SPORING BACILLI 319 



liquefying, and produces acid and gas in bile-salt glucose 

 media and in peptone water + glucose or mannite. It 

 forms a spore nearer one end. Its growth in milk is highly 

 characteristic, and this medium is commonly used for its 

 isolation. 



Method. A small quantity of the suspected material 

 is inoculated into sterile milk (" whole milk "), using at 

 least 15 c.c. of the medium. Heat for 10 minutes at 8o C. 

 to destroy all non-sporing forms, cool the tube, and incubate 

 anaerobically for twenty-four to thirty-six hours. If the 

 casein is precipitated and torn into irregular masses, with 

 a moderately clear whey and abundant gas formation, 

 the result is positive, but it is desirable to verify by animal 

 inoculation. (In the examination of water and milk, the 

 result is observed after two days' incubation.) The 

 culture has a smell of butyric acid, and numerous bacilli 

 are found in the whey. If 1 c.c. of the whey be injected 

 into a guinea-pig, the animal becomes ill in a few hours, and 

 dies in twenty-four hours. At the point of inoculation the 

 skin, subcutaneous tissues, and sometimes the adjacent 

 muscles, are green, gangrenous, ill-smelling, and cedema- 

 tous ; there may be gas formation. This pathogenic test 

 serves to distinguish the B. enteritidis sporogenes from 

 the B. butyricus of Botkin, which otherwise closely 

 resembles it. 



B. Aerogenes Capsulatus. First observed by Welch 

 in 1891, and obtained from the intravascular blood in a 

 case of ruptured aortic aneurysm. The post-mortem took 

 place six hours after death, and attention was called to 

 the blood by the presence of gas-bubbles throughout the 

 vessels. It was fully described by Welch and Nuttall in 

 1892, and in 1893 Fraenkel independently described (under 

 the name of B. phlegmonis emphysematosa?) a bacillus, 

 now considered to be identical with the B. aerogenes 

 capsulatus. Klein's B. enteritidis sporogenes is believed 

 by some to be the same organism, or a closely related one. 

 B. aerogenes capsulatus is widely distributed in nature, 

 being found in soil, dust, brackish water, and in the 

 normal intestinal tract of man and animals. In size 

 it is not unlike anthrax bacillus, but is more variable in 

 length and somewhat thicker. The bacilli are generally 



