The Significance of B. Coli in Water. 121 



industrial, and agricultural wastes of human life. If 

 pollution has been recent, colon bacilli will be found in 

 comparative abundance. If pollution has been remote 

 the number of colon bacilli will be small, since there is 

 good evidence that the majority of intestinal bacteria die 

 out in water. If derived from cereals or the intestines 

 of wild animals, the number will be insignificant except 

 in the vicinity of great grain-fields or where the water 

 receives refuse from grist-mills, tanneries, dairies, or 

 lactic-acid factories. 



The first recognition of the necessity for a quantita- 

 tive estimation of colon bacilli in water we owe to Dr. 

 Smith, who in 1892 (Smith, i893 a ) outlined a plan for a 

 study to be made by the New York Board of Health on 

 the Mohawk and Hudson Rivers. Burri (Burri, 1895) 

 pointed out that the use of so large a sample as a liter for 

 examination would lead to the condemnation of many 

 good waters. Freudenreich (Freudenreich, 1895) a * 

 the same time indicated the necessity for taking into 

 account the number of colon bacilli present. He recorded 

 the isolation of the organism from unpolluted wells, 

 when as large a quantity of water as 100 c.c. was used, 

 and concluded that it was entirely absent only from 

 waters of great purity and present in large numbers only 

 in cases of high pollution. This author also quoted 

 Miquel as having found colon bacilli in almost every 

 sample of drinking-water if only a sufficient portion were 

 taken for analysis. 



