OTHER INTESTINAL BACTERIA. 101 



other hand, 8 rivers, polluted, but not recently and exten- 

 sively polluted, showed no streptococci in one-tenth of a 

 ex., although the chemical and the ordinary bacteriological 

 tests gave results which would condemn the waters. Hor- 

 rocks (Horrocks, 1901) found these organisms in great 

 abundance in sewage and in waters known to be sewage- 

 polluted, but which contained no traces of Bacillus coli. 

 He found by experiment that B. coli gradually disappeared 

 from many specimens of sewage kept in the dark at the 

 temperature of an outside veranda, while the commonest 

 forms which persisted were varieties of streptococci and 

 staphylococci. 



In America attention was first called to these organisms 

 by Hunnewell and one of ourselves (Winslow and Hunne- 

 well, 1902"), and the same authors later (Winslow and 

 Hunnewell, 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 one of us (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 mono- 

 graph of Le Gros (Le Gros, 1902) of the many strep- 

 tococci described all without exception were isolated, 

 either from the body or from sewage. In the study of 

 259 samples of presumably unpolluted waters, by the 

 method of direct plating, Nibecker and one of the authors 

 (Winslow and Nibecker, 1903) found streptococci in 



