SWINE-PLAGUE. 421 



The symptoms of swine-plague, while closely resem- 

 bling those of hog-cholera, may differ from them in the 

 existence of cough, swine-plague being prone to affect the 

 lungs and oppress the breathing, which becomes frequent, 

 labored, and painful, and associated with frequent cough, 

 while hog-cholera chiefly presents intestinal symptoms. 



The course of the disease is usually rapid, a fatal result 

 often occurring in one or two days. 



At autopsy the lungs are often found inflamed, and 

 contain numerous small, pale, necrotic areas, and some- 

 times 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 com- 

 mon. There may be congestion of the mucous mem- 

 brane of the intestines, 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 com- 

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

 United States. 



The bacillus of swine-plague much resembles that of 

 hog-cholera, and not a little that of chicken-cholera. It 

 is a short organism, rather more slender than its con- 

 geners, not possessed of flagella, and is incapable of move- 

 ment and produces no spores. Its vitality is low, and 

 it is easily destroyed. Salmon says that it soon dies in 

 water or by drying, and that the temperature for its 

 growth must be more constant and every condition of 

 life more favorable than for the hog-cholera germ. This 

 germ is said to be widely distributed in nature, and is 

 probably present in every herd of swine, though not 

 pathogenic except when its virulence has been increased 

 or the resistance of the animals diminished by some un- 

 usual conditions. 



In its growth the bacillus of swine-plague is an optional 

 anaerobic organism. 



