194 INFECTIONS OF THE DIGESTIVE TRACT 



flora of these people, it seems fair to assume that they 

 are in these instances regular inhabitants of the digestive 

 tract, although they may not appear hi their character- 

 istic sporulating form in the microscopical fields. The 

 flora of persons free from symptoms of intestinal derange- 

 ment has not abundantly given us B. putrificus in our 

 bouillon-calcium-carbonate flasks. This is in harmony 

 with the statement of Bienstock that he failed to find 

 B. putrificus in normal persons. It is true also of the 

 intestinal flora of persons to whom the spores of B. 

 putrificus had been given by the mouth. 



One reason why it is difficult to define with con- 

 fidence the part of B. putrificus in intestinal processes 

 of putrefaction is that it is apt to be associated with 

 other microorganisms which may be concerned with the 

 processes in question, such as B. aerogenes capsulatus and 

 some coccal infections. The association of excessive 

 numbers of these three organisms in the large intestine is 

 not uncommon in cases of chronic excessive intestinal 

 putrefaction. 



In every instance in which B. putrificus is present hi 

 bouillon flasks prepared by growing the mixed faecal 

 flora from cases of intestinal putrefaction, there is found 

 also methyl mercaptan. This observation corresponds 

 to the fact that B. putrificus in pure culture in peptone 

 bouillon is capable of making mercaptan. It has not 

 always been possible to grow B. putrificus from cases 

 in which a methyl mercaptan reaction was obtained, 

 and for this reason and others I believe that methyl 

 mercaptan may be produced by other intestinal organ- 



