550 Hog-cholera 



which appear as circular, slightly projecting masses varying 

 in color from yellow to black. Occasionally these ulcers 

 are slightly depressed. When cut across they are found to 

 consist of a firm, solid growth extending nearly through the 

 intestinal wall. They are most frequent in the cecum, upper 

 half of the colon, and on the ileocecal valve. In the chronic 

 form of the disease the spleen is rarely enlarged. 



In hog-cholera the first effect of the disease is believed 

 to be upon the intestines, with secondary invasion of the 

 lungs. 



The most characteristic lesions of the disease are the 

 petechiae and ecchymoses, the ulcerations of the large intes- 

 tine (Fig. 157), the collapse, and the occasional broncho- 

 pneumonic changes in the lung. Pulmonary changes, 

 however, are more characteristic of swine-plague (q. -v.). 



The kidneys are nearly always affected, containing 



Fig. 158. Bacillus of hog-cholera, showing flagella. 



numerous petechial hemorrhages, and the urine containing 

 albumin and tube-casts. 



The bacillus is disappointing in its effects upon hogs. When 

 they are subcutaneously or intravenously introduced or fed 

 to such animals they sometimes fail to become diseased, 

 sometimes show fever and depression, but rarely die. Ani- 

 mals thus made ill do not communicate the disease to others. 



