroyed by a solution containing .02-10 per cent, of lime. These two diseases resemble hogchol-era in the mode of dissemination of the virus. In all, the stools are the chief vehicle of the bacteria. Disinfection, therefore, becomes a most; important aid in the prevention of the disease.

Lime lias many advantages over other disinfectants. Itis, first of all, not poisonous. It may be used almost anywhere with impunity where mercuric chloride or strong acids are inapplicable. The soil, when containing the germs of the disease, is not injured by being covered with a small quantity of powdered or slaked lime. The material is exceedingly cheap and can always be obtained without difficulty. The experiments given in the following pages show that lime is a very efficient disinfectant with reference to hog cholera virus, and therefore with reference to the bacteria of swine plague, which are far less resistant than the form er.

The method is, in the main, based upon that used by Liborius, with some modifications, which it is not necessary to point out here.

(1) It was desirable to observe what percentage of lime in solution was necessary to destroy hog cholera bacteria not mixed with any appreciable quantity of organic matter. For this purpose water containing different quantities of lime in solution received about two drops from a beef-iufusion culture, each drop containing approximately500,000 bac-bacteria. At tlieendof one-half hour ahoutoue-thirtieth cubic centimeter of the fluid (usually 8 to 10 cubic centimeters) was removed with a flamed platinum spiral and transferred to liquefied gelatine in a test tube. The same was done at the end of three hours. This tube was then placed in ice water and twirled between the fingers while in a horizontal position.

The gelatine, as it congealed, nnifornily coated the inside of the test tube, whicli was immediately transferred lo a box in connection with a refrig-erator, where it was kept at a temperature of 75deg; F,* Tlie temperature of tbe laboratory daring these experiments was frequently as high as 95deg; F., scarcely ever below 80deg; F,,(Jnly). Any bacteria not killed by the disinfectant would show as minute yellowish-white points in the layer of gelatine within forty-eight boms. The number of points corresponded to the number of living bacteria iutrodaced into the gelatine. These cultures will be denominated roll cultures in the succeeding pages. By this method it was found that lime-water diluted with three times the quantity of distilled water was sufficient to destroy hog cholera bacteria in one-half hour. A dilution containing six times the quantity of water destroyed the bacteria in three hours, while a dilution containing twelve times the quantity of water was not capable of destroying them in twenty-lour hours.

If we take .1^ per cent, as the quantity of lime in lime-water, A)'.) per cent, of lime will destroy all bacteria in one-half hour, .019 per cent, in three hours.

Lime-water dilated .^o as to contain of CaO.

Kuiuber of colonies in roll cnltnres prepared Liquid cultures nl theend ofnbsp; nbsp; nbsp; nbsp; nbsp; nbsp;inoculated at

the end of twenty-four Onc-halfltour. Four hours.nbsp; nbsp; nbsp; nbsp; horn.-raquo;.

0.072 percent.............................................. Kone ...

0.0G per cent................................................. do -..

0.04 per i-viit...............................................'#9632;nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; (*)

None___ Sterile.

... do ....nbsp; nbsp; nbsp; nbsp; Do,

....do..... Do.

U.OU per cewt. Checls tttbo..

None..........do

Countless,

Do.

II.

O.o:! percent............................................... None........ None......nbsp; nbsp;Sterile.

0.019 per cent............................................. Very many......laquo;lo..... Do.

0.0092 pur cent.................................................do....... Very manynbsp; Turbid,

Cheek tube................................................ Countless.

* Contains bay bacilli.

The quantity of the disinfectant used must be increased, with many disinfectants, with the quantity of organic matter present in the material to be disinfected. The preceding experiment gives us therefore only the minimum quantity that is necessary to destroy hog cholera bacilli when organic, matter is practically absent.

A second series of experiments was therefore made by mixing beef infusion cultures with varying proportions of lime-water, and observing

quot;A description of this method is given by its author, E). Ksmavcli. in tbe Zeitschrift für Hygiene, i (1880), p. 293.

the quantity necessary to destroy all bacteria present. A preliminary experiment was made by adding lime water in varying proportions to culture tubes containing about 10 cubic centimeters each of beef infusion which had been inoculated the day before and were now opalescent. A flocculent precipitate formed after the addition of the lime-water, which soon settled to the bottom, the quantity of this precipitate varying directly with the amount of lime water added. The following table shows that in all the cultures made by transferring a loop of the mixture, of culture liquid and lime-water in the proportions there given at the end of thirty minutes, four hours, and twenty-seven hours, no destruction or retardation of bacterial growth could be detected. In the first tube containing beef infusion and lime-water in the ratio of 2 to 1 the precipitate left at first a perfectly clear supernatant liquid. This did not, however, mean complete disinfection, as the roll cultures proved. Moreover, at the end of three or four days this liquid became opalescent again, owing to the rapid unchecked multiplication of the contained bacteria.

A quantity of lime amounting to .04 per cent, was not sufficient to destroy the vitality of beef infusion cultures.

in.

Number of colonies in roll cultures prepared at the cuil of

One-half Four Twentv-seven Lnbsp; nbsp; nbsp; nbsp; nbsp;t

hour. l!.....s.nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; hours.nbsp; nbsp; nbsp; nbsp; nbsp;Seven .lays.

j c. c. 10 10 10

JO 10-

c.c.nbsp; nbsp; i Per cent.

5nbsp; nbsp; nbsp; nbsp; nbsp; .04nbsp; nbsp; nbsp; CountlcssiCouatless Countless.

2nbsp; nbsp; nbsp; nbsp; nbsp; .02nbsp; nbsp; nbsp; ...do.......do ....... do.....

1nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;.01nbsp; nbsp; nbsp; nbsp;...do.......do ....:....(l,i.....

Countless. Do.

.0057 ...ill

lo ...

.do

quot;Check.

Tins experiment was therefore continued with relatively larger quantities of lime. Four portions of 40 cubic centimeters each of beef infusion in culture fiasks, in which hog cholera bacteria had multiplied for twenty-four hours, were mixed respectively with one-half, one, one and one-half, and two volumes of lime-water, and thoroughly shaken. It was found by testing with roll cultures at the end of thirty minutes, four and twenty-seven hours that for every 40 cubic centimeters of culture liquid it required GO cubic centimeters of lime-water to destroy all bacteria, within twenty-seven hours, while a large number were destroyed within four hours. Jt required SO cubic centimeters to completely sterilize the culture fluid in four hours, although nearly all bacteria were destroyed within the first half hour. In the flask to which 40 cubic centimeters had been added there was a partial destruction of bacteria at the end of twenty-seven hours. At the end of six days the bacteria

were as uumeroas as in tlu' Mask uoutaioiug L'O cubic centimeters of lime-water, in whicL no destraction of bacteria or retardation of growth could be observed. The percentage of lime in these cultures is given in the following table :

IV.

NmiluT of colonies in roll cultures prepared ;it the i-iul of

Urn

Lirao.

Ouc-Mf ,-hour.

Twenty- i uiirlioiu-M. seven i Six days.

hours.

c. **.nbsp; nbsp; nbsp; nbsp; nbsp;c. c.nbsp; nbsp; nbsp; nbsp; P'-r cent.

10nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;'Jonbsp; nbsp; nbsp; nbsp; nbsp; nbsp;,04nbsp; nbsp; nbsp; Countless. Countless. Countless.

40nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;40nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;.00nbsp; nbsp; nbsp;du.........do.....Very many.

40nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;iraquo;nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;.072nbsp; nbsp;....do____!Afew.... Kono.....

40nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;SOnbsp; nbsp; nbsp; nbsp; nbsp; nbsp; .08 A r.laquo; ___ None___.....Ao ....

Countlcas. None.

AVlieii the lime-water was addtd to the beef infusion a light flocculent precipitate was formed immediately as in (lie preceding experiment, the quantity depending on the amount of lime-water adtletl. Tliis settled to the bottom in a very short time, leaving a i)erfectly clear, slightly yellowish layer of liquid above, 'n those flasks, however, in which disinfection was not accomplished, this layerof liquid remained turbid, or else became clear at first, with the partial destruction or precipitation of bacteria, and then became clouded again as the remaining bacteria multiplied in if.

The quantity of organic matter which is present in substances to be disinfected is ordinarily quite large. This is true of bowel discharges which contain the specific hog cholera bacteria,and which should therefore be thoroughly disiufected. To prepare a solution containing a considerable amount of insoluble albuminous mal l er, the met hod of Liborius was adopted. Beef was chopped finely and allowed to soak over night in the refrigerator in twice its weight of water, as in the preparation of beef infusion, After the meat had been removed from the liquid in a press the latter was neutralized and the white of an egg was added in the ratio of one egg to every (100 cubic centimeters of liquid. The winde was boiled and the coagulated masses allowed to remain in the liquid. The amount of solid particles and lumps, when deposited on the bottom, formed a layer nearly as deep as that of the liquid above it.

This mass of liquid and solid matter was placed in Erlenmeyer flasks, each receiving 150cubic centimeters. The whole was sterilized for several hours at a steam pressure of 12 pounds and subsequently inoculated with bog cholera bacteria. At the end of three days, when each drop of the culture liquid contained nearly a million of bacteria, milk of lime, made by adding lime in the ratio of one gram to 9 cubic centimeters of

water, or, in other words, milk of lime coiitaiiiiiif;' 10 per cent, of lime, was added in various quantities as shown by the following table;


						Kuuiber of colonies in roll cull		uvs made
	5					at i no end of
	quot;2	.Milk
No.	c	of	J	jlme.		i ;
	pq	Lime.				(lu.-liair hour.		Six days.
	pq
	c. c.	c. c.	Per ce:		t.
1	15Ü	40		2	1	None	Kone* Nono ...
2	150 130	20 10		1	02	....do..... ... ilot ...	... do.........do -.. .....1m.......,1m ...
4	150	5			a2	... ilut ....	....do........dt) .. Kone.
'*	150 (sect;1	-			13	Vi-ry many. Vt rv i!iaii\. 50 Very many. Conntless.
Al	out 12	'iinp.		t	All	mt 100 fun^i	vClu-ck (hvk	f infusion).

In all the experimeuts the cultures coutaiuing tue piecijiitated matter were shaken up before testing so that the quantity taken for the roll cultures (about t,\, to o¹,, cubic centimeter on a spiral of platinum) consisted of solid particles as well as liquid.

Within thirty minutes after the addition of the milk of lime the precipitate had settled so as to leave the supernatant liquid perfectly clear in flasks 1, 2, and 3; in flasks i and üit was still turbid as before the addition of the lime. It cleared up in No. i soon after, but remained permanently turbid in Xo. 5, In none of the other flasks did this layer become turbid even after .seven days. In these the bacteria were permanently destroyed, as the table shows. That the lime transferred to the roll cultures could have had no retarding effect on the growth of any bacilli present was proved by adding at least four times the quantity of lime to a gelatine tube which had been inoculated with a drop of culture fluid. Countless colonies appeared in the gelatine layer in due time. The check tubes were, tested o dy at the beginning of every csperiineut to test the vitality of the cultures used. .Since hog cholera bacteria will remain alive in the beef infusion employed for weeks and mouths, there was nothing to be gained in making loll cultures from these check tubes more than once.

The table shows that 'raquo; cubic centimeters of a 10 per cent, milk of lime was sufficient to sterilize within one-half hour 150 cubic centimeters beef infusion containing much suspended albuminous matter. This would be equivalent to about one half gram of ordinary unslaked lime, or about .01)32 grain for every cubic centimeter of liquid, i. c, .32 per cent. We may assume, therefore, that for every twenty pounds of fecal matter or discharges from diseased pigs only one ounce of lime in the form of milk of lime is needed, provided the two are thoroughly 15012 U c------7

mixed. The less complete tins mixing csm be the more lime must be added to make tlie disinfection thorough. By comparing the amount of lime necessary when there is little or no albuminous or other organic matter present and when there is a large quantity of it, we are impressed with the importance of always taking into consideration the circumstances under which disinfection is to take place. Thus the bacteria of hog cholera are destroyed in one-half hour when placed in water containing only .03 per cent, of lime. When there is present beef infusion diluted to one-third the original strength it requires .08 per cent, of lime. When the suspended albuminous matter is considerable it requires .32 per cent.

It may be more convenient to use unslaked lime either in small lumps or powdered shortly before application to the mass to be disinfected. That this may be done the following experiments are sufficient proof:

Erlenmeyer flasks, containing each from 100 to 2U0 cubic centimeters of beef infusion in which there was a large amount of suspended matter, as in the preceding experimeot, were used for this purpose. After iiiocnlatiug each with hog cholera bacteria they were allowed to stand for forty-eight hours. At the end of this time the flasks contained many millions of germs in each cubic centimeter. Unslaked lime was broken up into lumps as large as peas or beans, and thoroughly heated over a Bunsen flame to destroy any adherent spores and drive away any moisture. After cooling, this was thrown into the culture-flasks in the proportion, by weight, of 2,1, J, and ^ per cent., respectively. The flasks became very slightly warmer. After thorough shaking the suspended matter soon began to settle down, leaving a clear, supernatant liquid, which remained clear after ten days'observation. The liquid in theraquo; last flask (^ per cent, lime) cleared up most tardily. The attached table shows that even as little lime as .J gram in 100 cubic centimeters was sufficient to permanently destroy all bacteria in a liquid very rich in albuniinous substances. Even at the end of eight days the flasks containing the smallest amounts of lime were sterile.

VI.

Boof infusion.

Percent. of CaO.

Number of colonies developed in roll culture prepared with ^j cubic centimeter ol Infasion at the

end of

One boar. Four lilt;

Twenty- ,,. , . , four hours. Eigbtdn

100 cubic centime tors plosSgramsCaO. 120cubiccentimctcrs])!us l.'J grains CaO 200 cubic centimeters plus 1 gram CaO 200 cubic centimeters plus .rgt; gram CaO

2 ; None....... Xone .

1nbsp; nbsp; nbsp; nbsp; ....do...... A few.

.5 Veryniaoy.. Xone, ,25 ...do.......... do .

None. Do.

The table shows that in the flasks containing one-half and one-fourth per cent, of lime there were still a considerable number of living bacteria

at tbo end of the first hour, altbougb destroyed at the end of lour hours. The presence of bacteria in the flask coutainiug 1 percent, of lime at the end of four hours, altboagh none were detected at the end of the lirst hour, shows that all bacteria are not necessarily destroyed simultaneously.

A second experiment, conducted precisely as the preceding, confirmed the latter in every respect. The quantities were chosen somewhat differently, as the appended table shows, in order to find out the lowest percentage of lime that will destroy all bacteria within a given period of time.

VII.

Number of colonies in roll cultures made with ,}., cubic centimeter of the Iieef infusion at the end of

Lime.

One hour.


	Twenty-
i'hivc boms.	lour
	hoars.
None.......	Xouo ...	NOBC.
...do.......	...do ....	1)0.
50	...do ....	Do.
Very many..	no	Do.

Per

'cnt. 1

100 cubic centimeters plus 1 gram CaO .. --U0 cubic centimeters plus 1 gram CaO . . ^00 cubic centimeters plus . 5 ^ram CaO .. 'joo cubic centimeters plus . 3 jrrtun CaO.. Check tube........................ .....

Very main^- .

Xoue.......

Very many . Countless. ..

...,lll.......

The lime was powdered, and heated in a platinum evaporator to destroy all adherent spores. There was scarcely any perceptible rise of temperature when thelime wasadded to the liquid. The first flask contained a culture eight days old, the remainder contained cultures four days old. From the table it will be seen that one-half per cent, of unslaked lime is sufficient to sterilize a very turbid albuminous liquid in four hours, one fourth per cent, in twenty-four hours. Fifteenhiin-dredtbs percent, wasalmost enough to destroy all the gems in one day while at the end of live davs all were dead.

DISIXFECTION OF THE SOIL WITH LIME.

The same line loam used in the experiments to determine the vitality of hog cholera bacteria in the soil was used here. The method pursued was briefly as follows:

Into small beakers, plugged with cotton wool and sterilized at 150deg; C. for several hours, about 50 grams of slightly moist soil was introduced, and the whole sterilized under steam pressure at 110deg; O. About 10 cubic centimeters of a beef-infusion culture of hog cholera bacteria was then stirred up with it. After a certain length of time milk of lime was added and thoroughly mixed with the soil. The destruction of the. bacteria, was noted at certain intervals of time by taking small bits of the soil on a platinum loop and making roll cultures therefrom.

100

The table appended gives tin- results of a series of experiments carried out according to tbis plan:

Number of colonies in roll cnltnrea prepared from a small Int of soil after-


	Number tuilt;] date o l-\\|H'nilR'IltS.	,. Quantity ¹ of lime in soil.

	18SS.	Per cent.
	LJon. IS ...	1
	H..Tan. 20....	2
	III. -Jan.23. ...	X
	IV. Jan.24..	i
	V.Tan. 31 ....	*
	VI.-Jan.3I ...	#9632;\
	VILFeb. 10....	i
	VlII.-Feb.10 ....	i
	IX. -Feb.23³...	.V
	K.Feb. 23raquo;. ..	ä
	XI.-,T,i!H-T-. ..	:
	Xn.-Juno/'. ..	i

Check ,, , . i

i-.tttM.... On.--liai : I hiif ,,nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;,,,nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; ,,,,

#9632;

Five days.

Six Seven days. days.

quot;quot;quot;'quot; toono tofour

laquo;iiiy. days. .lays.

bour.

hours.

(#9632;) 100 ' 0

0 I.

onbsp; nbsp; nbsp; nbsp;::-.i ; o

230nbsp; nbsp; 1000 I x

x (-) i ......nbsp; nbsp;I 20 0

k C-)nbsp; nbsp; nbsp; nbsp;! 8 '

(#9632;) #9632;.......... 0nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; 0

(#9632;#9632;) 0 0nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; 0

x C) 0nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; 0

m (') 12nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; (i

0= (#9632;( (^L'.lnbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;0 0

x 0 0nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; 0 (I

iinbsp; nbsp; nbsp; nbsp; nbsp;0

0 ! 0

C) : (-)

(1 (I

IInbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;0

¹ Countless colonies.

^! Less than oj, but still too numerous too be esti mated. #9632;^{ Fungi present. ¹ .V few ningi present.

^s Eabbit died of hog cbok'r.i after iuocolation ^\'itli soil cm nineteenth day.

^fi A microcetis multiplies in i ho soil.

⁷ Rabbit inoculated with soil on eleventh flay remains alive.

The following may serve to explain more fully the tabulated experiments and results obtained:

I.nbsp; nbsp;Fifty grams sterile moist soil, infected witb 10 cubic centimeters of a beef-infusion culture January .quot;raquo;. January 18: 5 cubic centimeters of a, 10 per cent, milk of lime (9 cubic ceutimeters water and 1 gram ordinary unslaked lime) was stirred up witb it. This is equivalent to 1 per cent, of lime. A roll culture from the infected soil was made in all experiments before the lime was added, to make sure of the pres ence of living germs. Roll cult ares, to which three toopsof milk of lime were added, showed no diminution in the growth of colonies, proving that the small amount of lime (fraction of a loop) added with the soil bad no retarding effect, la this experiment 1 percent, lime was sufficient to remove from the soil countless bacteria (as shown by chock-roll) in three to four hours.

II.nbsp; January 20: Toanotherbeakerof soil, prepared and infected with tinquot; preceding, 2 percent, milk of lime was added and stirred up. The result identical with Experiment I.

III.nbsp; January 23: 2^ cubic centimeters of 10 per cent, milk of lime added (= J percent.). The check-tube contains so many colonies as to Lave an opalescent appearauce. Disinfection is nearly completed after one hour. A few colonies develop in the one day and three day tube.

IV.nbsp; January 24: ].{ cubic centimeters of 10 per cent, milk of lime (= | per cent.); no disinfection is brought about. Daring the first twenty-four hours there is a decided diminution in the number of colonies, but a decided increase thereafter.

V.nbsp; XL .January 31 : The sterile soil in two beakers was infected yesterday with a beef-infusion peptone culture three days old, 10 cubic centimeters being added to each beaker. Today enough milk of lime

101

i5 i)cr cent.) i.s added to two beakers to make one-half per cent, and one-quarter per cent., rospectivoly. The check tubes show subseqaently coantless colonie.s. The table shows a slight diminution in the number of colonies for tlie first twenty-four hours, then an increase. No disin-fection. For the one-half per cent, beaker there isapparently a complete destruction during tlie first two days, but subsequently the few remaining multiplied again. No disinfection here. This result seems to disagree with the third experiment. The discrepancy was, however, caused by the fact that tbc milk of lime was not thoroughly shaken up when used.

VII, VIII. In these experiments the lime was thoroughly stirred up before use, and in both beakers disinfection has taken place. The germs in the soil before adding the lime were not so numerous, because the soil had been infected from a liquid culture only fifteen minutes previous and no multiplication could have taken place.

IX, X. The conditions of the experiment are the same as before. The soil is infected with a liquid culture two days old. Seven days later check-tubes are prepared from each beaker of soil. One receives one-half per cent, lime, the other three-quarters per cent. (/. r., 5 cubic centimeters and 7.5 cubic; centimeters of a 5 per cent, milk of lime to 50 grams soil). The table shows that the beakers were invaded by a mi-crococcus after the first day, wbicb multiplied enormously in the soil, so that hog cholera colonies could not be detected. After nineteen days two rabbits, inoculated with a little infusion made from the cumbed to hog cholera.

------------..........,.. .. -----------_!Ty........, - n-

A second rabbit inoculated from the three-quarters per cent, lime soil in the same way and at the same time. Eabbit dead March 21. Lesions the same, in addition to a hemorrhagic condition of the lower portion of large intestine. In both hog cholera bacteria present.

XT. XII. Experiments carried out as the preceding ones, The bacteria were permanently destroyed, as shown by the roll cultures made up to the seventh day, and unsuccessful inoculation of rabbits later on the eleventh day.

From these experiments we may conclude that three-quarters to one per cent, of lime will destroy hog cholera bacilli in the soil. It is highly probable that a smaller per cent, of lime (one quarter to one-half per cent.) will be amply sufdeient when simply scattered in a thin layer over the surface where the great majority of the disease germs will remain until destroyed by natural agencies.

IS MERE ANY RESISTANT SPOKE STATE IN THE LIFE HISTORY OP THE BAOrLLITS OF HOU CHOLERA?

This question can now be answered with the help of the foregoing experiments.

Stained in dilute aqueous solutions of aniline colors the bacilli from the tissues of animals which have succumbed to the disease stain in such a way as to leave the impression that each bacillus contains an endospore. A narrow band of stained substance bounds an oval pale

102

body, whicb is but slightly tinged. It appears that a rather resistant envelope prevents the coloring matter from passing readily into the interior of the baeilli.

If a drop from a recent liquid culture be suspended from the lower surface of a cover-glass and examined in a glass cell with a homogeneous immersion objective and small diaphragm, the following appearances are worthy of record : Tbe bacteria in tlie center of the drop of culture fluid are in very active motion. If the periphery of the drop be examined there will be found a dense layer of bacteria (.'aught there by tlie slow desiccation and consequent contraction of tbe drop. These, some of which are still moving slowly, appear slightly larger than the forms in the center of the drop. As the drying proceeds and the film of water becomes thin, the bacteria appear to be made up of a distinct dark border surrounding an almost transparent body. In most forms there is a slightly thicker border at the ends than at the sides of the short, rod-like bodies. When stained slightly this border takes the stain well, while the body of tbe rod remains pale. The fact that the structural and color pictures correspond is strong evidence that the microbe possesses a rather dense membrane, which in optical section is seen as a narrow dark border.

Involution forms may occasionally simulate endogenous spore formation. When hog cholera bacilli arc placed upon the surface of gelatine with a drop or two of blood, a few days are sufficient for the formation of a large number of filaments from two to many times the lengtb of the, bacilli as they are found in the tissues of animals. The ends are rounded or irregularly pointed: the width of the bacilli varies; in general, they have the physiognomy of abnormal forms. In each bacillus there may be from one to four oval, square, or oblong, clear spaces. When stained they remain without color, thus simulating spores. When carefully examined in a fresh condition, there isnorefraugibilitythey are mere holes or spaces left by the irregular breaking up and retraction of the protoplasm.

Microscopical characters, however, are now and then misleading, uu-less we interpret them by physiological experiments. Judging from what have, hitherto been considered properties of bacterial spores, the microbe of hog cholera can not lay any claim to the production of true endogenous spores. Their absence is determined by results of experiments recorded in the preceding pages:

(1)nbsp; The thermal death-point of the bacilli at 58deg; C. An exposure to this temperature for fifteen to twenty minutes destroys not only the vitality of cultures of all ages, but also the germ in the tissues of the infected animal. A momentary exposure to boiling water is equally efiTi-

cacions.

(2)nbsp; The bacteria are destroyed by disinfectants in solutions which are

incapable of destroying spores.

103

(3) They are killed by simple drying fur more quickly than are spores; at the same time their resistance to drying is mnch greater than might be expected under the circumstances. In the experiments recorded some dried bacteria in spleen pulp were killed in less tbun a month ; others resisted forty-nine days. For cultures we may put the limit, according to experimental data, between one and four months. It is this continued vitality in the dried state that suggests the existence of a membrane which is more resistant than that possessed by the great majority of bacteria in their vegetative state.

(i) Subjected to various conditions of moisture and dryness, of freezing and thawing in the superficial layers of the soil, they are destroyed after an exposure of between two and four months.

The facts brought out by the study of the bacillus lead to the conclusion that a distinct spore state, so called, does not appear cither within the animal body or in nature.

WAYS IN WHICH SWINE BECOME INFECTED.

15V WAV OF THE DIGESTIVE TWACT.

(a) Feeding diseased viscera.En at least !gt;(raquo; percent, of swine, hog cholera may be induced by feeding to them the viscera of animals which have died oi' the disease. The lesions produced are exceedingly severe. The mucous membrane of the largo intestine is extensively ulcerated or completely necrosed. In animals which have contracted the disease in the ordinary way in infected pens the laquo;Iccration of the large intestine, at times very severe, nsnally stops abruptly at the ileo cascal valve. When this is slit up, the mucosa belonging to the small intestine up to the free border of the valve is in the great majority of eases normal, while the mucosa of that surface of the valve facing the ca-cuni may be extensively ulcerated. In many animals fed with infectious matter the ulceration involves the entire ilenrn. This is well illustrated by the following cases:

January 8, 1S8G.Pig ^'o. IG5 was fed with the viscera of two pigs which had died of hog cholera. It was found dead January 26, after manifesting no marked symptoms of disease except a tendency to lie quietly in its pen. On examination the subcutaneous fat was found diffusely reddened. There was a slight peritonitis, indicated by a considerable quantity of straw-colored effusion and some fibrinous stringy deposits. There were also a few local excrescences on the small intestine, due to the irritation oi echinorhyncM, Spleen somewhat enlarged : on its surface a few bright red punctiform elevations, ßiglit heart distended with a clot. Local hepatizations in lungs, probably caused by lung worms.which were very numerous. Stomach Imt slightly reddened. A numberof ulcers in the duodenum, the mucosa of which was reddened. The mucosa of the ileum for U feet from valve laquo;'as completely necrosed, the walls thickened, and the serosa of (his portion dotted with ecchymoses. On the upper portion of the ileum there were scattered ulcerations on a deeply congested membrane for 6 or 7 feet. The entire length of the large intestine was covered with dirty, yellowish ulcerations varying in diameter from a pin's head to neatly an inch. The mucosa itself was very deeply congested in the cajcum and colon, and the walls much thickened. Ascarides and ecMnorhynclii numerous in small intestines. The liver attached to diaphragm in several places by a whitish exndate.

A tube of meat infusion with peptone inoculated from the spleen of this animal was found to be a pure culture of the motile bacillus of hog cholera. Line cultures on gelatine plates confirmed the microscopic examination. A tube of nutritive gelatine inoculated from the spleen at the same time contained in each needle-track, several days later, from ten to fifteen colonies of the same organism. Two cover-glass preparations revealed no bacteria. This fact, combined with the small number of colonies in the tube culture, gave evidence of the, small num-

ii).-)

106

her of genus in the spleen tissue. Inoculations on mice and gninea-pigs gave sulistnntiall.v the same results as those obtained hitherto.

No. 159 was fed with viscera of No. lOii on January -18. February ö, its eyes were sore, and nearly closed ; it was quite weak. It died the following day, only eight days after infection. The skin on ab-(ioiiien was reddened in patches; the subcutaneous tissue ditfusely. Thesuperfici.il inguinals. as well as the glands in the abdomen, were deeply congested, the cortex more especially. Those of the thorax were nearly pale. The spleen was dotted with a lew punctifonn blood-red elevations. BeueatL the epicardinm and endocardium of both auricles and the endocardium of the left ventricle were extensive patches of extravasated blood. Kidneys enlarged and congested throughout. The lesions of the ileum, caecum, and colon in this animal were quite as extensive as those of the case Just described ; there were no ulcers in the rectum, however. Those of the colon bad black centers, pointing to a recent origin from blood extrava;.atioiis on the surface of the mucous membrane.

In the spleen of this case the characteristic bacteria of hog cholera were exceedingly numerous, as determined by cover-glass preparations. Two liquid cultures proved pure when tested on gelatine plates. In the needle tracks of a tube culture in gelatine innumerable colonies appeared in a few days. Inoculations into animals from subsequent cultures proved equally positive.

Pig No. 156 was fed with the viscera of Xo. lö!) February 18, and after manifesting the usual symptoms of bog cholera, died February 25, seven days after feeding. Among' the marked lesions produced by the disease was a complete necrosis of the upper two thirds of the colon, with scattered ulcers along the lower third. Eight feet of the lower portion of the small intestine, beginning at the valve, was necrosed. In the spleen there were numerous small grayish spots, probably centers of necrosis, as they showed no longer cell structure when crushed on a slide and stained. The fuiidus of the stomach was also deeply congested.

The spleen, to which organ the microscopic examination was limited, contained the characteristic bacteria, as shown by cover-glass preparations. Three liquid cultures made from the same organ were found tobe pure cultures of the same microbe when tested by line cultures. A tube culture in gelatine developed in each needle track numerous non-liquefying colonies.

In these animals the mode of introduction of the virus determined the #9632;seat of the severest lesions. It is probable that the food passes quite rapidly through the small intestine; that in the stomach the action of the bacteria is more or less limited, because they have not sufficient time to multiply, and probably because hindered by the acid condition of the organ, though they will multiply with considerable vigor in slightly acid solutions. The prolonged stay of the food in the large intestine permits multiplication, and thereby causes the first and severest lesions to appear here. When these have become very extensive, so as to paralyze the action of the large intestine, the ileum becomes involved in a similar manner, possibly by a partial stoppage of the infections matter in this portion of the intestine.

It may therefore be said, in general, that the feeding of hog cholera viscera produces lesions like those found in natural infection, only more

107

severe aud more extensive. The dnratiou of the malady is also mucb shortened. The notes given above are quoted from we of the reports of the Bureau. Since they were written numerous other pigs have been fed in this way in the course of vaccination and other experiments'with precisely the same result. We must therefore empiatically deny the truth of statements made now and then in agricultural Journals that hog cholera can not bo communicated to healthy swine feeding upon the viscera of those dead from this disease. Such statements are pernicious in tendency, and aggravate the evil which this malady carries with it. * {b) Fccdiny pure cultures of hoy cholera bacilli.The successful reproduction of this disease by feeding pure cultures of bog cholera bacteria proves not only that the bacteria fed are the true cause of the disease, but also that infection may and does take place in this way. Wo again quote from the report for 1886 some experiments which demonstrate that swine may take the disease and die by simply swallowing somewhat more than half a pintof beef broth in which hog cholera bacteria were growing.

-December 13, 188Ü.Three pigs were fed with 300 cubic centimeters each (three fifths of a pint) of a beef-infusion culture of hog cholera bacilli kept in the thermostat, at 'Jo⁰ F., for three days. The culture was contained in two flasks. When examined both were found pure. The pigs were prepared for the feeding as follows: No. 348 received no food for over twenty-four hours. A 2 per cent, solution of sodium carbonate in beef infusion was then given to increase the alkalinity of the stomach. Of this about 1 liter was consumed. 11 was then fed with 300 cubic centimeters of culture liquid mixed with beef broth to make 1 liter. Xo. 350 was starved in the same way, but received no alkali before consuming the culture. Xo. ;!42 was not deprived of food before eating the culture.

The result confirmed our anticipations. Xo. 348 showed signs of disease in two days. On the third it was unable to rise, and died on the same day. The post-mortem examination showed a considerable, congestion of the mucous membrane of the duodenum and Jejunum, as well as of the large intestine. The fundns of stomach affected in the same way. The liver was gorged with blood, as well as the portal system. There were no marked lesions of the other viscera. That hog cholera bacilli had also entered the blood was shown by two pure cultures in beef infusion obtained from the spleen. A gelatine culture from the liver contained about six or seven colonies.

Xo. 350 was a more typical case, and demonstrated the severe local effects of the bacillus much better, since the animal lived longer. It-ate fairly well until the fourth day, when its appetite gave way and diarrhea set in. From this time it grew weak and thin, being scarcely able to walk. It died on the tenth day after feeding. The lesions of the alimentary tract were exceedingly grave. Beginning with the stomach, the mucous membrane was dotted with closely-set elevated masses as large as split peas, and larger patches of a whitish viscid substance, made up entirely of cellular elements (diphtheritic?). When removed, a raw, depressed surface was exposed. The membrane itself

* It may be possible that those wjio make this claim were confronted with swine plague. This disease, althongh resembling hoj; cholera very closely in many features, we have not been able to reprodnce by feeding.

108

was pale. Besides :i general injection of the ilcuni, Peyer's patches were more deeply cougesteil, and the uppermost covered with a thin, yellowish film, nut removable, and most likely dead epithelium. In the cse-cum and colon the mucosa was superficially necrosed, and converted into a continuous layer of a dirty whitish mass about 1quot;quot;quot; thick. The walls of the intestine were greatly thickened ami very friable.

Microscopic sections showed an extensive cellular infiltration of the subnmcons connective tissue which had separated the masses of fat cells, concealed the connective tissue fibers, and caused a great thickening of the entire layer. The inncosa itself was greatly altered. The surface was necrosed and converted into an amorphons mass. In some places the necrosis involved the entire depth of the crypts of Lieber-kiihn, a scries of stria' indicating their former existence. Those whose epithclimn still remained were plugged with a cylindrical mass, inclosing broken-down nuclei. The bacteria had exerted their poisonous effects from the surface of the mucosa towards the depths, destroying the surface epithelium and glandular structures and involving secondarily the submucons layer. Near the rectum this continuous mass of dead tissue was replaced by isolated ulcers embedded in an intensely reddened mucosa. The ileo-csecal valve was much swollen, but the necrosis did not extend into the ilcuni, although there were a few ulcers near the valve, and the epithelium had a pale, Insterless aspect, as if dead. The liver was filled with blood, which readily clotted as it tlowed from the cut surface. Spleen congested and but slightly enlarged. Lungs hypostatic. The lypmphatic glands in general not much affected. Two liquid cultures from the blood were turbid nexl laquo;lay. ami contained hog cholera bacilli only. In a gelatine tubecultnre from the liver about a dozen colonies developed in each needle-track.

No..quot;.!:.', which was fed with the same quantity of culture liquid, bn( was not deprived of food previously, wassomewhai illonthefollowiugday. It recovered, however, and continued apparently well fir several week's. It began thereupon to grow thin and weak. On January 20 it was no longer able to rise, and was therefore killed for examination, in order to conclude the experiineut. On opening the abdominal cavity it was at once perceived that the animal had been suffering from a very intense disease of the large intestine, a portion of which was firmly attached to the bladder. When dissected out and slit open, the mucous membrane of the csEcam and colon was found replaced by a brownish friable layer of necrosed tissue. The wall of the intcsane was infiltrated tosuchan extent that it was nearly one-fourth inch thick, and so degenerated that the forceps easily tore through it. The thickness of the walls prevented the intestine (Vom collapsing after it was opened. Its only contents was a brownish liquid mass. The glands of the meso-colou were very large, some like horse-chestnuts. On section the entire tissue was very pale, almost white. Thespleen was somewhat enlarged; theMal-pighian corpuscles unusually large and prominent on section. Lungs and heart normal; kidneys deeply reddened throughout.

This case is very interesting in completing the information gained by this feeding experiment. Xo. 348, which had been fed with sodium carbonate, besides being deprived of food, died three days after the ingest-ion of the culture. No. 350, which was simply starved, died ten days thereafter, while No. 342, which ate the culture without being previously starved, was dying on the thirty-fourth day.

These results show that infection may occur by way of the digestive system, provided the destructive action of gastric, digestion be pre-

109

rented, as was done by starving and by the use of an alkaline carbonate.

They also indicate huw jmrely local tbis destructive action maybe. Gelatine cultures from these animals .showed that the internal organs contained but very few bacteria. 80 few were they in fact that the microscope alone could not have demonstrated their presence, in the spleen.

In addition to the eases given, equally positive results were obtained at four different times by the feeding of pure cultures. Some of these results have been mentioned in other places (see page 207 of the Keportof Bureau of Animal Industry for 1885). It was also found that small quantities up to 100 cubic centimeters (,! pint) may be fed to most pigs without obtaining any fatal results. Sometimes the fed animal becomes very side, but recovers; sometimes no disturbance whatever is produced.

These experiments prove conclusively the causal relation between the bacilli of hog cholera and the disease so called. They show that pigs fed with nothing but sterile beef infusion, to which the minutest speck of growth from a hog cholera culture was added and in which the bacilli thus introduced were allowed to multiply for one or more days, were destroyed by a disease, identical with hug cholera, but far more rapid in its course and more severe in its manifestations.

SUBCUTANEOUS INOCULATION.

Subcutaneous inoculation with hog cholera bacilli from cultures is successful in only a small percentage of cases, except when these germs are unusually virulent. In the report for 1885 several cases of successful inoculation are given, among which the following deserve to be briefly quoted:

November 27, 1885.Two pigs (Xos. 112, 114) were inoculated sub-cutaneonsly into the thigh with ;gt; cubic centimeters each of a pure liquid culture. ZS'o. 114 died nine days after inoculation. The superficial inguinal glands were swollen, with liemorrhagic points hi medulla. Spleen enlarged, laquo;lark. Extravasations on auricular appendages of heart. Lungs cedematous; bronchial glands enlarged, dark red throughout {liemorrhagic). Glands of abdomen in general hemorrbagic, except those of mesentery ; petecchise under serosa of csecntn. Kidneys with glomeruli appearing as blood-red points, the entire organ congested. Macosa of fundus of stomach, lowest portion of ileuin.and of the Cfecuin and colon deeply reddened with slight extravasation. Cover glass preparations as well as cultivations in gelatine and beef infusion revealed hog cholera bacilli, and these only.

2s^To. 112 died on the läth day. Diarrhea appeared two days before death. The lesions in this animal resembled those of No. 114, with the following differences: Spleen very large, dark, friable. Kidneys less congested. Lungs with minute hemorrhages throughout the parenchyma. Ecchymoses beneath the endocardium of left ventricle. Lymphatics and digestive tract even more congested and liemorrhagic than in Xo. 111.

110

The .success of these iuoculatious among niimcrou . tailures in subsequent trials must be ascribed to tlie exceptionally virulent disease of tiiat year, for no cases have been observed since wliicli died so sud-denly and presented such severe hemorrbagic lesions of the various vital organs.

The followiug experiments, made with blood taken from the heart of swine affected with hog cholera and killed for the purpose, are taken from the report for 1880:

September 10.A pig dying with the disease, was killed, the heart carefully exposed, and the blood drawn with a disinfected hypodermic syringe. Xos. 329 and 333received subcutaneously 5 cubic centimeters each, one-half in each thigh. No. 329 in a few days lost its appetite, became weak and stupid. Found dead October 5. Slight local swelling at the points of inoculation; superficial ingninals greatly enlarged; hypo-static congestion of lungs; complete necrosis of mucous membrane in Ciccum; large scattered ulcers in colon, showing as whitish patches on serous surface and encircled by a crown of enlarged blood vessels ; bacteria in spleen.

1^0.333. Slightly ill for a time; fally recovered; died December 2, with no other lesions than engorgement of liver; no signs of former ul-ceration.

A second experiment was made in the same way.

October 13.Xos. 324 and 'ol~gt; inoculated as in the preceding experiment, 10 cubic centimeters of blood being used for each animal. Xo. .'524 was found dead November 1. after being off feed for a time ; deeply reddened skin over caudal half of abdomen; superficial lymphatics extremely large and serously infiltrated ; on section, hemorrhagic points; at point of inoculation the connective tissue is infiltrated; 50 to To cubic centimeters clear amber serum in abdominal cavity : papilhe of kidneys deeply reddened ; slight congestion, but no ulceration in large intestine; lymphatics in general moderately tumefied and congested.

No. 325 found dead October 29; reddening of skin as in 324; extravasation in connective tissue; spleen greatly enlarged, purplish; lymphatics of thorax and abdomen purplishenlarged; petecclihe on section of kidney and pelvis, also over entire surface of epicardium; lung tissue mottled both on surface and on section with purple spots, due to blood extravasation into alveoli, so that it scarcely floats; mucous and serous surface of small intestine dotted with peteccbise : small hemorrhages on the surface of the mucous membrane and into the subnm-cous tissue of the ca'cum and upper colon; ulceration beginning.

On first thought we might be inclined to attribute these successful results to a greater virulence of the germs in the injected blood. This view needs further confirmation, however. The injected blood coagulating in the connective tissue contains in it the bacteria, which are not only protected from the aggression of cellular elements, but have actually a store of nourishment upon which they may live and multiply. No such advantages are presented to bacteria suspended in liquids which arc readily absorbed, leaving them to the mercy of the tissues surrounding them. The local reaction in the above animals was very insignificant compared with that produced by liquid cultures. In order

Ill

to come to any couclnsion it would be desirable to add a few bacteria from cultures to fresli blood, ault;1 observe the relative virulence by subcutaneous iuociilation.

Elsewhere in tijis volume will iie found a small number of successful inoculations with pure liquid cultures among a large number of unsuccessful ones. The inoculations were made for the purpose of determining whether tliey would confer immunity. In reading over these experiments it will also be seen that such injections produce swellings varying from the size of a pea to a hen's egg. The tumor is developed in the subcutisand consists of a yellowish white, tough tissue, breaking down in the center into a gruinous mass after a period of one or more mouths.

In view of these facts we can not consider wounds or bites inflicted on the surface of the body a means of infection, excepting, perhaps, in epizootics of extreme virulence. ^Nbr can we ascribe much influence to the stings of insects in inoculating the virus from one animal to another, as this would correspond to subcutaneous inoculations on a minute scale. Flies may, however, infect food in various ways, to be dwelt upon in subsequent pages.

INTUAVEXOrS INOCULATION.

The injection of hog-cholera virus (from the spleen of a pig examined near the city of Baltimore, Md.) into the circulation was tried but once, and this trial was successful in producing a heiuorrhagic septicaemia such as we frequently encounter in outbreaks of the disease, and which proved fatal in less than three days.

November 12,1888.Pig No.90,black and white,about live mouths old. The right crural vein was exposed by raising a triangular flap of skin over it after thoroughly disinfecting the latter with a one-fifth per cent, solution of mercuric chloride. Five cubic centimeters of a beef infusion peptone culture inoculated from an ngar culture about a week old was injected into the exposed vein with a hypodermic syringe thoroughly disinfected with 5 per cent, carbolic acid. The liquid culture was two days old when used. Two hours after the inoculation the temperature had risen from t03| F. to 107deg;. November 13 there was no swelling, but a slight serous oozing at the place of inoculation. The appetite was good. November 14, at 3 p. m., the temperature was 107f. The animal was disinclined to move, although it came to eat in the morning and evening. November 15 it lay on its side quietly, with occasional kicking. Found dead at 4 p. m. Autopsy held immediately.

General blush on skin of ventral aspect, snout, and lips, ifo swelling at the point of inoculation; slight blood extravasation. Spleen enormously enlarged, 14 inches long, 2 to 3 inches wide, and one-half to 1 inch thick, gorged with dark blood, and friable. Superficial in-guinals enlarged, oedematous; on section diffuse pale red spots; cortex congested. Bronchial and renal glands enlarged, partly hemorrhagic, gastric glands hemorrhagic throughout substance. The blood is thick, dark colored, coagulation slight, even after several hours' exposure to the air. Several peteccfaise on epicardinm of right auricle. Right side of heart distended with blood ; in it a small white clot. Left side

112

contracted, empty. Liiugs nortual, excepting oue-tliird of left ventral lobe, which is collapsed. Kidueys cularged, deeply congested tbrough-out. The surface is thickly dotted with miuuto deep red points. The papillso so deeply reddened that any extravasations would be nurecog-uizable. A few peteccbia! in pelvis. Bladder contains about .quot;gt;() grama of urine tinged with blood. The whole mucosa of stomach is deeply congested. In fundas it is hemorrhagic with numerous patches of nee-rosed epithclinra oue-fourtb to one-half inch across.

The upper 8 inches of duodenum in the same condition as the fnndus of stomach. Numerous red points scattered over mucosa of entire small intestine. In lower ileum a few hemorrhagic points. The mucosa of ciecum ami upper colon very slightly congested, but the remaining two-thirds intensely so. ETemorrhage here and there sufficient to stain the feces with blood which were otherwise normal. The niesenterie and meso-colic glands all deeply congested throughout their substance.

CoTer-glass preparations from spleen i)iiligt; showed a large number of hog cholera bacteria. Cultures from the same revealed the presence of the same organisms only.

INFECTION liV WAV OF Tilt: LUNGS.

It has been maintained by some observers that infection may take place through the lungs. Bacteria dried and carried about with the dust are supposed to be deposited in the luug tissue by the inspired air. It is of considerable importance to determine whether germs carried by currents of wind can in this way produce an outbreak at a distance. There are two questions involved which must be dealt with separately in order to get as clear an idea as possible of this rather perplexing subject. (1) Do bacteria of Log cholera when inhaled produce a disease which is similar to the disease described in these pages, i. v.. without extensive lung lesions ; and (2) do hog cholera bacteria produce a specific disease of the lungs when there deposited just as they produce intestinal disease when swallowed ? Theiirst question, whethi t thelungs may be considered an entrance of the virus when in the dried condition, is one for which not sufficient proof is at present forthcoming, Several experiments have been made at the experiment station to produce the disease by spraying pigs in a tight box with liquids containing boy cholera bacteria and by injecting them suspended in liquids into the trachea. In no instance was the disease produced. Several times bacteria were injected through the walls of the thorax into the pleina! cavity and lung tissue without any result, excepting in two instances given on page 55. In one animal there was some plenritis but no pneumonia. On the other hand the large intestine in this animal was severely diseased as in natural infection. Jn the other animal death occurred seven mouths after inoculation. The lung disease was most likely the combined effect of lung worms and the mechanical injury resulting from the inoculation.

If we must conclude, therefore, that animals are but rarely infected through healthy lungs, it is still less likely thai these, bacilli produce quite uniformly disease of the huigs,as has i een assumed bv other ob-

113

servers without adequate proof, In the notes of tue outbreak given on ]):i!,^fe 54, this subject has been pretty tliorougbly discussed in the light of evidence furnished by bacteriological tests. The results there readied may be briefly summarized that lung disease or pneumonia of a severe character is not often round in bog cholera. The slight broncho-pneumonia frequently met with is most probably due to eataniial cuuditiuiiä and to the aspiration of foreign bodies. There is, however, this very (iis eased condition of the lungs which may favor infection through tiieiu. When there are present foci of broncho-pneumonia, bog cholera bacteriu inhaled may lodge there,multiply in the secretion of the smaller bronchi, and cause an extension of the disease not possible in healthy lungs. From there they may be coughed up and swallowed, carried iisio the large intestine, quot;where they exert their most destructive activity. In this sense the lungs may become the entrance of the virus, but only when previously diseased. In t he examination of such diseased lobules of the lungs, in the outbreak referred to, hog cholera bacteria were found in almost every ease. In these eases it is difflcnlt to decide whether they entered the diseased lobule from without by way of the bronchi i. c, with the air inspiredor whether they were deposited there by the circulating blood.

The question of the relation of lung disease to hog cholera has been complicated by the existence of an iufectious pneumonia in swine, which we have called swine plague. This disease, which will be treated of in a special publication, appears over a large part of our country at times in virulent epizootics. It. is caused by a widely distribute 1 septic organism, and appears occasionally in swine sufifering from bog cholera, in a number of such cases both disease germs have been obtained from the same animal.

We do not exclude infection through the lungs as improbable in hog cholera, especially in epizootics characterized by more than usual virulence. At the same time long experience at the experiment station has shown that swine do not become infected in pens only a few hundred feet away from pens full of sick and dying animals. Currents of air can thus have but little power in distributing germs capable of inducing the disease.

SOIMB OBSEKTATIONS

o.\^T THE PATHOLOGICAL ACTIOH CHOLERA BACTERIA.

OF HOG-

We have frequently recurred to the fact that the intestinal tract seems to suffer more or less exclusively in hog cholera.. The changes there produced belong chiefly to the necrotic ami ulcerativo type, oomblued with a variable amount of ueoplastic growth in the bottom of the ulcer. In connection with this work it has been impossible to make any extended observations on the genesis of these ulcers owing to the exactions of other work. Whatever may be suggested here most bo regarded simply in the light of inferences from lesions as they were observtd post mortem.

15612 ii c-8

114

The ulcers are produced in mosl cases by a process beginniug at the surface of the mucosa. This is shown very well by sections of ulcers in which only a portion of the tubular glands have been necrosed. What this process is must be left an open question. It seems very probable that the bacilli invade tbe tubules and blood-vessels of the mucosa, by their rapid multiplication plug the latter, and cause a coagu-latiou necrosis of the most: superficial portion of the membrane. The various bacteria present in the intestine then complete the breaking down of the membrane, and an ulcer is formed. Ulcers may, however, be formed by bacteria carried thither by the blood, for ulcers are present in those animals upon which subcutaneous inoculation has been practiced (p. 110). In these cases the plugs or infectious emboli are situated probably in thesnbmucosa. The resulting ulcer is deeper and more extensive.

The formation of plugs or thrombi is confirmed by inoculations in rabbits (p. G9). The process of coagulation necrosis, as the result of plugs in the capillaries of the liver, may 1 e seen in almost every case. Microscopic examination likewise reveals their growth in masses iuthe internal organs.

The nature of the hemorrhagic hsions so frequently observed in bog cholera demands some attention. The rupture of minute and sometimes larger blood vessels is no doubt due to the same process of thrombosis and embolism in which the thrombi and emboli may be made up more or less entirely of bacteria. Whether these pings have a directly destructive action (necrosis) upon the delicate vascular wall SO as to produce rupture and extravasation, as has been suggested in former reports, or whether the action is merely mechanical, or whether both causes are at work, it would be impossible to say. A!gt; all events these hemorrhages are frequently the precursors of ulcers in the intestine, and in some cases the only lesions which were observed were hemorrhages fioni large and small vessels. We may picture to ourselves the process, beginning, in most cases, with local ulceration in the large intestine (caecum). The bacilli may be carried thence through injured vessels into other parts of the body, and to other portions of the intestine, where fresh ulcers may appear; or the bacilli may be carried onward from the first ulcers to portions of the intestine lower down, where they again attack the mucous membrane.

In many cases the quantity of virus introduced into the digestive tract is 80 greatas when pure cultures of hog cholera bacilli are fed that destruction of the mucous membrane goes on at the same time throughout the ctecum and colon, becoming less severe as the rectum is approached. The paralysis of the large intestine may cause extensive necrosis of the ileiim. In these cases the action of the bacilli is purely superficial at first, penetrating deeper and finally reducing the entire vail to a friable mass, greatly swollen by the infiltration of leucocytes, in such feeding cxnerimeuts we may also observe grades of lesions aa

115

we yo away from the valve in tlie ileam and in the colou. Instead of the conversion ofthemacosa into a thickened, discolored, and roughened membrane, an amorphous, dirty grayisli exudate maybe foand on it. The destraction, going on very slowly, causes a reactive inflammation, manifested by the exudate.

The genesis of the intestinal lesions in the rabbit is somewhat different. They appear quite late in the disease as a result of the discharge of bacilli from the necrotic foci of the liver tissue into the bile duct. They are limited to the duodenum and large intestine, and are especially severe in the latter, forming there peculiar haematomata or blood tumors, accompanied with a Bhrinous exudato. The same lesions are obtained by feeding cultures. In view of this localization in the rabbit and pig we must admit that bog-cholera bacilli exert their primary action where they are retained for a considerable time by the feces, and thus have an opportunity of multiplying before they attack the mucous membrane.

The size of the spleen, sometimes enormous, seems to stand in no direct relation to the number of bacilli present. Sometimes a very highly congested spleen harbors only the average number of germ-.

The presence of hog cholera bacilli in the lung lesions met with in a small percentage of cases has already been dwelt upon (p. 5i). The lesions themselves show nothing characteristic. They are usually restricted to the most dependent lobe, the ventral on one or both sides, and to the writer they simply indicate a proneness of catarrhal inflammation in young pigs, due, no doubt, to the aspiration of food and dirt, consequent occlusion of bronchi, atelectasis, and broncho pneumonia. The hogquot; cholera bacilli which may be found herein most cases are present for the same reason that they are found in the spleen. Circulating in the blood, they lind the contents of the diseased and plugged air tubes and alveoli a very suitable medium for multiplication. In this way they may add to the irritation and cause extension of the disease.

It seems pretty certain that the chief damagedoneby hog cholera bacilli lies in their power to grow in plug's in the small vessels. The simple reason why we have such severe lesions in the intestinal tract, although the bacilli are present in small numbers in the internal organs also, lies in the anatomical nature of mucous membranes in general and their exposed situation with reference to putrefactive processes.

If the obscure action of these bacilli on cells and cell-life could be formulated ;it. all, in the present state of our knowledge the writer would assume: 1. That they exercise ii more mechanical influence by Uiiombosis, which leads, in the mucous membranes, to circumscribed necrosis. Death occurs not by the direct poisonous action of ptomaines, but from secondary causes, such as changes in the liver, septic infection, i*. In acute cases the bacilli possess a greater power of invading the circulation. There they multiply rapidly enough to cause rupture of blood vessels in all t he vital organs. Death may occur in these cases

116

by a ptomaiue poisoning of tlie nerve centers duo to the large number of bacilli in I hequot; blood, or the loss of so tnucb blood drawn from tbe circulation, or, wlial is more probable, by hemorrbages in tbe substance, of the central nervous system, Whet her this greater ability to invade the vital organs depends upon the production of a more poisonous ptomaine, which paralyzes opposing forces, or toother physiological properties, belongs to the future for solution.

Concerning the variation in the destructive nature of hog cholera bacilli little that is positive can he said. We baveobserved, for instance, that tbe disease dies out after a time in a herd, very frequently because there are no inoie animals left, or because the few that have survived have been exposed in such a vray as to acquire immuuity. But it has also been observed at tbe experiment station thai the disease may disappear, even when fresh animals are exposed to it from time to time. The decline in virulence may be due to tbe particular season with its frosts or droughts, and other meteorological changes, or it may be due to a gradual weakening of the virus as it passes through the system of the exposed swine. We have observed several times that when a series of animals are fed with infected viscera, each from the one preceding it, the earlier ones of the series will develop the most severe disease. The later ones are affected by a more chronic malady, and finally a point is reached when no disease is produced, in such an experiment self-inoculation or vaccination must be eliminated, as the animals are not exposed previous to the feeding. But aside from this gradual dying out of particular epizootics, wc have noticed a difference in the outbreaks themselves from year to year. In some the acute, bcmorrhagic type would prevail, in others a more chronic ulcerative type. Such differences are most likely duo to modifications of the disease germ itself, although here also it is diflBcult to eliminate differences in the animals due to race, feeding, cleanliness, etc., and differences due to the time of the year. As regards the manifestation of differences in the bacteria themselves none can he formulated.

BACTEKIOLOG-ICAL [NVESTIG-ATIONS OK HOG CHOLERA IN KEBEASKA,

iLUXOIS, AND MARYLAND.

The facts which have been gathered concerning the bacillus of hog cholera were obtained chiefly from epizootics ocenrriug in the District

of Columbia. The advantages of a bacteriological laboratory connected with the Bureau made investigations possible which could not be made in the field. It was, howev( r, necessary to confirm the results already obtained by investigations elsewhere. These have led to the discovery of the same bacillus in Nebraska and subsequently in Illinois, thus identifying the, disease in widely-separated localities.

Wehraslca.ln March, 1886, the bacillus of hog cholera was isolated from one of ten spleens sent from Kansas and Nebraska. Though carefully removed by the inspector and placed in steiilized bottles plugged

117

with cotton wool, none camo in good condition, owing to the long delay on the road. Small bits of spleen were placed under thcskia of a number of mice. Two which bad been inoculated from the same spleen died of hog cholera. These experiments are reported in full in theThinl Annual Report of the Bureau, and therefore need only tobe summarized in this place. The bacillus obtained iu a pure condition from these mice was carefully tested upon other mice, upon rabbits, and upon pigeons. The pathogenic effect was the same as that of the bacillus from eastern outbrealis. [t was, howerer, readily observed that the Nebraska Igt;a-cillus was less virulent, as ii did not kill guinea [tigs. A number of inoculation and feeding experiments were, made upon pigs in order to produce the disease. All but two failed to show any disease. These two, fed with liquid cultures, were made ill, and one very sick was killed on the ninth day after feeding. The large iutestine showed intense congestion,\rith a few patches of adiptheritic membrane in theclt;ecura. Is'o bacteria were obtained in cultures from the infernal organs. This experiment, which was uot rery satisfactory, was repeated by feeding a larger quantity of culture liquid. The result was entirely satisfactory, as the following description of the experiment will show. Moreover, the feeding took pla ;e nearly nine months after the microbe had been obtained originally from the spleen. During this time it bad been cultivated in various media, passed through mice and rabbits,so that no trace of any spleen substance or foreign material could have been present in the culture liquid which was fed. The result also indicates that the pathogenic power of the bacillus was in great part retained during this time.

A tlask containing between oOOand 600 cubic centimeters of sterile beef infusion was inoculated from a culture (rabbit), and after standing six days in the incubator the entire amount was given to a pig which had not been fed for thirty six hours. The culture liquid was covered with a thin membrane, and on microscopic examination contained only the motile bacillus. The animal became dull and weak, eating little. The bowels were loose on the fourth day. On the fifth it was unable to rise, and on the sixth it was found dead. The autopsy notes are briefly as follows:

In the abdominal cavity several hundred cubic centimeters of a reddish serum, a thin translucent exudate covering the peritoneum of the intestine, which Is diffusely reddened. Between the layers of the mesentery, along the line of attachment lo small intestine, an abundant translucent gelatinous exudate. Spleen very dark on section; the surface dotted with elevated points of extravasated blood. Liver congested. Lungs normal, with exception of a few lobules, which are simply collapsed.

Almost the entire digestive tract was found involved. Around the cardiac orifice of the stomach a zone of mucous membrane about 2 inches in width was covered with whitish diphtheritic patches. Isolated

118

ulcers in duodenum. About 0 or

it of the lower portion of tiie

small intestine very iiuif.h thickened, the mucous luuuibraue covered with a thin sheet of necrosed tissue, whitisb, brittle. The c;e;:iiiii and portion of the colon greatly thiclceuod ami covered with a thick layer of necrosed tissue very rough ami browmsh. Near rectum necrosis gives way to closely set, isolated, roundish diphtheritic elevations of a whitish color, which leave a raw surface when scraped away.

These lesions were, therefore, as intense as any produced by feeding pure cultures of hog cholera bacteria obtained from the East, The specific identity of the two bacteria from Nebraska and the East was thus completely established.

In the liver and spleen the bacteria were few, for a cover-glass preparation from each organ did not show any after some searching^-. Liquid cultures from the blood (heart), spleen, and liver were; turbid on the following day, andali contained the motile bacillus. Within four days complete membranes had formed on the surface. That the bacteria were very few in blood from the heart was indicated by a gelatine tube which hadbeen inoculated several limes with a platinum wire dipped in blood; no colonies were visible on the fourth day. Of three liquid cultures, each inoculated with a loop of blood, two remained sterile. It was presumed that the liver would contain the largest number, inasmuch as the portal circulation received its blood from the seat of the disease. This assumption was confirmed by the very abundant colonies surrounding a piece of liver tissue, which hadbeen dropped into a tube of nutrient gelatine.

In order to make certain of the pathogenic powers of the cultures obtained from thiscase of feeding the, tube culture from the liver was used to infect two rabbits. The skin on the inner aspect of one thigh was carefully shorn and disinfected with .1 per cent, corrosive sublimate. An incision was made through the skin, and with a loop dipped in the surface growth of theculture a minute quantity was introduced into this pocket. The larger of the two rabbits was found dead on the fifth day. The lesions were briefly as follows:

Sligbt amount of pus at the place of inoculation. Neighboring inguinal glands enlarged and infiltrated with blood. Surrounding vessels much injected and very tortuous. Liver very friable, spleen dark and enlarged; both dotted with points and stellate spots of coagulation necrosis, especially nninerous on the caudal surface of the liver. Both organs contained the bacteria of hog cholera in large numbers. Lungs hypostatic. A small number of ecchymoses beneath pleura; very few bacteria in kidneys and heart's blood.

The second rabbit was found dead on the sixth day. The lesions were the same, if we except the more pronounced coagulation-necrosis in the liver and its absence in the spleen. The bacteria of bog cholera were distributed as above; very abundant in spleen and liver ; lutigs normal.

Gelatine tube cultures from spleen and liver of these rabbits confirmed the niicroscopi(! examination. Liquid cultures from the blood contained

119

the motile bacteria, whieb had formed a brittle surface rnoinbrano on tlie second day.

Differential chardcters of the hog cholera havi Uns from Nehraska.The bacillus Miicn stained on cover-glass preparations from the spleen and other viscera, closely resembles the one ibniid in the disease prevalent in the Hast, so that it is impossible to distingaish them in this way.

A few minor differences revealed in the various culture media indicated, however, that the two microbes were notalikoiu every way, and brougbt up the very interesting question of the variation of species of bacteria and the iniiaence of such variation on the severity of epidemics.

The most noteworthy difference was observed in liquid cultures. Within twenty-four hours after inoculation from the spleen or blood the culture liquid became turbid, and upon its surface a complete membrane was present in nearly every case. This whitish membrane is not homogeneous, but made up of patches of varying thickness, and when shaken slowly settles to the bottom in lumps and flocculi. The microbe of Eastern outbreaks does not form a membrane within several days after inoculation, and then only when the tube remains perfectly quiet. It appears as a whitish ring attached to the glass.

In other respects the two microbes differed so little that no mention need be made of these differences here. We have, therefore, only the membrane'on liquid cultures and a slightly diminished virulence, by which the bacilli from Nebraska were distinguishable from those obtained from Eastern epizootics. Both of those characters are variable ones. The membrane can be produced in part by cultivating the Eastern germ for a long time at a high temperature. The variation in virulence is observable during the course of almost every epizootic.

Illinow.From the spleen of an animal affected with hog cholera the specific bacillus was obtained during some investigations conducted in this State in the summer Of 1886. The bacillus presented no differnces whatever from the one obtained in Eastern outbreaks. Its effect upon rabbits and mice, was precisely the same. Its fatal effects when fed to a pig is well illustrated by the following experiment:

A pig was kept without food for over twenty-four honrs. A L'.', per cent, solution of sodium carbonate in meat broth was then given to it. Of this itcousumed about one liter, taking thus about IT) grams of the salt. It was then fed with aboutSOcubic centimeters of gelatine cultnres and 100 cubic centimeters of liquid cultures of the quot;nog cholera bacillus obtained from rabbits which had succumbed to inoculation and from the original gelatine culture of the spleen made in Champaign County, 111. The animal was found dead December -1, scarcely three, days after feeding. This was the briefest period of illness thus far observed. The lesions were very pronounced. Pyramids of kidiiegt;s deep red throughout; glomeruli visible as dark points. Lungs pale, not fully collapsed. Eight heart filled with semi-coagulated blood. Livergorged with blood. Mncosa of stomach intensely reddened, especially along fundus, and covered with a thick layer of tenacious mucus. Mucous membrane of ileum similarly affected. Peyer's patches exceedingly

120

dark it'll, showing throngli scions coat. When viewed from the laquo;m-cous surface the elevated border gives eacli a sligbtly concave boat-shaped appearance. The colon also deeply congested, almost hemor-rhagic in patches, filled with a small quantity of seini-liquidfeces. The rectnm still filled \vit'ii consistent masses. The meseuteric glands congested.

The feeding had thus jiroduced a very severe inflammation of the digestive tract. Thediagnosis was further confirmed by obtaining pure liquid cnltnresfrom the spleen, the liver, and blood from the heart. The. bacteria were not snlticiently numerous in these organs to be detected by the microscope. To make sure that (lie carbonate of soda had no corrosive, effect, anol her animal was 1 reated precisely in the same way by starving and feeding a solution of thesalt. No ill effects whatever were manifested.

In order to test the specific pathogenic character raquo;ill he bacillus obtained from thisanimal a largerabbit was inoculated sabcutaneously with about one-eight cubic centimeters of a liquid culture from the blood. On the sixth day the rabbit was lying on its side; abdominal breathing very labored. It was found dead on the next day. Slight thickening of the subcutaneous tissue and fascia covering the thigh muscles at the point of inoculation. The muscular tissue covered with minute ecchymoses around the infiltrated patch. Small quantity of serum in the peritoneal cavity. Spleen very large, blackish, exceedingly friable, and crowded with bacteria. Liver enlarged; interlobular tissue pale; the entire parenchyma very soft and brittle. Dotting both surfaces of all the lobes are small, grayish-white patches, involving one. two, or three, rarely more, acini, and bounded very sharply by the acini themselves. Peculiar figures are thus formed, three contiguous ones giving the patch a clover leaf appearance. On section they are found to extend to the depth of one or several acini into the parenchyma. The sreat majority of these masses ol coagulation-necrosis involve lobules on or near the sui face. Only a few are in the depths of the organ. When such a whitish mass is spread on a cover-glass and stained innumerable bacteria of hog cholera make their appearance. The rest: of the tissue is iikevn.-e crowded with them. Beneath the pulmonary pleura are large purplish patches of extravasation, which on section extend deeply into the parenchyma. The lung tissue is in general congested. Blood from the heart contained very few bacteria. No cultures were made.

Maryland.During September ami October, IS.sS, an epizootic of hog cholera was started at the experiment station by a sick pig brought from near the city of Baltimore, Md. The bog cholera bacillus had been previously obtained from the spleens of two animals killed at Haiti-more. At least twenty, which had been either simply exposed in pens or fed with the viscera of dead animals, succumbed to the disease. In all cases pure cultures of the specific bacillus were obtained directly from the spleen. Cts effect upon rabbits and mice, its appearance and mode of growth, did not differ from the bacillus as described in the foregoing pages.

RELATION OF HOG CHOLEEA TO IHE PUBLIC HEALTH.

The importance of knowing whether or not certain infectious animal diseases have any deleterious influence upon human health, or are the

121

tliiret cause of human disease, is not even second to the economic im-portance attachiug to animal diseases. There are some animal diseases, such as glaTiders, tuberculosis, anthrax, and rabies, wiiidi are directly communicable to man. This (rausmissibility was known before the specific bacterial organisms of Uk-so diseases had been discovered. There are other animal diseases not proved to be transmissible to man, whose causes have only been definitely recognized within the past few-years. As regards these it is quite pertinent to ask, in the light of present knowledge, whether they have any relation to human diseases. Animal diseases when communicated to man may become so changed in character as to be unrecognizable. Hence we must determine whether the specific micro organisms of animal diseases are found in human diseases or not | in other words, whether the causes are identical. During the coarse of these investigations this problem has been constantly borne in mind. The question to be settled first has reference to the presence of hog cholera bacilli in human diseases. There are two maladies of mankind which resemble hog cholera in many respectstyphoid fever and dysentery.

Typhoid lever is an infectious disease of man, prevalent throughout the civilized world, while hog cholera is known to exist only in North America and the British Isles, and during last year it has been identified on the continent of Europe. Hence there could be no close relationship between the two diseases, for they would naturally occur together if they were identical. But there is another reason for their non identity; the micro-organisms which produce them are different. Tims the typhoid fever bacillus is a longer rod than the hog cholera bacillus, its movement in liquids is more .sluggish and of a somewhat different char. acter. Its growth on boiled potato is almost peculiar to itself. Moreover, it has no pathogenic effect upon any animal thus Far tried, and we know that the hog cholera bacillus is fatal to mire, rabbits, guinea, pigs, and pigeons after subcutaneous inoculation, and to pigs when fed to them. Hence there remains not the shadow of a doubt that genuine typhoid fever and hog cholera are distinct diseases.

They do, however, belong to the same general class of infectious diseases, in both, infection very likely occurs chiefly through the food and drink. In both the lesions are nlcerative in character, located in the pig in the upper portion of the large intestine, in man in the lower portion of the small intestine. It is true the ulceration may be the secondary stage of processes primarily different anatomically speaking, but we know as yet too little of the relative effect of irritants of the same kind, but of different intensity, to venture any positive statement. In both diseases the invasion of internal organs by the specific micro-organisms takes place, so that they are readily obtained from the spleen. In both they appear in clumps or colonies in the capillaries. There is also a general resemblance of the two organisms, both as regards their appearance, motility and growth in various media when we compare

122

them with the bacteria of other infectious diseases in man and animals. We may therefore couclade that although these two diseases are entirely distiuct there exists a close relationship between them as to the cause, the manner of infection, and the type of disease.

Hoy cholera is allied to the disease or group of diseases known as dysentery even moie closely than to typhoid fever. It resembles, perhaps, most marly that form called epidemic dysentery. Of the causes of this disease very little is known. That the epidemic typo is caused by inicroorgnnisms of some kind is now generally accepted, and it is also believed that there may be several distinct species of microorganisms which are capable of producing diphtheritic and ulceratire lesions of the large intestine.* Anatomically hog cholera and diphtheritic dysentery are very mach alike. The question whether hog cholera virus can ever prodnce a dysenteric affection in man is not answered until we have learnt more of the causes of the latter disease.

The danger, if any there be, of causing disease in man Mould only occur upon farms where the opj ortunity is afforded for infection of food and water by the discharge of diseased pigs. The preparation of pork by cooking is sufiicieiil to destroy the bacilli if by any chance the flesh of diseased animals should get into the market. Experiments have shown that a temperature of 140deg; F. is sufficient for their certain destruction. The temperature reached in boiling, roasting, etc., is of course much higher than this.

In addition to these conclusions, which follow from the facts developed by our experiments, it may be said that with the thousands of posi-mortem examinations made by ourselves and other investigators, there has not been a single case where the operator became infected. In several instances it has been recorded that fresh wounds upon the hands have been covered with virulent material duriugthe examinations without producing any appreciable effect. And through all the years that this disease has prevailed so extensively in the United States there has not been a case reported where, it has been shown on good evidence to have been transmitted to the human species.

Notwithstanding these facts, however, we should expect, with the prevailing carelessness in disposing of the carcasses of swine in many sections during such outbreaks, that there would be a more or less deleterious effect upon human health, not from tin; specific nature of the disease, but from the decomposing organic matter. Too often these carcasses are left to putrefy near dwellings, or arc thrown into streams to contaminate them with decomposition products. Such practices arc dangerous to the betilth of the community and should be prevented by the local sanitary officers.

'Investigations of the Egyptian dysentery by ICocb ;uiil Kartulis have shown that the cause is an organism belonging not to tbc class of bacteria, bm to the protozoa. and assnming the Ibnn of an amceba. This is fonnd in large numbers in the nlcerated

walls dIquot; the intestine.

PREVENTION OF HOG CHOLERA.

ISOLATION, DISINFECTION, AND CLEAKLINESS AS PRETEKTIYE MEASURES.

It is frequently necessary to apply preventive measures before infectious diseases hare actaally appeared in a herd. The disease may have appeared on a neighboring farm, and the problem then arises : How can the infection be prevented from spreading to other fiinns '. How can the surrounding farms keep the malady from their premises ?

Tlie sources and channels of infection are as follows, the most common and important being placed first:

(a)nbsp; nbsp;Pigs purchased from infected herds, or coming in contact icith those from infected farms, or running over f/rouuds occupied by diseased steine tcithin two or three montlis.

(b)nbsp; Infected streams may communicate the disease to herd* below the source of infection.

{c) Virus may tgt;e carried in feed, implements, and on the feet and clothing of persons from infected herds and premises.

{d} Winds, insects, birds (particularly buzzards), and rarious animals way transport hog cholera virus.

(a) In regard to a, it may be said tbat no pigs should be purchased from any locality until one year after the death of the last case of cholera. There are frequently near the end of an epizootic chronic cases which may live for three or four months without showing any distinctive signs of disease until they suddenly die. The post-mortem examination usually reveals extensive ulceration of the huge intestine. The disease may thus linger in a herd long after all danger has apparently subsided. Igt;.v bringing any chronic cases in contact with hitherto uuexposed healthy swine the disease may spring up anew, as a dying tiro would when supplied with fresh fuel. Although our experiments have shown that the disease germs may all disappear from the soil in three or four months, the unceriainty of knowing whether there are any chronic cases continually adding fresh virus to the soil makes the period of one year not too long to avoid the introduction of uuexposed pigs. It is advisable, in districts where hog cholera is very prevalent and is rarely absent for any length of time, for farmers to raise their own pigs and not trust to any animals from outside. In this way infection may be at least in part kept nuder control. When animals have been obtained from places which are not above suspicion they should not be brought in contact with swine already on the place, but quarantined as

123

124

far us possible from them ami kept ander careful observatiou for at least one month.

(ft) Perhaps the most potent agents in the distribution of hog- cholera are streams. They may become iufected with the specific germs when sick animals are permitted to go into them or when dead animals or any part of them are thrown into the water. They may even multiply when the water is contaminated with fecal discharges or other organic matter. Experiments in the laboratory (p. 76)have demonstrated that hog cholera bacilli may remain alive in water Cor four months. Making nil due allowance for external influences and competition with other bacteria in natural waters, we are forced to assume that they may live at least a month in streams. This would be time enough to infect every herd along its course.

(c) Hog cholera germs are not immediatelv destroyed bv drvinff. Laboratory experiments show that they may retain their vitality from two to lour montlis. Hence it is not difficult to see how a person walking on infected ground and among infected animals may carry on his Shoes and clothing dried germs of the disease to any neighboring herd. For the same reason hog cholera germs may be carried from infected grounds to others by feed, and by farming implements which have come iu contact with infected ground.

('/) There is no reason to suppose that currents of air have much influence in spreading the disease. Observations at the experiment station of the Bureau have left no doubt that healthy pigs may be kept on the same farm with diseased ones without becoming infected, provided the infection is not carried in feed and implements,or on the shoes and clothing of persons from the sick to the healthy. Moreover the disease issin intestinal malady, am! all evidence points to infection through the food rather than through the air inspired.

The agency of Hies and other insects is perhaps equally limited when infection is to be carried from one place to another. Our experiments show very well that the sting or bite of an insect is not sufficient to produce the disease. Jt is possible, however, that they may carry the virus from one place to another in the same yard. This will be discussed more fully under another head.

The agency of buzzards in distributing the disease in the Southern States seems probable, although there is no positive proof. These birds will readily consume carcasses of dead swine. If the hog cholera germs are not destroyed by digestion it is reasonable to assume that the feces contain the living germs, which may cause the disease to break out at some distant place. Of course, the remedy would be to immediately destroy or bury dead animals.

There is some reason to believe that rats, dogs, and perhaps other small animals may carry the germs upon their feet or in their hair and thus infect premises. It is probable that the contagion is only rarely transported in this manner, but there are outbreaks the origin of which

it is (liflicalt to explain otlii.Twisc. We may readily conceive, bearing in mind the lads enumerated above, how such animals might become contaminated with moist,semi-liquid, or liquid matters containing the germs, and that these substances drying upon the feet or hair would adhere for a considerable time. If an animal thus infected should go into uninfected lots occupied by swine and deposit there the smallest particle of the germ-containing material, cither in liquids standing in the feeding troughs or in moist organic matters suitable for the multiplication of the microbes, an outbreak of the greatest virulence might be set up. The nuinberof conditions which must coincide for the spread of the disease in this way probably accounts for the comparative rareness of this kind of infection.

Granted, then, no communication between infected and uninfected farms, there still remains the danger of infected watercourses, upon which it is impossible to lay too much emphasis. In fact, if the disease exists anywhere along a stream all farms below that point are liable to infection unless use of the water in any form whatever is given up during the season.

By paying particular attention to these points, there is no doubt that the disease can be warded, (iff, even when in the immediate neighborhood. Hog cholera is analogous to typhoid fever, dysentery, and Asiatic cholera in man in many particulars, and there is a quite unanimous opinion that these diseases are most commonly transmitted through drinking water. The same may be predicated of hog cholera, and. the mysterious spreadof this plague will no doubt frequently be understood by examining the water courses.

When the disease is in the neighborhood it has been customary with some fco feed swine on some so-called ' preventive''medicine. These are frequently prepared or invented by individuals who have little, if any. knowledge of the action of medicines. The outcome is that the animals fed with these unknown compounds are not only not benefited, but their vitality is actually reduced, and when the disease appears it destroys the weakened animals much more easily. The writer has made post-mortem examinations of several animals in the West where such preliminary treatment was going on, and the peculiar changes of the internal organs, not like any known disease, could only lie referred to the action of such preparations. It must be remembered that there are few medicines which are not injurious or poisonous in large doses. They should not be used thus excepting under special conditions, and only given as recommended by those who have been trained to know the peculiar value and effect of drugs.

The condition of the animals themselves is of great importance in favoring or preventing infection. When pigs are fed with liquids in which the specific bacilli only are present, those that have been deprived of food for some time previous take the disease, while those, whose stomachs contain food that is undergoing digestion do not take it

126

readily. It', besides starving the animals, tliej are fed with some alkaline solution, by which the alkalinity of the stomach is increased, the pathogenic effect is still more pronotmced. Any disorder of digestion by wliicli the secretion of gastric juice is diminished or checked and tlie mucus is increased in quantity will increase the susceptibility of the animal in infection, because the alkalinity of the mucus will favor rather than destroy the virus. Any mode of feeding which produces ((instillation and over-distension of'tlie large intestine is likely to favor the disease, as the virus is retained fora longertimc. During epizootics, therefore, besides the preventive measures suggested, the animals should be carefully fed upon food which tends to keep the bowels (iigt;eii and the feces soft, and which does not interfere with normal digestion.

When there is a suspicion that a herd has been infected, although the disease has not yet appeared, disinfection, and all the rules laid down below (p. 130) should be carried out with great care, as if the disease were actually present.

When hog cholera has appeared in a herd or on a faun, precautions should be taken for two reasons: (l) To prevent the virus from being carried to other farms and infect other herds. (2) To prevent the loss of the entire herd, or, if this is not possible, to stamp out the disease in such a way that the ground shall not infect healthy animals subsequently.

The rules under the first head should be prescribed by law to protect property from the consequences of the carelessness or the willfulness of those who refuse to take proper precautions. They may he summarized as follows :

(a) The dead animals should be immediately disposed lt;if. cither by burial or by hnrn'nxi, tu- if they are 1{i!:en to some rendering establisJiment their transportation should he governed by well-defined rules which icill prevent the dissemination of rims on roods, in wagons, ears, etc.

(/gt;) Streams should he 'carefully protected from pollution,

(c) JVe animals should he removed from any infected herd or locality to another free from the disease fir at.least six months after the last case of disease.

{a) The proper disposivl of dead animals is a matter of great importance, for the bodies not only contain the germs of the disease, but the latter will multiply enormously during summer heat in the internal organs after life has been extinguished. Each dead body must therefore be regarded as a focus of the disease unless properly disposed of. It may be buried. In such case it must be so deep that no animal can get at it. It should be covered by a layer of powdered or slaked lime several inches thick, and the ground over the body likewise sprinkled with a thin layer of the same. If the carcasses are burnt, care should he taken that any parts not consumed are buried as directed. If they are carried away some distance to rendering estahlislimeuts, at best a dangerous pocednre, employes of such establishments .should be compelled

127

to wrap around the carcasses iinperviotis elotlis wetted with a'- per cent, solution of carbolic; acid, so as to protect tiie roads from the virulent drippings.

{h) The danger from infected streams lias already been mentioned at length. These must be protected by law in such a way that no sick ani mals should be allowed to go near them, and that no carcasses be thrown into them or deposited where drainage may carry the virus bom the body into the water. Nor should the drainage from pens be permitted to flow into them.

(c) Hogs are frequently affected with cholera of a mild form, which lasts for several months before some form of septic infection or degenerative changes in the internal organs produce death ; hence it is important to insist upon knowing^- when the last case of disease occurred. Since it has been demonstrated that hog cholera germs may remain alive in the soil from three to four months, this rule will not appear unreasonable as a safeguard.

These rules will be sufficient, if properly executed, to eoiitine the disease within narrow limits. There is nodoubtthat hog cholera virus dies out over the greater part of our country after epizootics have swept over it. We have no reason to believe that it can survive in the soil from one end of the year to the other. It is, in fact, highly probable that it is transported and distributed from a few places where,for some reason, cases have occurred throughout the year and have thus kept the vims alive. There are no experiments on record which show that the hog cholera germ may be found in the soil and water independent of the disease. It has been looked for, but has never been found, excepting in the body or discharges of diseased swine.

Ju view of the fact that the disease can be kept under control, the legislatures of those States which sutler most severely from this plague should take steps to enact rules similar to those formulated above. The States of Kansas and Nebraska have on their statute books laws of this character, which read as follows:

AN ACT to prevent the aprlaquo; ad of disease among swine.

lie it enacted hy the legislature of tin' Slate of Kansas, It is hereby made the duty of every person who owns or wlio lias (he control of any hog that has died of any disease to bury or burn the same within twenty-four hours after such hog has died, and any person who knowingly fails or refuses- to comply with the provisions of this see-lion shall lie deemed jjuilfy of a misdemeanor, and npon conviction thereof shall be lined not exceeding one hundred dollars.

Sice. 2. Whoever shall knowingly harter or sell any hog afflicted with any disease without giving full information concerning said disease shall be deemed guilty of a misdemeanor, and npon eonvietion thereof shall be lined not exceeding one hundred dollars.

SEC. :gt;. Whoever shall knowingly barter or sell any hog which has died of any disease .shall be deemed guilty of a misdemeanor, and npon eonvietion thereof shall he lined not exceeding one hundred dollars.

SEC. 4. Whoever shall throw or deposit a dead hog in any river, .stream, creek, or ravine shall he deemed guilty of a misdemeanor, and npon eonvietion thereof shall lie lineil not exceeding one hmidred dollars.

128

AN ACT fco prevaot Un

Bproat] ot liog c-lmlii.-i nnj other kiudrcil dkuaacs,aud prevent IruMc in ao-imals dyiug from iurcotioits or other diseases.

Be it enacted h\j the legislature of the sialc of Xchraska, That it sliaU bo the iluty oi the owners of swim.' or other dotuestic auiiuals ilyiiiiA¹ from cholera or other diseases, within twenty-four hours after their death, to cause the carcasses ol' such animals to be suitably buried or burned up on the premises owned or occnpled by sutli person.

Sec. 2. [f the owner of any swine or other domestic animals dying from cholera or other disease, or any other person, shall sell or dispose of the carcass of such swinu or other dornestic aniuuils, to any person for the purpose of manufacturing the siune into soap or rendering the same iuto lai'd, or for other purposes, or if any person shall buy or otherwise obtain the carcass of any swine or other domestic animals, dyiug from cholera or other disease, for inannfacturiug purposes as aforesaid, or any othe^ purpose except that of burial or Imrniug, as provided in the preceding section, every such person shall n|i(jii conviction 'quot; lined in any sum not less than twenty-flvu dollars nor mere than one hundred dollars, or he imprisoned not exceeding six months.

Sec. '#9632;'#9632; Whereas an emergency exists, this act shall bo in force and take effect from and after its passage.

Approved, March I, 1885.

These laws, altliougli not sufficiently explicit, tondi upon the most important points, ami areimportaut moveiueutsin tlieriglit direction. We would suggest laws embodying the tbree heads in their entirety as i^ivcii above under a, b, and c, together with directions for their proper execation. The disease,spreading so easily and rapid!j,requires great promptness of action and quite different rules from tbose which musi be adopted in the suppression of glanders or tuberculosis, for example. Fhe difference is due to the nature of the specific microbe, so unlike those causing the two diseases mentioned.

It is not strange that so little attention has been paid to the restric tion of this disease in the past, since legislators and boards of bealth and State veterinarians have had no scientific basis upon which to frame laws. Even now efforts are being made in various quarters to controvert or openly deny the accnt^acy of the investigations and results obtained by the Bureau, and throw the whole subject back into the chaos in which it was but a lew years ago. This must have anything but a salutary effect upon those intrusted with the framing and execution of specific laws for the protection of domesticated animals.

Having thus far dwelt upon the means which must be adopted to prevent the spread of the disease from one place to another, it becomes necessary to consider some of the measures that should be employed in checking it after it has once taken foothold in a herd. But how are we to recognize the disease .' To answer this (iiiestion it may be well to recapitulate briefly some of the more important features of the malady in as simple language as possible:

It is quite common for the disease to announce itself by a few sudden deaths. The stricken animals may seem well a day. perhaps only a few hours, before death. In order to remove any doubts as to the precise nature of the disease, it is best to examine one or more of the animals before burying or baruing them. This shoald be done in a secluded

129

place which pigs can not roach, and the groautl thoroughly disinfected, as will be described later. The disease in the sudden cases can be easily recognized. The spleen is, as a rule, very black and enlarged. Spots of blood from the size of a pin's head to a quarter inch or more will be seen in the fat under the skin, on the intestines, lungs, heart, and ku'iievs. The lymphatic glands are purplish instead of a pale pink. When tin' large intestines are opened they are (ound covered with these dark spots of blood more or less uniformly and entirely. Often the contents are covered with clotted blood. Any or all of these, may be considered as signs of the disease in its most virulent form. In many outbreaks the early cases do not succumb so rapidly. They grow weaker, lie down much of the time, eat but little, and usually have, diarrhea. Most of such cases may linger for weeks, meanwhile scattering the poison in the discharges. The disease may be recognized in these cases as soon as they are observed to act suspiciously, and there should be no delay in determining at once the nature of the disease. When the aniiunl has been opened the large intestine should be carefully slit up and examined, beginning with the blind or upper end. 'there will be seen roundish, yellow or blackish spots, having an irregular, depressed, sometimes elevated surface. These spots correspond to dead portions of the mucous membrane, and they are frequently seen from the outside as soon as the animal is opened. Sometimes the membrane has been entirely destroyed. (See also pp. 39-52.)

In order to comprehend fully the reasons for the preventive measures suggested, let us briefly trace the various ways in which hog cholera. bacteria may pass from a diseased or dead animal to a healthy one.

Pigs may become directly infected byfeediugon the carcasses of such as have died of the disease, or by eating food contaminated with the fecrs and urine of sick animals, or they may become indirectly infected by feeding upon material in which hog cholera bacteria are accidentally present, and in which they have multiplied. This would include milk water, and perhaps most vegetables in a boiled condition. It lias been pointed out in preceding pages that hog cholera bacteria multiply very abundantly in milk, especially in warm weather, that they remain alive in water for months, and that they multiply upon boiled potato. It has also been shown by an extended series of experiments (p. 80) that they may remain alive in the soil for from one to four months. The sources of infection are thus numerous enough. It has likewise been demonstrated that these disease germs will resist drying. Hence, dried discharges of the sick or the dried body of dead animals arc still infectious.

The channel of infection is in most cases the food and drink. This has been frequently demonstrated and emphasized in these [raquo;ages.

The food, after leaving the stomach, passes in a liquid condition through the small intestine, so that this never seems tilled ; in fact, its only contents are a. coating of semidiqnid matter over the mucous meiu-1,5012 ii c------9

ciivk' ol' iiilVci iiui.

hi order to preveul the remaiuiug liealtLy animals in au infected herd from takiug tLe disease thefollowiug measures are suggested as of importance, some or all of wbicli may be carried out according to circumstances:

(a) Removal of still healthy animah to inclosed uninfccteA ground or pens, ax far as possible from infected localities,

[li) Destruction of all diseased animals.

(.-) Careful burial or burning of carcasses.

{(1) Repeated thorouyJi disinfection of the infected premises.

ylt;) Great clcunliness, both as to surrounUings and as regards the food, to prerent its beco)ning infected.

(laquo;) TLe importauce of (his measure need not be insisted upon, after \vli:ii lias been stated of tlie various ways in wliicb pigs may bo infected. TLe distance to wbicli (Ley may be removed will, of course, depend on circumstances. They sbould be kept so far away Ibat there can be no means of coinmunication, either by direct contact, by drainage of the surface (if the soil, or by gusts of wind. Tbey should nor be kept too closely confined, for if the disease should have attacked one or more and not manifested itself before removal, the infection would beegme general. Even after this precaution is taken, latent disease among such as are apparently healthy may infect the new grounds and the remaining healthy animals. This danger is increased by the fact that not un-froquently a number of animals become infected from the same source, at the same time. Home will show symptoms very speedily; in others tlie disease will remain latent for a longer time. [Inder such circumstances it is impossible to properly isolate the well (Vom the sick. Then there is the difficulty of preventing the well animals from carrying tho virus on the skin and feet into their new quarters. These drawbacks may be in part overcome by very prompt action when the first signs of disease aivncar in a herd, hpfnrfl Hirtvirna imu m..i m,, ,,gt;,,.....,,,..:^.. ..e

131

all sick animals is tlie simplest and most ccouomical procedure in the

fiid.

(c) Tlie disposal of carcasses lias already been discussed (p. 128). This very iraportanl measure should never be lost, sight of.

(il) Among^- the various disinfectants whicli can be recommended arc the following:

No. I. Slaked or unslaked lime, used both as a powder and as slaked lime, containing about5 to 10 per cent, of dry lime (from .\ to 1 pound of lime to a gallon of water).

No. 2. Crude carbolic acid, prepared by adding to the crude carbolic acid obtainable, from druggists at about 90 cents a gallon an equal quantity of ordinary sulphuric, acid. This mixture is to be carefully added to water in the proportion of 2 ounces to 1 gallon of water, about 1J per cent, volume (see p. 91).

No. 3. A 1 per cent, solution (volume) of ordinary sulphuric acid (1 j ounces of the acid to 1 gallon of water).

No'. 1. A 2 per cent, solution of pure carbolic acid. This is prepared by heating the crystals slightly until they melt and adding the resulting liquid to hot water, in the proportion of 1 [ ounces to half a gallon of water. (A pound of carbolic acid, crystallized, retails at Tm cents.)

No. ~gt;. Boiling water.

The careful laboratory experiments with these disinfectants, upon which their practical application is based, are given on p. ST. We shall conline ourselves in this place to a description of their employment.

Disinfectants are substances which, in solutions of a certain strength, are capable of destroying disease germs. Consequently they should be applied wherever the disease germs are supposed to be. In case of hog cholera they are attached to the sides and floorings of pens and to the various utensils used, in cleaning them. They arc mixed with the earth over which the diseased animals have run, or in the water which they have frequented. In the report of the Department for 18SG the. use of mercuric chloride (corrosive sublimate) was recommended, as it is a powerful disinfectant. Since that time other disinfectants have been tested which are equally cheap and easily procurable. The main objection to mercuric chloride is its extremely poisonous character, which makes it undesirable to deal with. This substance lias, therefore, in spite of its powerful germicide properties, been thrown out of our list of available disinfectants.

The woodwork of pens, fences, flooring, etc , is best disinfected by using upon it, with a broom, solution No. 2 until thoroughly wet, in preparing this solution it should be stated that the mixing must be done in a glass bottle or jar and the mixture poured slowly into the proper amount of water in a wooden pail. This should be rinsed out after using to prevent the acid from slowly destroying the iron hoops.

Whenever No. 2 is not obtainable No. 3, which seems to be equally efficient, may be used in its place.

132

Lime is a very eflicknl disiufectant for hog cliolerji. Experiments have shown (p. 93) that a solution containing only .02 per cent, will destroy the bacteria. When much organic matter is present, as much as .5 per cent, to 1 per cent, may be necessary. quot;We recommend the proportions given under 2sn. 1, which give from 10 to 20 times the strength required. The resulting liquidisnot too thick to be easily manipulated It may be used on wood-work as a whitewash, and it may be spread as a thin layer over the soil whieh has been infected.

The 2 per cent, solution of pure carbolic acid should be used whenever Xo. 2 may act injuriously by virtue of the sulphuric acid which it contains.

In general we recommend the use ol'Xo. 2 or No. 3 as often as it may M'em necessary. It should be dashed upon the infected pens, troughs, tools, and over the infected soil. When there is no objection to lime this may bo used on the soil, as it is equally efficient. The discharges should be covered with powdered or slaked lime, und this should be thrown in abundance into pools or wherever water stagnates. In the case of troughs for feed, iron tools, etc., which are liable to injury, the disinfectant should be washed away with boiling water if this is at hand. Boiling water will destroy hog cholera germs by simple contact, and the disinfection will thus be made more complete. Shoes may be disinfected b\ rubbing them with solution No. -1.

It must be carefully borne in mind that no manure from sick pigs should be removed until it has been treated with disinfectants. The. cleaning must be done after disinfection and not before, to prevent the dissemination of living virus.

The agency of mice and rats in transporting virus will depend upon the promptness and thoroughness with which disinfection and cleanliness arc practiced. Mice are more dangerous than ruts, in so far as they may take the disease by feeding (p. 71'). Flies can only carry sneb small quantities of the virus that they are not likely to prove dangerous if disinfection and cleaning of feed troughs nre attended to.

ff these measures are carefully carried out, thedisease may either be checked or else mild cases only will appear, owing to the small quantity of poison which the animals are likely to consume with the food.

The epizootic, may be terminated by the destruction of most of the herd. This unfortunately is usually the case. What precautions must be taken to prevent subsequent outbreaks?

if only a few animals remain, it is best to slaughter them j they are likely to suffer with the disease in a mild form and continue to infect the premises. If no more animals remain, there should be a final thorough disinfection and subsequent cleaning of the whole exposed territory, including every nook or corner where the disease has existed. This should be done with solution Xo. 1'or Xo. ;gt; as directed, used as freely as possible. After one or two days the ground may be covered with a tbin layer, one eighth inch or more,of slaked lime in (hostrengtb

above given ami left audisturbecl. If tbere is no objection to wLitewasli, tliis may be applied to infected wood-work as au additional .safeguard. Even after tliis tborougL treatment, it is best not to place any fresh pigs on the premises for at least four months after the linal ilisinfection. When animals -still remain that have been exposed and have not taken the disease, no fresh animals should be introduced for at least six months after the termination of the outbreak. The disinfection must have been equally thorough.

After all this trouble has been taken there is still remaining the danger of a fresh introdactiou of the disease, and we would therefore again call iitleution to the rules laid down in the beginning of this chapter. These, after all, must be considered as most important. It is inucli easier to keep the disease away than to eradicate, it aller it has been introduced, without great loss of time and money. We would also suggest that in those regions where the danger from hog cholera epizootics is always present, the methods of keeping hogs be simplified in such a way that disinfection maybe practiced without too much labor and uncertainty as to the results. It is only necessary to visit a few farms to be convinced of the difficulty that may be met with in endeavoring to eradicate the disease. The hogs arc allowed to stray into the most out-of-the-way places when sick instead of being kept in inclosurcs of definite form and size, which are readily accessible. The poison is thus scattered in such a way as to make disinfection impossible. It is certainly not necessary in raising pigs to allow them to si ray into arbors, behind hedges, hide themselves nmlcr barns ami outhouses. Jn some farms which we have visited, and which were said to Lave hog diseases most of the year, there seemed to be no places about the house or garden where pigs did nor go. Cnder such circumstances disinfection is is qniteimpossible. The pens and other wooden structures, fences, etc., are also apt to be in a very dilapidated condition, so that cleaning is very much complicated. Even under sneb circumstances the germs will finally perish without disinfection if enough time be given, since they gradually die in the soil and water, as our experiments have shown. A period of from six to nine months after all animals have been removed will be, in general, sufficient to purify the soil of these disease germs. In fact the natural disinfection is very probably accomplished in many cases in from three to four months, but it would not be safe to rely upon this.

HHATMl'NT OF HOli CHOLERA.

Upiiii this subject very little slioulil bo said, for the reason that ills eased animals are a source of poison and a menace to healthy animals, ami shoukl ha destroyed. Moreover treatment is exceedingly imsntis factory, as the disease either terminates fatally, whatever reinedies are used, or generally makes the animal useless ii' ii should recover. We tberefore urgently recommend slanghterof the sick and tborongli disinfection as the safest and most economical treatment in the end.

Treatment, however, is resorted to by a large number of owners of swine. The number of specifics, so-called, wbich are being advertised is legion. We have tried some of the best recommended and found Ihem of no avail. Nor is there any quot;specificquot; known in the range of vctvr inary or human medicine that will cure diphtheritic and nlcerative disease of the large bowels except time, combined with careful dieting, rest, and n, few palliatives to relieve pain, [t is impossible to curry oni this treatment on swine. The success frequently reported with spj-cifics iu hog cholera are very probably due to the.fact that the treat-mentis usually adopted in mild forms of disease of a different nature which is tuistaken for cholera, or when the acute outbreak is over and the plague has assumed a chronic character. The affected swine linger for a time with very slight symptoms of disease, and this change is credited to the quot;specificquot; employed. Remembering that the severest injury is done to the walls of the large intestines in this disease, we regarded it important to determine what medicine would give a prompt and copious evacuation of the bowels in the very beginning of the disease. Various medicines were tried by Dr. Kilborne, at the Experiment Station, among others the following-:

(1)nbsp; nbsp;Calomel and jalap.February 20, 1SSS. To Uto. 4C3, 30 grains calomel: to No. 407, L'.'J grains Jalap; to No. 4C8, 30 grains each of calomel and jalap. February 21. Same laquo;lose given again to Nos. 103 and -MIS: no result.

(2)nbsp; nbsp;Calomel.Mamp;rch 7. To Xos. 441 and 442, each one dram of dry calomel. March 8. To 411 same dose mixed witb castor-oil; to i!.; about U drams with castor-oil. .No. 4 1! was freely purged after second dose, continuing for twenty to thirty-six hours. No. 412 was freely purged after sixteen hours, continuing sixteen to twenty hours, when it died. At autopsy were found intense inflammation of stomach, superficial necrosis of the mucosa of large intestine with deep reddening resembling hog cholera. No bacteria found in cultures from spleen.-These changes were no doubt due to the calomel.

135

13G

(3) Coiowie/.Marcb 8. Nos. 4G3 and 4CS receiveil (M(^li oue dram colomcl in 2 drants castor-oil. No. 468 was purged freely iu twcnty bours, continuiDg thirty-six hours. Xo. -KJ.'J was purged in sixteeu hours and made ill for several days.

(4) Epsom salts,Nos. 403 and 405 (weight 50 pounds) received each 1 ounce. Bowels slightly relaxed for one or two passages. Nos. 339 and 377 (weight 50 pounds) received each 2 oivuees in water. No. 339 was purged and made slightly ill. No effect on 377.

(.quot;gt;) Barbadoes aloes.Nos. 402 and 404 (weight 50 pounds) received one-half dram each; no effect. Nos. 372 and 380 (weight 65 pounds) received eaeii 2 drains, mixed in molasses ; no effect. The same animals, five days later, received each 4 drams with molasses; no effect, except discoloration of feces.

(0) Castor-oil and turpentine.Nos. ,'5.s7 and 388 (weight 50 to 00 pounds) received each l| ounces castor-oil and one-sixth ounce turpentine; no effect. No 387 received, live days later, 2^ ounces oil and one-sixth ounce turpentine. No. 388 received, live dayslaler, L'A ounces oil and one-third ounce turpentine; no effect.

(7) Linseedoil and turpentine.Eos, 383 and 300 (weight 50 to GO pounds) received each 2A ounces oil and one sixth ounce turpentine; no effect. No. 383 received, five days later, 4 ounces oil and one-sixth ounce turpentine. No. 309 receiveil live days later, iounees oil and one-third ounce turpentine. Doth were made sick for a day or two. No catharsis.

These trials show how difficult it is to cause movement of the large bowels in swine, and they also suggest that this very sluggishness may make them susceptible to inlhunmations and ulcerations such as we find in bog cholera and frequently in swine plague.

It was our intention to obtain a cathartic which would freely purge without causing any iuflamination or irritation of the large intestine. lt; )f those tried, calomel is the only available one. This must be carefully given, as it may produce the very iuflaminatious which it is designed to check, and destroy life, as was actually done in experiment '2.

Concerning calomel Ellenberger* says:

Calomel (in combination witli castor-oil) is especially serviceable witliswiue; witb larger an i ma Is when tbe co-utents of the iutesUnal canal are to be disinfected, and in inflammatory fevers. It should be given to ramiuants with the greatest caution.

it was our purpose to try calomel alter having made these trials upon healthy animals, when the disease died out at the Experiment Station, and further investigations bad to be postponed.

If the large intestine has been promptly evacuated the next important step is to give only that food which leaves but little irritating waste to pass into the large bowel, such as milk and gruels. Jn short, it is best to use only boiled or scalded food so as to hell) tbe process of digestion as much as possible, it may be necessary to repeat the dose of calomel after a few days. As to this mode of treatment our experience is not sufficient to warrant any positive statements, and it is simply suggested to those who wish to run the risk of treating this disease. ' Lehrbuch il. allgemeinen Therapie d. Haiusäiigetkiere, ls-rgt;, \gt;. (i7'gt;.

1 OT

io7

There is another llaeof preventive mul curative treatment which may prove vnliiable in the future, namely, the feeding of substances with the daily food which, while not injurious to the animal itself, may keep in check the multiplication of the vims in the intestine by an antiseptic action. It is very important, however, to bear in mind that a large, number of those medicines which act as disinfectants and antiseptics are likewise injurious or even poisonous to the animal itself. A too abundant feeding of such material, while it may reduce the mortality and lessen the severity of the disease in the sick, is liable to cause in jury to liver, kidneys, and other vital organs, whereby the nutrition of the animal may be permanently injured. Such medicines, when carelessly given to healthy animals as preventives, may irritate the large bowel sufficiently to reduce its vitality am? power of resistance wdien the disease actually appears. The proper medicine to feed must therefore bo selected with care, and we trust that experiments to this effect may be carried on at the Experiment Station at an early date.

There is still another line of treatment which demands attention, namely, the introduction of a sufficient amount of some disinfectant into the body to be absorbed and thus to make, the whole body oppose the multiplication of bacteria. Koch died this method by injecting mercuric chloride into guinea-pigs and afterwards inoculating them with anthrax bacilli. The animals all took the disease and died.

At the laboratory of the Bureau mercuric iodide, a still more powerful disinfectant, was tried upon rabbits.

A solution was prepared containing .001 gram mercuric iodide ami ,002 gram potassic iodide in a cubic centimeter. Of this ,5 cubic centimeter was injected beneath the skin of the back of four rabbits (Xos. 1. 2, 3, 4) for eight successive days. On the third day Nos. 1, 2, 3, and afresh rabbit (check\ No. 5, received bypodermically into the inner surface of the thigh ', cubic centimeter of liquid containing one millionth cubic centimeter of a beef infusion culture of hog cholera bacteria about one day old.

All the inoculated rabbits died,thedates being given in the appended table. Babbit No. 4, which had received the iodide only, to observe any poisonous effect, remained well. The lesions were those of hog cholera, and the specific bacteria were present in the spleen. The total amount of the iodide given was .004 gram, about ^ grain.

No,*

,5 cubic centimeter of ,',. per i-cut. mercui ic icdido daily.

[noculated with one-iuil-liontfa cubic centinaeter culture litraquo;^ cliolora bacteria.

June22 to 20. inclusive Iimi^ 2J...................: nicil June 30.

....do......................ill'..................... Died July 3.

...ilo.....................du.....................\ DiedJulyO.

...dO...... ......................................;

... do................... June 'Jt .................. DiedJulj ::.

\Vr!4iliMi,u eacli raquo;boat - pounds.

138

At the same time healthy pigs were fed with the same substance in minute closes, to observe any toxic effect that might appear. These experiments were likewise iaterrupted in their application by the disappearance of the disease at the beginning of the year. While we therefore recommend in general the use of a purgatirej such as calomel, in the beginning of the disease, and careful feeding subsequently, we have as yet no actual experimental evidence that such treatment will be of any avail, owing to the frequent interruptions of Hie work.

EXPERIMENTS ON THE PREVENTION 0

INOCULATION.

HOG CHOLERA BV

During tlilt;' pasl six or seven years the attention of the world lias been ceutercd upou tlie brilliant experiments of Pasteur in tbelineof preventive inoculation for animal diseases. Many others have since then followed bis lootsteps with variable success. Among tliose diseases for whicli preventive inoculation is more, or less in vogue in seme European countries, especially in France, are anthrax among cattle and sheep, cliarbon symptomatiqtte, affecting the same animals and perhaps identical with the disease known as black quarter or black leg in this country. This is not the place for discussing the absolute value of vaccination in these diseases, nor to point out the reasons why they are not regarded of much value by scientists of Germany and other States. Suffice it to say that the Bureau has devoted a large amount of time in (esling all the available methocls of attenuating hog cholera virus for vacciual use, to determine whether any vaccine could be placed at the disposal of the public that mighl prevent the enormous losses entailed each year by this dreaded germ disease. In the following pages most of the work done (chiefly during the n inter and springof 188G) is briefly reproduced.

Inoculations of small doses of strong vims in theform of liquid cultures was first resorted to, because it bad been observed that pigs rarely take the disease when culture liquid in such quantities is injected directly under the skin. We reasoned that, if injections of small doses do not cause the disease, why may they not prove effective in preventing natural infection ? The cultures were not therefor.' attenuated, as Pasteur has done, with anthrax, because the step was deemed unnecessary.

A lot of animals were at lirsr inoculated twice with very small quantities, the period between the two inoculations being about two weeks. This time was sufficient to reveal any disease which might have been induced by the inoculations. Two weeks after the second inoculation the animal was infected either by allowing it to feed upon the internal organs of pigs which had died of the disease or by exposing it to the sich and dying in an infected pen. It was soon found that the inoculations were by no means prot ctive, in whatever way the virus entered

140

the .system, fbr subsequent feeding usually produced cases of the most acute character aud with the most severe ami extensive lesions. The doses of inoculated cultures were gradually increased in quantity wilii-out yielding any better results. Of a large number of animals subjected to inoculation only live took tlie disease uninistakably as a consequence of the operation. The experiments, including tables and post-mortem notes, are given in extenso as they were made.

In reading them over it will be noticed that the virus was cultivated eliielly in liquid media, ami the solid media, more particularly nutritive gelatine, were only employed to test the purity of the cultures. Whenever these cultures were used for inoculations they were previously tested on gelatine plates by drawing a platinum wire, dipped into the culture, through the gelatine layer two or three times before the gelatine had become solid. Among the hundreds of cultures thus rested in the space of several months not one was found impure. Series of cultures extending up to the tenth generation were usually carried on by inoculating fresh tubes each day. The last culture tested as described above gave precisely the same colonies as the first in all the series thus far prepared. The, culture-tube, desciibed in the First Animal Keport of the Bureau, was used almost exclusively for these cultures in liquid media. The, advantages and accessibility of cultures in liquids for purposes of inoculation, the readiness and ease with which quantities or doses may be determined, linally, certain characteristics of growth in liquids, place this method on a level with, if not above, that of solid cultures for experimental purposes. For diagnostic purposes, solid media are today a sine qua noil of bacteriological work.

Experiment 1.Pigs Nos. 1Ö2, IGT, 108, and 17ö were inoculated with pure cultures in beef-infusion peptone as follows: On January 2.J. one drop of the seventh cnltme, derived from the spleen of pig No. 114; on Februarys, with one eighth cubic centimeter from a culture derived Irom a guinea pig. Both cultures \vi re diluted in sterile iionnal salt solution in such a way that I cubic centimeter of fluid was injected each time. The inner aspect of the thigh near Poupari'sligamentwas chosen, and the liquid was introduced beneath theskin into the subcutaneous tissue with a hypodermic syringe. There was no perceptible swelling at the site of cither inoculation, excepting in No. 17Ö, in which there were two tumors, each the size of a walnut, at the sear of the first inoculation. In order to test the extent of the immunity which these inoculations lyight have conferred, feeding the viscera of pigs which hail succumbed to hog cholera was resorted to, the animals being transferred to the large infected pen for this purpose. Nos. 108 and 1 To were fed in this way March 5, and two animals not inoculated (Nos. 158 aud 189) were fed with them. All four died ; the two vaccinated animals in about twenty days, the others in about fifteen days after feeding. March !#9632;'gt;, Nos. lä:2 and 107 were fed with two check animals,Nos. 170 and L90. These four also died of hog cholera : the two vaccinated ones averaging twenty days, the others eleven days after feeding. The inoculation may be said to have simply retarded death from live to nine days. A table

141

giving a summary of these furt.s is a^tpeuded,togetber with a brief descriptiou of tlie_poslt; mortem appearances:


Ko.	January 23.	Fed with Iioje- Ifaraber of Fcl)ruary8. cholera vis- Died. ' days after (fi;t. rceduig.
152 107 108 373 158 189 1711 i no	Drops. _i 1 1 1	i Mar. 13 ... Apr. 3...... 21 i Mar. 13..... Apr. 1...... 19 ,', Mar. 0...... Mar. 28..... 23 I Mar. 5...... Mar. 22..... 17 ............. Mar. 6...... Mar. 21..... 10 ............ Mar. 5...... Mar. 19. ... U ............ Mai. 13 ... Mar. 23..... 10 ............. Mar. 13.... Mar. 'Ja.... 1 12

Autopsy noics.No. 152. Skia of limbs and abdomen dotted witli purplo spots; on abdomen, general reddening. Points of extravasation and ecchymosed spots throughout the subcutaneous connective and fatty tissue and on gastro-splenic omeutum. Superficial inguinal glands greatly enlarged and congested. Spleen enlarged, tilled with blood, and very soft. Petecchise on epicardinm. Numerous lobulosof the lungs collapsed. Glomernli of kidneys appear as deep red petecchiie. In ca'cmii and upper portion of colon extensive and deep ulcers. A few in the ileum near the valve. The mucosa of the stomach, small and large intestine, thickly covered with dark rod points or petecchiie,

No. Kw. Dyingquot;, and hence killed by a blow on the head. Spleen swollen, friable; epicardium dotted with points and spots of extravasation. In lungs a few collapsed lobules. Lymphatic glands generally very deeply congested, similarly the mucous membrane of fundus of stomach and the kidneys. Large ulcers in csecum and upper portion of colon.

No. IG8. Subcutaneous ami sub-peritoneal tissue contains numerous eccliymoses from one eighth to three-fourths inch in diameter. Spleen enlarged, gorged with blood,friable. Petecchite on epicardinm. Lungs not collapsed; its parenchyma contains numerous deeply-congested areas from one-eighth to one-half incli in diameter. Kidneys enlarged, with extravasations on surface and in parenchyma. Cortex of lymphatics in general deeply congested. Extensive, almost continuous, ulceration of ciecnm, and upper portion of colon, in part blackish, the remainder of the large intestine being the seatof severe inflammation and extravasation. Mucous membrane of stomach similarly Involved.

No. llö. Subcutaneous tissue dotted with pale red spots. Tumor at the place Of the first inoculation firm throughout, pale yellowish. Superficial inguinal glands, as well of those of thorax and abdomen, with purplish cortex. Spleen tissue still firm, dotted with numerous bright red points, but slightly enlarged. Beneath the entire epicardium and endocardium many extravasations. Caecum and upper portion of colon extensively ulcerated. Serous surface of large intestine dotted with extravasations.

No. 17(J. Slight reddening of skin and subcutaneous fatty tissue. Cortex of lymphatic glands in general deeply congested. Spleen much enlarged and surface dotted with numerous bright red elevated points. A few petecchhe on endocardium ami epicardium. Lungs deeply congested throughout; kidneys likewise- inflamed. Stomach slightly red dened at fundus; small intestine also slightly congested. Serosa of large

#9632; ;

142

iiitestiiio dotted with extrarasatious. The taucosa of cecnm aud small portion of colou one muss of necrosed tissue. Walls thickened.

No. 180. Extensive anddeep reddeuinfr of skin of abdomen, throat, and limbs. Subcutaueous tissue onl.v slightly reddened; spleen en-lai-yed, goi'ged with blood, friable. Besides the general congestion of the lungs there are small darkerareas,representing hemorrlmgiclobules. Bronchial glands and those along- lesser cuivatnre of stomach swollen and gorged with blood; the other lymphatics only moderatelycougested. Besides a small number of ulcers throngbonl the large iutpstine, the inncons membrane is deeply congested and doited with occasional heinorrhagic points. Kidneys extensively inflamed; on section the cortex shows extravasations.

No, 100. Considerable reddeniugof the skin of abdomen and ventral aspect of limbs; very slight in subcutaneous tissue. Spleen greatly enlarged, dark purple; blood Hows freely uu cutting into it; very soft. Lungs contain regions of congestion and hepatizations, possibly due to the presence of a few lung worms. Lymphatic glands near stomach, the bronchial and superficial inguinal glands, deeply congested. .Mucous membrane of stotnacb extensively congested; a large patch of extravasation in fiindns; large intestine severely inflamed, with occasional extravasations; no ulcerations.

The diagnosis of bug cholera was confirmed in every ease by finding the specific bacillus in cover-glass preparations of splenic tissue and obtaining therefrom pure cultures in liquid media and in gelatine.

Experiment 2,In conjunction with the first series of inoculations, two pigs (Xos. 140 and l(il) were inoculated at the same time, as follows _:January 23, with 1 cubic centimeter of the seventh culture in beef-infusion peptone. No reaction at the place of inoculation in No. 140; a tumor as large as a marble in No. IG1. On February S both received a second injection of 1 cubic centimeter. Two swellings as large as a chestnut at the place of the second inoculation in No. I 11raquo; ; in No. llil also a considerable thickening was present. No. 140 was fed March 5 with four of the preceding series; No. IG1 on March 13 with tin-remainder of the preceding series and some to be subsequently spoken of. Both died of hog cholera. The accompanying table and brief autopsy notes explain themselves:

Feb. 8.

Days Died.nbsp; nbsp; nbsp; nbsp; nbsp;after

r.-idmi;.

I Mar. 6 Mar. -1 1 Mor. 13 Apr. 11

No. 149. Slight reddening of the skin and subcutaneous connective tissue; the tumors produced by inoculation firm, pale yellowish, only one showing softening within ; spleen considerably enlarged aud full of blood; ascarides in gall bladder, which is ulcerated; uuicoiis membrane along fundus of stomach intensely congested; the mucous membrane ofesecum and upper portion of colon one mass of ulcers; in the remaia-der of colon they are isolated; kidneys congested.

143

No.lGl. Great emaciation; spleeu euhirgeil and gorged with blood, very soft; all exceptiug the posterior region of eacli lu.ng bepatized

and the bronchi tilled with a thick creamy mass, which consists almost entirely of pus corpuscles; lymplmtics but slightly coiigesteil; adhesious between adjacent coil of large intestine and bladder; ctecmu and colon studded with large deep ulcers; valve greatly enlarged; intense congestion of mucous membrane oi' fuudus of stomach.

Coyer glass preparations t'roin the spleen of both contain the characteristic bacilli. Gelatine and liquid cultures from the same organ were pare.

The comparatively large dose of strong virus nsed tor vaccination was not capable of protecting these animals from the disease communicated by feeding. There was no suspicion of disease caused by the vaccination when they were fed, and the time intervening between the two injec tions was sufficient for any development of disease from the injected virus.

Experiment 3.Pigs Fos. 151, 169, 170, and 178 were inoculated as in the preceding experiments on February 8 and 23 with J cubic centimeter of a beef iufasion peptone culture derived from a guinea pig and the seventh culture from the spleen of a pig in the same medium. The dose was diluted in salt solution so as to make 1 cubic centimeter of liquid. In No. löl the second inoculation produced a tumor about 1 inch long and one third inch thick. The first was scarcely noticeable. In No. LG9 the first inoculation resulted in a beau like nodule; the second produced several of the same size. In No. 170 neither inoculation showed more than a very slight swelling. [11 No. 178 both inoculations produced rather extensive swellings.

On being fed with the viscera of jigs known to lone died of the disease all took the disease and died; two on March 13 and the remaining two on March 19, i. e., one in thirteen, one in eighteen, and two in twenty-two days after feeding. A table summarizing these facts and brief post-mortem notes are appended:

No.

Euoculatio

gt;.

1laquo;:

-11.

Da afl

. r

eb. 8.

[el

fed

quot;,-

c. c.

(

l;.i

M n-

. 'Jd

Ifi!)

,'.

Uar

A pi

III

170

ä #9632;

Unr

A pi

. -1

178

Mar

A pi

. 1;

Autopsy notts.No, 151. Purplish spots on skin of abdomen and paler ones in subcutaneous tissue. Inoculation tumor cuts like cheese; yellowish-white. Extravasations under endocardium and pericardium; left lung mottled from hemorrhagic areas ; cortex of lymphatic glands inliltiiited with blood; those of meso colon and lesser curvature of stomach dark purple throughout; kidneys pale; hemorrhage into pelvis of left kidney; extravasations into mucosa of stomach; moderate

144

number of ulcers in ctBcum and colon; large quantity of blood in the lower lt;i or 8 feet of ilenin and in the large intestine, clotted in the former tube, where the mucoas membrane is deeply congested.

Xo. lOiraquo;. Small tumor on the left side, the place of the second inoculation ; spleen enlarged and congested, with large hetnorrhagic infarcts; considerable effusion in the large serous cavities. Besides the general congestion of lungs, there are scattered throughout its parenchyma Iiemorrhagic foci. Hemorrhagic inflammation of kidneys manifested by bright red glomernli throughout its cortex; lymphatics in general deeply reddened; numerous petecchise in stomach, small and large intestine. In ciccnm and colon, large, deep ulcers.

Xo. 170. Redness of skin in abdomen; nothing at places of inocnlation; spleen enlarged, friable, full of blood ; abdomen, thorax, and pericardia! cavity contain much yellow serum; congestion of the lungs with darker hemorrhagicfoci throughout; anterior lobes collapsed; kidneys enlarged, with a few extravasations on surface and in parenchyma ; mucous membrane, of stomach and intestines covered with many hemorrhagic points and spots. In large intestine, including rectum, numerous old ulcers, some 1 inch across. Lymphatics in general hemorrhagic.

No. 178. Died quite unexpectedly/ At the place of first inoculation two firm whitish masses; spleen eularged, friable; its substance contains Iiemorrhagic infarcts; extravasations beneath both serous surfaces of the heart: congestion of lungs, with numerous darker hemorrhagic foci; lymphatic glands of abdominal cavity very dark and gorged with blood; extensive ulceration about the ileo-CEecal valve, in the cse cum, and colon; in the lower portion of colon and in the rectum numerous small extravasations. Hemorrhage into pelvis of both kidneys.

The post-mortem determination of a severe type of hog cholera in these four cases was confirmed by finding in the spleen of each animal, by means of cover-glass preparations, numerous specific bacteria of this disease. Cultures in liquid media made from every spleen were found pure when examined microscopically as well as ou gelatine plates. This experiment likewise proved the inefficiency of small quantities of nou-attennated virus introduced beneath the skin in preventing an invasion of the micro organism from the alimentary canal.

Erperiment 4.A third lot of four pigs (Xos. 117, 171, 172, and 17-4), between three and five months old, were inoculated as before with .2 cubic centimeter each from the second beef infusion peptone culture derived from a pig's spleen. On March J they were inoculated with .2 cubic centimeter from the second culture derived from a pig's spleen. In No. 117 there was a slight swelling after the first, and one as large as a chestnut after the second inoculation. In No. 171 a mass 1 ^ to 2 indies long and three-fourths inch in diameter was found at site of the first inoculation. There was but a small nodule at the place of the second inoculation. In No. 17:.' two lamps, like small marbles, formed after the first inoculation ; alter the second only a small nodule formed. In No. 174 the reaction after the second inocnlation was manifested by an irregular tumor about 2 inches long and one. third of an inch in diameter, the reaction at the place of the first inoculation being less marked.

Of these four, two (Nos. 117 and 172) were fed with the viscera of pigs dead from hog cholera, together with two control animals (Nos.

145

192 and 193), on March 19. The rest (Xos. 171 and 174) were simply placed in the large infected pen March L'l*, with those that had been fed with infections matter. Below the result is given in a tabulated form. It shows that all the animals succiimbed to tiie disease, those simply exposed by contact with the sick as well as those fed. Of the inoculated animals, those fed died in twenty-one and eighteen days after feeding; those exposed, in twenty two and twenty-five days,.respectively. Those not inoculated died twelve and nine days, respectively, after feeding. Here, likewise, we notice the prolongation of life in the inoculated pigs.


Xraquo;. 117 171 172 171 192- 193*	Feb. 13.	Mar. 1. c. c. .2	Date of feeding ami exposure.	Died.	Days after exposure and feeding.
	Feb. 13.	Mar. 1. c. c. .2	Fed Mar. 19....... Exposed Mar.22.- Fed Mar. 19....... Exposed Mar. 22.. Fed Mar. 19....... ...do -	Apr. 13 Apr. tl Apr. 10 Mar. 31 Mar. 28	21 22 18 25 12 ⁹

The lesions found at the autopsies of these pigs arc briefly as follows:

Iso. 117. Extensive reddening of the skin of abdomen ; great enlargement of spleen, which is gorged with blood, very soft; pelecchial dis-colorations on surface of lungs and on section ; large intestine studded with broad, deep ulcers as far as the rectum; a few in ilenm.

No. 171. Skin over ventral aspect of body deeply reddened ; beinor-rbagic spots under peritoneal covering of diaphragm and large intestine and under capsule of kidneys; lungs congested, containing numerous dark hemorrhagic lobules; part of anterior lobes collapsed. The spleen very large, dark colored; nodes slightly raised above surface, shown on section to be hemorrhagic infarcts; lymphatic glands generally highly congested; petecchial spots ousiirtaceand in cortex of kidneys; hemorrhagic foci throughout mucosa of stomach and intestines. About four large ulcers in caecum and colon.

No. 172. Reddening of skin of ventral aspect of body and of subcutaneous tissue generally; firm, pale yellow, cheesy masses, surrounded by a thin membrane at place of inoculation ; engorgement of spleen and lymphatic glands; extravasations in parenchyma of kidneys. lu caecum and colon numerous deep ulcers, some coalesced. Mucosa of stomach generally congested, and that of intestines thickly dotted with petecchiee.

No. 174. Deep reddening of skin of abdomen; encysted cheesy mass at site of first inoculation ; great enlargement of spleen; prominent red points on surface; effusion into abdominal cavity; anterior lobes of lungs collapsed, remainder normal; lymphatics highly congested ; three large ulcersin cfecutD; valve thickened and ulcerated ; petecchiaj numerous throughout mucosa of stomach and intestines.

No. 192. Qontrol animal; reddening of skin of ventral aspect of body and of subcutaneous tissue; spleen swollen j full of blood : friable; at-10512 h c------10

140

electasis of the small anterior lobe of each lung; ulcers on the mucous

smface of gall bladder; cortex- of lymphatic glands infiltrated with blood ; mncosa of large intestines congested; numerous ulcers in caecum and upper colon.

Xo. I!);). Subcutaneous connective tissue considerably reddened; spleen bnt slightly enlarged; not much softened; inucous membrane of stomach, of large and small intestines, deeply congested ; contents of large intestine tluid, chocolate colored.

In cover-glass preparations from the spleen pulp of these animals, numerous bacteria of hog cholera were found in each preparation. Both gelatine and liquid cultures from every spleen proved to be pare cultures of the bacillus of hog cholera.

The diagnosis made on post mortem was thus confirmed by microscopic examination and culture.

Experiment 5To determine the effect of a single inoculation, on February 13 two pigs {Nos. 115 and 1G0) received subcutaneously- each 1 cubic centimeter of the second beef infusion peptone culture obtained from the spleen of a pig. In Xo. 115 a tumor as large as a marble was found at the seat of inoculation Marcb 9. In Xo. 1GO the tumor was elongated, about 2 inches long and three-eighths of an inch thick. X'o. 115 was fed with viscera taken from cases of hog cholera March lit. Xo. 1G0 was simply exposed to the disease by being transferred to the large infected pen. Xo. 115 died April 8. X'o. IfiO recovered and was well May G. The detailed account of this experiment is appended:


No.	Fel	. 13.	Date of feeding and exposure.	Effect. Died Apr. 8 . Recovered ..	Days after feeding.
100	c.	c. 1 1	Fed Mar. in........ Exposed Mar. I2'J___	Effect. Died Apr. 8 . Recovered ..	29

Post-mortem notes,2^0. I!.quot;raquo;, firm, pale yellow tumor at seat of inoculation, encysted ; center undergoing softening. Spleen tumefied, very dark and friable. A few extravasations beneath serous coverings of heart. In cortex of kidneys numerous hemorrhagic points; cystic degeneration of right kidney; advanced ulceration of caecum and colon ; scattered petecchiae imnucosaof stomach and small intestine.

Xo. 160. Was very low for a time, beginning with April 1. It was barely able to stand and its appetite was poor. It rapidly recovered, however, and was gaining flesh in May. Whether the animal was suffering from hog cholera or from the Selerostomapinguicola (kidney worm), with which some of this lot were found affected, can not be said.

In order to determine whether a single injection of a comparatively large quantity of culture liquid, while not inducing the disease, would protect against the disease itself, the following experiment was performed :

Experiment G.Four pigs (Xos. 202, 204,205, and 212) were inoculated April 2 with H cubic centimeters of a seventh culture in beef infusion with 1 percent, peptone one day old. Four additional pigs (Xos. 206,207,208,

147

ami 209) received but one cubic centimeter of the same culture. Tliero-maiuiugfourof tliesame lot (Xos. 203,210,211, and 213) were reserved as cbecks upon tbe experiment. Of tliese Nos.203and213had a temperature of 100deg; F., and hence were suspected of disease. This suspicion wassoon confirmed after they had been placed in a pen alone. Both had aseverc diarrhea, one dying April 11, the other April 13. The lesions were confined to tbe mucous membrane of the large intestine, which was dotted with numerous elevated lemon yellow tough masses afew lines across, simulating ulcers. On close examination, however, tins impression was dispelled. These tough masses were easily removed in toto from the mn-cosa, which presented a slight depression without any loss of substance. They were evidently exudates from the mucosa (croupons ?). There were no bacteria in the blood or in a bit of spleen dropped into a culture tube. No development took place in either tube.

Of those inoculated with 1 i cubic centimeters two died from the immediate effects of inoculation. Xo. 204 died in eleven days and 2so. 212 in seven days. TuXo.204 a tough tumor had formed atthe point of inoculation on each side. The mucous membrane of the large intestine was completely necrosed and the spleen enlarged. In Xo. 212 local swelling was present on one side. The stomach and large intestine were deeply congested, with points of commencing ulceration in the latter. In both animals the bacillus of hog cholera was presentin cover-glass preparations of tbe spleen. Xos. 202 and 205 seemed to remain unaffected by the inoculation. One month and a half later both were exposed to the disease in the large infected pen. A month later they were removed with others to a clean pen, after having apparently resisted infection. Xo. 202 was gradually wasting away, and died July 24, more than two months after exposure. In the large intestine were cicatrices of healed ulcers and such as were healing. The severest lesions were in tbe lungs. Both were adherent by means of bands to the costal pleura, and were extensively hepatized. Xo. 205 was alive and well August 15.

Of the second lot, which had received 1 cubic centimeter of the same culture the results were nearly the same. Two succumbed to theinocula-tion, one died of infection, and a fourth survived. Xo. 208 died fifteen days after inoculation. Besides the inoculation swellings, enlarged and congested spleen, the mucous membrane of t lie large intestine was covered with extensive deep ulcers, and the walls much thickened and softened. The corresponding lymphatics in the meso colon deep purple. Xo. 209 died in six days after inoculation. There was general congestion and extravasation of blood in tbe internal organs, involving the entire mucous membrane of the alimentary tract, especially the large intestine, the lymphatics and serous membranes, the spleen, and kidneys. Ulceration bad not yet begun. In both animals the spleen was crowded with bacteria and furnished pure cultures of the specific germ.

Xos. 200 and 207 were not affected by the inoculation. They were exposed with the preceding lot, as indicated in the table, Xo. 207. after

148

apparently resisting iufectiou in tlie infected pen foramonth, died July 18, after having been in a clean pen since June 21. The extensive necrosis of the mucous membrane of thecseenm and upper portion of colon,

#9632;withtlie absence of any acute inflammation elsewhere, gave evidence of a chronic ease of hog cholera. No. 20G, though still alive, is emaciated.

The two remaining check pigs, which wore exposed with the preceding animals in the same infected pen, both died of hog cholera; ]S^To. 211 found dead June 21. The most: marked changes were a small number of ulcers on a pale mucous membrane scattered over the csecum and colon. No. 210 lived a month longer than its mate. The existence of hog cholera was demonstrated by a general necrosis of the mucous membrane of the caecum and an extensive pigmentation in the remainder of the large intestine. The lungs were adherent in {daces and much congested.

When we gather together the facts presented by this experiment we shall find a certain number of interesting c ductlons springing therefrom. In the first place, we note the peculiarity of the intestinal lesions of the two animals which died from some unknown cause, presumably not hog cholera. We next point to an additional demonstration of the specifiu nature of the bacillus of hog cholera, for out of eight inoculated four died, and the age of the, lesions corresponded well with the length of time elapsing between inoculation and death.

Those animals which resisted the inoculation were in part protected, as two among four were still alive on August 17, and the remaining two died, probably from effects of the ulceralion, months after exposure.

No. lunfiilutt (1 April :

r,. ... Kxti-'suiv Removed Dieflrrom '; _! _from |

¹ ^,lquot;.quot;'^lgt;- Infected ; intbctoit : ^laUun-nbsp; nbsp; nbsp; nbsp; nbsp;pens. I pens, j

202 IJ c. c. cultnre liquid......... May is Jtmo 21 i Died July 4.

204 ......do................\pnlV,.................j

203 '......do............................'Iquot; June 21 ; Alive Angus) 17.

212 ......do................Vpril 9 ....................j

200 I 1c. c cultnrj liquid..!......... Mai^- 1laquo; Tune 21 i Alive August II, but unthrifty.

207nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; ,1................................... ..........I Died July 18.

COS |......do................i.prill7 ...............

l;o:j '......do................ipril 8 ...............

1210 .

mi |

t213 i.

May 18 Juno 21

Died Apvil 11, hum siini- unknown disease. Du-rt .Tnly 21. of hogoholeTa. lgt;;,.il .Tune 21. of hog cholera.

Died April 13, from same disease us No.

#9632;jo;i.

These animals were one and a half months old a! ifato of inoculalion. I Checks.

Experiment!.BLaviag determined that even large doses of liquid cultures of the bacillus of hog cholera can be borne without producing the disease in most cases, it was thought advisable to make two inoculations of strong virus, a first one with a small quantity and a second with a large quantity.

i4Sraquo;

First inoculation, April L'l : Hos. 214, 227, '223, and 222 received -}_tcubic centimeter of a third culture in beef infusiou containing .1 per cent, each of peptone and glucose. The liquid was diluted with sterile salt solution, go as to make \ cubic centimeter. It was injected, one-half beneath the skin of each lliiyh. Alter waiting two weeks, in order to determine whether the inoculation had not produced disease, a second injection was practiced May 0, the thirteenth and fourteenth cultures of the same series being^- used for this purpose. The animals received 1, IS, 2, and 2.V cubic centimeters of the culture liquid, respectively. No untoward results following the injection of these large doses, they were transferred to the large infected pen May 25.

A second lot {Xos.22ß, 228,215, and 220) were treated in precisely the same way and at the same time, excepting in receiving A cubic centimeter for the first dose instead of i cubic centimeter.

No.

H'U

rst lati

[.21

nj.

Sec Enocu

ond

iulion y U.

Espos*

lire in

Infected

pen.

Time of

death.

Days after first exposure.

May 25

July

#9632;IT,

1.V

.. do ....

Jllllu

22;j

...do....

July

232

...do ...

July

226

.. do ...

July

228

...do ...

July

215

...do ....

July

#9632;it;

229

...do ...

Jimo

#9632;quot;M-

.. .It.....

A ag. Juno

#9632; Iraquo; ..

'hfcl;s.

Xo. 214, being in a dying condition July 1, was killed. In the csecam and colon were found very large, deep, blackish ulcers upon a pale mu-cosa. The case was evidently one of chronic, bog cholera. A pure liquid culture of the hog cholera bacillus was obtained from the spleen.

JSo. 227 died June 27. The lymphatic glands were deeply congested; the inncosa of large intestine was generally pigmented and covered with large blackish ulcers. Small yellowish ulcers were also found in the ileum. The points of injection were occupied by encysted, partly liqac-lied masses.

]S^ro. 223 was found dead July 2. At the points of injection encysted masses were found, the con tents of one of which were (lisch urging through an opening in the skin. The mucosa of the entire large intestine deeply congested. Scattered ulcers of varying age and size in the csecnm and colon. Bacilli in spleen.

Ko. 2.32, after a period of unthriftiuess, was found dead July 1. The autopsy revealed a chronic broncho-pneumonia, with pleuritic adhesions of right lung. The inucons membrane of the ciecum and colon, besides being studded with a large number of shallow ulcers, was deeply and unifonnly congested, the congestion involving also the lower portion of the ilciun. On both thighs an encysted semi-liquid mass indicated the seat of the inoculation.

150

Of the seflond lot, which Lad received A cubic ceutimeter of the first inocnlatioii, all succainbed to the infection.

No. 220 died .July 3. The characteristic lesion was extensive olcera-tion, together with deep congestion of the macosa of large intestine. Encysted masses tit the points of inoculation. A considerable number of hot;' cholera bacilli in the spleen.

Xo. 228 died July 13. In this animal the macosa of ciccum and colon presented acontluuous mass of necrosed blackish tissue, the ileo-ciecal valve being enlarged to twice the normal size. A few scattered yellowish ulcers in the lower portion of the colon.

iNo. 215 died July 10, probably affected in the same way, though no postmoricm examination was made.

No. 22'.) died July 27. In this case the lymphatic glands were in general deeply congested; ecchymosis beneath the serous membranes. Pigmentation of the. mucous mem braneof tbe stomach, duodenum, ileum, and large intestine from former extravasations. Several large ulcers on the valve and some others in colon. Ulcers in the cardiac portion of tbe stomach. Encysted masses at the point of inoculation.

Hos. 224 and 225 were penned with the above eight animals as (hecks. ;Xo. 225, alter being side for a few days, was found dead June 27. The mucosa of the cfecura and upper half of the colon was extensively pig-meuted and ulcerated, the lower half deeply congested. The ileum ulcerated for ä or lt;gt; feet from the valve. Many of the ulcers were so deep asto have produced inflammation of the serous membraneand thickening of the intestinal walls. The othercheck (No. 224) lived over two months after exposure, being unthrifty during this period. On j)Ofilt;-raquo;Koyfmexamination the mucosa of large intestine was considerably pigmented, and scars of healed ulcers were present. A large suppurating wound of the lower Jaw, involving the bone, may have contributed towards the fatal issue.

Experiment 8.These inoculations having failed to produce immunity from natural infection, another experiment was tried hy augmenting the dose of strong virus used for the second inoculation. ThusNos. 230, 242, 244, and 245 received each i cubic centimeter for tbe first inoculation May 27, ]So. 243 being retained in the same pen as a check. Of these Xo. 230 died of hog cholera as the result of the inoculation. The remaining three, received two weeks later, on June 10, 2 cubic centimeters each of strong virus. The cultures were prepared in beef infusion with 1 per cent, peptone. They were usually the third or fourth culture, not more than one day old. A second lot (Xos. 240, 2Ö4, 255, and 256) were inoculated at the same time and in the same way, with this exception, that the second dose was increased to 3 cubic centimeters. On June 24 all were placed in the large infected pen.

iNo. 230 died June 2, within six days after receiving I cubic centimeter of tbe culture, and as a result of the inoculation. The lesions were those of a very acute, case, engorged spleen and lymphatics, intense congestion of the mucosa of the large intestine and of the intestinal tract in general. The lungs were likewise engorged and dotted with extravasations. This animal was eating and apparently well on the morning of death. Tbe spleen was crowded with bacilli of hog cholera, and pure cultures wore obtained from it.

No. 242 died July 17. The characteristic lesions of bog cholera were found in it; extensive ulceration of thecsecum and colon; engorgement

151

of spleen ami lymphatic glands with blood. Encysted masses at the point of inoculation. Ko. Ül'-l succumbed July 9 with practically the same lesions, besides the presence of a considerable quantity of serum in the abdominal cavity.

The check to this lot died July 13. The depth of the ulcerations in the Cfficum and colon had implicated the serous covering, so that adhesions had formed between the caecum and abdominal walls. Pmictiform ecchymosis on serosa of ileum; the mucosa not aßected. The mucosa of ciccum was found completely ulcerated, the necrosis stopping abruptly at the edge of the valve; in the colon the necrosis resolved itself into large isolated ulcers.

Of the second lot, No. 240 died July 10. At the place of inoculation a firm pale yellowish mass, about 1 inch long, was found. The lower portion of ileum, the ca-cuni, the upper portion of colon, contained ulcers of different sizes. The duodenum was occluded by a clot of blood. ^o. 2Ö-4 died the same day, with lesions of a similar character. No.255 died July 20. The spleen in this case was greatly augmented in size, and gorged with blood. The, right lung was congested and adherent to wall of thorax ; considerable effiisiou in this pleural sac. The caecum and upper portion of colon covered with deep blackish ulcers. A few small ulcers in ileum.


No. 239 242 244 245 #9830;243 240 254 255 250 253	First Inooulation M:iy 27. c.c. y i i	Socood Inocnlatlon J uue 10.	Exposure in lufocted JK-It.	Time of death.	Days after liis! exposure.
		c.c.		June 21 July 17 July i)	Days after liis! exposure.
		.1 2	June 24 ...lt;lo ... .. do	June 21 July 17 July i)	15
		.1 2	do	July 13 July 10 .. do ... July 20	19 16 16 26
	1 i i	3 8	.. do .... ...il.) ....	July 13 July 10 .. do ... July 20	19 16 16 26
	1 i i	3 8	1 ¹
					1

raquo;Cljocli.

f From inoculation.

The foregoing experiments demonstrate the important fact that pigs can not be made insusceptible to hog cholera by subcutaneous injections of pure cultures of hog cholera bacteria, according to the method used by Pateur in anthrax vaccination. They show how injudicious it is to draw conclusions extending to infectious diseases in general from experiments made upon one disease only.

THE EFFECT OP FEEDING SMALL QUANTITIES OF CULTURES.

It has been already demonstrated (p. 107) that hog cholera can be produced in pigs by feeding such as had been starved for a day with considerable quantities of cultures of the specific bacteria. From 200 to 400 cubic centimeters of a beef-infusion culture were necessary to destroy the animal.

152

Assuming that small doses may produce a mild form of the disease, it seemed worth while to determine whether animals which had been fed with small quantities of culture material would resist infection when placed with sick animals in thoroughly infected pens. The following experiment shows that even after this treatment pigs are still susceptible to tlic disease;

Nos. 379, 380, 381, 382, and 370 were starved for thirty-six hours and then fed pure cultures of hog cholera bacteria in simple beef infusion. The quantities given are tabulated below. They were diluted with quot;)eef broth to facilitate feeding.


Xo. 380 :i79 382 381 370 t:;laquo;:i t3S7	A^.', January 21.	Quantity Placed in Died in f^⁰' ofculture infected infected .quot;.'., ,-\ liquid fed. pen. pen, ^J
Xo. 380 :i79 382 381 370 t:;laquo;:i t3S7	5 immths . ....do..... ....ill. .... ....do .... ....do .... 4 müntha -....do .....	c.c. I 10 Apr. 15 : .Tune 20 ; 60 20 ...ili. .... May 2-1 39 4ii ...do .... May 10 25 CO ...do .... May :;i ' 46 100 ..do ... Apr. 20* 5 .............ipr. 19 May 11 22 ...............do ... Apr. 30 11
1399	....do____ ....do .....	........... Apr. :i0 May 17 17 .............. do..............^:..........
	....do____ ....do .....

* From injury.

t Checks.

All appeared to be affected by the feeding on the following day by refusing food more or less. (Slight improvement on the second day, with the exception of 381. On the third day 3S1 still very ill. On the fourth day 382 seems more affected than 38t. Within the next few days 382 refuses food, the rest eat. In the second week they had recovered. The growth of 382 was materially checked by the feeding, so that it had not gained any weight even after several mouths.

April 15 they were transferred to a pen infected with hog cholera, in which acute cases had lately appeared. A number of check animals were transferred to the same pen soon after. The result may be briefly summed up as follows:

No. 379 began to fail from May 10 and died May 2i. Lymphatic glands generally enlarged and congested; those of mesocolon very much so. Spleen very much enlarged; quite firm. Large number of yellowish coagula iu abdominal cavity. Adhesions between Ciecum and adjacent organs. Liver very much cirrhosed; gives a gritty sensation when cut. Several deep, extensive ulcers from 1 to 2 inches across in ca;cum, involving the serous membrane. In lower colon and rectum considerable congestion and hemorrhage. Lungs normal, with exception of a few subpleural ecchymoses. Both sides of heart tilled with white thrombi. This animal, therefore, had chronic hog cholera, which, no doubt, caused the fatal peritonitis.

Xo. 382, the stunted pig, showed signs of the disease May 1 and died May 10. Very emaciated; connective tissue of body stained deep yellow. Spleen very large and full of blood. Lymphatics but slightly enlarged and reddened. Considerable yellow serum in abdominal

153

cavity. Bight heart filled with dark and washed clot. Lungs normal, excepting' a few subpleural eccliymoses. Extreme cirrhosis of liver. Mucosa of great curvature of stomach deeply congested, mncosa of large large intestine in patches.

No. 381 took sick soon after its removal to the infected pen, but the disease seemed to be mild until it was found dead May 31. Animal with a fair quantitj' of fat. Skin of ears, pubis, and throat deeply reddened. Lymphatic glands generally enlarged and intiltiated with blood. Spleen very much enlarged, but tissue quite firm. Lungs hypostatic; no hepatizatiou. Epicardinm covered with pale spots of extravasation. Liver partially sclerosed; hepatic ducts filled Avitli viscid yellow bile. Medulla of kidneys dotted with petecchise. Mucosa of large intestine. apparently normal, in the lower colon the feces are bloodstained, and occasional small clots are loosely attached to mucosa.

Xo. 370 was injured by fightingaftei being transferred to the infected pen so as to be scarcely able to stand, and died April L'O. On both hind limbs there, was extensive extravasation in the subcutis. The superficial inguinal glands were deeply congested. Spleen enlarged and congested. A moderate number of bacteria present, which are not hog cholera bacteria as shown in cultures. Left lung collapsed, reddened in part and adherent to chest wall by a plastic exudate. Centers of acini of liver deep red, tissue soft. Kidneys congested. Stomach congested along fundus; digestive tract otherwise normal. This animal died from injury to limbs and lung, and there may have been septic infection as indicated by bacteria in the spleen.

No. 380 became ill May C, died June 20. Decomposition advanced. Lungs and glands normal. Liver small, sclerosed. Superficial necrosis in ca-cuin and upper colon with cicatrices of healing ulcers.

Gelatine tube cultures from the spleens of 383, 383, and 397 showed innumerable colonies of hog cholera bacteria. Cultures from the spleen of 381 remained sterile. A larger number of cultures would probably have shown rheir presence.

As to the fate of tlie check pigs exposed with the preceding lot very little need be said.

No. 383 had been fed with 250 cubic centimeters of a beef-infusion culture of the hog cholera bacteria from Nebraska as far back as December 19. it recovered, however, after an illness of three or four days. March Itraquo; it received a tracheal injection of swine plague bacteria, without any untoward result. It was exposed to hog cholera as a check April 1raquo;, and died very suddenly May 11. It had hemorrhage in subcutis, lungs, lymphatic glands, in stomach, small and huge intestine. In the caecum there was an ulcerated patch about 2 inches across. Its base was very firm and nearly one third inch thick. Was the ulcer the result of the feeding five months ago ?

No. 387 became very dull and off feed one week after its removal to the infected pen, and died April 30, Skin of abdomen reddened. Lymphatics generally hemorrhagic. Eccliymoses on lungs. Extravasations in medulla of kidneys. Beginning ulceration in large intestine. Congestion and slight hemorrhage in fundus of stomach.

Xo. 394 died May 17 after a few days of dullness. Hemorrhagic condition of spleen and lymphatic glands. Inflammation and extravasation in stomach. Ulceration and intense congestion of large intestine. Eccliymoses beneath pleura of lungs.

No. 3Ü9 was alive and apparently well June 15. Hog cholera bacteria were found in the spleen of 387 and 3!t4, especially numerous in the latter. They were not looked for in 383.

154

There was no protecticm from the feeding of cultures even in those animals which were most severely affected thereby. There was, however, a marked difference between this lot and the check animals, in that the latter died of the most severe septiccemic or hemorrhagic type of the disease, while the former succumbed to a chronic infection. If we take the average duration of the disease in the pigs fed with cultures and those not fed, the ratio will be approximately as 19 to 8 or as 2^ to 1. These figures indicate a considerable retardation of the fatal issue, which is equivalent to a partial immunity. Another fact of importance needs to be considered in connection with these figures. Three of the pigs fed with cultures were affected with a more or less advanced cirrhosis of the liver and the post-mortem notes will show that this liver disease largely contributed to the death of the animals. An iuiportant question arises in this connection as to the origin of the cirrhosis. It may have been due to the feeding of the cultures. If so, the remedy would be as bad as the disease. lgt;ut even setting aside this possibility, the method of feeding living bacteria can only have a theoretical importance in leading to other methods. It not only scatters the living virus, but it may induce nlceratiou in the large intestine which, while not recognizable, maybe slowly destroying the animal.

INJECTIONS OV STEEILIZEB CULTUEE LIQUID TO PRODUCE laDTONITT.

Bacteriological investigations of the past few years have shown pretty conclusively that during the multiplication of pathogenic bacteria there are formed chemical substances or ptomaines which are poisonous to the animal economy. The researches of Brieger have done more than any others to conlinn this theory. It is now generally believed that it is these poisons which produce such grave symptoms in infectious diseases rather than any other vital manifestation of bacterial growth. In the spring and summer of 188(5 Sirotinin made some experiments {Zeitschrift für Hygiene, I, 463) with the bacillus of typhoid fever, in which he endeavors to show that the smaller experimental animals can not be infected by this bacillus, but that death caused by injection, subcuta-neously or otherwise, must be attributed to an intoxication caused by the presence of a ptomaine in the cultures. The results actually proved that the injection of sterilized cultures may produce death accompanied by lesions resembling those produced by living bacilli. Benmer and Peiper (Zeit sehr iß für Hygiene, II, p, 110), after a long series of experiments, are brought to the same conclusion, that the typhoid-fever organism does not multiply in the body of smaller experimental animals, that there is, indeed, no true infection, and that the severity of the symptoms depends entirely upon the quantity of culture material injected; in other words, upon the quantity of the poison or ptomaine therein contained. They also point out the important fact to which we wish to call attention, that death does not follow the injection of large doses if small non-lethal doses have been given previously, and from this fact they argue that perhaps immunity may finally be brought about

155

by the injection of sterile cultures iu successively larger doses. That the chemical products of bacterial growth may produce immunity is no new theory, but it seems to have gained ground but recently among iu-vestigators.

TESTS WITH STEEILIZED CULTURES ON PIGEONS.

In our experiments pigeons were selected at first, because more easily obtainable and manageable. Tiiey proved, however, a very good choice, since they do not take the disease readily and thus are made insusceptible by small doses of culture liquid. A culture in beef infusion, containing 1 per cent, peptone, iu which active multiplication of bacteria ceases iu a few days, is fatal to adult pigeons, as a rule, when three-fourths of a cubic centimeter is injected subcutuneously over the pectoral muscle or superficially into the muscle itself. The intra-museular injection is more rapidly fatal. The effect of these inoculations has already been dwelt upon, but it is restated here on account of the important principle involved.

The pigeon, after such an injection, may be dead within twenty-fou_rhours. The inoculated pectoral muscle is more or less discolored throughout its depth. There may be a regurgitation of food from the crop, as grains are found mixed with mucus iu the mouth and (esophagus. The injected bacteria are present in small number in heart's blood, liver, and spleen.

About one half of the pigeons do not die so soon. The bird stands quietly in a corner of the coop, with feathers raffled, wings slightly separated, and tail feathers drooping. The discharges are usually abnormally liquid, at times mixed quot;with considerable mucus. The bird usually dies within a week. The pectoral muscle will then be found extensively necrosed, the surrounding tissue very hypenemie. The injected bacteria are found, sometimes in considerable number, in the liver and heart's blood.

The rapidly fatal cases might be regarded as the result of simple intoxication or ptomaine poisoning. There is, however, some bacterial multiplication. In the more chronic cases there is an undoubted infection, characterized by multiplication of bacteria in the internal organs. Pigeons are for more susceptible in winter than iu summer, conse-queutly in the heat of midsummer the control animals occasionally resist and thus impair the value of the experiments.

The experiments were carried out as follows:

Culture tubes containing about 10 cubic centimeters of beef infusion with 1 per cent, peptone were inoculated with bog cholera bacteria and placed in the incubator at 34⁰-36⁰ C. After a certain number of days, varying from three to ten, the tubes were exposed to a temperature of 58⁰-C()⁰C. for about one hour. Inoculation of fresh tubes showed that bacteria had been destroyed. This test was always resorted to to make sure that no living bacteria were injected.

156

From 1 to 1.5 cubic centimeters of this culture liquid wore injected with a hypodermic syringe beneath the skin of one pectoral muscle. This injection was repeated ouce or twice. Some days after the last injection the bird was inoculated with living- bacteria. About :l cubic centimeter of a beef infusion peptone culture was injected beneath the skin of the other pectoral or into the superiicial layer of rauscnlar libers. The vaccinated pigeons remained alive and well; the control pigeons nearly all died. These statements are best illustrated by the tabulated results of a few experiments.

The first one. made in -lanuaiy, 1886, is given below. 'Jhe control bird and the one which bad received a very small quantity of sterile culture liquid died within two days after the test inoculation ; the rest were well more than a week later.

r.isss-m

lujectioD of

No.

amp;teif'!jzeO ( lilme i qmtl.

Cnlture

liquid con-

hiluiug

liviug

bacteria.

Remark]

!Deo.24. Jau.21. Jau.29. F.I.. C. Xotal. Fcb.13.

C. 

10nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; .4

11nbsp; nbsp; ^:.......

12nbsp; nbsp; nbsp;.......

13nbsp; nbsp; nbsp;.......

snbsp; nbsp; nbsp; nbsp; nbsp; nbsp; .8

14nbsp; nbsp; ;.......

1.5

1.5 1.5

1.5 1.5 1.5

1.5

4.0

4. r.

4.5

Well February 20. 3nbsp; nbsp; nbsp; nbsp; nbsp; Do.

Do. Inbsp; nbsp; nbsp; nbsp; nbsp; Do.

;} Died in forty-elglit hours. ,] Died in tweuty-four bout's.

A second series of injections, made to confirm these rather remarkable results, was equally unequivocal in its answer:

ri.1886.

Suliciitmifons injectiou of

No.

Sterilized caltun

Fresh cnlt-ure lilt;|uiii.

gt;. 19.

Feb. 24.

IT.

Tot:

Mar.

c.c.

c. c

03.

^:i

1 i

I'l

)

quot;1

*gt;

#9632;gt;)

quot;4

i quot;Well after several weeks. Do. Do.

I)...

lgt;o.

Do. Dead March 9. Do. 3 Remained well.

157

The third control bird (Xo. L'4) was of a difTerentrace of pigeons. A good authority consulted at the time regarded it as having some of the characters of the carrier pigeon. Leaving this aside, the result is sufficiently convincing.

In a series of experiments made more recently, cultures were used #9632;which had been concentrated by evaporation in vacuo. About 100cubic centimetersoflieef'iufusiou,containing 2 percent, peptone and one-half per cent, sodium chloride, was inoculated and kept in the incubator for five days. It was then reduced to L'O cubic centimeters by evaporation at 40deg; (J., and sterilized at 00deg; O., for three-quarters of an hoar. Subsequent inoculation of fresh tubes showed that the liquid was free from

livin

lacteria. The injections were made as usual, the needle entering

the pectoral muscle very superficially.

III.1887.

Sterilized concentrated culture liquid.

Fresh

culture.

liquid.

Equivalent

Apr.id. Ap,-,-,,;;;:;#9632;;;!;,,. a,,,-.^.

mi- fluid.

3 VVeUMaySl. 3nbsp; nbsp; nbsp; nbsp; nbsp;, Do.

:; .Sliulilly ill April ÜIJ; well May 31. ; WeUMaySl. i 'nbsp; nbsp; nbsp; nbsp; nbsp; Do.

Do .'; Died April 26, 9 :i.m. ä Died April 26, 1 p. ill. : Died April 30.

lii order to determine whether the introduction of sterilized culture liquid into the digestive tract of pigeons would be equally efficient in giving them immunity, three pigeons were fed on three days (September 8,10,13), each receiving about 30 cubic centimeters in all. The culture liquid consisted of beef infusion, to which 1 per cent, peptone had been added. The feeding was carried out by introducing a catheter into the pigeon's crop and injecting through this by means of a syringe. On September 10, three days after the last feeding, these three pigeons and two checks were inoculated with sect; cubic centimeter of unattenuated culture liquid. The three fed pigeons and one check died from the effects of the inoculation, the second check was well September 29. The blood and liver of 2so. 1 were examined by adding a few loops of heart's blood and a minute piece of liver tissue to two roll-cultures. In each about 50 colonies developed. In the liver of Ko. 2 bacteria were very

numerous

The feeding therefore had no effect whatever in confer!mg

immunity

158

IV.


ftd with Bterüizecl onltnres five days and aine days old.				Inoculation of imbeated culturo liqnid Sept. 1U. c.e. i i a i 3 i	KtMtiarkä.
Ko. i Sept. 8		Sept 10 c.e. 10 10 10	Sept. 13. c. C. 10 10 10		KtMtiarkä.
1 2 3 i	e. e. 10 10 10	Sept 10 c.e. 10 10 10	Sept. 13. c. C. 10 10 10		Dead September 17. Dead September 23. Dead September24, Died September 19. Well September 29.
s

The, protected pigeons very rarely show any signs of illness. They are as active and as eager for food as before the final inoculation. In all a small seqiiestruni is formed in the pectoral muscle, where the injection has beeu made, and this, at the end of a few weeks, is sor-roiraded by a dense membrane which seems to act as an absorbing surface for the sequestrum, ^o indication of any reaction is found on the side into which the sterile cultures are injected. The, three tables may be summarized as follows: Of twenty-four pigeons sixteen received sterilized cultures, eight being reserved as checks. Of the former none succumbed to the final inoculation; of the latter seven, or S7.5 percent.

The conclusion to be drawn from these experiments is obvious. The birds are protected by the injection of sterilized cultures so as to resist a fatal dose of living bacteria. The sterilized cultures contain only the products of bacterial growth. Among these the ptomaine-like bodies some of which we now know, owing to the researches of Eriegerare very likely the agents that produce immunity.

In the pigeon the mode of infection before and after vaccination is probably as follows: The injected bacteria multiply very actively in the muscular tissue; the ptomaine there produced may enter the circulation in quantities largo enough to produce speedy death. If the animal resists for a time, the absorbed ptomaine reduces the vitality of the tissues to such a degree that bacteria, entering the circulation, begin to multiply in the internal organs. The, additional quantity of ptomaine thus produced finally kills the bird.

When ptomaines in culture liquids have been previously introduced the first shock caused by the local production of ptomaines in the muscular tissue is overcome. The bird resists successfully general infection until the bacteria have been destroyed locally. The, process is then checked, and the sequestrum in the muscular tissue becomes encysted.

It has already been stated (p. GO) that rabbits, mice, and guinea pigs are very susceptible to the inoculation disease, a millionth of a cubic centimeter of culture liquid being sufficient to cause a fatal issue. Experiments like those on pigeons were made, upon rabbits with slightly larger doses, but no iiiiiuujuty was gained thereby. The rabbits succumbed invariably fifter jnoculatioin (Seo report of Department Agricult-urc for 18SG, p,

159

637.) Iu the light of later experiments* made in Pasteur's laboratory, the failure of the method in case of rabbits must simply be ascribed to the small quantity of culture liquid used. In the experiments there recorded from SO to 120 cubic centimeters of culture liquid were required to protect guinea-pigs from malignant oedema, while in our rabbit experiments oiily 5 to G cubic centimeters were used in all. We did not delay, however, with the further demonstration of this principle upon small animals, and applied it experimentally to pigs. The quantities injected were not sufficient, however, and the animals took the disease, as the following experiments show:

TESTS WITH STEEILIZED CtTLIUEES ON PIGS.

Experiment 0.In order to test the effect of heated cultures upon pigs, the following experiments were made March 1: Two animals (Xos. 1G2 and 173) received hypodermically each 9 cubic centimeters of a second and third culture, twelve and thirteen days old, respectively, which had been devitalized by heat. March 9 a second dose of 9 cubic centimeters was ftiven in the same way, using a fifth and eighth culture eighteen and fourteen days old, respectively. These cultures were made in beef infusion containing 1 per cent, peptone, excepting one, which contained about 2 per cent, of blood serum in place of the peptone. After the second inoculation of Xo. 102 a swelling appeared on one side. Both were fed with viscera infected with hog cholera, and placed with sick and dying pigs in a largo infected pen. 'So. 102 was found dead March 29, and Xo. 173 April 5. The appended table and notes give a summary of the experiment:


Xo.	Mar. 1. JIar. 9. Total.	Fed. Died.	Xo. of davM after feecl-
j 1 c. e. c. c. c. c. 1(12 \| 9 9 IS 173 9 9 18		Mar. 19 Mar. 29 Mar. 19 Apr. 5	10 IT

^o.l02. Subcutaneous fatty tissue much reddened. Mneous membrane of stomach considerably ulcerated: mucous membrane of small intestine deeply congested. For 8 or 10 feet above the ileo-csecal valve the mucous membrane of ileum is completely necrosed. Large ulcers in Ciccum and upper portion of colon.

[No. 173. Subcutaneous fatty tissue slightly reddened. Petecchise under pulmonary pleura. Extravasations under serosa of csecnm and colon. Inflammatory adhesions of large intestine with walls of abdomen. A patch of extravasation beneath peritoneal layer of dorsal abdominal wall nearly 2 inches across. Spleen very much enlarged and softened. The mucous membrane of large intestine and several feet of ileum necrosed ami breaking down. Fundus of stomach deeply congested.

This experiment clearly showed that this method was no protection to the animal when the latter was infected by feeding,

'Jinuihs de VInstUiit Pasteur, December, ,1.^87; January, 1.88S.

1G0

It now became necessary to determine whether this method would confer immunity upon animals simply exposed to the disease by cobab-iting with diseased animals in infected pens. Observations made upon other diseases by investigators, and by us upon this disease, seem to lead to the inference that it frequently depends on the quantity of virus introduced into the system whether the disease will make its appearance or not. In feeding, this quantity is considerable; in simple exposure in infected pens to diseased pigs, the amount of virus taken into the body with the food and drink is necessarily in small and repeated doses. The following was therefore planned :

Erperiment 10.Four pigs (Sos. 103,164, 177, and 196) were inocn. lated March 13 with heated virus, each receiving l.l cubic centimeters beneath the skin of each thigh. The cultures in beef infusion with I per cent, peptone were about fifteen days old when heated. The second inoculation was made March 10 from a culture in an Erlenmeyer flask about eleven days old, and containing about 50 cubic centimeters of culture liquid. Each animal received 10 cubic centimeters as before.

March 'M these animals, together with two check pigs (Xos. 195 and 201), were placed in a large infected pen. Within a period of three weeks from this (bite at least fifteen pigs died of hog cholera in this pen. The two check animals died on the l-lth and 19th of April, respectively. Of four vaccinated animals only No. 103 showed signs of the disease and gradually developed into a chronic case, dying of general debility on May 1. The three other vaccinated animals remained apparently well for months after, although constantly exposed to the disease in the infected pen.

Vaccination.

X...

Exposure. Died.

Kuxnber days after exposure.

Mar. 13 Mar. 10

_ _

103nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; !gt; ^: 10 I. Mar. ?1 May 1 Thirty-ore days.

III!nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; i) inbsp; nbsp; nbsp; nbsp; nbsp; 10 ....................j

177nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; ö io Mar. 31 July '2'1 ' Three months and twenty-three days.

190nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; !} ; 10 ..laquo;In.... July 7 Three months and seven days.

195.......................do___ Apr. 19 ^: Nineteen days.

201 i..........:.............itraquo;___ Apr. 11 , Fourteen days.

Autopsy notes.No. 103. Spleen not much enlarged; texture firm; effusion into pericardial and thoracic cavity: lymphatic glands enlarged but pale; two ulcers in stomach; small intestine normal; mucosa of Ciecum and colon studded with many extensive and deep, yellowish ulcerations. On cover-glass preparations of the spleen only a few bacteria could be seen. Two liquid cultures inoculated from the same organ remained sterile. No colonies appeared in the gelatine tube inoculated with blood from the heart. A few developed in the gelatine tube inoculated from the spleen.

No. VX). .Spleen greatly enlarged; gorged with blood: very friable; shreds of afibrinous exudate on serosa of intestines; much serum in abdominal cavity ; petecchhc on epicanlium of auricles ; small ventral lobes of lungs hepatized; mucous membrane of gal! bladder ulcerated;

extensive ulceration and iiifliunmation of mucous membrane ofca?ciiin and colon. Hemonitagic inflammation of kidneys.

No. 201. Spleen but slightly enlarged ; lungs extensively hepatized ; intense congestion and commencing nlceration of the mucosa of large intestine ; stomach and portion of ileum similarly congested. Though no bacteria were found on a cover-glass preparation, a pure culture was obtained by carefully dropping a piece of spleen tissue into a culture tube. This was tested on gelatine.

After apparently resisting the infection for several months, the remaining pigs (Fos. 164,177, and I'.tO) were transferred to a clean pen. jSo. 177, not very thrifty, began to decline, and finally died July 23. Among the most prominent lesions were a plastic exudate on the epicardium and numerous large old ulcers in the large intestine. The mucosa itself was extensively piginented. No. 196, on removal from the infected pen, seemed in good condition, but it died July 7, after some days of unthrifty condition. In this case, the mucous membrane of the large intestine was piginented and there were what appeared to be cicatrices of old ulceratious. In all of the large serous cavities there was considerable effusion, lu cover-glass preparations of the spleen there were no lieg cholera bacteria to be seen, but numerous bacilli resembling those of malignant (edema.

Experiment II was made in the same way upon Kos. 107 to 200, inclusive, and Xo. 157. March 24 each animal received in the thigh about 10 cubic centimeters of a mixture of heated cultures in beef infusion with 1 per cent, peptone about fourteen days old. March 29 an equal amount was injected, one-half into each axilla, these cultures being about fifteen days old. These animals were kept until April 20, when all but Xo. 157 were placed in the large infected pen. From that date on pigs died almost every day of the disease, so that the infection must have been quite thorough. Unfortunately no check animal was exposed at the same time. In these animals the slight swelling at the seat of inoculation disappeared in a few weeks.

They remained well, with the exception of Xo. 199, which became emaciated and was found dead May 11), about one mouth after exposure. The three remaining animals were apparently unaffected nearly two months after exposure. At this time No. 107, which appeared rather thin, was killed, to determine if any ulceratious were present. But the mucous membrane of the intestine was entirely normal, with no indications of former ulceratious.


	In	i'	ction oI'Ih virus.		iteil
No.						cxposnro.	Bemarks.
	M	a	. ^4	Min	. 29
197		c	10	c	c. II)	Apr. LO	Killed June 10; healtliy.
1S8			10		10	...do ...	Well June 1quot;.
199			ID		10	...do....	Died Mav 10.
200			10		10	...do...	Died July 13.
137			10		10	Mii.v 25	Died June 28.

1ÖC12 n c

-11

162

Autopsy.Xo. 109. Slight extravasation in sulu-iitaiiooiis connective tissue. Spleen somewhat enlarged jfllled with bio oil, friable; considerable eiJusion in peritoneal cavity. Eight lung in part hcpati/ed; pleuritic adhesions to chest-wall; hemorrhage in and about pelvis of kidneys; lymphatic glands purplish; extensive and deep ulceration of the mueosa of large intestine.

Pig 1⁽J7, killed for examination, was very aiiiemic. There was some pale sernin in abdominal cavity. Tbe kidneys and lymphatic glands showed evidence of chronic inflammation. The lungs were exceedingly pale. Xo evidence of inflammation or ulceration in any portion of the intestinal tract.

It must be borne in mind that these animals were constantly exposed for a period of several uionths to the virus of the disease, and that a continual struggle between the organism and the invading parasites must have- been going on, which naturally would lend to lower the vitality. Such severe conditions as these arc probably never realized among herds.

quot;The later history of Xo. 20!) does not, however, bear out the tirst supposition that complete immunity was attained. After being continually exposed in the infected pen from April 20 to June 21 it was removed to a clean pen, where it continued to grow very weak. Jt died July 12. The autopsy revealed a plastic pleurisy over the right lung aud a tibrinous exudate upon the epicardium. The mueosa of the csecnm was extensively necrosed ; in the colon the ulcers were isolated : the solitary follicles were very prominent. A small bit from the epicardial exudate was placed beneath tbe skin of two mice. One of them died on the eighteenth day. The spleen was greatly enlarged. Numerous hog cholera bacteria were present in this organ aud the liver. The epicardial exudate of the pig must have contained but very few, for they could not be demonstrated in cover-glass preparations. The long period of time from the inoculation of the mouse to its death is also evidence of a very small quantity of virus.

No. 157, inoculated with the rest, became quite lame in the hind limbs, so that it was thought best not to expose it to the disease in the infected pen for tbe time being. It soon recovered its power of locomotion, aud was transferred to the infected pen May 25 and removed therefrom June 28. In the new pen it grew rapidly weaker, and died June 28. On postmortem examination the right lung was found entirely hepatized and adherent to the chest-wall. The mueosa of ca'cum and colon was studded with large ami deep ulcers; that of the fundus of stomach was deeply congested.

Experiment 12.It became desirable to determine whether repeated subcutaneous injections of heated cultures, until a large amount had been introduced into the system, would be more efficacious in producing immunity. For this purpose the culture liquids were concentrated, by using a 2 per cent, solution of meat extract with 2 per cent, fieptone for some of the injections ; for tbe remainder a 2 per cent, solution of

163

peptone in beef infusion. The eultiiies were made in Erlenmeyer flasks, plugged with cotton wool.

The table given below gives tbe date of the injection and the quantity used each time. It will be noted that Nos. 191 and 194 received two, Xos. 21(5 and 21S three, and Nos. 217 and 221 four doses each of the heated culture liquid. The injections were made two days apart, the exposure in the infected pen and among'diseased animals about one week after the last inoculation. 2s^Tos. 220, 232, and 235 were placed in the infected pen at the same time, to determine tbe virulence of the infection upon pigs which had not received any injection.

Soatod virus

No.

Total.

Bumarka

Apr:20. Apr. 22. ^pr. 24. Apr. 26.

210

217 218 221

li)l Mil '220 *2T.' raquo;2:raquo;

C. (:.nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; C. C.nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;C C.

7J ;......... i Hi May}...nbsp; nbsp;Died May 17.

7inbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;8 ,nbsp; nbsp; nbsp; nbsp; 1121 ...ilo ....nbsp; nbsp;Dii'il -May li).

7J ;.........nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;21i -..(1.1....nbsp; nbsp; nbsp; nbsp; Do.

7*nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;Snbsp; nbsp; nbsp; nbsp; nbsp; nbsp; :i2J ...do....nbsp; nbsp;Di.il May 2;i.

10 10

8nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; 18 ...do.... Do.

8nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; IS ...do ....nbsp; nbsp;Died May 19.

...................do___nbsp; nbsp;Dii'il May 17.

..................do...nbsp; nbsp; nbsp;Diiil May 2:1.

------- ............do...nbsp; nbsp; nbsp;Died Juno 12.

Checks.

All of the inoculated and control animals died with periods ranging from thirteen to nineteen days, only one living thirty-nine days, and this one a control animal. Of those that had received two doses, Xo-1!)1 died May 23 (nineteen days after exposure) with considerable ub ceration in ca'cnin and colon. No. 194: died May 19, with extensive and deep congestion of the lymphatic glands in general, of the kidneys, stomach, and large intestine. In the latter, nlceration was not yet begun. Xo. 21(5, which had received three doses, died very unexpectedly thirteen days after exposure. The lesions were of the bemorrhagic type, involving extravasations and ecchymoses of the intestinal tract, more especially of the large intestine, heart, lungs, lymphatic and subcutaneous fatty tissue Ulceration in largo intestine very slight, the congestion being intense. No. 21S, treated like the former, died fifteen days after exposure. Tlur lesions were like those of Xo. 210, but not so severe. Ulceration as yet very slight.

Xos. 217 and 221, which had received four injections, died fifteen and nineteen days after exposure, respectively. The lesions in Xo. 217, which died very suddenly, were bemorrhagic in character, the, ulceration in the csecnm and colon being quite superficial. In Xo. 221 the nlceration was more pronounced, the general congestion and extravasation much less so.

1G4

Of the coutrol auimals the lesionsof No. 220 wereof the hemorrhagio typo, resembliug those of No. i!'4 very closely. In No. -'.'ü tberc was extensive ulceratiou of the mucoas meiabrauc of the large intestine. In No. 235, whicL lived for thiitynine days after exposure, the mneosa of the cjecuna and upiier portion of the colon was involved in complete necrosis nearly 5 millimeters thick. Jieyond this the necrosis took the form of isolated ulcers. (Iwing to i be depth of the ulceratiou intlamina-tory adiiesions had formed between the caecum and adjacent organs. There was no leaetionary swelling of the inoculated animals at the point of injection.

Those animals in which the disease took the hemorrhagic type succumbed very suddenly, as if the invasion bad taken place In a single day. In those auimals in which symptoms of weakness and loss of appetite appeared some days before deatb the well delined lesions were as a rule limited to the large intestine in fbo form of ulceratious. The former cases represent a class in which the bacilli invade the entire. vascular system ; in the latter the absence of a general congestion and extravasation seems to indicate a more local multiplication of the spc-eilic disease germs in the intestinal tract.

This mode of vaccination, as shown by the results recorded, did not prove to be any protection to the animals, as they died, most of them, within a brief period after exposure from a very acute attack of the disease.

The spleen examined in about one-half of these cases contained the bacillus of hog cholera, usually in large numbers. From a few⁷ cultures were made which were found pure.

Experiment 13.A final experiment was tried in which each animal received hypodermicall.v iO cubic centimeters of heated culture liquid in two doses. The cultures were made in beef infusion with 1 per cent, peptone, the growth being killed by a temperature of 58deg; C. the third day after inoculation. The flasks used were shaped like Krlenmeyer tlasks, a glass cap being fitted over the flask by means of a ground-glass joint, which contracted into a straight narrow tube plugged with glass wool. The removal of a cottonwool plug was thus avoided, the cap being removed for inoculation. This culture flask affords better ventilation and a more rapid evaporation of the culture liquid than does the culture tube with the bent ventilating tube.

16;')

Tho followiug table gives ail the facts necessary fot an auderstand-

iiiigt;' of tbc experiment and its results:

Heated viriia

Espos-ore in

infccteil pens.

Uomarts.

Days after fii-st exposure.

Total

Juno 14. June 17


	e c.	r. c.	r. c.
LMl	20	I'll	40 Juno
JX1	13	^(1	33 . i'h)
206	20	20	40 ..do
230 .			........do
JtiT	:io	1^0	in ...illt;gt;
208	20	^0	Id .ili)
260	#9632;_gt;o	-1)	(Ü ...do
270 .			..........^llquot;
			* Checks.

uieil July 7.. Died July ll .

.. ilo .......

Died July 8 . Died Julj 0 . Died July 10

IS 18 IT 15 IS 10 18

Hied Jlilv i).

it will be seen that all the experimenta

ininials died, inoculated as

well as cheek animals, within a few days o

one another, death taking

place about sixteen to eighteen days after the first day ofquot; exposure. A brief synopsis of the^osi mortem appearances will not be amiss in this connection.

In No. 231 the spleen was very much enlarged and gorged with blood. The intensely congested mucous inembrauc of the Cfecum and colon was dotted with small snperlieial nlcerations. In No. -X) the congestion ot spleen, and ulceration with congestion of the large intestine, were also marked. TSo 2(gt;(j presented the same lesions. The ulcers in the ca'cmn were fron one-quarter to one-half inch across No. 230 (check) differed from the preceding cases in presenting severer lesions, greatly enlarged and congested spleen and lymphatic glands, superficial necrosis of the entire colon and great thickening of the walls, extensive extravasation of blood beneath the inncosa of (luodenum.

Of the second lot of four, treated in the same way, No. 267 presented very severe lesions, consisting of intense congestion and extravasation, involving the spleen,lymjthatic glands, lungs, and kidney. The left lung was adherent to costal pleura. There was considerable hemorrhage in the pelvis of both kidneys. The large intestine was least changed, the inncosa being slightly ulcerated mid containing some liemorrhagic spots and points. This animal was first to die ont of this lot of eight. In No. 208 tho congestion involved the lymphatic glands generally and the mucosa of the large intestine, which was extensively necrosed in its npper portion. No, 269 resembled No. 207 In the severity-of the lesions. The lungs were not affected, however, while the ulceration of ctecnm and upper colon was very extensive and deep. No. 270 (check) presented extensive ulceration of the large intest ine and a greatly enlarged spleen. In live eases the spleen contained the bacteria of hog cholera more or less abundantly. In two none could be seen on one or two cover-glasses. No local swelling had developed at the points of injection in any of the inoculated animals.

The quantity of culture liquid in these cases was likewise too small to have any beneficial effect. Experiments are now being prosecuted in

1GG

the stimo dircctiou lgt;,v injectiug very large quantitics. These arc, however, not completed.

The experiments on the u-se of sterilized cnltures have thus not become practically applicable as yet. The great importance of this principle, however, has been duly appreciated within the past year in foreign countries, notably in France, where experimentation of this kind has been carried on by pupils and assistants of Pasteur. The principle is destined to be serviceable in other infectious diseases, and may eventually take the place of the older methods of Pasteur which utilize attenuated cnltures of bacteria. These are often sufficiently virulent to destroy slice]) (anthrax), and in this way may themselves become the agents that distribute the disease. For this reason anthrax vaccination is only practiced in those regions where the disease is more or less endemic, and where the losses exceed a certain percentage each year.

Chantemesse and Witlal* have recently endeavored to set aside the claim of the Bureau of Laving first demonstrated this principle, in favor of the more recent researches made in Pasteur's laboratory, lliippet has, however, shown the absurdity of this claim in pointing to the experiments of the Bureau as having been published nearly two years prior to those of Ghamberland and Koux.

' Anmles de I'IhsHIiU I'aateur, February, 1808. \ Fortochritle der Mediulraquo;, 1888, 28⁽3.

EXPERIMENTS ON THE ATTENUATION OF HOG CHOLERA BACILLI

BY HEAT.

Heat has been used by Pasteur in the attenmtiou of anthrax vims by exposing cultures of anthrax bacilli to a temperature of 42deg;13deg; 0., continuously for a certain number of days. Cultures kept in a tliermo-stat at this temperature for about tliirty-one days were so attenuated that they were incapable of destroying' animals larger than very young mice. Kept in the same, conditions for only twelve days inoculation i'ailed to destroy adult guinea-pigs.* The former culture was denominated the first, the latter the second vaccine. To make sheep immune they were inoculated subcutaneously with the first vaccine, twelve days later with the second vaccine. Subsequent inoculation with strong virus bad no effect upon the vaccinated animals, although it was quite invariably fatal to those which had not been so treated.

Although Pasteur's discovery must be considered a scientific event of great importance, its practical application is by no means a perfect success. Experiments conducted by Koch, Gaflfky and Loftier, in Berlin, have shown that the process of attenuation docs not always go on uniformly, and that the strength of the vaccine can not always be relied upon. A few animals may die as a result of the first or second inoculation. This fact induced the last International Congress of Hygiene at Vienna to adopt the resolution that anthrax vaccination should not be practiced upon sheep in any locality unless the disease causes a loss of 2 to 3 per cent, annually. It was also shown in the experiments at ßerlin that immunity after vaccination is not absolutely perfect when the virus is introduced with the food. This is perhaps the most common way in which infection takes place.

The results obtained by Pasteur are sufficiently valuable to make it at least desirable to try heat attenuation for other bacterial organisms, although it does not follow by any means that the same process will suffice for all or even a small number of disease germs, for these differ among one another very widely.

Kitt* has tried heat in the attenuation of the virus of Black Quarter in Germany by exposing the diseased muscular tissue, which had been thoroughly dried in the air and ground to a line powder, to the steam of boiling water at 100deg; 0. for four, live, and six hours continuously. The spores of the bacilli of this disease were sufficiently attenuated after a six-hours' exposure that sheep inoculated with the powder in certain doses remained well after inoculation with strong virus. The reaction

* Campt, rfinl. .laid, ffes Sciences Maroli 21, ISÖt. 'Centralbl.f. Bakteriologie und Pwasitenkunäe, 1888, i. 571.

Iü7

168

tit'lel' tlie Vacctnal ttiocttlatiou was very slight. Uoj;' cholera vims is destroyeil by a fifteen to twenty miuutes' exposure in a water-bath at 58deg; 0.; a inonientaiy contact with boiling water Is suflicient to destroy it, so that ivitfs method is not applicable to it, but only to bacteria which form spores.

The following experiments were undertaken with a view to test the method of Pasteur on hoy cholera bacilli, and to obtain, if possible, a vaccine similar to that employed in the prevention of anthrax. Although only a preliminary step has been taken in this mutter, and the promise of favorable results is not flattering, we consider it best to publish the results thus far obtained.

The first step in the process was to obtain, if possible, a cultivation which should prove harmless to rabbits. This was to be accomplished by placing tubes in a thermostat, kept at a certain fixed temperature as nearly as possible, and inoculating rabbits from time to time to determine any diminution in the pathogenic activity.

Aprild, 1888.Four Salmon tubes of beef infusion peptone were inoculated from an agaragar culture of bog cholera bacilli two weeks old and placed in a d'Arsonval thermostat, the internal temperature of which registered between 42deg; and 43deg; C Two series of inoculations were made on rabbits, one from one of the original liquid cultures at different intervals, the other from a culture renewed at the end of every five days by iaocnlating a fresh tube. The result is most easily under stood by examining the following table:

A'jar culture.

Apr. 0. b. i.p.*(a).

Apr. 14, b. i.p.(ai).

.Apr. 11raquo;, rabbit iuoculatod Apr. 25, died.

Apr. 10, b. i.p. (a.,).

Apr. 10. rabbit Lnoculatei Apr. 24, died.

Apr. 24, b. i.p. (aa)

Apr. ;J0, r.tbbit. May 4, died.

Apr. :i0, 1p. i.p. (ai).

Apr. 30, rabbit. May rgt;. died.

May I, b. i. p. (at).

May 9, rabbitnbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;May 0, b. i. p. (alaquo;).nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;May 0, rabbit.

May 18, died.nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;May 16, died.

' Beef inluaioti plus 1 jut cent, peptone.

169

Tlie first inoculations were made April lit, with culture laquo;, whicb liad Leen in the tliennostat tin laquo;lays, nzd cnlturo Oi, which Lad been freshly made on Aprill4. Jjoth rabbits received about ^ cubic centimeter of the

culture liquid bypodemically. Rabbitlaquo;! died in live days with extensive coagulation necrosis in liver and enlarged spleen. Eabbit a died on the following-day with the same lesions, in both hog cholera bacilli were very numeioiis on cover-glass preptiratious of spleen, and obtained pure in cultures. The same results were obtained i:i all subsequent cases, so that no farther mention need be made of this.

Two rabbits were inoculated in the same way April 30, one from the original culture a, the other from laquo;,. Both died May 4 and 5, respectively. Lesions the same as with the first pair.

Two rabbits weir inoculated May !raquo;, one from the culture a, now thirty days old; the other from a_:,, the fifth renewal of a. Both rabbits died on the 7th and the 9th day, respectively. The lesions were practically the same, with the addition of slight hemorrhagic lesions in the intestinal tract. Tbc period of the disease was slightly prolonged.

The result was not very satisfactory. If any attenuation was going on, its final attainment would demand too long a period of time. The experiment was therefore stopped and auotber undertaken. The temperature of the tliennostat was raised to lö⁰ 0., to hasten the process of attenuation.

Apr. 23. agar cnlturo. May 12, b. i. p. (b).

May 22, rabbit Inoculated. May 17, b, i. p. (Ii¹)

May 20, died.

May 22, b.i.p. (braquo;).

It was found that cultures inoculated from b failed to develop at the assigned temperature, so that tbis experiment was not continued any farther. It deserves to be mentioned, however, that a rabbit inoculated from the original culture, which bad been kept at itP C. for ten days, died seven days alter inoculation with enlarged spleen and coagulation necrosis in liver.

170

A temperature of 434-44deg; C. was next chosen and llie experimentcpa-dacteii in the same manner, as the appended table will show:

(1031).)

May Ifi, oik'i- i alfuro.

May 2n, b. i. p. (a) (43.5⁰-44lt;¹ C.)

Juuo l. b, i p. (a.)

June 8. rabbit. Juno 14. dead.

Juno 8. ralil.it. Juno 15, dead.

.JiincS. b. i. p. (fails tc cruw).

June 18. rnbbii. Juno 23. (had.

Juno Ki. b. i. p, (aj).

June 18, rabbit.

June 24. ilc ail.

Jane 18. b. i. p. (a^).

Juno 28, rabbit. i ßemaiua alive.¹(Calture dead.)

June 28. ralilij, July 5, dead.

Jinn' 23, b. i. p. (ai).

iSupposed iinjmre,

but found pure.)

Juno 2.^, sninea-pig. July 10, laquo;cad.

Juno 28, b. i. p. (a.i).

July 10, rnbbil. July tO.rabbit (Remainsalire.) (RcTnatna alivo i

May 10. (iyoy culture. MaySfl.b.i.p. (b) (43JO-4/OC.)

.Inly U. placed a I 30^o-3no C.

July in.b.i.p. (a,,). (Culturo dead.)

July 25,rabbit July 30, dead,

A ugust 0, rabbit.

'Keniiiin.s well.)

An^iist 4. b. i. p. (Sterile.)

171

The rabbits inoculated from tlie original culture after reniainiiig at the temperature of 43.5^o-44⁰ 0. for ten ami twenty (lavs died from the inoculation disease, but those inoculated from the same tube, after thirty and forty-three days, remained permanently well. This was not due to an attenuation of the culture, but to its death. Turning to the series of rabbits inoculated from the cultures renewed every five or ten clays, those receiving culture liquid ten, twenty, and thirty days old died from the inoculation disease, while one inoculated after forty-three days remained alive, because the culture was dead, i. c, it failed to fertilize fresh tubes after repeated inoculation. An adult guinea pig, inoculated from the same culture material, thirty raquo;lays old, died in twelve days as a result of the injection. In this ease only a few drops had been injected. This experiment demonstrates that in general the pathogenic power of hog cholera bacilli is onlynbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; .

destroyed by the death of the organisms themselves. This is a very important fact. It will be remembered that in the attenuation of an-thrax bacilli their virulence was gradually diminished, ami a time was reached when they failed to kill all but mice, while they still retained the power of multiplying in nutritive liquids. In the above experiments even guinea-pigs, which are less susceptible to this disease than rabbits, died twelve days before the culture was found dead. The latter may have been dead some days before this, for no tests were made meanwhile.

This fact has an important bearing upon the nature of the pathogenic activity of hog cholera bacilli. It shows that there are two elements involved, (1) the ptomaine action of the organisms; (2) their mechanical effect. That there is a ptomaine action of these bacilli has been conclusively proved in the experiments of the Bureau made upon pigeons several years ago. But this ptomaine action is evidently secondary to the mechanical effect of the bacilli in forming plugs or thrombi in the blood vessels and thus causing destruction of tissue by impeding the circulation. This tendency to act mechanically is not lost as long as the bacilli are alive, as shown by their fatal effect on rabbits and guinea-pigs shortly before they themselves are destroyed.

At the temperature employed (43.0deg;ti⁰ C), the original bouillon-peptone culture (( died between the twentieth and the thirtieth day afler the beginning of the exposure. The culture from this, renewed at the end of every fifth or tenth day, died between the thirtieth and forty-second day. Another culture b (see table), which had been removed from the thermostat after the forty-sixth day and kept at the temperature of the laboratory (about 30^o-,'53^o C, during duly) was still fatal to a rabbit on the fiftyserenth day. Another rabbit, inoculated ten days later, remained well, and a fresh culture made at the same time remained sterile, showing that theapparent immunity of the rabbit was duo to the death of the bacilli injected. This experiment also shows pretty conclusively that the pathogenic power of these specitic organisms expires only with their life, and not long before.

172

It is evident from our own experiments, and more recent ones nmtle in France and Germany, conducted on tlie same lines, that the amount of immunity which we may expect to gain from preventive inoculation will depend on the quantity of ptomaines produced by the specific microbes i. e., upon their poisonous nature. !n other words, our success will depend upon the relation borne by the ptomaine to the disease process. If this factor is very great it is highly probable that preventive inoculation either with ptomaines or with attenuated cultures will be successful. But if there is in addition a mechanical element, which may or may not overshadow in importance the ptomaine element, the problem is not only complicated, but may fail.

There are two other points in connection with these experiments which demand attention. One is the variation in the length of life of the different cultures exposed to the same conditions. This would be a serious hindrance in obtaining vaccinal cultures of uniform strength, should this method ever prove successful.

There was a noticeable change in the appearance of the serial cultures after a sojourn in the thermostat. There was a tendency to multiply rather more abundantly, to grow in minute flakes and to rise to the surface to form a thin, unbroken membrane. The motility was somewhat impaired after a time. These changes gave rise to the suspicion of impurities, but tests on gelatine plates showed that the suspicion was unl'onuded. These experiments will be continued on pigs under similiar conditions to determine whether any immunity can be produced by this method.

HOG CHOLERA, OK DISEASES CLOSELY ALLIED TO IT, IN OTHER

COUNTRIES.

OBEAI Til? ITAIN.

This disease was first detected in 1802, where it has been known under various names, the most common of which is swine fever. Owing to the fact that there are recognized at the present time three distinct in-lectious diseases of swine in diflferent parts of Earopeand America, it is impossible to state whether the disease known as swine fever in England represents two distinct maladies, hog cholera and swine plague, or hog cholera alone. This question can only be solved by a thorough bacteriological investigation, such as lias not been made there in very recent years. There is enough evidence, however, to warrant the statement that hog cholera is prevalent in (heat Britain. There is, on the other hand, no experimental basis for the statement that the other disease, swine plague, also exists there. Those two diseases produce lesions of the large intestine, so easily confounded with each other, that great care must be taken in making a diagnosis. We must also consider that the three well-marked swine diseases now known as hog cholera, swine plague and rouget, were only a few years ago regarded as one disease designated by a great variety of names; that even today no clear idea exists among most pathologists as to what the precise differences between these diseases are.

In a brief report on swine fever in Great Britain, by Professor Brown, of the Agricultural Department, in 1886, we do not notice that any doubt exists in his mind as to the oneness of the disease in Great Britain and its identity with hog cholera. He e\ en reproduces a plate from the report of the United States Department of Agriculture for 1885, in which the characteristic ulcers of hog cholera are shown as an illustration for his text.

That there may be several diseases included under the term swine fever is evident from the statements made in this report concerning the annual importations of diseased swine, from other countries. Swine fever is said to have affected animals imported from Holland, Denmark, Sweden, Norway, and the United States. Now, hog cholera appeared in the North European countries for the first time in 18S7. The swine marked diseased may have been affected either with swine plague, which exists ou the Continent, or with lighter non-infectious forms of lung disease not uncommon in pigs at any time in the year.

173

174

We quote from Professor Biown'.s report those parts which may prove tuteresting to American readers, using the language of the report itself wlieuever possible:

Symploms of steine fero-. lt is most important that the farmer should be acqualuted with the signs which indicate the existence of swine lever at the earliest period of its development; but unfortunately the disease is very difficult of detection in the early stage in the greater nuniber of eases, and the syiiiptoins which are generally believed tobe specially indicative of the affection, viz., redness of the skin on certain portions of the bodj¹, and diarrhea of a peculiar kind, do not appear until the disease is fully developed, and in numerons instances are not observed at all. The animals feed fairly well, show no rise of temperature; they are vigorous, and for several days, and even for several weeks, betray in no way the disease. It requires very careful and prolonged observation to notice that at one time or anotherat any rate at rare intervalsthe swine have a short cough, not an important departure from the healthy state. Very few experts, to say nothing ofthe owner of the pigs, would suspect swine fever because lie happened to hear the animals cough at rare intervals; and there is in these mild cases, which Dr. Klein considers constitute the majority, absolutely nothing else which would be noticed: the skin remains quite, free from any appearance of disease, it is true that the inguinal glands are distinctly enlarged, but unless the owner thinks of inspecting these small lymphatic glands (kernels) under the skin of the pig's groin, and knows what their proper size is in health, lie has no chance of recognizing the disease in this obscure form. In the organs of those apparently healthy pigs there are found on dissection very pronounced symptoms of disease, so pronounced in fact, that it seems astonishing that during life the animals presented such slight signs of it. And these very slight signs, it may be remarked, were only noted by the observer in the cases of pigs which were under constant observation after they had purposely been infected with the disease.

Swine which are affected with swine fever in the occult form may be moved about freely, sent to market, bought and sold over and over again, distributing the infection wherever they go, without exciting the least suspicion in the minds of those who buy or sell or keep them that they are infected with a deadly and highly contagious disease, and in this way many outbreaks may occur without the origin ofthe infection being discovered.

In the more pronounced forms of swine fever the symptoms which are shown by the sick animal will not be very definite until the affection is fairly advanced. Dullness and diminished appetite, with hot skin and occasional shivering fits, with rise of internal temperature from the normal 103deg;to 105deg; or JOG⁰ F., are among the first signs of infection, and should always be taken as justifying a strong suspicion of the existence of swine fever, especially If the disease is known to be in the locality.

It has been remarked that pigs when suffering from swine fever in the early stage often seek to hide themselves beneath the litter on the floor of the sty; but this action is so common among swine that it would hardly lie likely to attract any attention, and even when noticed it would not he looked upon as a symptom of any disease. There is, however, to the practiced eye a great difference between a healthy pig, which, in its desire for warmth, or quiet, or for some other reason, buries itself uuder n lot of litter, and one which pevfonus the same act in obe-

175

(lience to the iustinctive effort of a sick animul to get out of the way of tlio light and its coinpamous, and everytblug ander the sun, anil suffer in seclusion. The healthy i)ig when disturbed emerges from its retreat alert and ready Cor action. The sick one objects to move, and if compelled, crawls from Ills lair., trembling and discontented.

Sometimes there ailt;; signs of partial paralysis, and the |)ig moves in an unsteady manner from side to side, frequently losing'the use of one or both hind quarters, and dropping to one side, or dragging both hind

legs as it attempts to move forward. There is no loss of sensibility with the defective motion, as the animal if touched will indicate pain

by a sharp cry.

Inbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; Diarrhea may occur early in the disease, after a short period of con-

stipation; and the evacuations are generally light in color at first, becoming darker by and by, often from the mixture of effused blood. In severe cases the intestinal discharge consists almost entirely of blood, with masses of clot and loosened pieces of exuded lymph from the in-flamed and ulcerated mucous mein braue of the digestive canal.

A symptom which is considered to bo characteristic of swine fever may sometimes be detected early in the disease, lied patches or blotches appear behind the ears, inside the arms, and under the belly. Professor Axe describes a distinct eruption in the form of red spots, from one to three lines in diameter, slightly raised above the surface, so that they may be felt by drawing the finger over the skin. The eruption is not always present, and often there are not more than half a dozen spots extending over a large surface; but in other cases they are very numerous. After two or three days the spots subside, and are followed by a second, third, or even a fourth crop, and after their final disappearance the cuticle becomes ragged and scales off.

Small water bladders (vesicles) appear on the surface of the red spots when the fever remains very high, and the fluid contained in them either escapes or becomes dried up, forming a gray crust on the surface.

Discharges of thin fluid from the eyes and nose commonly takes place early in the course of the disease, and, as it advances, the discharge becomes thick and purulent, sticking about the eyelids and openings of the nostrils. Diarrhea is more constant as t he disease goes on. The voided matter is offensive and often streaked with blood; prostration occurs and is soon followed by complete collapse, and the animal dies in a state of unconsciousness or in violent convulsions. Death may take place at various periods from the commencement of the affection, sometimes after a few days' illness, while in other cases the animal may linger for two or three weeks.

In reference to the change of the color of the skin in marked cases of swine fever, it may be observed that there may be, independently of the raised spots which Professor Axe describes, a diffused redness, or regular patches of redness, or a purple tinge in different parts of the surface; but these signs arc not to be expected in all or even in the majority of eases of the disease; and it is well known that redness of the skin is a symptom of some common diseases of swine. It arises, for example, from exposure to wet and cold; contact with sea-water, or spray during a voyage, will also produce it; a journey in a railway truck which has been lime washed is another cause; consumption of wash with which salt liquor has been mixed is followed by severe, often fatal, inflammation of the mucous membrane of the digestive canal and sympathetic irritation of the skin; and the symptom has also been noticed in acute indigestion which has resulted from eating freely of maugokls. Redness of the skiu, therefore, cither in patches or gener-

170

ally, fun not be accepted as safflcieut evidence of the cxisteuce of the swine fever.

In certain instances the symptoms lt;gt;f swine fever may be so well de-flned duriug life that an opinion maybe given promptly and without mach risk of error, Imt under ordinary conditions the conclusion must be the result of the careful consideration of the history of the outbreak, or of the evidence which can be obtained by dissection of the organs of a diseased animal; and for this purpose it is better to kill a suspected pig than to take the carcass of one which has died some time before the commencement of the inquiry, and has probably anAergone post-mortem changes which will render obscure the true morbid appearances.

Experience has placed beyond all doubt the fact that swine fever when it once obtains a hold on a herd of swine does not spare theiu. It is true that a proportion, and it may be a considerable one, of the older animals particularly, will escape with a mild attack, and in some of these mild cases there will be no characteristic symptoms to attract attention. In fact, it, will appear that animals have escaped the disease ; but the crit ical observer will find some signs of the disease in the majority of the swine which have been exposed to infection. Cases which are often reported of swine fever attacking two or three swine of a large herd and sparing the rest, may safely be put down to the credit of any disease but swine fever. And the same thing may be said of those cases which are traced to the consumption of indigestible food, or the exposure of the animal to hardship or unsanitary conditions of existence.

Postmortem appearances in simne fever.Some of the changes which are affected in the organs of the body by the ravages of swine fever can only be appreciated by the pathologist; others, and those most distinctive perhaps, are patent to the ordinary observer; and on this point it is worth while to note the description quot;which was given before the members of the Eoyal Agricultural Society in 18(iö by Dr. William Budd, of Clifton, who was the first scientist in this country to investigate the disease, which was at that time looked upon as anew one. Dr. Uudd's attention was particularly attracted to the changes which had occurred in the digestive organs,' which he called a series of ulcer-ations of peculiar character, variously distributed over the intestinal tract, from the stomach to the rectum inclusive.

The first stage of the local affection appears to be the development (amid all thephenomena of acute inflammatory disturbance) in the substance of tbe mucous membrauce and in the snbraucpas tissue of an adventitious deposit (or cell growth) resembling in many of its characteristics the well-known yellow matter of human typhoid. When Dr. Budd gave this description, the outgrowth from or deposits on the mucous membrane of the stomach and intestines were seen more frequently than they have been of late years; in fact, in all well marked cases they were the prominent objects in the post mortem appearancessoft, spongy masses, sometimes in very severe cases stained a dark red by the blood, which was extravasated into the intestines, varying in size from that of a large pea to a walnut, circular or oval in shape; sometimes several masses were joined together; but whether large or small, separate or continent, the deposits, from their color in contrast with the membrane on which they were placed, were very striking objects.

A very curious appearance was sometimes seen in the intestines of swine which had partially recovered from the fever and afterwards died from exhaustion, or were killed for the purpose of examination. The mucous membrane in these cases was spotted with the small masses of

177

deposit which had lost the soft, spongy or fungoid character, and become dense and, so to speak, leathery lookiujf, not unlike yellow leather buttons, marked with concentric rings, or, as Dr. Baddquot;remarks, like slices of columba root.*

The first simile will perhaps be more suggestive to the fanner thou the latter, as slices of columba root arc not familiar objects. The mucous membrane of the intestines, especially the large' intestines, was often covered with ulcers, and the masses of deposit which have been . referred to were generally found to be in connection with deep excavations, the result of the ulcerative process; but in all cases the edges of the ulcers were elevated above the surface of the mucous membrane, and presented a soft ftmgoid character.

In some cases the whole of the mucous membrane of the intestine was covered with a croupous or diphtheritic deposit of a dirty white color; and it was only after the deposit had been cleared away that patches of inflamed, and perhaps ulcerated, structure could be seen.

In some instances the diphtheritic deposit was so abundant as to fill the intestinal tube, and leave no canal for the passage of the feculent matter, and rapture of some part of ibe intestine was the natural result of this blocking up of the passage.

The next illustration is copied from a report on swine plague in the Eeport of the Bureau of Animal Industry, Washington, United States (for 1885), and it may serve to indicate at the same time the characteristic appearances of the disease and the identity of the swine plague (hog cholera) in the United States of America and the swine fever of this country.

Besides the appearances which have been described as occurring iu the stomach and intestines, especially in the large intestine, there are nearly always observed patches of congestion in the lungs, with here and there condensation of the lung structure, which present a fleshy character quite distinct from the healthy state. There are also changes, easily distinguished by the pathologist, in the liver, kidneys, spleen, lymphatic glands, and also in the cavities of the heart. In short, it may be aflkmed that the morbid changes in swine fever are so perfectly well defined that no error in opinion can occui when all the evidence which a jgt;o.it mortem inspection affords is in possession of the inquirer.

In this description we arc led to infer that the writer has before him genuine bog cholera. At the same time some of the features d wel t upon, such as the croupous and diphtheritic deposits orexudates in the large intestines, are more like those found in severe epizootics of swine plague.t

There is another fact which proves that at least part of the swine fever of England is the hog cholera of the American continent. This is presented by the investigations of E. Klein. In his report upon swine

* Those neoplasms we Lave also encountered chiefly in adults. They must be looked npon as results of a greater resistance on the part of the mucous membrane, sueh as we may expect in old animals.

t A plague like Log cholera ipay perhaps change its character under influences such as climate and locality, or under innnences found in race, breed, etc.. laquo;f animals. This may frequently account for modilieations of diseases caused by the same microorganism.

15612 h c-----12

178

fever in the supxdement to the Seventh Aunual Report of the Local Gov-eiiiment Board for 1877 Dr. Klein gives a very good account of the pathological anatomy of this disease, together with some researches on the nature of the cause ami the mode of infection. Though calling the disease pneiunoeiiteritis, his text, as well as the statements of Professor Brown, quoted above, show that the accompanying lung disease is no more severe than in hog cholera. The microlie which lie described in this report is a huge spore-bearing bacillus. The methods which he employed in his bacteriological work were those of the times, not considered now as capable of giving any trustworthy information. Conse-quentiy, at a later date he regarded it as necessary to again go over the ground, and published his results in Virchow's Archiv, XCV, 468, in 1084. In this monograph he describes the inoculation disease in mice and rabbits very inueh as we have found it, laying particular emphasis ni)Oii the coagulation-necrosis found in the liver. His cultures contained a motile bacillus from .002 to .00;} millimeter in length. We may therefore conclude that a germ closely resembling or identical with the hog cholera bacillus is found in cases of swine fever, and that hog cholera actually exists in England.

The history of the straggle with swine fever in Great Britain since 1878 shows that it has been very severe. Numerous orders have been issued, beginning with the contagious diseases act in IS7S, to restrict the extension of the disease, but all appear to have been without avail, since the malady was as widespread and as virulent in 188.quot;raquo; as ever before. This was without doubt due to the inefficient and incomplete execution of the orders. By the order of December 17, 1S7S, the slaughter of swine affected with the disease was made compulsory, and compensation was to he paid out of the local rates for all swine slaughtered by order of the local authorities. Tlie order also provided that no swine should be moved out of a pig-sty or other place without a license, and then only for slaughter. After this order had gone into effect weekly returns were received from the inspectors of local authorities, which showed that in 1879 the disease had prevailed, at some time during the year, in forty-four counties in England, six in Wales, and three in Scotland.

The continued spreading of the disease gave rise to the swine fever order of 1879. This contained provisions for the declaration of infected places and for the slaughter of healthy swine which had been herded with diseased ones, and also for regulating the exposure for sale of swine in fairs and markets. This order Avas only partly carried out, for out of 17,074 swine attacked ;gt;,410 were allowed to die and 124 recovered. In 1882 the disease was more prevalent than in 1879. Slaughter of diseased and exposed animals was continued as before. Thus of 14,7(!.'i swine attacked 11,903 were slaughtered, 2,79!) died and 18 recovered. An order of council was passed in July, 1882, providing for the tlecla-

179

ration of swine fever infected areas by tlie privy coimeil, and giving power to local authorities in England and Wales to prohibit or regulate

the movement of swine into tbeir districts from the district of any other local authority in Great Britain. The order also empowered local authorities in Scotland to prohibit or regulate the movement into their district of swine from tlie district of any other local authority in Scotland; it did not appear, however, that the local authorities availed themselves of these powers, except in very few cases.

In 1SS4 the area of the disease rather increased, while the mimbcr at-* tacked did not grow larger. Further orders of council were passed this year containing provisions relating to swine fever. The most important change made referred to the provision for slaughter of diseased swine, which was objected to by some local authorities as a costly and comparatively ineffectual measure. By an order passed in May the compulsory provision was revoked, and tlie slaughter of diseased swine, as well as those herded with them, was left to the discretion of the local authority. Another order of council, passed in July, 1884, provided for the formation of a swine fever Infected circle round an infected place in any district to which the order might be applied by the privy council at request of a local authority. The order was applied during-the year to five counties and ten boroughs.

In 1SS5 the disease grew to dangerous proportions, threatening the entire stock of pigs in the country. The extension was due to the purchase of swine at fairs and markets, and it was therefore deemed expedient to impose restrictions on the sale of swine in all parts of England. Accordingly an order of council was passed prohibiting the exposure for sale of swine except for slaughter within three days, and then only with the license of the local authority of the district in which the sale was to be held. Provision was also made for the exhibition of swine at agricultural shows.

This so-called markets ami fairs order did a great deal of good, but, as it did not prohibit private sales, the disease even increased in some counties, owing to the unrestricted sale and movement of swine.

quot;It was continued in operation until the end of November, and during its operation the centers of disease were so far advanced in number nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;that it was deemed expedient to have recourseraquo;, to .slaughter of diseased

swine, and also of those which had been in the same pig-sty or shed with diseased swine. With this view the swine fever compulsory slaughter order was passed, ami came into operation on the 1st of December. The order provided that local authorities should slaughter all swine that at any time in the month of December were affected with swine fever, and all swine being or having been in contact, or in the same pig-sty or shed, with swine affected with swine fever.

quot;Compensation was to be paid to the extent of half the value of a diseased pig and the full value of a healthy pig, but the amount was not to exceed 40s. for a diseased and £ I lor a healthy pig. During the four weeks to the end of 1885, the effects of the system of compulsory

180

slaughter were not altogether satisfactory. In fact, i'resli outbreaks of laquo;nine fever eonliimed to occur in the same districts, and even in the same premises, owing to the way in which the order was carried into effect iuregard to the slaughter of swine which had been exposed to infection. For example, if a lot of swine were in ast.v which was separated a few feet from the sty in which disease existed, the animals were not slaughtered, because they could not be said to be in contact, and they were clearly not in the same sty, although it might fairly be pre-suiiicd that the swine so situated were exposed to risk of infection through the atmosphere, or by the agency of persons or things by which the virus of the disease could be conveyed to a- considerable distance. * * *

quot; Slaughter of diseased and infected swine was adopted in some districts with satisfactory promptitude. In others a Dumber of animals were allowed to die before any action was taken. The disease, after being stamped out iu some districts by the energetic action of the authorities, was reintrodaced from other parts of the country where the law was administered in a perfunctory manner. In short, nothing like a serious and decided effort was made to get rid of the uflection, and as a natural consequence the good effects of restrictions were partial and temporary.

quot;Imperfect cleansing and disinfection of premises maybe reckoned among the causes which have contributed to the continuance of swine fever, notwitlistanding the operations of regulations which might have been expected to produce good results. Very frequently swine are kept in places which can not be cleansed and disinfected effectually, so as to make them safe for the next lot of pigs which will be brought in as soon as the place is declared free. Old, half-rotten styes with moldy floors can not be cleared of infection by any known process. The only course in such cases is to remove the infection-saturated timber and soil and submit them to the action of fire; but no power is vested in the authorities to do this necessary work, and the only expedient which they can employ is that of refusing to declare the infected premises free until the necessary alterations and improvements are completed. In tlm somewhat roundabout way they may attain the objectthat of keeping out fresh swine to become victims to the disease, but this kind of pressnre can only be applied under certain circumstances.

quot;Free movement of infected and of actually, although not observably, diseased swine, and their exposure in fairs and markets, has all along been a fruitful cause of the spreading of swine fever. Many inquiries have been made with the view of tracing the origin of different outbreaks, and the conclusion has generally been that they were due to introduction of swine recently purchased at public sales.

quot; Fuder the system, which lias obtained for years, of slaughtering diseased swine, and allowing the appareut'y healthy to live, tbe extinction of the disease could not possibly bo secured. And it is only in the common course of things that the malady has gradually extended all over the country from the sale and movement of diseased and infected swine which often showed no signs of disease, and would he, passed as free from swine fever by any one but an expert who is familiar with every phase of the malady. * * *

quot;In reference to the measures which should he adopted for the extinction of swine fever in this kingdom, it is not necessary to enter into details. On three occasions in tin* last twenty years the stamping-out system was successfully applied to cattle plague. Exactly the same

181

means would certainly succeed in ridding as of swine plague, and there is no ground for the expectation that any less severe measures of repression would be effective. It is, however, an essential condition of success that the action taken should be uniform and general in application. But it is impossible to suggest any means of securing the necessary uniformity wliile the execution of the law is in the hands of some hundreds of local aurhorities who entertain different views as to the necessity for attempting to get rid of the disease by legislative measures, and are not agreed as to the proper means of effecting the object.quot;

SWEDEN AND DENMARK.

In the fall of 1887 a disease closely resembling hog cholera appeared in Sweden among swine, which rapidly spread from place to place, showing itself very fatal and causing alarm and consternation among the agricultural population. The disease invaded the territory of Denmark, where stringent measures were adopted to prevent its further spread. The following communication, received by the Department of State from our consul at Copenhagen, and kindly forwarded, may serve to illustrate the measures employed by the authorities in checking the epizootic. Alter giving briefly the symptoms of the disease, and the lesions caused thereby, Mr. II. Igt;. Ryder continues as follows:

The very prompt and stringent measures taken by the Danish Government, it is to be hoped, avIU be the means of localizing as well as of effectually stamping out this malignant pest. For example, circulars have been sent from the home department to all the sheriffs through-oat the kingdom, instructing them to make publicly known that all persons who within the last two months may have purchased hogs or young pigs from Copenhagen, or in its vicinity, should immediately give notice thereof, so that their entire herds might be submitted to Veterinary inspection. Furthermore, an ordinance has been issued strictly prohibiting all transport of live hogs or young pigs from one district to the other , and that no removal of the animals shall be made from their present dwellings, excepting by special permission for the purpose of immediate slaughter; and, lastly, power has been given to all the police authorities, on any suspicion of disease, to order the iiumediato slaughter of the animals, and a post-mortem examination of the carcass to he made by the veterinary officials; and on the appearance of the, disease in any locality under their jurisdiction to order the immediate slaughter of a part or the entire herd as may be deemed necessary.

It is thus to be hoped that by these measures further spread of the disease may be arrested. It is, however, much to be feared that, in addition to the losses entailed upon the kingdom in the destruction of animals in the course of the disease, the sorely tried farmers in these days of agricultural depression will also be subjeted to material loss in a diminished sale to foreign countries of their swine products. An order has already been issued by the German federal council prohibiting all importation into the German Empire of swine, pork, and sausages from Sweden, Norway, and Denmark, which will be most seriously felt by the agricultural interests, as the exports of live hogs and young pigs are almost entirely directed to Germany, whilst the exports of pork

182

and liams are mainlyforwardeil to Greal Britain,as will \w seen bylhc following table, namely:

Countries.

Of T.ve hogs and pigs tonbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;Ilmd.nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;Ilnul.

Gonwauj^- ...............................................................nbsp; nbsp; nbsp; nbsp; nbsp; -Ti;, iiifinbsp; nbsp; nbsp; nbsp; nbsp; nbsp;lii2,2T;J

IToi laquo;raj..................................................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; (gt;, 814nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; 4, 704

Great Britain.............................................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;2,81)5nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;128

Uolliui.!...................................................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; 1,243 ............

Of jinrk ;iii(l hams tonbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; Foundn.nbsp; nbsp; nbsp; nbsp; Pmtnds,

Great Britain............................................................nbsp; 12,530,000nbsp; nbsp; nbsp; 20,240,000

Germany.................................................................nbsp; nbsp; nbsp;2, 030,000nbsp; nbsp; nbsp; nbsp; 7,180,000

Sweden.................................................................nbsp; nbsp; nbsp; :;, 070,(00nbsp; nbsp; nbsp; nbsp;:i, 030, ooo

Norway...................................................................nbsp; nbsp; nbsp;1,200,000nbsp; nbsp; nbsp; nbsp; nbsp; 700,000

From tbeforegoingfigures full evidence is afi'orded that whilst the exports cif live stock have met with considerable decline in the latter years a great increase has taken place in the exports of swine products, due to t he large number of slaughtering and salting establishments which have been erected in this country for the development of the pork, bacon, and ham trade with England; and thus the loss to the agricultural interests, it is to be hoped, will not be quite so severely felt as would have been the case in former years under similar nnfoitmiate conditions, and it is scarcely to be feared that England will likewise place obstacles in the way of the free imports of the products into her ports ; for iuas-mnch as the imports of swine into Great Britain from this country have for some time only been admitted in slaughtered condition, and setting apart the facts that swine in mature stage for slaughter are far less exposed to this disease than young pigs, there will be found at the same time, under the close inspection which has been introduced thronghont the Kingdom, and the energetic steps taken by the authorities in all cases of suspicion, an almost certain probability that no pork from a diseased animal can possibly be exported. The sale of swine products for homo consumption plays likewise a very important part; audit is here again to be feared that restricted sales will be sensibly felt until the temporary scare in partaking of swine flesh has bad time to subside.

In order that the energetic measures taken by the Government for the stamping out of the plague may be crowned with full success it will be necessary that theagriculturists should giveat the same time a loyal support to the issued instructions and work hand in hand with the authorities. Ue who may delay in reporting or may attempt to conceal any disease or suspicion of disease that may show itself at his place will simply be committing a crime against the class to which lie belongs, and honesty in this as well as in other cases will be found the best policy; for whereas be who reports the breaking out of disease amongst his stock will receive two-thirds of the valueof the slaughtered diseased animals, and full compensation forthe slaughtered sound ones, the dishonest party will incur not only risk of confiscation of the diseased meat offered by him for sale, but will also render himself liable to heavy tines. The closing of Germany to the importation of these products undoubtedly can not fail to entail severe loss upon the agricultural classes; but if success can only attend the stringent measures

183

adopted for preventing thefurtUer spread of thedisea.se it must be hoped the orohibitioa will be of short duration, and that agricnltaral interests willquot;soon recover from the blow. ISiit should the devastating plague, on the other hand, spread over the whole Kingdom it will be nothiug short of a national calamity, the destructive effects of which will long be felt, as will easily be understood from the following table of lliemnn-ber of hogs and young pigs to be found in the Kingdom under census of 1881, vrz:


	Ilogs.	Y	mad. 302,884 334, 707
Iraquo; the Islands........... In Julliuul..............	Head. 28:., DIT 2-12, 100	Y	mad. 302,884 334, 707
Total..............	,'.27,417		7-27, 591

Great responsibility will thus rest not only upon the veterinary and police authorities but also upon the agriculturists in devoting all possible energy in their mutual exertions to prevent the further spread of this dreaded evil.

The disease is supposed to have been introduced into Sweden by diseased boars, imported from England for breeding purposes. Thence it was carried to Denmark,* in wbicb country it first appeared on the dumping grounds near Copenbagen, on which numbers of swill-fed pigs were kept.

Chiefly young pigs up to the age of four months were attacked, '.bo period of incubation lasting from five to twenty days. The infected animals refused food and wore at first constipated. Later on diarrhea set in, characterized by the discharge of yellow putrid masses, frequently mixed with blood. The temperature often rose to l05^o-107.5^o F. The animals were indifferent to snixonndings. Tail and head drooping. Conjunctiva reddened, frequently glued together with dried-up mucus. Respiration in many cases quickened and labored. Occasionally a muco-purulent discharge from the nose. Not infrequently reddening in patches was observed on the ears, snout, abdomen, about the anus, and inner _side of tbiglis. The animals became very weak : postfirior part of bods-swayed in moving about. They concealed themselves in the bedding^ and finally were unable to rise. Death followed insensibility and con-vulsions.

A characteristic sign of this plague were diphtheritic changes on the apex, sides, and under surface of the tongue, as well as on the mucous membraneof the cheeks, hard and soft palate, and the tonsils. On these parts grayish white or yellowish opaque patches appeared, which were sharply defined and Mere converted later into ulcers by removal of the slough.

In one herd the teats of several sows were affected with dark gray, sloughing sores, with inflammation of the udders. These were infected

'Schiit:: Dir Sclnrciiirpe*! in IMiicmark. Arch.f. irhs. n.prakt, Thierlteilkiinde, XIV, 1898, p. 376.

184

from the diphtheritic sores in tbe months of the snekiug pigs. In Denmark the disease was first recognized in this way. Tbe acute disease lasted from five to eight days, but sometimes death occurred sooner than this.

The disease appeared in Denmark in September. In December tbe plague took on a more chronic character and became less infectious. The infected animals frequently showed no indications of disease, only they were smaller and thinner than others of tbe sameage. Therewas occasionally coughing and diarrhea. Some recovered, others perished by a gradual wasting away. The postmortem appearances were very characteristic. The large intestine was attacked in every animal, and in acute cases the small intestine and stomach likewise were reddened and swollen, and the surface in part covered with a thin layer of a grayish white or grayish yellow soft mass, wbieb consisted of fibrin. This same layer was very thick in the large intestine, easily lifted away m toto in some places; in others the attachment was firmer (diphther itic). In other acute cases there was simply reddening and swelling of tbe mncosa of stomach and small intestine, and diphtheritic changes in the large intestine, the fibrinous exudato being absent. Moreover, the follicles, Peyer's patches, and mesenteric glands were always tumefied.

The seat of the diphtheritic process was the whole large intestine, more especially the crecmn. The follicles and Peyer's patches were nearly always affected. The ulcers appeared when the slough bad come away. In the place of the follicles button like sloughs were formed, which gradually invaded the whole thickness of the wall, spread laterally, and ran together into larger patches. The wall thus converted into a cheesy mass was frequently one-fifth to two-fifths inch thick, on the surface irregular, colored yellow, brown, or green. Hemorrhage, due to tho uleeratiou, was observed in one case.

In many animals the lungs were healthy. In some a inuco-purnlent catarrh of the bronchi was present, which caused atelectasis in one or more places with young and weak animals. Usually the ventral and anterior lobes were affected. In the diseased lobes homogeneous, cheesy masses appeared later, sometimes as large as walnuts. These masses led subsequently to inflammation and adhesion of the pleura to chest-wall, pericardium, etc. Tbe spleen was not changed as a rule. In a few cases only it was somewhat enlarged, soft, dark red.

Whenwocompare these lesions with those found in our country, weob-serve tbe absence of hemorrhagic lesions and enlargement of the spleen, and more marked exudative and diphtheritic changes in the large intestine. In numerous sections of ulcerati ve changes we have not observed any relation between these and the follicles. The lung lesions correspond closely. Whether they arc due to tlie disease or not must be left undecided. Wc have frequently seen caseons changes in the lungs of animals free from infection, and they are, perhaps, due to collapse,

185

broncbo-pnenmonia. and snbseqnent interference of tbe circulation, ratber than to the direct action of bacteria.

The specific bacteria which are the cause of the swine disease are described briefly by Selander,* and according to liis description they closely resemble hog cholera bacteria in form, motility, growth in gelatine, and appearance in tissue. Their growth on potato i.s said to resemble that of the bacilli of typhoid fever in man, and thus to differ from that of Log cholera bacilli. Their effect on the lower animals correspond also, although the descriptions are too brief for careful comparison. There is no mention of the coagulation necrosis found constantly in the liver of rabbits inoculated with American liog cholera.

In the beginning of the present year (1SSS). Dr. John Lundgren. professor of veterinary medicine, in the University of Stockholm, was sent by the Swedish Government to study swim' diseases in this country. He spent several weeks in the laboratory of the Bureau studying tbe bacilli of hog cholera. A cnltnre of tbe swine pest bacilli from the Swedish epizootic was at that time subjected to a careful examination.

In gelatine, the swine pest germs grow very much like hog cholera bacilli. On the surface of the gelatine the growth is very thin,translucent, of a pearly luster, and spreads more rapidly than the hog cholera growth. On agar-agar the growth is more abniulant and more rapid. Beef infusion, with or without peptone, is converted into a very turbid liquid within twenty-four hours at 95deg; P., while hog cholera cultures are barely opalescent at that time, and remain so. Two mice were inoculated from an agaragar culture of the Swedish germ under the skin of the back. Both were slightly ill next day. On the second day one was found dead. The cultures from it remained sti rile. It probably died from some other cause. Tbe second mouse remained well. On a rabbit the effect was equally negative. No rabbit survives inoculation with bog cholera bacteria.

The effect of both germs on pigs was next tried. Two Erlenmeyer Hasks, containing each about 300cubic centimeters (two-fifths of a pint) of sterile bouillon, were inoculated, one with the American, tbe other with the Swedish germ, and placed in tlie-thermostat at 95deg; F. On tiie following day both flasks were clouded ; the Swedish culture was covered by an iridescent, very thin membrane. A comparative microscopic examination showed tbe Swedish bacteria to be nearly twice us large as the American; their movement was far less active than that of the latter. On the same day two pigs, starved for about twenty four hours, were, fed with these cultures by drenching, i. e., the liquid was poured into the mouth, so that none was lost. The pig fed with the Swedish culture showed no signs of disease at any time after. The other pig on the fourth day had a very liquid diarrhea, and was found dead tbe next morning. On examination the spleen was found gorged with blood, but only slightly enlarged, Mesenteric glands enlarged and reddened.

Cmiralblattf. bahteriologie, tic, 18)38-

186

Stoniiicli and ileara intensely inflamed (enteritis); grayish masses (diphtheritic) attached in patches. The ileum was invaginated and projected for 2.1 inches into the e;ecmn; mucosa of this portion necrosed; walk; infiltrated, thickened, and eccliymosed. In csecnin the mucosa was covered by a very thin slough. In the colon the membrane was deeply reddened, covered by a catarrhal exudate, and dotted with numerous very minute ulcers. Heart and lungs normal. Koll cultures in gelatine as well as liquid cultures from the spleen contained only hog cholera bacteria. The invagination was very likely the result of the violent inflammation.

These comparative experiments show that the two germs, though very much alike in appearance, were quite different with reference to their pathogenic effect. Professor Lundgren was inclined to the opinion that he had taken the wrong culture on leaving his native country. It may also not bo improbable that this was the true germ attenuated on the way hither. As no communieation has been received from him since his visit here, the qaestiou must remain an open one.

FRANCE.

Daring the summer of 1887 a disease was introduced into the vicinity or Marseilles by swine from Africa, which dev.doped into an epizoo'ic of a very fatal character. It caused great losses in the south of France, and at the time scientific men were sent from Paris by the Government to investigate the cause and suggest a remedy, if possible. According to Kietsch, Jobert, ami Martinand* the disease is chiefly restricted to the intestinal tract, lasting from ten to twelve days alter the first symp toms have appeared. Occasionally it may last but three or four days, or be prolonged to several weeks, but it is quite invariably fatal. Sometimes there is diarrhea, sometimes constipation; the fever is not con stant, the cough very rarely heard. The hind limbs are weak, the walk tottering. Appetite often persists to the end. The skin may become reddened in spots, especially on the limbs and ears. Pigs over a year old are much less susceptible.

At the autopsy the lungs, liver, kidneys, and spleen are usually found unchanged, and the disease limited to the digestive tract. The stomach and the small intestine near the valve arc ulcerated. Ulcers are present in the large intestine on the valve, in the csecam and colon. They may measure 3 to 4 iuchesin diameter. In animals affected with a chronic form of the disease, there may be ulcers on the inferior surface of Hie tongue and on the inner aspect of the lips. The internal organs are free from bacteria. I3ut from the contents of the intestine and the ulcers a motile bacillus was obtained. M ice are. killed in ten days after sub cutaneous inoculation with cultures of this organism. Of ten adult mice fed with cultures two died in fifteen days. Of ten young mice all Camitl i-cuil. Aiad. Scienceraquo;, Jiiniiaiy 26, 1888.

187

died when fed, the first in thirty hours, the others in (if'tcen to twenty-three days. Babbits are but slightly susceptible. A youug guinea-pig-, fed with cultures, died twenty-two days later. The intestine showed characteristic ulcers.

Dr. Itietsch very kindly sent to the Bureau a culture of the germ which he found. It was compared with the American hog cholera germ and the following characters determined:

The motile bacilli of the same form as hog cholera bacilli, but larger, grow far more abundantly and rapidly in beef infusion. A thin membrane and a copious deposit are produced in a few days, and the liquid becomes very turbid. On gelatine the colonies do not differ appreciably from those of hog cholera. The surface colonies spread in thin iridescent patches from 2 to ö millimeters in diameter. Tn tube cultures the isolated deep colonies grow to about one-third of a millimeter in diameter. (Jn the surface the growth is rapid and spreads over the greater part of that which is available. The patch produced is whitish, uniform in thickness, very irregular in outline, inclosing round spaces of uncovered gelatine. In the bottom of the tube a few air-bubbles appear. On potato the growth forms a glistening, pale-yellow patch at the ordinary temperature.

They thus resemble the Swedish germs very closely, differing by so much from hog cholera bacilli. A rabbitand two mice inoculated with the Marseilles germ remained well. Equally so a pig fed with 4(10 cubic centimeters (four-fifths of a pint) of a beef infusion peptone culture.

So far as our examination of the Swedish and Marseilles cultures have gone, they have shown them identical both as regards their positive and negative characters. They differ from hog cholera bacteria enough to constitute at least a variety. Hut the investigations of French savants of this Marseilles epizootic differ somewhat as to the cause.

Cornil and Chanfemesse* described a disease discovered among swine in the vicinity of Paris, which they consider identical with the German Schiceitieseuche and our swine plague. Subsequent experimentst to determine the biological properties of the bacteria causing the disease show that they are not dealing with the true swine plague germ (cer tainly not as we have observed it in this country), but with one resembling more nearly hog cholera. Their researches concerning vaccination are reported to have been successful on rabbits and guinea pigs, hut since that time nothing has been published concerning experiments on pigs.

While Kietsch and Joberti come to the conclusion that the Marseilles disease resembles hog cholera closely, Cornil and Chantemessc regard it identical with swine plague, although the germ they describe

* Compt. rend. Acad. Sciences, 1387, CV, p, 1381. t Compt. rend. .lead. Sciences, 1S88,CVI, p. (iTJ. fl. c, p. 1096.

188

is not identical wiHi the swine plague germ as studied in Germany and in tlic United States.*

It is interesting in this connection to trace the marcb of infection in the south of France as reported to the French Academy liy Fouqnet as an excellent illustration of the waj-s bj which infections diseases may be scattered broadcast over a country:

' The disease did not, as was supposed, appear in Marseilles toward the end of June, but in the month of April, and I have been able to locate three entirely distinct centers of the outbreak due to the same caa.se the introduction of African swine. These three centers are : The village of Caillols, midway between Anbagne and Marseilles; the village of St. Marthe, ü'¹'quot;. northeast of Marseilles, and the herds of the Mediterranean distilleries.

(1)nbsp; nbsp;From the lüth to the loth of April, a breeder of Caillols received a drove of black swine from I lie province of Oran (Algiers). From the lirst week some eases of pneumoniat showed themselves among the last animals; the disease gained rapidly', causing many deaths. The survivors were, sold on the tth of May following.

On the Stli of June the same piggeries were restocked, partly with African and partly with Russian swine. Towards the end of the month there were cases of pneumonia. The Russian swine resisted less than the others. August l(i the piggery was again emptied. Finally during September the third attempt was made, exclusively with African swine. This also proved a failure. The survivors were sold in October.

During this time the disease reached the neighboring piggeries stocked with a mixed Marseilles breed. The breeders of Caillols, alarmed by the ravages of an epizootic the nature and cause of which they did not know, decided to sell out at any price. The neighboring localities, St. Marcel, St. Loup, San Joan du Desert, etc., were successively infected. Infection was spread by the sales and exchanges of sick and suspected animals, by means of transportation {carts often used in common by several establishments soiled by the dejections of the sick and afterwards used to transport healthy animals and their feed), and also by the lateral canal of Iluveaune, which receives at certain points running water coming from the grounds on which the piggeries are located.

At the beginning of September all the valley of Iluveaune, from An-bagnc as far as Marseilles, was infected. Diseased pigs from this region we meet again in the market of Anbagne, at the fair of September 21, and which became later one of the most active agents in spreading the disease in the departments.

(2)nbsp; nbsp;Toward the middle of the month of August the disease appeared ina piggery in St. Marthe, stocked exclusively with African swine. These animals came directly from Oran without coining in contact with any other of their species. Several days later one of the largest breeders in that vicinity, who for three months had not brought a single pig to his establishment, and whose piggery was at least GOO feet away from the preceding one, sustained a considerable loss, especially among the pigs of 130 to 175 pounds.

quot; In a recent review of the reports of the Bureau of Animal Industry by Dnclanx (Annalea de V Tnatitut Pasteur, .July, H^-'). the reviewer regards this disease as iiten-tieal willi ho;; clioleni, and states that (.'cirnll and Cbantcinesso had at first overlooked the motilitji raquo;I' the germ they were sindvinj;.

11 c. p. (570.

{The writer calls the disease infections pneamuuia for want of a heller term, although Kietseh distinctly states the intestinal nature of the malady. Fonqne was no doubt led astray by the early, misleading notices of Coroil and Chanteinesse.

189

(3) Finally, ou the 2.gt;tli of Juno, .sick pigs caaio from Oran to tiie piggeries of the Medifcrraiieaii distilleries. There were very soon a iiiuu-ber of victims of ijueumouia, not only in the distilleries but also iq the neighborhood, where there were from 4,000 to ö,00J in a comparatively small territory. A great many of the sick died ; the others were quickly sent to different cities to be delivered to the butchers. I have traced the history of six sows which were sold from the midst of infection to Estaque; thence they passed tlirougli the commune Rove and arrived in August at Gignac, where they introduced the disease. By an odd coincidence some sick pigs from the same locality were taken to the fair at Aubague and bought by a breeder of Gignac.

The fair at Aubagne, on September 21, marked the most important phase in the progress of contagious pneumonia. During the first fortnight in October there was a veritable explosion of the disease, which, up to this time, had been scarcely known.

The importation of the disease by animals bought at the fair of Aubagne can be traced with the greatest precision in the suhurhs south and north of Marseilles, also as far as Gardanne, in the communes of Septeaies, Vitrolles, IVnnes, etc., to Gignac, as mentioned above, even into the neighboring departments, which continued with the others to receive consignments of Marseillos swine. It is also necessary to men tion i'uget, Vilie et Grasse, among the localities infected.

In the beginning of December 153 swine were shipped from Marseilles to Nice; nearly all died in a few days. From that time cases appeared among the native pigs.

On December 22 another lot of 133 pigs were shipped; 33 were destined for Nice and 100 for Italy. These last were sold on the 24th, in the market of Viutdmille; nearly all died very soon.

Tor several years .Marseilles annually exported to Spain, and especially to Barcelona, a great number of pigs. Contagious pneumonia had been causing losses there for several months, even, it is said, at Majorka, in the Balearic Islands. The Spanisb breeders, believing the outbreak of the disease with them was attributable to the importation of French port, obtained from the authorities the permission to impose a qnarantine of six days, at Fort Bone, on swine from Marseilles, to he-gin on the 1st of the following February. This measure has not been enforced up to the present day.

From what has preceded I believe I can conclude that the epizootic of contagions pneumonia which has raged during the year 1887 in the interior of France, and which at this time continues its ravages there, is of African origin. It has been introduced by Algerian swine which came from the province of Oran. This disease has made 20,000 victims in several months in the province of Boncbes-du-Ehone.

Figs, and especially those from three to nine months old, areoftenest attacked; larger pigs appear less susceptible. The Marseilles breed, the English (Yorkshire and Berkshire), and the Russian swine are more susceptible than the African swine.

Two months ago about 50 pigs two to three months old, coining from Cazcres and Le Fousseret, in the arrondisseinentof Muret, were used to stock a farm in Gignac. These pigs, placed in the pens which had contained sick ones, and which had only been very imperfectly disinfected, remained in good health, while more than a hundred cases of contagious pne'tnionia appeared around them in the same piggery. Afterwards more than 2,000 Gascon swine were imported by the. single com-ninne of Gignac. Up to the present time the diseasehas not re-appeared. Are we here confronted by a new example of natural immunity com-

190

parable to that noticeil long ago by Chauveau in Algerian sheep in regard to authrax?quot;

Taking into consideration what we know now of these epizootics and enzootics of swine diseases in foreign countries, we are forced to the conclusion that the disease in Sweden, Denmark, and France is closely related to if not identical with hog cholera as it is found in our own country, while the minor differences in the disease as manifested in these epizootics, and in the germs producing it, can be explained on the principle of the variability of disease germs, a principle in favor of which much evidence has already been obtained in recent bacteriological researches.

DESCRIPTION OF PLATES.

Plate I;

CiBCUm of apigaffectod witli hog cholera laid open to show the ulcers of the mucous mombrano. Tlio ileo-ccecal valve is near the center of the page, and the small intestine, with the cut end tied, is above. The smallest nlcers have sloughs of a iinilbrmly yellowish color; the larger ones have zones of different color, while the largest are brown or blackish. It will be seen from the plato that the slough or new growth in most nlcers projects slightly like a small flat button.

Plate II:

CÜBcnm of a pig fed with viscera from a case of hog cholera, slit open to show the mncons membrane thickened and quite uniformly necrosed, with isolated deeper nlcorations. The ileo-csccal valve is very mueh thickened, its mncons membrane occhyinosed and ulcerated. The lymphatic glands of the meso-colon and those in the angle formed by I lie entrance of the ilcum into the cicenra arc purplish, with cortex engorged with extravasated blood. They illustrate the eoudition of the lymphatics of both thorax and abdomen in the acute hemorrliagio form of the disease.

Plate III:

Ciccum of a pig inoculated with blood from a case of hog cholera. The entire mucous membrane is necrosed. In the upper portion of the figure about the valve there are groups of minute pigment spots. The valve is open to show the intact mucosa of the ileum. This figure also serves to illustrate the condition of the raucous membrane of cajenm and colon in pigs fed with cultures of hog cholera bacilli.

Plate IV:

Ciecum of a pig, showing round and elongated cavities on and around the ileo-ciecal valve. These are ulcers from which the slough dropped away during removal. The base of the nlcers is formed by the! runscnlar tissue of the intestinal wall. The ulcers appear as if the mucosa had been punched out with a sharp instmment. The edge of the nlcers In the upper portion of the colon with the slough still adherent. The lungs in ibis animal were normal, if we except a few collapsed areas from one-half to three-fourths inch across.

Plate V:

Ulcers in the lower portion of the small intestine (ileum); not very frequent. \ote the large, deep ones with puckered, ragged border, and the very small ones with a thin superficial slough, stained with bile.

Plate VI:

Kidney from pig No. 7 (see p. 11), showing the hemorrhagie eoudition of cortex and engorged glomenili. In this animal the disease was marked by the hemorrhagie condition of other organs.

191

192

Plate VII:

Right lung from :i oast! of Iior cholera. The lunj; tissue is nowhere inflltiated or hepatized, but studded with homorrhagio spots which are found iu the parenchyma as well as under the pleura. This animal, placed in an infected pen, died ou the twenty-second day of exposure. There were hemorrhages in the subcutaneous connective tissue; lymphatics in general hemorrhagio. I'etechhe iu stomach and largo intestine. In the caecum and ou the valve a few ulcers with hemorrhagiü ha.se.

Plate VIII:

Heart with snbepicardial hemorrhages especially numerous ou left auricle.

Plate IX:

Fig. I. Collapse of various groups of lobules in the prucipal lobe of a pig's lung. Frequently found in young pigs which have died of hog cholera, in those affected with lung worms, and in a small percentage of those slaughtered during health.

FiG. 2. Broncho-pneumonia affecting animals under various conditions and not infrequently found in animals which have succumbed to hog cholera. (See p. 54). The air cells and .smallest air tubes are shown distended with a yellowish material which is of a dry, caseous consistency, and may be teased out in the form of minute branching cylinders. Plate X:

Fig. 1. From a cover-glass preparation of the spleen of a pig which died of hog cholera. Stained in an aqueous solution of methyl violet and mounted in balsam. Outlined with a camera lucida, using a -fa homog. immersion (Zeiss), ocular 2 (x 800) : fl, distorted red blood corpuscle ; h. bacilli in pairs.

FlG. 2. Section from the enlarged and congested spleen of pig Xo. 94 (see Second Annual Report Bureau of Animal Industry, p. 193), which died very suddenly with extensive homorrhagio lesions of various organs. Spleen hardened in alcohol two hours after death ; stained in aniline water methyl violet and decolorized in I per cent, acetic acid ; mounted in xylol balsam ; outlined as in Fig. 1. Note the large group of bacil'i occupying the capillary meshes of the spleen pulp, all extra-cellular. Plate XI:

Illustrative of the growth of hog-cholera bacilli on gelatine.

FlG. I. Various colonies from gelatine plates: a, embedded in the gelatine layer (deep colony), usually spherical or egg-shaped; ft, flattened colony growing on the surface of the gelatine layer; c, c', oquot;, growing between the layer of gelatine and the glass plate as very thin films; the knobs on o', cquot; represent the part of the growth in the gelatine layer.

FlG. 2 represents both deep (a; and surface colonies (6) growing in a gelatine layer coating the inner surface of a test tube. A tube of gelatine was inoculated by stirring up in it. while liquid, a minute fragment of spleen tissue from a case of hog cholera (No. 4(14, p. 51), transferring a drop from this to a second tube, and then rolling out the latter in ice water. Culture seven (lays old. The zoues on the surface colonies arc very likely due to changes of temperature in the laboratory, alternately retarding and augmenting the growth. This mode of growth is by no means common.

Figs. 3 4 ^ represent the growth of hog cholera bacilli in tubes of nutrient gelatine, showing the isolated colonies in the depth of the gelatine and the cou-flueiit growth on the surface. Fig. 3 represents a culture three days old (epizootic near Washington City, 1885), inoculated from the spleen of a pig. Fig 4, fourteen days raquo;M, inoculated from a culture which was prepared directly from the spleen of a pig in Illinois, 1886. Fig. 5, Inoculated from the blood Of a rabbit which died from inoculation with bacilli from Illinois culture; ten days old. The differeuee in growth observed maybe duo to a greater or less alkalinity of the culture medium or to a slight physiological difference in the bacilli themselves.

193

Plate XII:

Fig. 1, Jgar agar culture of hog oliolera bacilli in thermostat, four days old. Fig. 2. Potato culture under a bell glass, twelve days old.

Fig. 3. Potato culture in a test tube containing an abumluuce of moisture. The plug was made impervious with sterile paraffinc. The growth is whitish, very glistening. The difference in color betweeu Fig. 2 and Fig. 3 is caused by the different conditions of moisture. Plate XIII:

Fig. 1. Coagulation necrosis in the liver of arabbit which died six days after inoculation. The small, yellowish spots are. groups of acini couipletely necrosed. The larger patch to the left shows the necrosis in the form of a network. Fig. 2. Liver of arabbit inoculated with one thirty-second cubic centimeter (hy dilution) of a beef infusion peptonecultureono day old. Dead on the seventh day. The coagulation necrosis on the left is more diffuse. On the right are cysts oicoccidium ovi/orme. Fig. 3. Enlarged spleen from the same rabbit (natural size). Weight of rabbit, 1-| pounds. The spleen of this rabbit was but moderately enlarged as com-pared with the spleens of most rabbits which succumb to hog cholera. FJg, 4. Spleen from a healthy rabbit weighing 2| pounds (i. c, one and a half times the weight of the diseased rabbit. Plati-.s XIV, XV, XVI:

Photomicrographs of hog cholera bacilli which developed in different media. All #9632;were made at n nniform magnification of 1000 diameters, with the Zeiss apo-ohromatic objective of 3^mm and 1.30 numerical aperaturo, using projection ocular Xo. 4 and Abbe condenser with largest diaphragm. OrtLochromatio plates and picric acid screen. Plate XIV:

Fig. 1. Coverglass preparation from spleen of rabbit inoculated with hog cholera bacilli. Stained two fn three minutes in aqueous solution of fuchsiu. Mounted in xylol balsam, x 3 000. Fig. 2. Coverglass preparation from bouillon-peptone culture five days old. Stained in aniline-water-fnchsin for five minutes, and decolorized in one per cent, acetic acid for a few seconds. Mounted in xylol balsam, x 1000. Plate XV:

Fig. 1. Coverglass preparation from bouillon-peptone culture, one day old.

Stained same as Fig. 1 of Plate XIV. Mounted in xylol balsam, x 1000. Fig. 2. Coverglass preparation from gelatine culture two days old. Stained same as Pig. 2, Plato XIV. x 1000. Plate XVI:

Fig. 1. Coverglass preparation from colony of hog cholera bacilli taken from an Esmarch tube, made directly from spleen of pig, fifteen days old. Stained same as Fig. 1, Plate XV x 1000. Fig. 2. Coverglass preparation of hog cholera bacilli from agar culture fifteen days old. Stained same as Fig. 1, Plate XIV. x 1000.

1S612 H c------13

.#9632;

ate 11!

I FLCERATED CAECUIVI

: #9632;: ; #9632; ;;

'S.

Plate VI

#9632;J'

#9632;#9632;^N #p i

,/:

#9632; ^J \ VM

'* I 11

amp;JhIanc tVvit

ULCERS IN ILEUM.

- #9632; V

Jf0

% %

inbsp; nbsp; nbsp; nbsp; nbsp;6.Marxflaquo;ci

HEM( IRRHAGIC HEART

Plate iX

i* i

COLLAPSE AND BRONCHÜ-PNEUMONIA.

late X


	Fig.]


	a
	Fio.2,
	laquo;
	'1! ^WP C	C
	raquo;1 #9632;#9632;laquo;#?

G.Marlaquo; fecit

HOC CHOLERA BACILLI ,

Plate XI.

#9632; #9632;.#9632;,-#9632;'

kgt;lt;_; ;i

Fic.2.

#9632;#9632;-

#9632; Mont focit.

CULTIVATIOJS OK HOC. CHOLERA BACILLI.

Plate Xli

(ri.TIVATlo.V OF H00 CHOLERA BACILLI.

Vu-.l

DIAüXOSIS OF HOG CHOLERA BACILLI-! RABBIT I

plate xiv Photomicrographs of Hog Cholera Bacillus.

'Vi

laquo;4

laquo; 'It f

^r* .'- 

^Klt;^

¹ * '

laquo;aS'' %'

3F -'

^aquot;.:;^*

Fig. 1. x 1000.

COVERGLASS PREPARATION FROM SPLEEN OF INOCULATED RABBIT.

nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;* ^

raquo;

Fig. 2. x 1000.

COVERGLASS PREPARATION FROM LIQUID CULTURE FIVE DAYS OLD.

HOT0 GRAVURf- CO. N

PLATE XV

Photomicrographs of Hog Cholera Bacillus.

s \

Fig. 1. x dOOO.

COVERGLASS PREPARATION FROM LIQUID CULTURE ONE DAY OLD.

, ' *

- . 1

^hj^i - ' #9830; -'S:* \ *laquo;raquo;-gt;/ -

m * r % ' -amp;*-*_ ^x '

#9830; *v

Fig. 2. x 1000.

COVERGLASS PREPARATION FROM GELATINE CULTURE TWO DAYS OLD.

Inbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; PLATE XVI

I Photomicrographs of Hog Cholera Bacillus.

Fig. 1. x 1000.

COVERGLASS PREPARATION FROM ROLL CULTURE (eSMARCH TUBE) FIFTEEN DAYS OLD.

fr'-*.quot;'nbsp; nbsp; nbsp; nbsp; nbsp; gt;

Fig. 2. x 1000.

COVERGLASS PREPARATION FROM AGAR CULTURE FIFTEEN DAYS OLD.

nor:gt; c.RAvitRr CO rj gt;

m-7-

_| _|

#9632; :-,-

#9632;

^^. ,......#9632;#9632;' '

quot;

IN D E X.

Page.

Jgar-agar cultures___....................................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;08

Attenuation of bog cholera virus by heat..................................nbsp; nbsp; nbsp; nbsp; nbsp;107

Uaeillus of hog cholera, description of................................_____nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;GS

Bacteriological observations..........................................__..nbsp; nbsp; nbsp;38,58

liiology of hog cholera bacilli.............................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;CRraquo;

Brine, vitality of virus iu............................................_____nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;88

Burial of carcasses...........................................____........nbsp; nbsp; nbsp; nbsp; nbsp;126

Butyric bacilli in hog cholera cases...................................____nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;58

Buzzards as carriers of disease............................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;01

Calomel, effect on swine...................................................nbsp; nbsp; nbsp; nbsp; nbsp;130

Carbolic acid as a disinfectant............................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;88

crude, as a disinfectant......................................nbsp; nbsp; nbsp; nbsp; nbsp; 91

Cathartics, effect on swiue.............................___................nbsp; nbsp; nbsp; nbsp; nbsp;13fgt;

Causation of hog cholera...................................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;63

Chloride of zinc as a disinfectant..........................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;KO

Complications iu hog cholera..............................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;54

Contact with the sick producing hog cholera..............................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;51

Corrosive sublimate {see Mercuric chloride)................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;88

Cultivation of hog cholera bacilli.........................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;OS

Cupric sulphate as a disinfectant..........................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;90

Denmark, swine disease in................................................ 181,183

Detmers, Dr. H. J., investigation of hog cholera..........................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;28

Diagnosis of hog cholera bacilli...........................................nbsp; nbsp; nbsp; Ofi.Clraquo;

Digestive tract as a channel of infection...................................nbsp; nbsp; nbsp; nbsp; nbsp;105

Diseased viscera, feeding to swine. (Sec Feeding.)

Disinfectants, effect on hog cholera virus..................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;87

use of......................................................nbsp; nbsp; nbsp; nbsp; nbsp;131

Distribution of hog cholera bacilli in the body.............................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;05

*} Drying, effect on hog cholera bacilli.......................................nbsp; nbsp; nbsp; nbsp; nbsp; 78

Dysentery, relation to hog cholera.........................................nbsp; nbsp; nbsp; nbsp; nbsp;122

Etiology of hog cholera. (.See Causation.)

.lt;

Feeding hog cholera bacilli to swine.......................................nbsp; nbsp; nbsp; nbsp; nbsp;107

viscera to produce the disease......................... 50,105

Food as a means of infection..............................................nbsp; nbsp; nbsp; nbsp; nbsp;105

Fowls, effect of inoculation on.............................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;73

France, swino disease in...................................................nbsp; nbsp; nbsp; nbsp; nbsp;186

Freezing, effect on hog cholera virus.......................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;76

Gelatine cultures of hog cholera bacilli....................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;67

Great Britain, swine fever in..............................................nbsp; nbsp; nbsp; nbsp; nbsp;173

Guinea-pigs, inoculation disease in........................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;73

Heat, effect on hog cholera virus..........................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;75

Hemorrhagic lesions......................................................nbsp; nbsp; nbsp; 34,52

History of hog cholera in the United States................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;9

investigations......................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;14

195

.mmmmm

196

Vage.

Hog cholera, bacillus of..........................................C3,CG, Trgt;,T8, SO, 87

causidion of.................................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; t'.'i

history of investigations concemiag...........................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;14

iutroiluctiou and spread in tlio Uuitod States..................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;'#9632;gt;

or allied diseases in France...................................nbsp; nbsp; nbsp; nbsp; nbsp;ISO

Great Britain.............................nbsp; nbsp; nbsp; nbsp; nbsp;l~i

Sweden and Denmark....................nbsp; nbsp; nbsp; nbsp; nbsp;1S1

prevention of................-...............................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;2(1

produced by feeding........................................öO, 105,107

inoculating pure cultures of hog cholera bacilli...nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;5rgt;

treatment of................................................. 25,135

Hydrochloric acid as a disinfectant.......................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;91

Illinois, investigations in..................................................nbsp; nbsp; nbsp; nbsp; nbsp;119

Infection of swine, modes of...............................................nbsp; nbsp; nbsp; nbsp; nbsp;105

luocnlation experiments. (.Sec Preventive inoculation.)

of small animals with hoji' cholera bacilli......................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; 69

Iodine as a disinfectant...................................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;89

Isolation in hog cholera...................................................nbsp; nbsp; nbsp; nbsp; nbsp;123

Klein, K., investigations in swine diseases.................................nbsp; nbsp; nbsp; nbsp; nbsp; 177

Law, Dr. J., investigations in swine diseases ..............................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;19

Laws with reference to hog cholera........................................nbsp; nbsp; nbsp; nbsp; nbsp;1-7

Lime as a disinfectant ....................................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;93

Lundgren, Dr.,]., investigations of........................................nbsp; nbsp; nbsp; nbsp; nbsp;1S5

Lungs, infection by way of................................................nbsp; nbsp; nbsp; nbsp; nbsp;H-

Long lesions in hog cholera...............................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;54

Marseilles, spread of swine diseases from..................................nbsp; nbsp; nbsp; nbsp; nbsp;18^

Maryland, hog cholera in...........................................-......nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;59

Nebraska, investigations in.....................................-.......nbsp; nbsp; nbsp; nbsp; nbsp;116

Pathological action of hog cholera bacilli..................................nbsp; nbsp; nbsp; nbsp; nbsp;113

Pens, vitality of virus in..........................................-.......nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;^o

Permanganate of potash as a disinfectant.................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;8',)

Pigeons, inoculation of..................................-.................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;' #9632;-'

vaccination of, with sterilized cnltnrcs............................nbsp; nbsp; nbsp; nbsp; nbsp; 155

Plates, description of.....................................................nbsp; nbsp; nbsp; nbsp; nbsp;l''^

Post-mortem appearances in bog cholera............................34,39, ölraquo;, 106,107

Potato cultures...........................................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;quot;deg;

Prevention of hog cholera .......................-......................*6i 123,179

Preventive inoculation of swine by feeding................................nbsp; nbsp; nbsp; nbsp; nbsp;151

with small doses of strong virus...........nbsp; nbsp; nbsp; nbsp; nbsp;Palraquo;

with sterilized cultures....................nbsp; nbsp; nbsp; nbsp; nbsp;lo'.l

Prevention of swine fever.................................................nbsp; nbsp; nbsp; nbsp; nbsp; 'quot;'

Public health, relation of hog cholera to...................................nbsp; nbsp; nbsp; nbsp; nbsp; l-'O

Rabbit, disease produced by feeding.......................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;'-

Rabbit, inoculation-disease in.............................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;'0

Snow, Dr. E. M., investigations of.........................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;V'

Soil, disinfection of, with lime,............................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;'#9632;^,'.gt;

vitality of bog cholera bacilli in.....................................nbsp; nbsp; nbsp; 80,86

Spores, do hog cholera bacilli produce.....................................nbsp; nbsp; nbsp; nbsp; nbsp;101

Staining of hog cholera bacilli............................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;quot;5

Streams distributing virus................................................nbsp; nbsp; nbsp; nbsp; nbsp; ''-''

Subcutaneous inoculation of swine........................................nbsp; nbsp; nbsp; nbsp; nbsp;lo'¹

Sulphate of copper. (ÄccCupric sulphate.)

Sulphuric acid as a disinfectant............................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;90

Sutton, Dr. G., investigations of swine diseases............................nbsp; nbsp; nbsp; PJ, 14

197

';

Paga.

Sweden, swiue discuses in.................................................nbsp; nbsp; nbsp; nbsp; nbsp; 181

Swedish and Americau lioj; cliolera, comparison of................,.........nbsp; nbsp; nbsp; nbsp; nbsp; 185

Swine fever, post-mortem lesions in.........................................nbsp; nbsp; nbsp; nbsp; nbsp; 17(1

symptoms of.................................................nbsp; nbsp; nbsp; nbsp; nbsp; 174

.Symptoms and post-mortem appearance in bog cholera......................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;X5

Table of hog cholera epizootics in the United Staves........................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;11

Tallies showing vitality of hog cholera bacilli in the soil................81,83,84,85

Treatment of hog cholera................................................. 25,135

Typhoid fever, relation to hog cholera.....................................nbsp; nbsp; nbsp; nbsp; nbsp; 121

1 'Icerative lesions......................................................... 35,53

Vacuo cultures............................................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;tilt

Veins of swine, inoculation into...........................................nbsp; nbsp; nbsp; nbsp; nbsp;Ill

Vitality of hog cliolera bacilli in the soil..................................75,80.8(5

Virus, at ten nation of, by heat___..........................................nbsp; nbsp; nbsp; nbsp; nbsp; 1G7

Water, life of h:)g cholera bacilli in.......................................nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;T(gt;



	*#9632;KJ.e-*	UL

	#9632;^:.:^;

	U. S. DEPARTMENT OF AGRICULTURE.

	HOG CHOLERA:

	ITS HISTORY, NATURE, AND TREATMENT,

	AS DETEISMISED I'.V

	THE INQUIRIES AND INVESTIGATIONS

	OF

	THE BUREAU OF ANIMAL INDUSTRY.




	WASHINGTON: GOVERNMENT FEINTING OFFICE. 1889. J5C12 u C-----1

	i;


	Ill U. Ml LUII .1 I	quot;^^^^^quot;

	rape. lt;)i:i)i.\Ai;v LniK as a Disinfectant: for Hog Cholera...................nbsp; nbsp; nbsp; nbsp; 93 Disinfection of the sun, with limk.......-------........................nbsp; nbsp; nbsp; nbsp; 99 Is there aw Resistant Spoke state in- the Life Histohy of the Bacillus of Hi Mi Cholera ..-............- ................... .........nbsp; nbsp; nbsp; l^fll Ways in which Swine become Infected.................................nbsp; nbsp; nbsp; 1quot;5 By way of the digestive tract...........................................nbsp; nbsp; nbsp; 105 a. Feeding diseased viscera...........................................nbsp; nbsp; nbsp; 105 h. Feeding pure culture of ITog Cholera bacilli.......................nbsp; nbsp; nbsp; 107 Subcutaneous luoculation...............................................nbsp; nbsp; nbsp; I¹'' Intra-venous inoculation................................................nbsp; nbsp; nbsp; 1quot; Infection by way of the lungs...........................................nbsp; nbsp; nbsp; U* Some Observations on the Pathological Action of Hue Choleha Bac- TERIA.....................................................................nbsp; nbsp; nbsp; nbsp;^11:! Bacteriological Investigations of Hog Cholera in Nebraska, Illinois, and Maryland....................................................nbsp; nbsp; nbsp; '#9632;'#9632;quot; Differential Chauacters of the Hog Cholera Bacillus..............nbsp; nbsp; nbsp; 119 Bacillus from Nebraska..................................................nbsp; nbsp; nbsp; ^1I'^J Bacillus IViur. Illinois....................................................nbsp; nbsp; nbsp; nbsp;''#9632; Bacillus from Maryland...............-..................................nbsp; nbsp; nbsp; ^l^⁰ Relation of Hog Cholera to the Pcblic Health......................nbsp; nbsp; nbsp; 120 Prevention of Hog Cholera.......................#9632;.....................nbsp; nbsp; nbsp; I²³ Isolation, Disinfection, and Cleanliness as Paeventive Measuresnbsp; nbsp; nbsp; nbsp;123 Tkeatmf.xt of Hog Cholera..............................................nbsp; nbsp; nbsp; nbsp;'#9632;'#9632;' Experiments on the Prevention of Hog Cholera by Inoculation nbsp; nbsp; nbsp; 139 1. luoculation of small doses of strong virus in the form of liquid culture..nbsp; nbsp; nbsp; nbsp;139 II. The effect of feeding small (iiian titles of eulturos on immauitj.........nbsp; nbsp; nbsp; 151 III, Injection of sterilized call are liquid to produce immunity..............nbsp; nbsp; nbsp; nbsp;154 Tests with sterilized rah arcs on pigeons.............................nbsp; nbsp; nbsp; nbsp;'#9632;'#9632;^, 'iVsis with sterilizeil cultures on pigs ................................nbsp; nbsp; nbsp; loJ Exteuiments on cue zVttenitation of the Hog Cholera Bacilli by Heatnbsp; nbsp; nbsp; 167 Hi.d Cholera ok Diseases closely Allied to it in other Countries..nbsp; nbsp; nbsp; 173 la Great Britain........................................................nbsp; nbsp; nbsp; nbsp; '' In Sweden and 1 ten mark............................................... , ,, .........nbsp; nbsp; nbsp; löG la 1rauce............................................................



	LLUSTRATIONS,

	Page. Investigation of Hog Cholera: Plates I, II, III, and IV. Illustrating necrosis and uleeration of (lie nm- cosa of the large iutestiue, more particularly the cajcum.......nbsp; nbsp; nbsp; nbsp;i'.M \^r. Showing ulcers in the ileuiu.................................nbsp; nbsp; nbsp; nbsp;1^lt;.)4 VI.nbsp; nbsp;Showing hemorrhagic kidney...............................nbsp; nbsp; nbsp; 194 VII.nbsp; Showing hemorrhagio lung................................nbsp; nbsp; nbsp; ]!i4 VIII.nbsp; nbsp;Showing hemorrhagio lieurt....................1..........nbsp; nbsp; nbsp; 194 IX.nbsp; nbsp;Collapse niul broncho-pneumonia............................nbsp; nbsp; nbsp; 194 X.nbsp; nbsp;Microscopic characters of hog cholera bacilli...... ..........nbsp; nbsp; nbsp; 194 XI.nbsp; XII. Growth of hoy; cholera bacilli in various culture media.-nbsp; nbsp; nbsp; 194 XIII.nbsp; nbsp;Spleen and liver of rabbit inoculated with hog cholera bacilli ..........................................................nbsp; nbsp; nbsp; nbsp;191 XIV,nbsp; XV, XVI. Photomicrographs of hog ehulera bacilli, showing variation due- to growth in different media.....................nbsp; nbsp; nbsp; 194 5



	LETTER OF TRANSMITTAL.

	WASHEsraiON, D. C, January IS, 1SS9. Sir : T have the honor to submit herewith a report upon the history nature, ami treatment of the disease known in the United States as hoy cholera. Oar knowledge of this pest lias been (lev eloped almost entirely by the inquiries ami experimental investigations of the Bureau of Animal Industry; and while much of the iufortnation contained in tiiis volume has been published in the reports of the Department of Agriculture, a systematic and complete statement of the facts has never before been made in a connected manner. It has been discovered in the course of these, investigations that there are two very different and distinct epizootic diseases of swine in this country which are widely prevalent, and which had previously been spoken of under-the one name of hog cholera or swine plague. These two names had, therefore, been used synonymously previous to 1S8G, when the differences between the diseases were pointed out in there-ports of this Bureau. It was then deemed best to apply the term hog cholera to that disease in which the intestines were found most affected, and in which the symptoms would come nearest to .justifying the appellation. The other malady appeared identical, not only in symptoms and lesions but in the microbe which caused it, with the disease recently described in Germany by both Loftier and Schütz under the name of tfc/HomeseMc/ie, or swine plague. For this reason it was considered best to call this affection swine plague in the reports, and thus preserve uniformity and prevent confusion of ideas in reference to the diseases of swine in different countries. This volume treats exclusively of hog cholera, as it is the malady which has been longest under investigation ; but the material is on hand for an almost equally complete volume on swine plague, which we hope soon to submit for publication. There are, of course, many other diseases of swine, some of which are. communicable In a certain degree, but none of which are so widespread and fatal as the two that have been named. Some of these, especially the parasitic ones, are receiving attention, and may in the future be treated at length in the bulletins of this IJureau. The greater part of the detailed study of the disease, the planning of experiments, and the bacteriological investigations have been carried



	8 out by Dr. Theobald Smith, while tho couducting of the experimeuts, the care of the experimental animals, and the general management of the experiment station have been under the direction of Dr. F. L, Eilborne. I can only speak in the highest terms of tlie untiring industry and sldll displayed by both of these gentlemen. The experiments in regard to prevention and medical treatment are being continued, but it is confidently believed that an understanding of the facts detailed in this volume will enable the owners of hogs to prevent or even arrest the great majority of outbreaks. It should be understood, however, that the measures indicated must be enforced promptly, energetically, and thoroughly. J). E. 8ALMOF, Chief of the Bureau of Animal Industry. Hon. Xorgt;ian J. COMCiN, Commissioner of Agriculture.



	10 country involved. This rapid increase of the number of affected sections would seem to indicate that ;i contagious disease had been introduced and carried to widely separated sections of the country, from which it extended until, with a year favorable to its propagation, we find a sudden and alarming increase. Turning again to the number of outbreaks reported, we und, in 1S-1G, that there were two in Xorth Carolina, one in Georgia, one in Illinois, one in Indiana, and one in Ohio, in 1847 four are given in Tennessee and one in Virginia. In 1848 we bear from it in one county in Illinois, two in Indiana, two in Kentucky, one in Forth Carolina, and one in Virginia. In 1849 it is mentioned as in one county in Indiana and in one county in Ohio. In 1850 we have accounts of three outbreaks in Georgia, one in Pennsylvania, one in Indiana, two in Kentucky, one in North Carolina one.iu Ohio, and two in Tennessee. In 1851 there were outbreaks in Illinois, Indiana, and Tennessee. In 1852 there were two reported in Illinois, two in Indiana, one in Missouri, and one in Ohio. In 1S53 it invaded two new counties in Illinois, two in Indiana, two in Kentucky, one in North Carolina, four in Ohio, two in Tennessee, one in Texas, and one in Virginia. In 1854 it appealed in one more county in Illinois, four in Indiana, five in Kentucky, two in North Carolina, two in Ohio, and one in Tennessee. In 1855 it is found m six counties in Illinois, five in Indiana, one in Kansas, four in Kentucky, one in Missouri, two in Tennessee, and one in Virginia. The number of outbreaks mentioned by correspondents, it will be seen, is not less than ninety-three for the ten years from 1810 to 1855 inclusive. As compared with the ten outbreaks reported for the previous thirteen years this is an enormous increase. There can be little doubt that it was during the period from 1840 to ISÖ.l that hog cholera became scattered over the country and fairly began that work of destruction which has become so familiar to us in later years. Below will be found a tabulated statement of the replies from nearly eight hundred and fifty of our correspondents. The figures show the number of original hog-cholera infectious reported for the different periods ironi the first recorded appearance of the disease in this country to 1SS7. Of course there have been many counties infected within that time which are not referred to in these communications, but the large number that were mentioned gives as perfect an idea as can now be obtained of the development and spread of this contagion. It is to be remembered that the outbreaks mentioned arenot secondary infections, but are the first outbreaks of the disease in the correspondent's local. ity, and in most cases the lirst which occurred in his county. In nearly all cases it is stated that previous to the outbreak referred to the health of hogs had always been good, and the losses from disease had been confined as a rule to a single animal at a time.



	12 of pknuopueumoiiia of cattle, than that it appeared spoutaneoosl; or was developed by the conditions of life in this country. Having been once introduced it spread gradually, following the lines of commerce and being for a long tinieconliued to them, until, extending step by step, it has at one time or another invaded every section of the country in which swine raising is a prominent industry. Dr. George Sutton of Aurora, Ind., in 1858, wrote as follows: I bavc seen notices of this disease prevailing in tlie States of Illinois, Kentucky, Indiana, Ohio, New York, Massachusetts, I'eimsylvania, and Maryland. It has prevailed extremely in Indiana, particularly in Dearborn, Ohio, Ripley, Rush, Deeatur, Brown, Bartholomew, Shelby, .Johnson, Morgan, Marlon, Boone, I'osey, and Sullivan Couuties. It has also prevailed in Campbell, Kenton, Boone, Gallatin, Carroll, Breck-iuridge, Bullitt, Bath, Heory, Henderson, Nicholas, Livingston, Union, and Crittenden Conuties, Kentucky. It has also prevailed in Hamilton, Butler, Clinton, Fayette, and Cletmont Counties, Ohio. Also indifferent portions of Illinois, and very severely in Wayne, White, and Gallatin Counties. It has also prevailed in the State of New York. The Ohio Fanner for January ;i, 1857, quoting from the Buffalo Republic the extensive prevalence of the disease, says that quot;in western New York especially we learn it, has been very fatal, but is now over. In conversation with one of the most extensive dealers in the neighborhood, a day or two since, he informs us that about six weeks ago he lost about four hundred in a very short space of time. A distiller in Jordan, during the month of September, lost fourteen hundred, which cost, in addition, over sect;1,000 to have them buried, lu Rochester, at all the principal points, and even among the farmers, the mortality has exceeded anything ever before heard of. A butcher in this city not long since purchased SöOO worth of fat hogs, but they died so rapidly on his hands that he scarcely realized sect;75 on the investment.quot; The Worcester (Mass.) Spy reports that many fanners in that city and vicinitA are losing their swine by the mysterious and fatal disease known as the hog cholera. In the southeast part of the town it prevails in a greater or less extent upon nearly every farm. In most cases the disease is traced to Western bogs that have been sold by the drivers the present season, and which seem to have communicated the contagion to the other inmates of the sties in which they have been kept. It is known that of many droves of Western shouts that have been sohl at Brighton this season, and peddled about the State, nearly all have died. The disease lias, no doubt, prevailed extensively in other part? of the country, of which I have seen no notice. In this section of the country it has been extremely fatal. Over portions of Dearborn County it spread from farm to farm, and some of our fanners lost from 70 to 80 out of 100 of their hogs. At the distilleries the mortality has been very severe. I received information that more than 11,000 died at the distillery in New Richmond, in the summer and fall of 1856. The owners of the distillery at Aurora inform mo that they have lost between 6,000 and 7,000. A gentleman informs me that he lost in 1856, at Ingra-ham's distillery, in Cincinnati, from the 1st of August up to the 2-lth of October, 1,235, losing 1,152 out of a lot of 2,408. Another gentleman informs me that at the distillery in Petersburgh, Ky., he lost from the 1st of June up to the 18th of October, 1850, 2,576. I have also received information from several other distilleries where the losses were large. * According to Dr. Sutton, this disease first appeared in Dearborn County, Ind., in July, 1850. * George Sutton, M. ])., Observations on the supposed relations between epizootics and epidemics, and experimental researches to ascertain the nature of the recent epizootic among the swine, and the effects which diseased meat may have on human health. The North American Medico-Chirnrgieal Review, May, 1858, pp. 483-504,



	13 Dr. E. M. Snow writes that Diiriny; the last live yours this disease has hc.en seen, from time to time, in portions of the more eastern States, sometimes, as in western New York in 185(3, proving qnite severe and fatal in comparatively limited localities, lint in the Eastern States it has, to a great extent, originated with and has generally heen confined to hogs imported from the West. I think that in no State east of Ohio has (he disease prevailed extensively, or attained the character of a wide-spread epidemic. In the vicinity of Providence, R. I., it has prevailed to some extent, more particularly among large herds of swine daring each of the last live winters, but has been mostly eontined to hogs brought from the West, and has usually disappeared with the approach of warm weather. During the last winter it was more severe than in any preceding, and was not eontined to Western hogs. Neither did the disease, as heretofore, cease with cold weather, but it continued until August, having destroyed more than ')U0 hogs in Providence and in the, adjoining towns during the first seven montlisof the present, year, 1861. I havealso heard of its prevalence in various towns in Massachusetts during the same period.' The losses from hosquot; cliolera in the United States have been enormous. Estimates Lave front time to time been made from carefully compiled data, and these have, so far as the writer is aware, never been less than $10,000,000, and have reached $25,000,000 annually. The inclusion of losses from other diseases is, however, unavoidable in such estimates, and consequently some allowance must be made for these. The recent identification of an epizootic pneumonia of hogs by the Bureau of Animal Industry, a disease which appears to be identical with the /Schweine-senche o£ German writers, shows that the varieties of swine diseases in this country are more numerous than has been supposed. The erysipelas of Europe (French, rouget; German, HotMauf), and charhon have not yet been identified as occurring in an epizootic or enzootic form among swine in the United States but the existence of these diseases is not impossible, as the investigations have not yet been sufficiently uu-nierous to reveal the nature of all such outbreaks. The diagnosis of such diseases has been very uncertain in the past, because the symptoms were not clearly defined, and not always sufficiently characteristic. The most reliable means of discrimination between these maladies at present is the isolation of the microbes which produce them. The characteristics of these organisms are now so well known that the bacteriologist has no difficulty in distinguishing between them. Kdwln 11. Snow, M. D., Hog Cholera. Annual Report U. S. Department of Agriculture, 1861, p. 147.



	15 mortality of hogs that were ia pastures or fed ou slop was from 33 to 45 percent., but it was frequently much more fatal if hogs were fVil on cimiin sortie instances ranging from seventy to eighty out of thu hundred, and in some instances even higher. I found on opening the bodies of hogs that had died of this disease that they all presented evidences of a diffusive form of inflammation. From sixty-seven hogsthat I have examined I found it was not confined to any particular tissue. Sometimes this inflammation was confined to one organ; in other cases it attacked several at the same time. The shin frequently presented patches of inflammation, and often had a purple appearance. In cutting through parts that were the most inflamed, the skin was swollen and the cellular tissue was infiltrated with serum. Frequently, however, the skin was merely discolored, without any swelling whatever. The stomach was occasionally distended with food, and the mucous membrane in nearly every instance presented evidence of inflammation, sometimes extending over the whole stomach, at others only in patches. It was generally of a deep-red color, thickened, and frequently softened. Sometimes it was covered with a viscid mucus: in other instances there was an effusion of blood into the stomach. The mucous membrane of tho small or largo intestines, where there had been diarrhea or dysentery presented in all instances evidences of inflammation ; in patches it was red, thickened, sometimes softened, and occasionally ulcerated ; where there had been dysentery there was generally bloody mucus found in the large intestines. The bladder generally contained urine ; sometimes its mucous membrane was inflamed, and in one instance there was an eflnsion of blood into this organ. In a large number of cases I found evidences of peritoneal inflammation, such as redness of this membrane, effusion of turbid or bloody serum, adhesions between the intestines and between the intestines and sides of the body. In three instances blood was effused into the peritoneal cavityin one instance more than a quart; it appeared in this ease to come from the liver. The liver was occasionally the seat of this inflammation, not only in its investing membrane, but tho parenchyma; sometimes there were abscesses, and iu one instance portions of it were gangrenous. Tho lymphatic glands were generally of a dark-red color, frequently resembling clots of blood. This disease of the lymphatic glands was of common ocenrrence. The lungs were frequently tho seat of this inflammation, portions of one or both presenting different appearances, from simple congestion to complete hepatization; .sometimes there was nleeration, and frequently there was a turbid or sero-purulent or bloody effusion into the pleural cavity; sometimes there were extensive adhesions between the lungs and pleura of tin- ribs. At first I was inclined to believe this malady to be a form of plenro-pneunionia, but after I became better acquainted with it I found that the inflammation was not uniformly confined to any organ. In a number of instances the mucous membrane of the bronchia, was deeply inflamed and the inflammation extended to the trachea and larynx. In several instance's the larynx was inflamed, resembling laryngitis. One animal that had groat difficulty in breathing and could make no noise I had knocked in the head, and on examination I found the mucous membrane of the larynx and epiglottis inflamed and swollen; also the tongue was swollen. There were evidences in several instances of pericarditis, which had produced adhesions between the heart and the pericardium. The brain, from the difficulty of opening the skull, was examined only in one instance; it- was found healthy, although I feel confident it was frequently the seat of tho disease. From these examinations we see that it is a misnomer to call this malady cholera. It is a contagious inflammatory disease, the inflammation being confined to no particular tissue, sometimes attacking only one, at others several, in the same animal. Evidences of this inflammation were found iu the dermoid, the cellular, tho serous, the mucous, and glandular tissues. I consider it a diffusive form of inflammation from the manner in which I have witnessed it spread along tho skin. In one night I have seen it extend from the eye to tho earthe car becoming inflamed and swollen.



	17 (7) I inoculated, ou the 38tb of CTotober, five healthy hoga witli tlio blood taken from the inflamed tissaes of hogs that had died of this disease. On the fourteenth day (November It) they were all unwell, and all died with the esception of one. In three inflammation spread from the point where they wen; inoculated, along the skin and down the legs, which became very much swollen. 1 can not say that this inflammation was caused by the iuoculatlou, for it did not appear until the fourteenth day, and many hogs had this external form of disease. From these experiments I think that we not only ascertained that this disease was infections,but that the infection had a latent period of from twelve to Qfteea days. Observations have since led me to consider the latent period as varyinj; from twelve to twenty days. These experiments also showed that the hogs in the pens were not dying from strychnine in the slop. A statement was going the rounds of the papers about this time that strychnine was used in making yeast at the distilleries, and was poisoning the hogs at these places in large numbers. The manner in which this disease in many instances spread among hogs from farm to farm also showed most conclusively that it was infectious. Otic farmer had 75 hogs that he turned into a eorn-lield to fatten. These hogs had been exposed to the disease, had become sickly, and numbers had died. He bought '#9632;''gt;gt; more; these were all healthy : they were put into the same field with the diseased hogs ; in two weeks they were unwell, and numbers died. He bought tö more, all healthy, and put them in the same field; in two weeks they began to show symptoms of disease, and in a few days after a number died. Finding that be was likely to lose all his hogs, he sold 50 of the fattest that were left to the butchers in Cincinnati, at a reduced price, as diseased hogs. These hogs, it was said, were purchased for their fat, to he used in the manufacture of lard oil. Alter deducting the ;quot;gt;lt; he sold, he lost, out of the 156 all but 10. A large number of facts could be given, if necessary, to show the contagiousness of the disease. Hogs thai had been once under the Influence of this malady appearnot to be susceptible to a second attack. Although placed in pens with diseased hogs they continue healthy and fatten, and not a single instance can I find of hogs having this disease twice. There is reason to believe that this malady occasionally prevails at the distilleries in a mild form, as the. old hogs at many of these places did not take the disease. Hut why it .should suddenly have assumed so malignant a character is as difficult to account for as that scarlatina, from being at one time the mildest of diseases, at another becomes one of the most malignant. On the farms the old and young hogs appear to be equally susceptible to the disease. In 1SG1 Edwin M. Snow, M. D., of Providence, II. I., contributed a paper on hog ckolera to the Annual Report of the United States Dc-partment of Agriculture (pp. 147-154). The symptoms of the disease lie gives its follows: The Symptoms, as described by persons uunccustomed to such observations, are extremely various. By combining the information obtained from others with results of our own observations the symptoms, as seen during the life of the animal, are nearly as follows : (1) Refusal of food.This is the first symptom usually noticed by those who have the care of the animals, though, as will 1w seen hereafter, this sympton by no means indicates the beginning of the disease. The refusal of food, after it is first noticed, generally continues through the whole; sickness, and food of every description is mostly refused. {2) Great thirst.This is constant, and large quantifies of cold water will be swallowed if it can be obtained. Even after the animal is unable to stand alone it will drink cold water with eagerness. {'#9632;]) After a time, the length of which varies very much, the animal begins to show signs of weakness; reels, staggers, and. in attempting to walk, often falls down. 15012 h C-----3



	19 the innei surface was alcerated to some extent. In two cases worms were found in siiiall intestines, Imt this \v;is probably a merely accidental occurrence, and had do necessary connection with the disease. Large inUslines.The inner coat of the huge intestines was generally inflamed and .softened with ulcerations to a greater or less extent, and they were frequently so tender as to be easily torn with the fingers. On account of their diseased condition their inner coat was frequently discolored. The inflammation and nlceration of these intestines are probably the principal cause of the diarrhea in this disease. Kidneys,These organs were, in every case, mach mure pale and yellow than natural; this condition was well marked. The /(Ver and MoWrr were generally healthy. In some eases water was found ill the cavity of the belly and of the chest, and in the membrane snrrounding the heart (heart-case). In two eases numerous minute purple spots were seen upon the membrane Uniug the walls of the belly. The urine was often changed from the healthy condition, containing albumen and other diseased products, not, however, noticeable to the eye. I'leers upon the feel and in the mouth were often found. The brain was not examined, as there were no symptoms observed which seemed to indicate disease! of this organ. It may be at times affected, hut is probably more rarely so than the other organs of the body. Such are some of the most important appearances which are found on examination of the bodies of hogs which havedied with this disease. It will be noticed that three of the diseased conditions I have described are prominent, important, and such as would be readily recognized by the most ignorant observer. These are, first, the pleurisy and inthnmnation of the lungs; second, the inflarama-tiou, nlceration, and softening of the inner coat of the large intestines: and, third, the pale and yellowish color of the kidneys. One or more of these diseased conditions will be found in every case, and in perhaps a majority of cases they will all be found in the same animal. While Dr. Snow admitted the disease to be epizootic lie did not consider it to be contagious. Indeed, be neither considered epizooticnor epidemic diseases to be contagious, but, on the contrary, held thattboy were caused by (1) quot;an epidemic atmospherical poison,'quot; and (2) quot;the local conditions or circumstauces adapted to receive and propagate tlie poison existing' in the atmosphere.quot; In 187.quot;) Prof. James Law contributed a paper to the report of tbo Department of Agriculture giving'his observations upon bog cholera, or ^u intestinal lever in swine,quot; in whicb lie so completely embraces tlie knowledge of our swine epizootics as it then existed that bis paper is here reproduced in fall. It is as follows: Synonyms.Typhoid fever, enteric fever, typhus carbnncular fever, carbuncnlac gastro-eutoritis, carbuncular typhus, pig distemper, blue sickness, blue disease, purples, red soldier, anthrax fever, scarlatina, measles, diphtheria, erysipelas. Definition.A specific, contagious fever of swine, characterized by congestion, exudation, ecchymosis, and ulceration of the mucous membrane of the intestines, and to a less extent of the stomach; by general heat and redness of the skin, efiaceable by pressure; by small red spots, complicated or not by elevations and blisters; by black spots and patches of estravasated blood on the integument, the snout, nose, eyes, month, and all other visible membranes, and on internal organs, ineffaceable by pressure and tending to sloaghing; usually by liquid and fetid diarrhea: and by a very high and early mortality. The malady has been long known to pig-raisers and pork-factors in the Old World and the New-, but in veterinary works it has been mistakenly placed in the list of malignant anthrax affections, to which many of its lesions bear a striking resciu-




	6	^ ,3-;: t Ä^ C -;: i c-; ^ _ - o-i-





	BIBLIOTHEEK UNIVERSITEIT UTRECHT 2912 638 4


	*tmmmmmm*

	mm

	I



	23 ward the pylorus, and its mncona membrane is often black thxongboat from tlio close aggregation of peteccbise. The small intestines are usually extensively congested, and of a deep red, in many cases approaching to Mack, as examined externally. Their mucous membrane in such parts is equally high colored, studded with petec-chiie, and in some cases lined by a linn, semi-flbrinous exudation. A more constant condition is the presence of minute sloughs or erosions in the seat of peteccbiea, and of equally small elevations, duo to excessive cell-growth, beneath the epithelium. These commonly have a whitish center, with a yellowish or red border. Such is the appearance in cases that prove fatal within two or three days. In those that have survived longer, extensive ulcers appear, of an inch and upward in diameter, evidently the sequel of the petecchite, and especially of the eruption. These ulcers are often covered by black scabs or sloughs, have irregular projecting margins and a variously colored center, consisting of cells in process of disintegration. They are sometimes situated on Fever's patches, but show no very marked preference for those over other portions of the mucous membrane. The large intestines present a similar varying vascularity, discoloration, petecchise, deposit, softening, and ulcera-tion. The changes are especially marked in the caecum and colon and in the rectum close to the anus. The solitary glands are often large and open, but the ulcers show no particular preference for the points occupied by them. Extensive extravasations of blood into the coats of the bowels and among their contents are not infrequent, and in certain exceptional and advanced cases the peritoneum is inflamed and false membranes bind the bowels together or to oilier organs, or to the walls of the abdomen. In the wind-pipe and air-passages within the lungs, the mucous membrane is usually mottled with black petecchise, or covered by a vise id mucous exudation. The anterior lobes of the lungs are of ten solidified by exudation, but remain bright, red, tough, and elastic (gplenisatiou). Limited hepatizatiou is also exceptionally met with, and oven false membranes on the pleura or pericardium. Petecchise are commou over the various internal organson the lungs, pleura, heart, pericardium, diaphragm, peritoneum, liver, pancreas, kidneys, and bladder. The spleen is large and dark, as is usual in connection with blood poisons. Uoth sides of the heart contain clots of blood, extending from the auricles and ventricles into the great vessels. In the worst cases, the clot is black, soft, and somewhat diffluent; exceptionally it is firm, and shows a distinct bully coat. The blood-globules, as seen under the microscope, arc more or less puckered or crenated at their edges, and mixed with an excess of granular debris and even in some instances spores of a fungus (tnicrococous), As illustrating tin! various lesions in different cases, I append from my notes of post-mortem examinations two that occurred with two years' interval, near Edinburgh and London, respectively: I.No. 4. A three months' old, while Yorkshire x'ig in excellent condition. Examined a few hours after death, being still quite warm, rigor mortis had set in strongly. Along the whole lower surface of the body, from the mouth to the tail, arc spots of dark red or purple. On the right side of the head and left side of the chest the spots run into each olhcr. so much i bat they seem to form a single continuous blush. On the back the spots are smaller and less numerous. There are no spots nor petccchia! on the snout, but a glairy bloody lluid runs from the right nostril. The membrane lining the eyelid is congested, having a dark hue, approaching purple, and a portion of the mucous membrane of the rectum, exposed by the relaxation of the sphincter, presents the same appearance. Dark red spots and petccchia! exist about the vulva. Under the belly is a subcutaneous layer of fat about an inch thick, and beneath the purple spots or. the skin this is discolored by blood throughout the entire thickness. The abdominal cavity contains (1 ounces of a dark bloody lluid. The intestines have a deep florid line externally. The stomach ami the greater part of the rectum are pale and without any lesions of the mucous membrane. Close to the anus this



	25 lgt;igs into liealtliy herds; the placing of healthy pi^s in pens, cars, stoam-boats, markets, etc., where diseased swine are then or have formerly been exposed; aftesh breeze from t lie direction of a diseased herd, though half a inile distant; the passage of nieu or quadrupeds or birds from the diseased to the healthy ; the use of food, litter, or water that has been ia near proximity to the affected animals, have each served to transmit the fever. The virus appears to be concentrated in the bowel-discharges and liquids of the eruption, but doubtless exists in all the liquids and tissues of the body, and is given oil'into the air from the skin and exposed macoas membraaes. Pigs are often born sick, and die in twenty-four hours. The feeding-troughs and water, contaminated by the lilthy feet and snouts, are particularly liable to convey the disease. The malady prevails at all the periods of the year, but it has opportunities for the widest diffusion in dry seasons and countries, where the virulent matter may be dried up ami preserved unchanged for an indefinite period, and in this state may be carried by winds and otherwise. Wet weather contributes to the decomposition and destruction of this, as of any other animal poison, but cannot influence its propagation by the direct contact of healthy with diseased animals, nor aflect its preservation inside dry buildings. Unwholesome conditions of life contribute largely to its diffusion, if not to its development de noi'O. The malady frequently appears in pigs that have been carried several days in succession in crowded boats or cars, among the accumulated tilth of tbeir own bodies and those of their predecessors, and subject to compulsory abstinence from food and water. Again, it will occur in fat hogs that have been driven a number of miles under a hot sun and then cooped up in a filthy, close, ill-ventilated pen, subjected to the reeking fumes of their own bodies and of long-accumulated Hastiness. Many think that dry-corn feeding and overcrowding on lilthy manure heaps are largely productive of the disease. But it is too much to assume that the poison is developed de noi'O in such conditions. .Similar unwholesome influences favor the development of all contagious diseases by loading the blood with effete and deleterious organic matter, and bringing about a feverish and susceptible state of the system. But, on the other hand, such abuse and maltreatnunt fail, in very many cases, to induce the affection, so that we are left in doubt in regard to those instances In which it appears as to whether the virus was not hidden away in the buildings, cars, etc., and roused into activity by the, presence of a fertile field for its growth in the bodies of the pigs, the blood of which was loaded with organic elements in pi'oc-ess of decoiupositiun. The important point is this: We know this as a contagions affection, to the propagation of which all probable insalubrious conditions contribute. So soon as we concentrate our attention on this point we have the key to its prevention, if not to its entire extinction. Jjuf, while admitting the influence of overcrowding, filth, starvation, and suffering in predisposing io this disease, it ought to be added that the very highest mortality is often reached among pigs kept in the best hygienic conditions, but among which the virus has been accidentally introduced, Again, some hogs, and even families, appear to be insusceptible, and resist the poison which is carrying off all around them. But similar instances of immunity are met with in all contagions affections. Treatment.In a fatal contagions disease like that under consideration it is rarely good policy to .subject to treatment. The enormous increase of the poison in the bodies of the sick, and the exireine danger of its diffusion through the air, as well as on the feet of men and animals, render the preservation of the victims eminently unsafe and unprofitable. Yet, in the case of very valuable animals, and where seclusion, disinfection, and careful nursing can be secured, it may be resorted to. A dry, airy, well-littered building maybe provided, abundantly sprinkled with a solution of carbolic acid or chloride of lime. Rugs steeped in a solution of one or other of these agents may be hung np at intervals, and sulphurous acid set free by burning a pinch or two of sulphur three or four times a day. The dung should be



	27 He goes on to quote instances of aHegod pievention by feeding hoose-slops without corn, and by giving once a week a teed of the boiled Jowls and waste parts of the jiigs killed the year previous, and adds: Generally diseased hogs run, sleep, and eat with the others, it being the general opinion that they'll all have it anyway, so no matter. I am of a different opinion. A few change the yards and sleeping places, but generally they stay in the same places throughout the disease. No attention is paid to disinfection. These alleged preventives are doubtless somewhat beneficial by maintaiuing a free action of the bowels and kidneys, and favoring the elimination of the poison, as does diarrhea in the milder cases of the disease. ISut there need be as little donbt that, like the salt, sulphur, and ashes, they would all fail in the presence of a strong dose of the poison. Meanwhile, they are made to serve an evil purpose in diverting attention from the one eli'ect mil means of restrict ing the disease, the extinction of fhe poison. Jt must be fully recognized that neither contact: nor proximity is necessary to contagion. The poison may be carried a certain distance on a stream of water without losing its vitality. It may be blown a long way by a favorable wind, when dried np, on light objects. It may be carried on the boots, hands, etc., of men (dealers) passing from farm to farm and from district to district. Horses, cattle, sheep, dogs, fowls, pigeons, and wild animals of all kinds are liable to carry the virus on their feet and limbs, and to deal out death to the pigs at places widely separated from each other. It is, therefore, quite impossible to trace all new outbreaks to contagion. But to attribute them to spontaneous evolution of the disease is to beg the whole question. It can be freely conceded that a certain number of eases probably originate spontaneously every year; but these are few and far between as compared with the enor-mons mortality caused by contagion. It can be equally conceded that certain seasons are far more favorable to the propagation and virulence of the disease than others, yet even in these the great majority of cases are infectious. It can be admitted even that a wholesome laxative diet is to some extent protective, as well as comfortable dwellings and antiseptic agents, like copperas, bisulphite of soda, charcoal, or carbolic acid. But all such protectives are comparatively limited in their operation, and, though they seem to have saved a few isolated herds, will fail disastrously if generally relied on. The epizootic inflaence, too, though apparently all-powerful in localities where the poison has already penetrated, fails to produce the disease in the neighboring States not previously infected. We can not give too much attention to secure the best sanitary conditions of life for the hogs, but if we allow a few of these so to engross our attention that our eyes are blinded to the most important of all the prevention of contagionwe shall only spread the poison and increase the destruction of our herds. On the other hand, the highest success must attend such measures as will slop the production of the poison and destroy and render innocuous what is already in existence. Diseased pigs must be removed from the healthy, killed, and buried. A thorough disinfection of all buildings, yards, and mauure must be made. Chloride of lime or zinc, sulphate of iron, or carbolic acid may bo used for all solids, floors, troughs, walls, etc., and for drains: and sulphurous acid or chlorine for the atmosphere. The snlplinrous acid may be produced by burning sulphur, and fhe chlorine by adding oil of vitro] to common salt and a little black oxide of manganese. The surviving pigs must be carefully watched for the first signs of illness. Any unusual sluggishness, stiffness, or inappetence, or any disposition to leave the herd, demands a careful ex-aminat ion : and if there is heat or shivering, and, above all, if the thermometer introduced into the rectum indicates a temperature above 103deg; Fahrenheit, the animal should be at once separated from the herd, and destroyed as soon as unequivocal symptoms of the malady are shown. Cave should be taken to avoid the possibility of contamination by water which has passed infected hog-pens or fields. If the malady exists within a wide radius, the visits of dealers and others must be absolutely for-



	29 continued with short interruptions until tlio present time, marks a new era in our knowledge of swine epizootics and of contagious diseases iu general. It was just at the time when the biological researches of Pasteur in regard to fermentation were, attracting so much attention, and had already inspired Lister to make his discoveries in antiseptic surgery, and Koch to institute those researches which definitely connected the iadllus anthrads with the causation of charbou. The time was propitious, therefore, for the institution of a new line of researches, in a direction which even then promised much, and which since lias practically revolutionized the position ot medical science as to the nature of contagion and the methods most important for its control. The writings of Drs. Sntton, Snow, and Law gave a very correct statement of the symptoms and postmortem appearances of the organs usually found in the swine epizootics of this country. They covered about all the points which can be decided by ordinary field observations, but they left many questions still unsolved which it was necessary to determine before measures of prevention could be formulated and made successful. There were many who believed that these epizootics were due to the ravages of more than one disease, and there were also many who held that contagion and infection played no part in their extension. As to the nature of the agent or agents which caused the outbreaks, or the conditions which were required to prevent their destructive ravages, no results of value had been obtained, or indeed could be, without a more systematic and persistent investigation, with all the instruments, apparatus, and laboratory facilities which are required to work out the obscure problems of pathological science. As with other contagious diseases of men and animals, the instruments of the post-mortem case had been the moans by which a certain amount of information had been gained, but there were problems which they could not reveal, and for these the microscope, the culture apparatus, the biological and chemical laboratories were necessary, and without these a reliable solution could not be reached. For the investigations of 1S7S nine men were appointed for a period of two months each, as follows : Dr. EI. J.Detmers, Illinois; Dr. James Law, New York; Dr. 1). W. Voyles, Indiana ; Dr. D. K.Salmon, Xorth Carolina; Dr. Albert Dunlap, Iowa; Dr. If. F. Dyer, Illinois; Dr. A. S. Payne, Virginia ; Dr. J. ZST. McNutt, Missouri; Dr. 0. M. Ilines, Kansas. The researches were to be made in the field in different sections of the country, and various remedies, suggested as applicable to the treatment of epizootic diseases, were to be tried. The result of this investigation may be summed up practically aa follows : (1) Swine diseases were found destructive in the most widely separated districts of the country. (2) The symptoms and lesions enumerated were similar to those formerly given by Drs. Sntton, Law, and Snow. (3) Xo evidence was discovered to show the existence of more than one disease which prevailed as an epizootic. (4) There was a preponderance of opinion that the outbreaks were duo to contagion and that the disease was com-



	31 The investigations of the Department of Agriculture were continued in 1879 by Dr.s. Law and Detiners; in 1880 by Drs. Law, Detiuers, and Salmon, ami in 188I-'82 by Drs. Detiners and Salmon. The efforts of Dr. Law were largely directed to obtaining a modified virus for preventive inoculation, a doubly difficult and discouraging task before the microbes of the diseases had been discovered and studied. While his results were more or less encouraging, no conclusions of practical value as to a method of preventive inoculation were established. Dr. Detmers continued bis microscopic observations and modified his first descriptions of the microbe so far as to speak of it in later reports as a micrococcus. The author devoted the greater part of his time during these years to an investigation of southern cattle fever and fowl cholera, but incidentally investigated a number of outbreaks of swine diseases. He found micrococci in the liquids of the affected animals, which he cultivated and inoculated into other animals, but his results were not sufficiently positive to demonstrate their connection with the disease. There was here a period of about four years when the investigations of swine diseases gave no very decided advance in our knowledge of the subject. The reason for this was that the investigation had been carried about as far as was possible by the methods then employed.. To get a better insight into the nature of the epizootics and the peculiarities of the contagion, it was essential that the pathogenic microbes should be discovered and accurately studied. The investigators saw this and were working in the proper direction, but at that time bacteriological science was young and the methods of research had not been clearly worked out. Another and equal difficulty was the fact that the investigators were working without proper laboratory facilities and apparatus for such researches, without assistants, and some of them were devoting much of their time to other duties. Under such conditions it is next to impossible to reach successful results in such a difficult field of study. These difficulties were not fully appreciated either by the officials of the Department of Agriculture or by the stock-owners of the country, for the reason that such investigations were new to them and their requirements but imperfectly understood. It was not expected that a chemist would go into a sorghum field and discover the proportion of cane sugar in the sorghum cane without apparatus or laboratory facilities, but, it was expected that the veterinarian would make much more difficult and delicate investigations than these with no other aids than an ax, a butcher knife, a scalpel, and a microscope. The author saw that more facilities must be provided for these investigations, and the work systematized and properly divided, or the final result would be disappointment and failure. It was through his urgent representations that a beginning was made in 18S;3, by securing an unoccupied room under the roof of the Department building, which was fitted up as a laboratory, and by obtaining permission to rent a small place in the suburbs of Washington ou which to keep experimental animals.


	TT

	34 liquid, fetid character appears in many cases. The color of the discharges laquo;lepeiuls largely upon the teed. In slop or garbage fed pigs they are usually of a dirty black color. In those fed with grain they are light yellowish. The diarrhea persists until death. Vomiting is absent. Respiration is only occasionally quickened and labored in the later stages. The pulse is more, rapid than in health, but its determination unsatisfactory, owing to the struggle of the animals when held. Cough is infrequent, and then only heard when the animals are aroused, as a single effort or in paroxysms. The skin is frequently found reddened on the nose, abdomen, inside of limbs, the ears, and over the pubic region. The redness is diffuse, varying from a slight blush to a deep bluish red or purple. It increases as death approaches, and is usually found at the autopsy. A skin eruption appears occasionally, which is followed by crusts or scabs of varying size. Reddening of the skin is a sympton comuion to the other swine diseasesrouget and swine plague. The eyes are apt to be watery. This is frequently the first outward sign. Later the discharge becomes thick, yellowish, often gumming the lids together. Towards the end of the disease the animals have a gaunt appearance, with arched hack anil staving coat. Emaciation is very rapid. The weakness manifests itself in a staggering, uncertain gait, as if the animal were about to fall. Death ensues quietly. Rarely convulsive kicking is observed. The mortality is very high, usually from 80 to 90 per cent, of those attacked die. These symptoms vary in intensity, and only n certain number are seen in one animal at the same time. In very chronic cases only the autopsy enabled us to make a diagnosis. LESIONS PKOD1 CED BY HOG CHOLEEA.POST MORTEM APPEARANCES. (See Plates 1-VIII inclnsive.J a. The acute type.This might with equal propriety be called the hemorrhagic type,inasmuch as thechief and perhaps the only changes are hemorrhagic in character, and these lesions arc seen most clearly when an animal is examined immediately after death. The spleen is variably enlarged, soft, gorged with blood. Sometimes it is twice as long as the normal spleen (the other dimensions being proportionately iucreased), and it may extend across the median line to the right side. Next to the spleen the lymphatic glands and serous membranes are most severely involved. The cortex shows, on section, as a hemorrhagic line or hand, according to the amount of extravasatcd blood, or the entire gland maybe infiltrated with it. Among the glands most commonly hemorrhagic are those of the meso-colou (large intestine),



	35 those at the root of tue lungs (bioncliial), and on the. posterior thoracic aorta. Besides these, the retro-peritoneal and gastric gland? (lesser omentam) may be involved. Most rarely the meseutric glands show extravasations to a slight extent. Hemorrhages are also quite frequent beneath the serous surfaces of abdomen and thorax. They are most abundant under the serosa of the large and small intestines as petec-chiae and larger patches. They are occasionally found under the peritoneum near the kidneys, the diaphragm, the costal pleura as extravasations nearly an inch across. The lungs, in a small percentage of cases, show subpleural ecchy-moses in large numbers, and on section small hemorrhagic foci are observed throughout the lung tissue. In a few eases severe hemorrhages, involving one or more lobes, have been observed. The kidneys are occasionally the seat of extensive hemorrhagic changes. The glomeruli appear as blood red points; larger extravasations occur in the medullary substance, and blood may collect around the apices of riic papil-Ige. The subcutaneous tissue over the ventral surface of the body may be dotted with petecchise and occasionally collections of blood (loemato-mata) are found in the superficial muscular tissue. The brain and spinal cord have not been examined for want of time. In one case, however, in which they were laid bare, peteechia' were seen on the cerebellum. The digestive tract usually is the seat of extensive lesions. The fun-dus of the stomach is as a rule deeply reddened ; there may be more or less hemorrhage on the surface, giving rise to patches or larger sheets of blood clots. The small intestine in some cases has subniucous ecchy-moses throughout its entire length, hraquo; the large intestine the ecehy-moses may be so numerous as to give the membrane a dark red appearance. The food is now and then found incased in sheets of blood clot due to hemorrhage on the surface. b. The chronic form is perhaps the most common, at least in those epizootics which we have studied. The acute hemorrhagic cases usually die in the beginning of an outbreak and are apt to be overlooked. Following these are the more protracted, milder cases. In these animals the disease is apt to be limited in its severe manifestations to the large intestine. The other organs, however, are not exempt from degenerative changes, owing in part to the impairment of the functions of the large intestine, consequent fermentations and the absorption of poisons thereby produced, in part to the presence of the specific bacteria in the spleen and presumably in other organs where they exercise their poisonous activity. The lesions of the large intestines are necroticand uleerative in character. The ulcers may be isolated and appear as circular, slightly-projecting masses stained yellowish or blackish or both in alternate rings. Or they may be slightly depressed and somewhat ragged in outline.



	37 months must be ascribed primarily to exposure rather than to the disease, as will be shown subsequently. In some outbreaks the acute and the chronic types of the disease are not so clearly distinct as given in the foregoing pages. Frequently re. cent hemorrhagic lesions seem to be grafted upon cases presenting extensive nlcerations, which certainly are much older than the extravasations. It may be that the latter are the result of asecondary invasion of the hog¹ cholera virus, either from the ulcers in the intestine or from tnbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;without. HISTORY AND AITTOPSV NOTES OF AN OUTBIIEAK OP HOG CHOLERA. There is perhaps no better way to illustrate this disease than by giving briefly the history of an outbreak in a single isolated herd. In the following pages are recorded the autopsy notes and the bacteriological examination of such an outbreak- near the city of Washington during the months of November and December, 1887. A study of this outbreak was taken up to ascertain more especially the condition of the lungs in hog cholera. As it is the fifth or sixth which has been observed during the past three years less attention was paid to careful bacteriological observations. At the same time this phase was by no means neglected, as the notes will show. The history of the outbreak as far as could be ascertained was briefly as follows: On October 28, there were in all one hundred and nineteen swine, chiefly young pigs, weighing from 50 to 100 pounds. Most of these bad been purchased in the city markets. At this same time some twenty boar pigs were castrated. Within two weeks these began to die, and soon after the others took sick, dying at the rate of three to four a day. Less than three weeks after the first deaths only sixty-seven remained out of the one hundred and nineteen. At the end of the year only about a dozen were alive out of the entire herd. These may have acquired immunity. The animals were kept in pens on the top of a hillock sheltered from the weather by large boxes. They were swill-fed, and this may account for their feeble resistance to the disease. In most of them there was a cirrhosis of the liver, with softening of the parenchyma, which was probably induced by the feeding. The origin of the epizootic could not be traced, as the animalshad come from various quarters. The city markets had proved themselves in the past the source of disease in several purchases of pigs for experimental purposes. The autopsy and bacteriological notes will be given in the order in which the animals were examined, any general remarks being reserved for the end. The rapidity with which the animals succumbed to the disease made any very thorough examination quite impossible, since it seemed more desirable to utilize all the material by examining those organs most always diseased in hog cholera. Most attention was paid jnbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;to the lungs and the digestive tract, while the lungs and the spleen


	w

	38 wore tlie only organs examined bacteriologically. These notes will serve to supplement the autopsy notes in the reports for 1885aud 1880. In making cultures from the spleen the following method was usually adopted. At the autopsy the abdomen was carefully laid open by first removing the skin and then cutting through the abdominal muscles with flamed instruments. The Haps laid back, brought into view the spleen not touched as yet by any instrument. It was then drawn out with flamed forceps, severed from its attachments with flamed scissors and placed in a large bottle plugged with cotton wool which had been previously subjected to a temperature of 15ü^o-l(!0^o 0. for two hours. In this way it was taken to the laboratory and either immediately examined or kept in the refrigerator below 55deg; F. over night. In making cultures the spleen was placed on a sterile glass support and the surface thoroughly charred with a red-hot platinum spatula. This was always done, although seemingly unnecessary when we consider the momentary exposure to the air in transferring the spleen from the abdomen to the sterile bottle. It may, however, destroy any bacteria which have entered the peritoneal cavity through ulcers. Through this charred area an incision or rent was made and a platinum wire introduced, and then a tube of gelatine or beef infusion inoculated with it. When roll cultures were made a minute bit of spleen pulp was torn away from beneath the charred portion and stirred about in the liqaefied gelatine. From this usually a second tube was prepared. Experience of past years had shown that frequently this is not sufficient to insure the fertility of the cultures, in chronic cases with the spleen but moderately enlarged, hog cholera bacteria are found in very small numbers. In such cases bits of spleen are cut out from the charred area with flamed scissors and transferred to tubes of gelatine or beef infusion with or without peptone. Hueii cultures rarely fail. It might be supposed that the chances ol accidental contamination are very great in this process. Hal a long experience with spleens of healthy animals and with organs in the study of other diseases has demonstrated the entire safety of this procedure. Salmon culture tubes with bits of organs in the bottom covered by nutrient liquids have remained sterile for months in the, laboratory. At present the Esmarch tube or roll culture is indispensable in such cases. In nearly all the cases examined both liquid and gelatine cultures were made. The former permit a diagnosis on the following day, while the latter require at least two days, usually three or four, before a reliable diagnosis can be made. The cultures were always examined unstained in a hanging drop, as the bacteria in this way are not deprived of their power of motility, which is one of the important diagnostic characters. Staining cultures was also resorted to, but it adds little information to that gained by a careful examination of the hanging drop. When gelatine cultures were examined the bacteria were always mixed with some sterile beef infusion to bring out their motility. In a number of cases rabbits were inoculated directly trom lung tissue. A small bit, about one half centimeter cube, was torn up with flamed forceps in a flamed watch glass containing some sterile beef infusion, and the turbid fluid injected beneath theskin of the thigh. The syringe used was an ordinary hypodermic syringe, carefully disinfected by 5 per cent, carbolic acid above and below the piston for one-half hour both after and before use, and each time thoroughly rinsed in boiling water. As hog cholera bacteria are, destroyed by a 1 per cent, solution of carbolic acid in less than ten minutes, and by a momentary



	39 contact with water near the boiling point the. disinfection was certainly all that could be desired. This method was regarded as less open to criticism than the insertion of hits of tissue under the skin. We still stand in need of a syringe which can be disinfected without much trouble, as the above method is extremely tedious. The syringes devised by Koch are both unsatisfactory. The joints formed by the glass barrel and tbe metal cap in the syringe in which the propelling force is air were fouiul to leak in üve out of six samples. From the fluid injected into rabbits either plate or roll cultures were made in order to get an idea of the approximate number and the kind of organisms present. In every case the portion of lung tissue from which the inoculations were made was transferred to sterilized bottles and protected from accidental contamination as carefully as possible. Unless otherwise indicated, the methods just given were employed throughout the investigation. November 16.Pig No. 1, just died and brought to experimental station. Is'o skin lesions; heart and lungs normal with exception of a few collapsed lobnles in principal lobe of one lung.* In abdomen omentum injected so as to appear bright red. Spleen enlarged, soft, dark. Some lymphatics have the cortex hemorrhagic. Stomach and small intestines normal. In caecntn near valve several large superficial yellowish ulcers and a number of smaller ones, an eighth of an inch in diameter. Two bits of spleen were cnt out and dropped into a tube of gelatine, and one of beef infusion. The gelatine culture remains sterile. The liquid culture contains the motile hog cholera bacteria and a large butyric bacillus growing only in the bottom of the liquid. No. 2 died last night. Buzzards have eaten into the thorax and penetrated the coats of the stomach. Only the small ventral lobe of right lung diseased. Bright red, mottled with pale yellow dots. (See Plate IX, fig. 2.) The smallest bronchi occluded by cylindrical plugs. Alveoli likewise occluded. The plugs consist chiefly of cells and arc so dry and firm that they may be removed as small ramifications or branchings when the lung tissue is torn away. Bronchial glands enlarged, hemorrhagic. Spleen enormously enlarged, liver in advanced stage of cirrhosis. Glands at portal fissure chronically enlarged. Tn Cfecnm four superficial ulcers one-half inch across, slough stained yellow. In upper colon four similar to these and a large number of small ones about one-eighth inch across with yellowish slough. A moderate number of bacteria found in cover-glass preparations of spleen. A gelatine tube culture contained, after three days about, seventy-five to one hundred colonies of the motile hog cholera bacteria iu * In order to understand the description of the lung lesions, the. following brici! outline of the anatomy of the lung and of the terms used may be of service: The right lang is made np of fonr lobes; the left has only three. (In text-books on anatomy The left lung is considered as being made np of only two.) In both there, is a large principal lobe resting npon the diaphragm and against the adjacent thoracic wall. Thislobe forms the major part of each long. The remainder, occupying the anterior (or cephalic) portion of the. cavity, is made np of two small lobes, one extending ventnilly (or downward in the standing position of the animal) and in the expanded state covering the heart laterally, the other extending towards the head and overlapping the, base of the beart. These small iobes may he denominated the ventral and cephalic lobes, respectively. The right cephalic lobe is longer and more distinct, from the ventral lobe than the corresponding left cephalic. Wedged in bet ween the two principal lobes and resting on the diaphragm is a small lobe, pyramidal, belonging to the right hmg (azygos lobe). This lobe rests on the left against the mcdiastinal membrane, and on the right it is separated from, the right principal lobe by a fold of the pleura passing from the ventral abdominal wall to inclose the inferior vena cava. This small lobe is almost completely shntoff, therefore, from the other lobes by folds of the pleura.



	41 A rabbit inoculated from the bepatizecl lunji^- tissue died on the eighth day. Slight libriuous exudate on intestines, diffuse coagulation necrosis in liver, spleen nuich congested, lininense number of hog cholera bacteria in spleen and liver. Cultures pure. A plate made from the same bit of (pig's) luug tissue contains about fifty colonies resembling Log cholera. Ko. (5, large black male, died last night. Extensive sero-tibrinous inliltratiou of subcutis from axilla to pubis and over right, thigh. The subcutis has a gelatinous aspect. Spleen much congested. Lungs normal. In cover glass preparations from spleen large bacilli, with ends square. Cultures in gelatineand beef infusion remain sterile. Animal probably died of malignant OBdema. NovetHber21,No. 7, mediam sized male, died yesterday. Tempera-tare of air varying from 20deg; to 50deg; P. Omentuiu deeply reddened. Spleen enlarged, soft; small hemorrhages under capsule one-eighth inch across. Liver imparts a Sensation of grittiness when cut. Cortex of kidneys dotted with hemorrhagic points. The patch of mucous crypts about valve in ca'cum dark, pigmented; no ulceration. Mucosa of stomach hemorrhagic in fundus. Thorax half full of blood-stained serum and some fibrin stretching i'roin lung surface to walls; small quantity of fibrin in pericardial cavity. Lung tissue infiltrated with blood (pulmonary hemorrhage). Two ventral lobes collapsed; subpleu-ral hemorrhagic patches. A cover-glass preparation from spleen contains numerous hog cholera bacteria. In each needle track of a gelatine culture, countless colonies. A liquid culture from a bit of spleen tissue contains hog cholera bacteria only. No. 8, small female, died yesterday. Patches of skin on ventral aspect of limbs and groin reddened. Minute petecchia! under serosa of ventral abdominal walls. Spleen very large, congested. Some delicate librils stretched over coils of intestine. Liver cirrhosed. Clauds of mesentery and inesocolon enlarged; cortex hemorrhagic. Fuudns of stomach moderately congested. Jn csecum are black pigment spots resembling former hemorrhage, chiefly on the summit of folds. In upper colon ulcers about three to a .square inch, each one-fourth inch in diameter, and covered by a convex, projecting yellowish slough. Ulcers found down to rectum. Small quantity of clear serum and a few fibrils in pleural cavities and pericardium. Left ventral and tip of right cephalic lobe collapsed. A gelatine and a liquid culture, made from a bit of spleen tissue contain hog cholera bacteria and a butyric bacillus which slowly liquefies the gelatine. No.!), small male. Diffuse reddening of ventral aspect of body especially marked on limbs. Spleen, lymphatics, and kidneys normal. A small abscess in pelvis attached to bladder, probably caused by castration. Venous congestion of vessels of meso-colon. The transverse folds of mucosa of colon covered by very thin yellowish patches of necrosis. Feces hard, distending the large intestine. Cephalic and ventral lobes of left lung solid, plainly mottled. The bronchioles and alveoli filled with consistent plugs of cellular exudate. llemainder of lungs normal. Owing to small size of spleen, two liquid cultures were made, each with a bit of spleen tissue. Jn both, hog cholera bacteria alone appeared. A rabbit inoculated with hepatized lung tissue remains well for weeks after. A plate culture therefrom is liquefied iu two days. No. 10, small castrated male, died yesterday. Has been sick for sometime according to overseer of farm. Spleen not enlarged. 1 nthuninatory changes in pelvis due to castration. Stomach slightly reddened and



	43 dornen, only suhcntis involved. Spleen engorged. Single acini and groups in the liver are completely necrosed, yellowish white, in both orgatis, hog-cholera bacteria. Cultures from spleen pure. November 25.Xo. 15, black and white male, died Yesterday morning. Redness of skin of abdomen, throat, and limbs. Superficial in-guinals bemorrhagic. Spleen very large, gorged with blood. Lungs normal, excepting a few lobules at the caudal border of principal lobes, which are red, collapsed, and contain lung worms. Pericardium contains deep-colored serum and coagula; left auricle dotted with petecchise. Bronchial lymphatics hemorrhagic. Liver .slightly cirrhosed. Cyst in right kidney one-half inch in diameter. Fundus of stomach intensely congested, similarly the caecum and colon ; no ulcers. Lymphatics of meso-colon hemorrhagic. A beef-infnsiou culture from a bit of spleen contains the motile hog-cholera bacteria only. A gelatine culture became liquefied by the heat of the. laboratory; no bacteria seen on a cover-glass preparation of spleen. ISo. 16, black and white female, died last night. Skin and spleen as in previous case. The small ventral lobe of both lungs collapsed, lungs otherwise normal. Liver in advanced stage of sclerosis; stasis of portal circulation. Lymphatics of abdomen as in No. 15. Fundus of stomach slightly reddened; one nicer three fourths inch across. Extensive necrosis of mucous membrane in colon and rectum, slight in caecum; wherever the membrane is free from a slough it is deeply congested. Numerous hog-cholera bacteriaand some large (butyric) bacilli in spleen. A beef infusion and a gelatine culture contain them. From a bit of collapsed lung tissue a plate culture is made and a rabbit inoculated. The plate contains in two days about six to seven liquefying and a large number of non liquefying colonies, the latter made up of motile hog-cholera bacteria; the rabbit died on the seventh day. Spleen very large, friable; contains large numbers of hog cholera bacteria. On left lobe of liver an area of necrosis one-fourth inch by three-fourths and one-sixteenth inch deep. On the right lobe only three or four acini necrosed. Pylorus and duodenum covered with hemorrhagic laquo;lots and patches. Culture from spleen pure. Wovember 26.No. 17, female of medium size; died suddenly this morning without previous illness. Subcutaneous fat abundant. Spleen moderately congested. Petecchiae in cortical portion of kidneys. Fundus of stomach slightly reddened. In lower ileum patches of congestion. Scattered petecchise in mucosa of large intestine; contents normal. Glands of mesentery and meso-colon with cortex hemorrhagic. Large quantity of blood-stained serum in thorax. Fibrinous deposit on pleura; lungs partly expanded ; cephalic half of right lung solid, blackish; air-

	it	tubes and alveoli filled with extravasated blood. Interlobular tissue

	distended with blood-stained serum (pulmonary hemorrhage). Left lung m the same condition. Trachea lull of reddish foam, Bloodand fibrin-ous coagula in pericardia! cavity. Beef infusion, into which a bit of spleen was placed, remains sterile; also a tube of gelatine inoculated from the spleen with platinum needle. In a cover-glass preparation of the spleen large (butyric') bacilli. No. 18, small female, died last night. Buzzards have consumed thigh muscles. .Diffuse reddening along median line of abdomen. Hemorrhagic spots one-eighth to one-fourth inch across, subepidermal, chiefly on ventral aspect of limbs; subcutaneous and snbperitoneal ecchymoses. All abdominal lymphatics with cortex infiltrated with blood. Serosa \nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; of large intestines as if sprinkled with fresh blood; several subserous 'nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; hemorrhagic spots one-half inch across on diaphragm, along inferior



	45 deeply reddened along median line of abdomen. Large quantity of blood-stained serum in peritoneal cavity. Serosa of ileuni and the mesentery completely covered with hemorrbagic points and patches. Lymphatics of abdomen bemorrhagic throughout their substance. Pe-tecchiic in cortex of kidneys. Mucosa infandusof stomach hemorrhagic. Macosa of lower ileum a confluent layer of necrosed tissue. Numerous round ulcers in ca'cum and colon ; slouch projects slightly. Lungs hypo-static, interlobular spaces distended with coagulated blood, most marked in dependent lobes. Simple collapse, of both ventral lobes and of the right principal near the root. Ventricles of heart dotted with petecchise, auricles black, covered with clotted extravasated blood. Hog cholera bacteria present in cover-glass preparations from spleen and in both gelatine and liquid cultures. No. 2_^,, male, Jersey red, died last night. Glands of abdomen with cortex infiltrated with blood. Spleen engorged. A few hemorrhagic patches in fnndus of stomach. In caäcum and colon ulcers abontthree-eighths inch across ; very thin, adherent, yellowish slough. About one ulcer to i square inches of surface. Considerable blood-stained serum in piemal cavities, hemorrhage in anterior half of left lung, which is solid, blackish on section. Clots and reddish foam in trachea and bronchi; hemorrhage seems somewhat older than in Xo. 21. ' Pleura of right lung roughened and parts adherent to chest wall. Ventral lobe solid, bronchioles (irmly plugged with dry catarrhal secretion. Hog cholera bacteria, on cover-glass from spleen pulp and in a gelatine and liquid culture made therefrom ; only five to ten colonies in each track of the platinum wire. A rabbit was inoculated from a bit of the solidified lung tissue and a plate culture made. The latter develops numerous colonies of hog cholera bacteria. The rabbitdied on the thirteenth day. Xnmerous hog cholera bacteria in both organs. A gelatine culture from the spleen contains the same organisms. No. 23, small black male. Buzzards had removed pectorals of one side. Lymphatics congested, not hemorrhagic Crowded peteccbiicin subcutis and beneath peritoneum of ventral abdominal wall. Spleen very large, congested. Four or live small hemorrhages on diaphragm. Mucosa of ca'cum and upper colon ulcerated in large patches. In lower colon the ulcers are small, yellowish, depressed areas embedded in a very dark mucosa dotted with numerous punctiform ecchymoses. At root of left lung there is some collapse, extending slightly into all lobes. Of right lung the ventral and cephalic lobes are collapsed, with occasional euiphysematous lobules interspersed. Langs otherwise normal. Extensive hemorrhage of both auricles in the form of diffuse patches and petecchise. A gelatine and a liquid culture from the spleen remain sterile. A plate culture made, from a bit of collapsed lung tissue con-tainsa considerable number of colonies, which are made up of bacteriare-sembling those of hog cholera, but differing from them in their manner of growth on gelatine, in beef infusion, and in the absence of motility. A rabbit inoculated from the same bit of lung tissue remains weil. A plate culture from a bit of normal tissue from the same lung contains but one colony. No. 24 died yesterday; medium-sized female. Spleen very large, extends beyond median line. Lungs normal, excepting collapse of a small portion of the right ventral lobe. Lymphatic glands in general with hemorrhagic cortex. Osecnm and colon very much congested, ul-ceration superficial and slight. Entire fnndus of stomach of a uniform deep wine color. A gelatine and a liquid culture from the spleen contain only motile hog cholera bacteria. In the former the colonies are



	47 der. Moderate amouut of ftbrinoas exadate. Valve completely ulcerated, ulcer deep. One near valve has caused thickeniug of serosa of intestinal wall. In cseeam an extensive patch of ulueratiou; in colon a few ulcers and numeions panctifonn hemorrhages. Right lang completely adherent tocostal pleura by means of fibrous tissue. A small ventral portion of principal lobe of left lung is airless, pale red, mottled with yellowish points. Air tubes ami vesicular portion occluded with dry cylindrical pings. A culture in gelatiue from the spleen develops numerous colonies in each track of the wire. A liquid culture contains the butyric bacillus also, A bit of the solidified Inug tissue was used for a plate culture and to inoculate a rabbit. The plate developed countless colonies of hog cholera bacteria as tested by other cultures. The rabbit died on the tenth day. The spleen was enlarged, the liver full of centers of advanced necrosis, involving one to three acini; hog cholera bacteria very numerous in both organs. December'S.No. 31, small black and white female, died yesterday. Well-marked odor of decomposition. No skin discoloration. Spleen but slightly enlarged. Lymphatics in general with hemorrhagic cortex. Liver in .state of advanced sclerosis. Stomach normal. A few large old ulcers and a considerable number of small ones throughout ca'cmn and colon. Mncosa itself pigmented with patches of fresh congestion. Lungs normal. A liquid culture from the spleen contains only butyric bacilli. Xo. 32, small black and white female. No skin discoloration. Lymphatics, including inguinal, bronchial, and peritoneal with more or less hemorrhagic cortex. Spleen engorged. Liver solerosed. Kidneys with numerous petecchise throughout cortical portion. Stomach pale. raquo;Several large old ulcers in upper colon. Caecum and colon pigmented. Lungs normal with exception of a few collapsed lobules in ventral lobes. Loth a gelatine and a beet infusion culture contain hog cholera bacteria. Colonies very few. 2s^To. ;gt;;gt;. large black and white male; said to have died last night. Advanced post mortem changes. No examination made, excepting to see the condition of lungs, which were healthy. 2gt;o. 34, medium-sized white, died last night. Considerable reddening over ventral aspect of body. Inguinals reddened on section. Small quantity of dark-colored serum and numerons yellowish flaky coagula attached to abdominal organs. Spleen very large, dark, friable. Liver cirrhosed. Kidneys with cortical portion thickly dotted with petecchise, hemorrhage into pelvis. Lymphatics in abdomen with cortex more or less hemorrhagic. Extensive and deep nlceration in huge intestines ; in caecum and upper colon as large patches, in lower colon as small ulcers. The mucosa which is not destroyed is deeply congested. Stomach along fundus deeply reddened. Extensive, fibrous adhesions of left lung to walls of thorax. Collapse involves ventral, cephalic, and portions of principal lobe of right lung, and small portion of principal and ventral lobe of left lung. Extensive muco-purulent secretion in trachea, bronchi, and subdivisions throughout both lungs. Bronchial glands with cortex hemorrhagic. A beef infusion culture from the spleen contains hog cholera and butyric bacteria. In the gelatine culture each track of the wire contains countless colonies of what are shown under the microscope to be motile hog cholera bacteria. Erom a bit of collapsed lung tissue a plate culture was made and a rabbit inoculated. The plate develops countless nou lupiefying colonies. The rabbit died on the eighth day. Spleen enlarged. Liver infested with coccidia. A

	^



	50 dish seram ; left hypostatic. Abundant mucous secretion in bronchi and smaller air tubes stained with blood. Fo bepatization. Roll culture from a bit of spleen contains a large number of colonies of hog cholera bacteria. Tlic same may be seen in cover-glass preparations from rhe spleen itself. So. 40. Large black-and-white male, died December 13. Spleen enlarged and congested. Abdominal lymphatics with cortex more or less congested. Liver slightly eirrliosed. One largo ulcer on valve about 1 inch across; several half as large in the middle of colon. Mucosa deeply congested in cfecum and colon ; much pale serum in pleural sacs. Lungs slightly oedematoas. Of right lung the principal near root, ventral and tip of cephalic airless, collapsed. One lobule on ventral (diaphramatic) surface of principal lobe airless, with faint oatarrhal injection of bronchioles and alveoli ; of left lung a small portion of the principal collapsed; the ventral and cepbalic emphysematous. The trachea, bronchi, and branches contain a large quantity of a translucent viscid mucus; no lung worms present. Bronchial glands enlarged, pale; those on posterior aorta with cortex iieinorrhagic, Extravasations beneath epicardium. A plate culture from a bit of lung tissue develops about seventy-five colonies of hog cholera bacteria. A rabbit inoculated from the same bit remains well. A roll culture from the pig's spleen contains about fifty colonies alike; one examined is made up of motile hog cholera bacteria. December 17.No. 17, small female, died yesterday. Superficial in-guinals entirely hemorrbagic. Mesenteric glands slightly congested. Spleen barely congested. Mucosa of lower ileuni completely ulcerated. Similarly that of caecum and upper colon, but more severely so as to make the intestinal wall very friable. In lower colon the ulcers are isolated. Lungs and heart normal. In a roll culture from a bit of spleen tissue about one hundred colonies of hog cholera bacteria appeared. No. 48, medium-sized black-and-white female, died last night. Superficial ingninals enlarged, pale. Abdominal lymphatics in general with cortex hemorrbagic. Spleen congested; surface covered with numerous elevated bloodied points. Liver extensively eirrliosed. Mucosa of ileuni dotted with petecchiae. It contains about fifteen ulcers, not limited to IVyer's patches, with longer diameter transverse, in some cases encircling the tube. The ulcer is covered by a thin yellow slough. One ulcer, one-half inch across, in ca'cnm, and two in colon. About one-half pint of straw-colored serum and a mass of semi-gelatinous pale coagulum the size of a list in each pleural sac. Lungs but partly collapsed, pleura slightly roughened. Jnterlobular tissue of dependent lobes distended with serum, parenchyma oedematous, so as to sink in water. Bronchi contain a slight amount of reddish fluid. In a roll culture from a bit of spleen pulp about two hundred colonies of hog cholera bacteria appear, Deceniher '2i.Xo. 49, large, black and white. Spleen gorged with blood. Lymphatics generally pale; liver eirrliosed. Ca-cumand colon with walls thickened and very friable; mucosa entirely ulcerated. One ulcer in rectum. A roll culture from the spleen melted, but found to contain on examination only hog cholera bacteria. DISEASE IN IIEALTIIV PIGS CAUSED BY MATERIAL FROM THIS EPIZOOTIC. Jfovember 21.Two pigs (Nos. 434, 435), about two months old, fed #9632;with spleens from several of the preceding eases. Two days later a few



	51 more spleens were given then). Both beeaine sick a few days later and died November 28, about twelve hours apart. No. 434. Spleen slightly enlarged, full of blood. All gloinemli of kidneys show ashemorrhagic points: lymphatics inorteratcly congested. Stomach along entire lundns deeply congested. Superficial small ulcers in Ciecum and colon; in the caecum they are covered by a projecting slough. Wight ventral and cephalic lobes collapsed, theformer developed into broncho pneumonia (catarrhal injection of small air tubes and alveoli). A few lobules of left principal lobe in the same condition. Hog cholera bacteria in the spleen as determined by a- gelatine and a liquid culture. A rabbit was inoculated with a bit of lung tissue and a plate culture made. This developed countless colonies, non-liquefying, alike, shown to be motile hog cholera bacteria. Rabbit dies on sixth day. Spleen moderately congested; contains many hog cholera bacteria. In liver, minute loci of necrosis. A gelatine culture from the spleen contains numerous colonies of hog cholera bacteria. No. 435. Spleen enlarged, covered with hemorrhagic elevations. Kidneys bemorrhagic as in No. 4.')4. Stomach near pylorus deeply congested. Ofecnm and entire colon covered with a dirty yellowish and blackish sloagh. Right and left ventral lobes, a small portion of right principal and left cephalic affected with broncho-pneumonia. Cultures from the spleen of this animal were confused with those of another pig (No. 25), but one set remained sterile; the other contained bog cholera bacteria, and it is highly probable that the fertile cultures belonged to this animal. A few additional cases are cited to show the infectious nature of this outbreak. No. 436 and No. 437 were placed, November 27, in the infected pen containing the two preceding animals. They were also fed portions of hog cholera viscera later on. No. 436 was found dead December 27. Red blotches on skin of ventral aspect of body. Superficial inguiuals hemorrhagic. Other lymphatics enlarged but pale. Spleen slightly congested. Mucosa of ca-cum and colon deeply congested and dotted with considerable number of small ulcers. A roll culture from the spleen melted, but contains only hog cholera bacteria according to microscopic examination. No. 437 did not take the disease. No. 41!) and No. 4Ö2, placed in the same pen December 17, but not fed with infectious matter, died December 21). The lesions were somewhat different from those, usually found, and are briefly as follows: No. 452. Spleen and lymphatics not enlarged. Large quantity of serum and fibrinous coagula in abdomen. Viscera generally agglutinated. ^; gt;nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; Lungs glued to chest wall by a recent exudate. Pericardium distended with serum and coagula. Lung tissue not affected. Kidneys deeply reddened. Mncosa of caecum and colon entirely covered with a thin layer of diphtheritic exudate; when scraped away a deeply reddened surface is exposed. Numerous small, deep ulcers present. A roll culture of spleen, also melted from the heat of laboratory, contains only hog cholera bacteria. In No. 449 the lesions were the same, excepting the pericarditis. The ulceration of large intestine less extensive. Two very instructive cases of hog cholera were caused by simply exposing pigs on an infected asphalt floor in a pen adjoining cases of the disease. No. 464 and No. 466, about three and one-half months old, exposed with six others January 4. No. 464 died January 11. Superficial inguinals



	54 lower ileuui was ulcerated (tfos. 5, 21, 38, 47, 48); the ulcers seemed to have no relation to IVyer's patches. Complications.Peritouitis, pleuritis, and pericarditis were not uu-comuion complications usually accompanying- old alceratlou. Lntiff lesions.This epizootic was studied mainly for the porposeof detcriiiiiiin.i;'the condition of the luugs in hog cholera. Swine plague is essentially a disease of the luugs, secondarily of the digestive tract. It may be possible to lind some cases of swine plague in which the largo intestines are primarily diseased. Thus far they have not eome to our notice. From the facts obtained from this epizootic we may safely assume that hog cholera produces no lesions which may not be found in the lungs of apparently healthy animals of the same age. and which may be due to the debility caused by the infectious disease. We must accept, however, the hemorrhages found in a small percentage of cases. Such are coexistent with hemorrhages in most other organs, and are not specilic lung lesions. (See Nos. 7, 17, 21, 22, 43, of autopsy notes.) The lesions found on post-mortem examination were eil her simple collapse or lobular broncho pneumonia following it. Simple collapse usually involved the two ventral dependenl lobelaquo;, more rarely portions of the small cephalic and the principal lobes. The collapsed lobes, or groupsof lobules interspersed among emphysematuus lobules, appcared slightly, it at all, depressed. The color approached thatof red flosli. In only a few instances could plugs he found occlud-ing the brouclii. Sections made from lobules in this condition show a number of interesting features. The alveolar walls are crowded together in sonic places till they almost touch one another. Besides the flbrin, there may or may not be one or several large cells, rouud, with much protoplasm inclosing a vesicular nucleus. The bronchi are all open; the epithelium intact. The alveolar walls are not changed, nor is there any rouud cell infiltration to be seen. In circumscribed areas the capillary net-work is distended with blood corpuscles, while all the larger vessels are similarly filled witli these elements. In the alveolar duct there is now and then considerable librillar fibrin well brought out by Weigert's slain. in about 15 per cent, of the animals examined one of the smaller ventral lobes was airless throughout and moderately enlarged. Viewed from the surface, the diseased lobe is blight red, dotted with minute, pale grayish or yellowish points of a diffuse hazy outline, each not more than 1 mülhneter (^ inebi in diameter. They are usually arranged in groups of four, and represent the ultimate air-tubes filled with cellular exudate. The larger bronchi are also occluded. The exudate is yellowish white, so firm thai it is possible to tear away the lung tissue with needles without necessarily breaking up the inclosed exudate. It may thus be teased out in flic form of branching cylinders,becoming smaller, and finally dwindling down to the size of a coarse hair. In microscopic sections the alveolar walls arc found beset with dis-



	55 tended capillaries. The alveoli are filled up with cellular masses, fibrin appearing very rarely. In most alveoli the cells are large, round, with vesicular nucleus, evKlontly derived from the alveolar epithelium. In some alveoli aud in the smallest air-tubes the cell mass is so dense that iiuliviilual elements can only be seen with dilliculty, but they appear to he identical with the cells just described. The process seems to be accompanied with very little inllammation. The desquamatiou and proliferation goes on in the alveoli and smallest air-tubes until they are occluded by the casts described. Of the 49 animals of the same herd, 17 were found with collapse (Nos. 1, 7, 8,12, 13, IG, IS, 21,23,24, 28, 32, 34,35, 41, 44, 4(5), and eight with lobular bionchopneumonia (Xos. 2, 5, 9, 14,19,22,30,37; see also Xos. 434 and 435). More than one half, therefore, had some defect of the lungs. it might be questioned whether such lesions as those of broncho-pneu-monii?. are not due to swine plague bacteria, since they closely resemble the appearance found in many swine plague lungs. This question is eÜ'octualiy disposed of by the inoculation of lung tissue into rabbits. From 10 lungs 10 rabbits were inoculated. Of these lungs 8 were involved in simple collapse; laquo;Sin broncho pneumonia. Of tlie 10. rabbits 4 survived (Xos. 9, IS, 23,46); the remainder died of hog cholera (Xos. 2, 5, 12, 14, Hi, 22, 28, 30, 34, 37, 14, 434). . (The notes on these rabbits will bo found in the autopsy notes of the swine as numbered.) Of the 4 survivors .'gt; had been inoculated from collapsed lung tissue, I from a bronclio-pneumonia. It is interesting to note that of these rabbits 1 died in six days, 4 in seven days, 3 in eight days, 2 in ten days, 1 in thirteen days, and 1 in flfteeu days after iiioenlation. Plate cultures from the corresponding bits of lung tissue showed a vari- i able number of colonies almost invariably non-liquefying, and in many cases identified as hog cholera bacteria. These facts lead to the inference that in hog cholera the specific bacteria will find their way to any diseased portion of lung tissue, and there multiply to a certain extent. In one case a plate culture from a bit of normal lung tissue showed but one or two colonies, while a bit of \nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;collapsed tissue from the same lung showed a large number. There is \nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp; nbsp;no doubt that the slight exudatc and feeble circulation in collapse and the abundant partly cellular, partly mucus or librinous exudatc into the air spaces in broncho-pneumonia furnish a. favorable nidus for pathogenic bacteria. These may have been carried there by the blood or they may have been introduced from without, if the latter supposition prove true, and there are no valid objections to it, diseased lungs in hog cholera may not only become the means of disseminating the disease through the mucus and expired air, but they may become the channel, the weak spot, througb which the virus enters the organism. To elucidate this question, if possible, the following instructive experiment was made: Two pigs (Xos. 4(jO and 4(il), about ten weeks old, received each into



	58 Bacteriological observatiom.The preceding experiments oil rabbits and the intrathoracic inoculation in case of the pigs are sufficient of themselves to establish the fact that the bacteria described in the reports of the Bureau for the years 1885 and 1886, and again found in this epizootic, are the cause of hog cholera. It may be added, however, that out of fifty-six cases (here reported) hog cholera bacteria were found in the spleen of all but six. Even in these the cultures made were too few to make the negative evidence of any value. In many cases the hoy cholera bacteria were associated with a.rather large bacillus, which, lor the sake of convenience, we will call butyric bacillus.* This organism was only detected when a bit of spleen was ' dropped into beef infusion, with or without peptone. The culture, kept at about 303 c., contained ou the second and third days a cloudy mass limited to the bottom of the tube. The cloud was made up of bacilli, rather large, with a spore in one extremity of the rod strongly refracting the light. The rod was not enlarged at this end in the fresh .state. AN hen dried and stained, the shruukeu protoplasm gave the spore bearing end a swollen appearance, remindiug one of the tailed bacteria of older writers. In the few tubes in which (his bacillus alone was present the liquid itself remained perfectly clear: when hog cholera bacteria were present, it became uniformly but faintly clouded. In liquid cultures, without the bit of spleen, the bacilli did not develop. This was evidently necessary as food material. In gclatinc-tul e and roll cultures the bacilli did not grow. They are very likely anaerobic organisms, abundant in the alimentary tract, and absorbed from ulcers or lesions of blood-vessels into the circulation before death, in the spore state, and their development kept in check until that occurs, it is also probable that they are important factors in the rapid changes which may take place after death. They arc quite constantly fo.....I in the liver of different animals when post mortem changes have begun to develop. In some half dozen cases decomposition was so far advanced that no thorough examination was made. At first it was thought that theani-mals had been dead several days, hut the person in charge of the herd asserted that they had died during the night. Although the temperature had fallen below 30deg; Fahrenheit (1deg; 0.), decomposition was far advanced. It may be that the live animals crowded upon the dead and thus kept the bodies warm. Vet this supposition is not capable of accounting for therapid changes. Tliehemorrhagic lesions may have enabled various bacteria to become distributed throughout the body. The heat disengaged by them during multiplication, aided by thebody heat of the animals still alive, may have been sufficient to keep up the process of decomposition. This post raquo;worte?raquo; growth may also account for the large number of hog cholera bacteria found in many spleens, * Wliotlier tliis bacillus is identical with the bacillns of malignant oedema, iis lias been asserted by some, 1 do not know, as no experiments were made to test its pathogenic power.



	!laquo;	59 although the temperature of the air was far below the point where mnl- tiplicatiou may take place. In the foregoiug epizootic, as well as in those studied in 1885, and 1880, there was no difficulty whatever in demonstrating the presence of the hog cholera bacillus in the spleen. The herd referred to in the preceding pages was swill-fed, and the animals were very likely crowding each other more or less, not being compelled to hunt for food. Heuce each one was exposed to a large quantity of vims. The same may be said of the penned pigs at the Experiment [Station. The diseased animals found in dillerent localities weie brought to the station and penned with healthy ones. A severe epizootic; was quite invariably the result, owing to the unusually good opportunity tor infection in the peus and the saturation of the floors and soil of the pens with virus. quot;When swine roam over a considerable extent of territory in search of food, the virus is more widely distributed but less concentrated. Less virus is therefore taken np by individual animals, and although the disease is equally fatal in the end, the course may be somewhat different and the lesions less extensive. At the same time the bacteria may elude observation. They may remain more or less localized, owing to the reactive power of the organism, which destroys those that have entered the internal organs. To those who would give up the search for hog cholera bacilli after a few nnsuccessful attempts to find them, we would reccommemi the perusal of the following three eases, after having reviewed the epizootic just described : Hog cholera prevailed more or less iu Montgomery County, Mary-laud, during the latter weeks of September and the early part of October, 1888. October 17 Mr. II-------- lost about 22 out of a herd of 55 to lt;gt;(gt; swine during the past four weeks. Of those now scattered in a large field 2 appear ill; 1, a small black shoat, is lulled by cutting its throat and examined. The superficial inguinal glands are very much enlarged, the surface mottled, dark red. The spleen large, but pale and rather firm. The liver shows signs of invasion of thu sclerosioma pinguicola. The lymphatic glands at lesser curvature of stomach are very large; cortex completely hemorrhagic. The left lung normal; the principal lobe of the right lung has in it a mass of tissue involved in broncho pneumonia, extending obliquely from the free border to near the dorsal region, about 1 inch thick; the lymphatics along the dorsal aorta are likewise hemorrhagic; the stomach filled with food ; small intestines contain a number of attached eehinorhyneM] the large intestines distended with semi-solid fecal matter ; the mucosa in general is normal, but in the ca'cum are two ulcers about three-eighths inch across, round, slightly elevated, with center black and periphery yellow; beneath the superficial slough is a whitish, firm, new growth, extending to the nmscular coat in the center of the ulcer. The spleen and the right lung were taken to the laboratory. From the former cultures were made on a^ffr, in gelatine and beef infusion, by adding bits of spleen tissue as large as peas. In no tube did any development take place.' A rabbit inoculated by tearing np a piece of liepatized lung tissue in sterile beef infusion and injecting the turbid liquid siibcutaneonsly remained well.