INFECTIONS OF THE DIGESTIVE TRACT 293 



microscopical examination of the Gram-stained faecal 

 fields, even in fields from diarrhceal stools. It is pos- 

 sible that in some of the cases that have come under 

 observation the typical colon bacilli have been replaced 

 by some allied form of Gram-negative organism capable 

 of forming less gas than is ordinarily found as the prod- 

 uct of normal colon bacilli on sugar bouillon. We have 

 not yet had an opportunity to make a careful study 

 of our cases of saccharo-butyric putrefaction from the 

 standpoint of the characters of the colon bacilli present. 



While the reduction in the total number of living colon 

 bacilli has been shown to exist in many of our cases of 

 saccharo-butyric putrefaction by means of plating on 

 litmus gelatin, there are exceptional instances in which 

 there is no evidence that the number of colon bacilli 

 has been reduced. The evidence, however, in these 

 cases is confined to the appearance of acid-forming 

 colonies on litmus gelatin and agar and to the occur- 

 rence of normal gas production in the fermentation 

 tubes. 



The presence of large numbers of putrefactive anae- 

 robes in the intestinal tract and especially of B. aero- 

 genes capsulatus, gives to the intestinal contents a pecul- 

 iar character. These organisms, as already mentioned, 

 are capable, under anaerobic conditions, of attacking 

 carbohydrates and proteids in a vigorous manner. In 

 either case there is a formation of butyric acid, often in 

 considerable amount. This may be associated with the 

 production of propionic, caproic, or valeric acids. The 

 odor of the movements from patients in whom this 



