BACTERIA OF THE COLON TYPE IN HUMAN INTESTINES 243 



Browne (1915) found that about 11 per cent of colon Qultures 

 from human stools fermented sucrose while about 40 per cent 

 fermented dulcitol. These results are in fairly close agreement 

 with our own. 



When we turn to the high ratio or B. aerogenes group we find 

 a more complex situation. The non-liquefying high-ratio grain 

 cultures were easily separable into three distinct types. For 

 purposes of comparison two of these are arranged with the high 

 ratio fecal group in figure 4. Type E, in which were included 

 only 8 cultures, presents a picture almost identical with that 

 shown by the diagram for the high ratio fecal group. There was a 

 higher percentage of indol formers among the grain cultures 

 and a slightly larger proportion of dulcitol fermenters; otherwise 

 the agreement is perfect and it may be assumed that the 8 grain 

 cultures were originally of fecal origin. 



The diagram for type D, which included 90 cultures, shows the 

 typical B. aerogenes culture found on grains. While it agrees 

 with the high ratio human feces cultures in certain characteristics 

 it is sharply differentiated from them by its feeble action on the 

 alcohols, particularly on adonitol. The B. aerogenes cultures from 

 feces without exception ferment this alcohol readily while with 

 the exception of those classified as of fecal origin only 6 of 103 of 

 the B. aerogenes cultures from grains were able to utilize this 

 substance. 



These results indicate that there is reason for separating the 

 high ratio type found in feces from the high ratio type found on 

 grain as shown by type D in figure 4. The difference in ability to 

 utilize adonitol is distinctive and if the separation is a logical one 

 it should be of value to water bacteriologists. 



In a previous paper (Rogers, Clark and Davis, 1914) it was 

 shown that the low gas ratio if not modified by oxidations of the 

 hydrogen remains constant under a variety of conditions which 

 permit wide variations in the high gas ratios. This together with 

 other considerations led to the conclusion that the carbon dioxid 

 and the hydrogen liberated by B. coli are intimately connected. 

 The establishment of so constant and simple a ratio between two 

 products furnishes a most reliable sort of cultural characteristic 



