24 INFECTIONS OF THE DIGESTIVE TRACT 



significance in its application to the bacterial processes 

 in the digestive tract. This significance comes from two 

 fundamentally important facts : first, that the initiation 

 of putrefactive decompositions in the digestive tract 

 (as elsewhere) depends very largely, though probably 

 not exclusively, on the activities of obligate anaerobes ; 

 secondly, that an important portion of the digestive 

 tract is most of the time under anaerobic conditions. 

 The importance of the role taken by obligate anaerobes 

 in bringing about putrefactive decomposition in native 

 proteids is only beginning to be appreciated. Bien- 

 stock * made an important contribution to biology when 

 on definite experimental evidence he insisted on the 

 inability of the ordinary facultative anaerobes to attack 

 native proteids, and showed that obligate and strict 

 anaerobes like B. putrificus are able, quite unaided, to 

 break down proteids. Dr. Rettger, 2 in his numerous 

 experiments on putrefactive decomposition, confirmed 

 and extended the work of Bienstock. He showed that 

 an egg-meat mixture is not attacked by B. lactis aerogenes, 

 B. coll. Streptococcus pyogenes, B. alcaligenes fcetidus, 

 proteus vulgaris, etc., whereas it is regularly decomposed 

 by strict anaerobes such as B. putrificus, B. maligni 

 cedematis, and B. anthracis symptomatici (bacillus of 

 quarter-evil). This is a severe test, and there are putre- 

 factive anaerobes which cannot attack the egg-meat 



1 " Untersuchungen iiber die Aetiologie der Eiweissfaulnis," 

 Archiv /. Hyg., xxxvi, p. 335, 1899; ibid., xxix, p. 390, 1900. 



2 "Studies on Putrefaction," Journ. of Biol. Chem., ii, p. 71, 

 1906. 



