BACILLUS AEROGENES CAPSULATUS. 



313 



The Bacillus aerogenes capsulatus is an obligative anaerobe, 

 and grows best at the temperature of the body. It stains 

 well with the anilin dyes, and also by Gram's method. 



Nutrient gelatin is peptonized but not liquefied. In agar- 

 agar grayish-white irregular round colonies are formed, which 

 have fine, hair-like projections. Milk is coagulated and 

 litmus-milk is decolorized. All the cultures are accompanied 

 by abundant evolution of gas. 



The bacillus is not very resistant to heat or to chemicals. 

 A ten minutes' exposure to a temperature of 58 C. is fatal. 



FIG. 140. 



Proteus vulgaris. X 285. (Hauser.) 



The organism is found in the soil and the intestines, and occa- 

 sionally upon the skin. 



Pathogenesis : The organism is not pathogenic, but when 

 associated with other germs it may be the cause of death. 

 It finds a ready lodgement in old blood-clots, especially in 

 aneurisms. After death, when the blood is no longer oxy- 

 genated, the germ grows very rapidly in the tissues with an 

 enormous production of gas. 



In man infection follows an injury, especially when dirt has 

 been ground into the wound. The gas produced by the 



