SIGNIFICANCE OF COLON GROUP IN WATER * 151 



waters of great purity and present in large numbers 

 only in cases of high pollution. This author also 

 quoted Miquel as havdng found colon bacilli in almost 

 every sample of drinking-water if only a suflacient por- 

 tion were taken for analysis. 



The practical results of the application of the colon 

 test from this standpoint have proved of the highest 

 value. As originally outlined by Dr. Smith, it con- 

 sisted in the inoculation of a series of dextrose tubes 

 with small portions. of water, tenths or hundredths of 

 the cubic centimeter. It was first used by Brown 

 (Brown, 1893) in 1892 for the New York State Board 

 of Health, and it showed from 22 to 92 faecal bacteria 

 per c.c. in the water of the Hudson River at the Albany 

 intake, and from 3 to 49 at various points in the Mohawk 

 River between Amsterdam and Schenectady. In some 

 previous work at St. Louis, the colon bacilli in the 

 Mississippi River were found to vary from 3 to 7 per c.c. 



Hammerl (Hammerl, 1897) used the presence of 

 Bacillus coli as a criterion of self -purification in the 

 river Mur. He considered, in spite of the position taken 

 by Kruse, that when a water contained large numbers 

 of colon bacilli, as well as an excess of bacteria in 

 general, it might be considered to be contaminated by 

 human or animal excrement. As, however, the organism 

 would naturally be present in large quantities of such 

 a water as that of the Mur, he used no enrichment 

 process, but made plate cultures direct; he defined the 

 B. coli as a small bacillus, non-motile or but feebly 

 motile, growdng rapidly at 37° C, coagulating milk 

 and forming gas in sugar media. In general, Hammerl 



