INFECTIONS OF THE DIGESTIVE TRACT 13 



be spared the organism. The presence in the colon of 

 immense numbers of obligate microorganisms of the 

 B. coli type may be an important defense of the organism 

 in the sense that they hinder the development of that 

 putrefactive decomposition which, if prolonged, is so 

 injurious to the organism as a whole. 



We have in this adaptation the most rational explana- 

 tion of the meaning of the myriads of colon bacilli that 

 inhabit the large intestine. These bacilli are essential 

 to the life of the individual mammal as a defense against 

 bacterial foes which it is impracticable to wholly exclude 

 from the digestive tract, and not as agents in directly 

 facilitating the processes of digestion in the narrow 

 sense. This view is not inconsistent with the conception 

 that under some conditions the colon bacilli multiply 

 to such an extent as to prove harmful, through the part 

 they take in promoting fermentation and putrefaction. 

 It seems to me not unlikely that the reaction of the fluids 

 of the digestive tract may influence the character of the 

 activities of the colon bacilli, an alkaline reaction favor- 

 ing their putrefactive functions if peptones be present. 



The following facts, first noted by Moro and Murath, 

 point to the existence of bacterial inhibitory powers 

 on the part of the fsecal flora of nurslings and bottle-fed 

 children, and deserve mention. If one allows faecal 

 matter from a normal nursling to stand in a thermostat 

 in a closed test-tube, the original not disagreeable odor 

 lasts for days or even weeks, although the material as a 

 rule contains small numbers of true putrefactive bacteria. 

 Indeed, it is possible to inoculate such normal material 



