139c ELEMENTS OF WATER BACTERIOLOGY 



COMPARISON OF LACTOSE BILE, LACTOSE BROTH, AND 

 DEXTROSE BILE FOR ISOLATING ORGANISMS OF THE 

 B. COLI GROUP FROM WATER SAMPLES 



Total number of samples showing fermentation 140 



Total number of samples confirming B. coli 116 



•POSITIVE FERMENTATION TUBES 



The U. S. Treasury Department, on the recom- 

 mendation of a special commission of experts appointed 

 for the purpose by the Secretary of the Treasury, 

 adopted on October 21, 1914, the following standard 

 for drinking water to be supplied to the public by 



