16 INFECTIONS OF THE DIGESTIVE TRACT 



B. coli communis and B. lactis aerogenes, usually grew 

 fairly well and suffered little inhibition. This was a 

 regular occurrence throughout the experiments. Indeed, 

 the phenomenon occurred so regularly that it was em- 

 ployed as the basis for distinguishing between typhoid 

 bacilli and colon bacilli. In the case of Staphylococcus 

 pyogenes, which is found in every nursling's stool, there 

 is observed very little inhibitory action. In the case 

 of B. pyocyaneus it was found that even in such strong 

 concentrations as 1 : 10 there was good growth with the 

 production of pigment.. It appears, therefore, that in 

 this case the medium favored the growth of pyocyaneus 

 to a certain extent. The dysentery bacillus of Flexner 

 in some cases behaved like the typhoid bacillus, but in 

 other cases showed growth in a dilution of 1 : 100. The 

 action of this medium was therefore more marked upon 

 the whole in its action against the typhoid bacillus and 

 the Kruse bacillus than against the Flexner bacillus. 



The Diplococcus intestinalis, a constant inhabitant of 

 the nursling's tract, behaved like the Staphylococcus 

 pyogenes in developing only moderately. The growth 

 of the thrush organism was more strongly inhibited than 

 B. prodigiosus. The development of color was checked 

 on all the plates in which the faecal concentration was 

 fairly strong. 



In general, the inhibitory substances to which the 

 restraining effect is attributed appeared to be less active 

 in the fseces of the nursling than in those of grown 

 persons. 



A difference between the inhibitory action of the fseces 



