88 ELEMENTS OF WATER BACTERIOLOGY. 



Merrimac, it is safe to assume that when B. coli is found 

 only infrequently in i c.c. of the effluent the typhoid germs, 

 necessarily fewer in number and more easily removed by 

 the filter, have been eliminated from the water." 



Another interesting contribution to this question was 

 made by the Massachusetts State Board of Health 

 (Massachusetts State Board of Health, 1901) in connec- 

 tion with the examination of the spring-waters bottled 

 for sale in the State. Ninety-nine springs were included 

 in this study; and in almost every instance 4 samples 

 were examined, 2 taken directly from the spring by 

 the engineers of the board and 2 from the bottles as 

 delivered for sale to the public. In the water of one 

 spring B. coli was found twice, once in a sample from 

 the spring and once in the bottled sample. This spring 

 was situated in woodland, but was unprotected from 

 surface drainage, and the method of filling bottles sub- 

 jected it to possible contamination. In 5 other cases B. 

 coli was found once in the sample from the spring; all 

 were subject to pollution from dwellings or cultivated 

 fields, and 4 of the 5 were shown to be highly contam- 

 inated, chemically. In 7 other cases B. coli was found 

 in the bottled samples alone ; 3 of these sources were of 

 high purity, but the bottling process furnished opportunity 

 for contamination. 



Probably the most elaborate application of the colon 

 test which has ever been attempted was made by Jordan 

 in his recent examinations of the fate of the Chicago sew- 

 age in the Desplaines and Illinois Rivers. At one time 



