264 INFECTIONS OF THE DIGESTIVE TRACT 



indol. If, however, there is no ascent of the colon bacilli 

 to the region in which these organisms would find pep- 

 tones to attack, the abnormal production of indol is not 

 excluded, for, as already stated, the action of the anaerobes 

 in the ileum and large intestine permits the hydrolyzing 

 of proteids which then fall subject to the colon bacilli 

 with a resulting production of indol. Both these methods 

 of indol production may occur in the same individual, 

 namely its production in the small intestine through the 

 action of colon bacilli on peptones, and, secondly, the 

 formation of indol in the ileum and large intestine through 

 the combined action of putrefactive anaerobes and colon 

 bacilli acting upon such native proteids as may have 

 escaped digestion at higher levels. The occurrence of 

 constipation may be considered as favoring both these 

 methods of indol production, but only under abnormal 

 conditions of digestion. The stagnation of food rem- 

 nants and bacteria in the large intestine would cause no 

 indol production according to the hypothesis here set 

 forth unless masses of undigested proteid or hydrolyzed 

 proteid material had entered the region of the large 

 intestine. The stagnation of food in the small intestine 

 would not lead to the production of indol there except in 

 the presence of colon bacilli or other microorganisms 

 capable of making indol from peptones or albumoses. 

 Of the actual ascent of such bacteria from the upper level 

 of their normal habitat into the higher levels of the small 

 intestine we know as yet very little that is definite. 

 The invasion of the gall-bladder by colon bacilli under 

 conditions which make it improbable that there has been 



