THE BACILLUS OF HOG CHOLERA 279 



ulcers which are frequently encountered in the chronic form of hog 

 cholera. These round ulcers vary from 1 to 2 mm. to several centi- 

 meters in diameter, and are elevated above the surrounding healthy 

 mucous membrane. They are tough and hard, and their centres are 

 usually dark greenish-yellow in color, and in the case of the larger 

 ulcers, all four coats of the intestine are involved. The ulcers at 

 times are so numerous as to destroy the mucous membrane, or at 

 least to affect it over extensive areas in the cecum and colon. The 

 liver may exhibit extensive fatty degeneration with areas of coagu- 

 lation necrosis or an increase of connective tissue. In the acute 

 form of hog cholera, minute hemorrhages may be visible beneath 

 the capsule. In acute hog cholera the kidneys are practically always 

 the seat of hemorrhagic changes, which vary more or less in extent. 

 At times the cortices are intensely congested, and all of the glomeruli 



FIG. 139 FIG. 140 





Kidneys of hog in hog cholera. (Dorsett, Bolton, and McBryde.) 



are visible as minute deep red points. In other instances the general 

 congestion is absent, the major portion of the kidneys being rather 

 paler than normal, dotted here and there with minute, sharply defined, 

 punctate ecchymoses. At times the medullary portion of the kidneys 

 is involved, and blood clots may be found in the pelves. In chronic 

 hog cholera these ecchymoses are seldom seen." 



In addition to the lesions which have just been described, the 

 acute form may show nearly all of the serous membranes of the body 

 dotted with hemorrhages. The blood and internal organs of hogs 

 which have died of either acute or chronic hog cholera usually yield 

 pure cultures of the Bacillus cholerse suis. 



Hog cholera is conveyed from sick to healthy animals almost always, 

 if not quite without exception, by contact, by feeding the viscera of 

 diseased animals, and by the subcutaneous injection of the blood of 



