128 



Elements of Water Bacteriology. 



PRESENCE OF B. COLI IN POLLUTED AND UNPOLLUTED 



WATERS. 

 (WINSLOW AND HUNNEWELL, 



Unpolluted Waters. 



Polluted Waters. 



As the authors pointed out, these tables indicate that 

 bacteria capable of growth at the body temperature and 

 fermenting dextrose and lactose are infrequently found in 

 unpolluted waters, and colon bacilli are very rarely present. 

 In 157 samples, typical colon bacilli were found only 5 

 times out of 157, in i c.c. Lactose fermenting organisms 

 appeared in only 8 per cent of the normal samples and in 

 100 per cent of the polluted ones, in i c.c. Incidentally 

 it may be pointed out that these tables well illustrate the 

 dangers of overgrowths, particularly in large samples. It 



