OPINIONS ON SEWAGE CONTAMINATION. 47 



In regard to B. coli as evidence of sewage pollution, quotations 

 from the following authors are cited: 



Mason 44 says : 



Water which persistently shows B. coli in 1 cc sowings is of very questionable char- 

 acter, and, should similar results be found when operating with sowings of 0.1 cc, the 

 water should be condemned. 



Regarding the colon bacillus, Dr. Abbott * says: 



In the normal intestinal tract of human beings and domestic animals, as well as 

 associated with the specific disease-producing bacillus in the intestines of typhoid- 

 fever patients, is an organism that is frequently found in polluted drinking waters, 

 and whose presence is indicative of pollution by either normal or diseased intestinal 

 contents; and though efforts may result in failure to detect the specific bacillus of 

 typhoid fever, the finding of the other organism, Bacillus coli, justifies one in conclud- 

 ing that the water under consideration has been polluted by intestinal evacuations 

 from either human beings or animals. Waters so exposed as to be liable to such pol- 

 lution should never be considered as other than a continuous source of danger to those 

 using them. 



In their work on water analysis, under this subject Prescott and 

 Winslow 56 conclude as follows: 



Although the evidence is quite conclusive that the absence of B. coli demonstrates 

 the harmlessness of water as far as bacteriology can prove it, that when present its 

 numbers form a reasonably close index of the amount of pollution the authors above 

 quoted have proved beyond reasonable cavil. It may safely be said that when the 

 colon bacillus, as defined by the tests above, is found in such abundance as to be 

 isolated in a large proportion of cases from 1 cc of water, it is reasonable proof of the 

 presence of serious pollution. 



In speaking of the bacterial content of drinking water, Jordan 3e 

 says: 



The most widely used and, by general consensus, the most valuable of these tests 

 is the "colon test." This is based upon the circumstances that the colon bacillus, 

 B. coli, is a common inhabitant of the human intestine, and is found in great abundance 

 in sewage. 



McNaught 42 states that 



The detection of B. coli in a small quantity of a drinking water is a sign of danger 

 because it indicates excretal contamination, and where excretal contamination occurs 

 there is a risk that the excreta may contain specific germs of disease. 



According to the views of Houston 33 : 



The continued persistence of J5. coli in any number in estuarial water may be traced 

 by continuous excremental pollution and the presence of the unoxidized organic 

 pabulum in the water. 



In his bacteriological report, Connolly 16 says: 



Regarding the presence of B. coli in water used for drinking purposes, we have 

 learned to look with suspicion upon water which contains this bacillus in quantities 

 of of a cubic centimeter, or less, even though the source of the water is apparently 

 above suspicion. This applies to surface waters, such as are usually collected in 

 sparsely inhabited watersheds, when there is a greater possibility of colon pollution 

 from animals than from man. In deep well water the presence of B, coli to any 

 extent should positively condemn the supply. 



