INFECTIONS OF THE DIGESTIVE TRACT 209 



times found in the human intestine. Whether it is 

 ever found in large numbers or ever possesses patho- 

 logical significance is at present unknown. The bacil- 

 lus of malignant oedema resembles the gas-bacillus in 

 morphology, but sporulates more readily, is motile, and 

 forms less gas on sugar media. Its behavior on milk is 

 wholly different from that of the gas-bacillus. When 

 injected into a living rabbit which is subsequently killed 

 and incubated it is found that there has been little or 

 no liberation of gas in the liver and elsewhere a 

 feature which easily distinguishes it from B. aerogenes 

 capsulatus. 1 An organism which closely resembles B. 

 aerogenes capsulatus in many respects is the bacillus of 

 rauschbrand or symptomatic anthrax (the cause of the 

 quarter-evil or black-leg). This organism is, however, 

 frequently Gram-negative under conditions of staining 

 in which the gas-bacillus is Gram-positive; it is also 

 motile. It resembles B. aerogenes capsulatus in being 

 an abundant gas producer, the gas formed showing a 

 relation between hydrogen and carbon dioxide closely 

 resembling that obtained from the gas-bacillus. This 

 organism is the only one of the anaerobes which I have 

 found to be able to give rise to a large production of gas 

 in an incubated rabbit. It might be supposed that this 

 organism could be mistaken for the gas-bacillus, but I 

 think the difference in the conditions of sporulation would 



1 Ghon and Mucha gave a comparison of the gas-bacillus with 

 the bacillus of malignant redema and a third organism (derived 

 from a case of peritonitis) closely related to these ("Beitrage 

 zur Kentniss der anaeroben Bakterien des Menschen," Cen- 

 tralbl. f. Bakt., Orig., xl, p. 37, 1905-06). 



