112 EEPOET OF THE BUEEAU OF ATOMAL INDUSTEY. 



Intestinal lesions. In the severe types of this disease, there are 

 very extensive lesions of the large intestine. These on superficial 

 examination resemble those of hog cholera so much that this simi- 

 larity alone may have prevented the separation of these two diseases 

 by pathologists who have studied them very carefully. 



Although the lesions seemed to us at first sight different from the 

 ulcerations found in hog cholera, yet it was only after the futile 

 search for the specific bacillus of this disease in the spleen of the 

 affected animals that we ventured to consider them as something 

 entirely different from the lesions produced by that disease. 



In the following pages we shall try to state as clearly as possible 

 the difference between the appearance presented by the large intes- 

 tine in hog cholera and in swine plague. 



Croupous and diphtheritic lesions. The mucous membrane is 

 dotted by a large number of closely set, convex, circular masses of 

 a yellowish tint. These are rarely larger than one-eighth to one- 

 fourth inch in diameter. They can be readily lifted away from the 

 membrane, leaving a slightly depressed, raw surface. This mass which 

 has exuded from'the membrane is tough, evidently made up of a 

 fibrinous coagulum. It is very easily mistaken for an ulcer when 

 the examination is carelessly made. The hog cholera ulcer, it will 

 be remembered, is a circumscribed death or necrosis of the mucous 

 membrane. The hole thus made is occupied by a soft, granular 

 matter, in some cases projecting above the surface like a button, 

 which is scraped away with some difficulty, leaving an irregular 

 excavation, very rarely the ulcers are flat, button-like masses, pre- 

 senting concentric bands of a dirty yellow and black. They are 

 then made up of hard, tough, homogeneous, whitish tissue, extend- 

 ing at times as a neoplasm through the entire intestinal wall to the 

 peritoneum. These ulcers vary much in size, from a pin's head to 

 an inch or more in diameter. The lesions found in swine plague are 

 therefore different in that they consist of masses of exudate, either 

 isolated or running together into large patches of variable size and 

 thickness. The rectum (rarely diseased in hog cholera) is quite fre- 

 quently involved with the colon. In some cases a continuous sheet 

 of deposit covers the mucosa entirely. This may adhere with con- 

 siderable tenacity, or it may be removed simply by the stroke of the 

 scalpel, or it may not be attached, but appear as a part of the intes- 

 tinal contents. It then consists of small lumps stained with bile and 

 feces and easily overlooked. Sections of the intestinal wall show 

 the exudate to consist of a mesh- work which may or may not inclose 

 leucocytes. When the inflammation is very severe the membrane 

 beneath the exudate is liable to necrosis, and the process must then 

 be regarded as diphtheritic. It is probable that in all cases the 

 epithelium is destroyed in order to give rise to the exudate, and all 

 varieties of lesions, from the simply croupous to the diphtheritic, are 

 to be met with, depending on the quantity and quality (or virulence) 

 of the infectious agent. The anatomical distinction between croupous 

 and diphtheritic lesions seems at least in this disease to be simply 

 due to a more or less intense action of the same cause. In diph- 

 theritic conditions, therefore, ulcers may subsequently appear. Our 

 observations on this stage of the process are too few to warrant any 

 conclusions. Once or twice ulcers were seen which differed from 

 hog cholera ulcers in being perfectly round, as if punched out of the 

 membrane, from one-eighth to three-eighths of an inch in diameter. 

 The bottom of the ulcers was concealed by a thin, creamy deposit, 



