[HARRISON & VANDERLECK] ANALYSES OF OTTAWA RIVER WATER 2 1 



A small quantity of a young broth culture of B. coli obtained from 

 river water was added to each of 4 flasks of river water. Each flask 

 coBtained two litres of water and two of them were sterilised. 



These results showed increase in numbers of B. coli in both 

 sterilised and unsterilised water, but the amount of increase was much 

 less in the unsterilised water, possibly due to the competition with other 

 bacteria. A slight trace of peptone would also be present in the flasks 

 from the added broth cultu^-e. 



On July 31st we transferred from flasks 3 and 4, 20 to 40 c.c. of 

 water into 6 2-litre flasks of unsterilised river water. Three of these 

 flasks were kept at 16° to 18° C. and three at 25° to 27° C. Each 

 flask was tested daily for the number of B. coli. 



Number of B. coli per c.c. 



