THE COLON GROUP OF BACILLI 113 



Fromme (1910) in this connection reports the results 

 of 673 colon tests made on the water of the Elbe during 

 a period of a year and a half. We have calculated 

 from his figures the average results for the winter 

 months and the summer months in the table below. 

 It is evident that typical colon bacilli are nearly twice 

 as numerous in the cold weather (for reasons discussed 

 in Chapter I) while organisms fermenting dextrose 

 broth but proving not to be B. coli are absolutely 

 more abundant and relatively much more abundant 

 in simmier. 



GAS PRODUCERS AND B. COLI IN ELBE WATER 



(After Fromvt:, 1910) 



Positive Dextrose B. Coli 



Broth Tests. ; Isolations. 



October-March 415 363 



April-September. ... 258 170 



Per Cent of Dex- 

 trose Broth Tests 

 Showing B. Coli. 



87 

 66 



Phelps and Hammond (1909) cite a very interesting 

 case of the same phenomenon in the case of a ground 

 water. A deep well at a hospital in Trenton, N. J. 

 was temporarily polluted from a leaking sewer and after 

 the source of pollution had been removed the condi- 

 tion of the water was carefully studied for a period of 

 two months. During the period between Sept. 10 and 

 Oct. 12 (the pollution being removed on Sept. 19) 

 of 107 dextrose-fermenting microbes isolated 40 failed 

 to produce gas in lactose broth; during the period 

 between Oct. 12 and Nov. 9, 52 out of 64 dextrose-fer- 

 menting microbes failed to give gas in lactose broth. 

 All through the investigation organisms of low fer- 



