INFECTIONS OF THE DIGESTIVE TRACT 47 



these infants number among their inhabitants the 

 following: B. bifidus communis and the headlet bac- 

 teria (which are probably varieties of B. bifidus), B. coli 

 communis, and B. lactis aerogenes, B. acidophilus, B. 

 aerogenes capsulatus, and certain intestinal streptococci. 1 

 It should be noted that of these bacteria the dominant 

 form, B. bifidus (and in the upper part of the large intes- 

 tine, B. coli communis and B. lactis aerogenes), is one 

 which forms lactic acid on sugar media, is antiputrefac- 

 tive, and does not attack proteids. It should also be 

 observed that B. aerogenes capsulatus, the most impor- 

 tant representative of the putrefactive type of in- 

 testinal bacteria, is an extremely scarce organism, and 

 finally, that spore-holding bacteria and free spores are 

 of rare occurrence (relatively) in the faeces and contents 

 of the large intestine. 



What has been already said regarding the results of 

 microscopical and cultural investigation of the nursling's 

 faeces makes it clear that the picture which we get from 

 the former method is quite different from that furnished 

 by the latter. Whereas one would conclude from the 

 microscopical field that he was dealing chiefly with one 

 race of bacteria (B. bifidus) supplemented by very few 

 other forms, cultural methods which include anaerobic 



1 Less constant inhabitants are the following, Staphylococcus 

 pyogenes albus, intestinal diplococci, B. putrificus, the motile 

 butyric acid bacillus (Amylobacteria of Briiber or granulo-badllus 

 mobilis non-liquefadens of Grassberger and Schottenf roh) ; B. 

 mesentericus vulgatus (Fliigge) ; certain actinomyces, especially 

 Actinomyces chromogenes; sarcinse ; Oidium albicans, and various 

 yeasts. 



