326 L. A. ROGEES 



The assumption that the two types, B. colt and the fecal 

 B. aerogenes, are distinctively fecal organisms without other 

 habitat may make it difficult to explain their occurrence in cer- 

 tain samples of water in which the chances of contamination 

 seem very remote. We have isolated both the B. coli type and 

 the fecal B. aerogenes type from water in which the chances of 

 pollution from dwellings or wash from farm lands is almost 

 completely excluded. In some cases the fact that all of the 

 cultures isolated belonged to one or the other of the two fecal 

 types would point to a source of contamination not found by 

 physical examination of the surroundings. 



In no case was the possibility of contamination by animals 

 completely excluded. This is especially true of the springs and 

 brooks in the Maine woods. Deer and moose frequent water 

 courses in the warm months and there are a number of kinds of 

 small animals which make their homes along the banks. 



Even a protected spring may be exposed to the visits of 

 squirrels and similar animals. It is possible that the occasional 

 colon bacillus of the fecal type found in waters presumably free 

 from pollution may be accounted for in this way. 



The possibility of fish as a source of intestinal bacteria in 

 water is suggested by the work of Browne, (Browne 1917), 

 who found B. coli in the intestinal tract of 39.8 per cent of scup 

 examined. The feeding habits of the fish may determine the 

 presence or absence of colon-aerogenes bacteria in its digestive 

 tract but in no case is it likely that fish would account for more 

 than occasional cultures. 



There is also a possibility that the digestive tract of animals 

 is not the only source of the so called fecal type of colon. At 

 the present time there is little or no evidence that this is the 

 case. It is true that some of our water cultures were not true 

 to the fecal type and therefore might suggest a different variety 

 or source. These differences were very slight, consisting for the 

 most part in failure to form indol or in a hydrogen ion limit 

 sHghtly lower than that of the typical culture. 



Whatever the final conclusion may be in regard to the occur- 

 rence of these occasional cultures the fact remains that there 



