OPINIONS ON SEWAGE CONTAMINATION. 47 
In regard to B. colt as evidence of sewage pollution, quotations 
from the following authors are cited: 
Mason “ 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 colt, justifies one in conclud- 
ing that the water under consideration has been polluted by intestinal evacuations 
from either human beings or animals. Watersso 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 * 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 procf of the 
presence of serious pollution. 
In speaking of the bacterial content of drinking water, Jordan * 
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, isa common inhabitant:of the human intestine, and is found in great abundance 
in sewage. ; é 
McNaught ” 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 **: 
The continued persistence of B. 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 4 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. 
