INFECTIONS OF THE DIGESTIVE TRACT 45 



medium of sterilized egg-white, but its presence in more 

 than small numbers is exceptional and it may be entirely 

 absent. 



A more important anaerobic spore-bearing micro- 

 organism than B. putrificus is B. aerogenes capsulatus* 

 which can be demonstrated by its growth on sterilized 

 milk to which an abundance of faecal bacteria has 

 been added or by its ready growth on blood-agar with 

 or without the addition of sugar. So long ago as 1894 

 Fliigge found that the faeces of children nourished wholly 

 on mother's milk contained Botkin's Bacillus butyricus, 

 and we now know from the critique of Grassberger and 

 Schottenfroh that Botkin's bacillus in reality represents 

 two distinct microorganisms, each of which is capable 



or spore-forming variety of B. bifidus. The headlet bacteria have 

 a morphological resemblance to another spore-forming anaerobe, 

 B. putrificus, which by appropriate methods of culture can some- 

 times be isolated from the nursling's stool. The resemblance is 

 so close that in faecal smears submitted to microscopical examina- 

 tion it is hardly possible to make a distinction with confidence. 



1 This organism is known by different names in different coun- 

 tries. The name B. aerogenes capsulatus was given to it by Pro- 

 fessor Welch and is the name by which it is best known in the 

 United States. The organism is identical with the gas-phlegmon 

 bacillus of Fraenkel and probably with the granulo-bacillus im- 

 mobilis liquefadens of Grassberger and Schottenfroh. In France 

 the organism is known as B. perfringens (Veillon and Zuber). 

 In England Klein described an organism which he called B. en- 

 teritidis sporogenes,b\it it is doubtful if he was dealing with pure 

 cultures, although it appears probable that he had B. aerogenes 

 capsulatus in his cultures. A trinomial name is considered objec- 

 tionable by botanists, and hence Migula proposed the name B. 

 Welchii for B. aerogenes capsulatus, but the latter name is now so 

 firmly established in the United States that it is doubtful if it 

 will be displaced. Welch's bacillus is often spoken of as "the 

 gas-bacillus." 



