HOG CHOLERA. 
9 
rhagic lesions. These would appear to resemble the condition 
found in chronic pieuro-pneumonia, where we find a cyst and at 
the same time a fresh inflammation of the lung tissue. What con¬ 
clusion is the pathologist to draw from this condition ? Is it the 
result of an increase of virulence of the bacteria which have been 
preserved so that they are able to penetrate and multiply in the 
tissues which have previously resisted them, or is it simply the re¬ 
sult of an extension of the bacteria, which have not increased in 
virulence but which have been limited to the affected part of an 
organ ? The answer to these questions must have great influence 
on our views of the preservation of virus and the sudden appear¬ 
ance of virulent epizootics which apparently have their starting- 
point in mild chronic cases. 
Peritonitis, pleuritis and pericarditis are not uncommon com¬ 
plications usually accompanying old ulcers. These are possibly 
caused by septic bacteria gaining entrance through the ulcers. We 
have demonstrated that cocci closely resembling those of suppura¬ 
tion and various other microbes are usually found in the peritoneal 
cavities in chronic cases. 
The lesions found in the lungs on post-mortem examination 
were either simple collapse oi 5 lobular broncho-pneumonia which 
apparently followed it. In about fifteen per cent, of the animals ex¬ 
amined, one of the smaller ventral lobes was airless throughout and 
moderately enlarged. Viewed from the surface the diseased lobe is 
bright red, dotted with minute pale, grayish and yellow points of a 
diffused, hazy outline, each not more than one millimeter in diam 
eter. They are usually ranged in groups of four and represent 
the ultimate air cells filled with cellular exudate. The larger 
bronchi are also occluded. Microscopic sections reveal a broncho¬ 
pneumonia. The process seems to be accompanied with very little 
inflammation. The desquamation and proliferation go on in the 
alveoli and smallest air tubes until they are occluded by the casts. 
Of the forty-nine animals of the herd mentioned seventeen were 
found with collapse and eight with broncho-pneumonia. In this out¬ 
break then, more than one-half of the animals had some defect of 
the lungs. It is to be remembered, however, that when healthy hogs 
are slaughtered, it is common to find more or less collapse of the 
same lobes as were found affected in these cases. 
