INFECTIOUS SWINE DISEASES IN THE UNITED STATES. 
81^ 
ton ” ulcers as the most diagnostic of the lesions. These, of 
course, do not appear in the acute type where death occurs in a 
very short time, and consequently they cannot always be relied 
upon in making the diagnosis. During the last year we have 
seen the disease in its congestive or haemorrhagic form, as de¬ 
scribed in the Bureau Reports, and the diagnosis was confirmed 
by obtaining pure cultures of the hog-cholera bacillus from the 
blood, liver and spleen. As pointed out by Smith, this form of 
the disease is rare. Welch and Clements mention it in cases 
produced by the intravenous inoculation of pure cultures, but it 
seems that they did not meet with it in more natural outbreaks. 
Space does not permit of a more extended account of the mor¬ 
bid anatomy as a wide range of lesions or modified forms is ad¬ 
mitted. Suffice it to say, that the tissue changes found in a 
typical case of chronic hog cholera are quite analogous to those 
described in a similar case of typhoid fever in the human sub¬ 
ject. 
Swine plague is considered by Smith* to be an infectious 
pneumoenteritis as the intestines are frequently involved, but 
more often the lesions are restricted, for the greater part, to the 
lungs and pleura, and hence it is also called an infectious pneu¬ 
monia. The morbid changes in the intestines usually consist, 
when present, of a superficial necrosis of the mucous membrane 
rather than distinct ulcers as in hog cholera. He describes it 
as an independent disease although frequently complicated with 
hog cholera. On this point there is some difference of opinion. 
Billings denies its existence excepting as a secondary infection. 
Welch and Clements * have not found outbreaks of pure or un¬ 
complicated swine plague such as occur of Schweinseuche in 
Germany, but they have reported isolated cases and do not doubt 
the possibility of its occurrence in epizootic form. It was found 
by them, as it frequently appeared in Smith’s investigations, 
complicated with hog cholera or with lesions which they be¬ 
lieved to be due to the hog-cholera bacillus. The disentangling 
of the lesio ns of these two diseases has been difficult, perhaps 
* Loc. cit. 
