INFECTIONS OF THE DIGESTIVE TRACT 25 



mixture but which are nevertheless intensely putre- 

 factive when grown in a medium containing a low per- 

 centage of sugars as well as native proteids. This is 

 true of B. aerogenes capsulatus. I can confirm the obser- 

 vation that B. coli cannot decompose media consisting 

 of native proteids even on long standing. On the other 

 hand, there is no more striking type of putrefaction than 

 that induced in proteids by B. putrificus upon egg-meat 

 mixture. 



At the present time I know of no evidence to show 

 that native proteids can be actively decomposed by any 

 of the ordinary facultative anaerobes, and in respect to 

 the digestive tract the facts all point to the correctness 

 of the view that we largely owe the initiation of proteid 

 cleavage there to the agency of the strict anaerobes. 

 But it must be remarked in passing that it does not 

 follow from what has just been said that intestinal 

 putrefaction is carried on through the sole activity of 

 strict anaerobes. The fact that these organisms are the 

 great destroyers of native proteids does not tell the 

 story of the entire putrefactive process. The intestine 

 abounds with microorganisms which are able to attack 

 albumoses and peptones and to effect a further degra- 

 dation of the proteid molecule, thus entering into a 

 symbiotic action with the strict anaerobes. 



It appears desirable to state at this point just what is 

 meant by the expression " anaerobic life' 7 as applied to 

 the strict anaerobes to which reference has been made. 

 When we speak of anaerobic life, we are liable to vaguely 

 picture a state of existence in which the microorganisms 



