328 MICRO-ORGANISMS PATHOGENIC FOR ANIMALS ONLY. 



rapidly and luxuriantly at the incubator temperature on all 

 the ordinary media except potato, on which the growth is 

 almost invisible. 



The bacillus is pathogenic for chickens, geese, mice, pigeons, 

 rabbits, etc. The injection of pure cultures produces a fatal 

 septicaemia with pronounced intestinal symptoms. The bacil- 

 lus is found in all the organs of the affected animal, but 

 chiefly in the intestine. Chickens inoculated with attenuated 

 cultures are made immune to infection with virulent organ- 

 isms. One peculiarity of this organism is that when injected 

 into different species of animals different diseases are pro- 

 duced in each species, such as rabbit septicaemia, swine 

 plague, etc. 



Bacillus Suipestifer (Hog Cholera). 



This organism belongs to the same group as the colon bacil- 

 lus. It is the specific cause of hog cholera, a disease which 

 is both common and fatal. It is a short, thick rod, with 

 rounded ends, flagellated and exceedingly motile. It does 

 not form spores. It is stained by the anilin dyes, but not 

 by Gram. 



The organism is easily cultivated on all the ordinary cult- 

 ure-media at the temperature of the body. The cultures as 

 well as the germ bear some resemblance to Bacillus typhosus, 

 but the bacillus of hog cholera produces both gases and acids. 

 It is exceedingly resistant to both heat and chemicals. 



The organism is markedly pathogenic for animals ; and is 

 found in the intestine of animals so diseased. 



The injection of gradually increasing doses of pure cultures 

 of Bacillus suipestifer into cows immunizes them and causes 

 the formation of an antitoxin in the blood of the cow which 

 is capable of protecting guinea-pigs from the disease. 



Bacillus Suisepticus (Swine Plague). 



This organism resembles the bacillus of hog cholera ; and 

 the two diseases are not infrequently associated. The one 

 may be mistaken for the other. The disease is rapidly fatal. 

 Bacillus suiseplicus is an exceedingly short, thick rod, which 



