154 Elements of Water Bacteriology. 



although in some cases the chemical analysis would not 

 have indicated dangerous pollution. On the other hand,- 

 eight rivers, not extensively polluted, showed no strep- 

 tococci in one-tenth of a c.c., although the chemical and 

 the ordinary bacteriological tests gave results which would 

 condemn the waters. Horrocks (Horrocks, 1901) found 

 these organisms in great abundance in sewage and in 

 waters which were known to be sewage-polluted, but 

 which contained no traces of Bacillus coli. He found by 

 experiment that B. coli gradually disappeared from speci- 

 mens of sewage kept in the dark at the temperature of an 

 outside veranda, while the commonest forms which per- 

 sisted were varieties of streptococci and staphylococci. 



In America attention was first called to these organisms 

 by Hunnewell and one of us (Winslow and Hunnewell, 

 1902*), and the same authors later (Winslow and Hunne- 

 well, i902 b ) recorded the isolation of streptococci from 25 

 out of 50 samples of polluted waters. Gage (Gage, 1902), 

 from the Lawrence Experiment Station, has reported 

 the organisms present in the sewage of that city, while 

 Prescott (i902 b ) has shown that they are abundant in 

 fecal matter and often overgrow B. coli in a few hours 

 when inoculations are made from such material into 

 dextrose broth. In the recent monograph of Le Gros 

 (Le Gros, 1902) of the many streptococci described, all 

 without exception were isolated, either from the body or 

 from sewage. Baker and one of us (Prescott and Baker, 

 1904) found these organisms present in each of 50 samples 



