194 



Elements of Water Bacteriology. 



a week at the Sewage Experiment Station of the Massa- 

 chusetts Institute of Technology, during two different 

 periods, were as follows: 



BACTERIA IN SEWAGE, SEPTIC EFFLUENT, AND TRICK- 

 LING EFFLUENTS AT BOSTON. 



(WINSLOW AND PHELPS, 1907.) 



1 Jackson bile test. 



The contact beds, as operated on a practical scale in 

 England, show considerably higher numbers. At Lon- 

 don the Barking and Crossness beds yielded effluents 

 containing one to five million bacteria per c.c., of which 

 100,000 to 600,000 were B. coli. 



There are few plants of the newer types now in opera- 

 tion in the United States, and fewer still are controlled 

 by bacteriological examinations. At Plainfield, N. J., 



