Lesions 557 



lowing the injection of the micro-organisms partakes of the 

 nature of a hemorrhagic edema, which is not present in 

 chicken-cholera, and rabbits especially commonly exhibit 

 fatty metamorphosis of the liver. 



Rabbits, mice, and small birds are very susceptible to 

 the disease, usually dying of septicemia in twenty-four 

 hours; guinea-pigs are less susceptible, except very young 

 animals, which die without exception. Chickens are more 

 immune, but usually succumb to large doses. Hogs die of 

 septicemia after subcutaneous injection of the bacilli. There 

 is a marked edema at the point of injection. If injected 

 into the lung, a pleuro-pneumonia follows, with multiple 

 necrotic areas in the lung. In these cases the spleen is not 

 much swollen, there is slight gastro-intestinal catarrh, and 

 the bacilli are present everywhere in the blood. 



Animals can be infected only by subcutaneous, intra- 

 venous, and intraperitoneal inoculation, not by feeding. 



As seen in hogs, the symptoms of swine-plague closely 

 resemble those of hog-cholera, but differ in the existence of 

 cough, swine-plague being prone to affect the lungs and 

 oppress the breathing, which becomes frequent, labored, 

 and painful, while hog-cholera is chiefly characterized by 

 intestinal symptoms. 



The course of the disease is usually rapid, and it may be 

 fatal in a day or two. 



Lesions. At autopsy the lungs are found to be inflamed, 

 and to contain numerous small, pale, necrotic areas, and 

 sometimes large cheesy masses one or two inches in diameter. 

 Inflammations of the serous membranes affecting the pleura, 

 pericardium, and peritoneum, and associated with fibrinous 

 inflammatory deposits on the surfaces, are common. There 

 may be congestion of the mucous membrane of the intes- 

 tines, particularly of the large intestine, or the disease in 

 this region may be an intense croupous inflammation with 

 the formation of a fibrinous exudative deposit on the surface. 



A hemorrhagic form of the disease is said to be common 

 in Europe, but, according to Salmon, is rare in the United 

 States. 



