ae or. ANIWAE ee 
4 ' I iY 
figced: Keaton habe ‘aodahon: In excum and aii an almost coutinndus yel- 
low sheet of superficial necrosis about 1™ thick. covering the mucosa. In lower 
colon it breaks up into isolated patches simulating ulcers. , In ae setil ao sections 
this layer is found to consist of necrosed epithelium with some round cells. On 
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 peri- 
cardium. Pleura thickened generally, serum very slight in amount, blood-stained. 
On lobes of left lang which are also glued together, and on right lung there is a 
very slight deposit “about 3 thick in the form of a net-work. As a rule the 
nleuritis and exudate is most marked on the most dependent portions of the lungs. 
avity 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 hemorrhagic, 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 No. 460 presented such a well-marked case, No. 461, although presenting at 
first the same symptoms, slowly recovered. The difference may have been due to 
the fact that with No. 460 a 6-inch needle was used, while with 461 one only 3inches 
jong. In the latter case the chance for the passage of bacteria into the lung tissue. 
_ and thence into the intestines was much poorer. 
f 
' This experiment proves, (1). That hog cholera bacteria when i in-— 
troduced into the lungs do not produce lung disease ; ( (2), that they 
may pass from the lungs by way of the pharynx into the digestive 
tract and there produce their characteristic effect. 
Bacteriological observations.—The preceding experiments on rab-' 
bits and the intra-thoracic inoculation in case of the pig are suffi- 
cient of themselves to establish the fact that the bacteria described 
in the two preceding reports, and again found in this epizootic, are 
_the cause of hog cholera. It may be added, however, that out of the 
fifty-six cases (here reported) hog cholera bacteria were found in the’ 
spleen of al} but six cases. Even in these the cultures made were 
too few to make the negative evidence of any value. 
In many cases the hog cholera bacteria were associated: with a 
rather large bacillus which, for convenience sake, may be called 
butyric ba villus. This organism was only detected when a bit of 
spleen was dropped into beet infusion with or without peptone. 
~The cultures kept at about 35° C. contained on the second or third 
day 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. When dried and stained, the. shrunken 
protoplasm gave the linet -bearing end a swollen appearance, re- 
minding one of the tailed bacteria of older writers. In the few 
tubes in which this bacillus alone was present the liquid itself re- 
mained perfectly clear; when hog cholera bacteria were present it 
beeame 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 gelatine tubes and roll cultures the 
bacilli did not grow. Any pathogenic activity can not be ascribed 
to them. They are anaérobic organisms, probably abundant in the 
alimentary tract, which were absorbed from ulee ers or hemorrhages 
into the circulation before death as spores, and their developme nt 
kept in check until that took place. It is also probable that they 
are important factors in the rapid changes which may take place 
after death. 
In some half a dozen cases decomposition was so far advaneed that 
no thorough examination was made. At first it was thought that 
the animals had been dead several days, but the person in charge of 
the herd asserted that they had died durimg the night. Although 
