OPINIONS ON SEWAGE CONTAMINATION. 43 
That broadly speaking, a fall in the ratio between organisms growing at 20° C. and 
those at 37° C. corresponds with sewage pollution. The same may be said with 
regard to spore-bearing forms. 
After completing their investigations, the Virginia State Board of 
Health ® reports: ‘‘We conclude that the colon bacillus is not found 
as a normal inhabitant of the oyster, either of the natural fluid of the 
shell nor of the intestine.” ; 
Every one of 34 samples of deep unpolluted sea water, according 
to Houston,* failed to show the presence of B. cola or cola-like organ- 
isms in quantities as large as 100 cc of the sample. 
Evidence is produced from Fuller’s?> report showing that fish from 
unpolluted water do not harbor the colon bacillus, while to the con- 
trary where water is known to be contaminated this bacillus is found 
in the intestines of fish. The influence ol birds, boats, and shore- 
line railroads is also discussed in this report, which concludes as 
follows: ‘‘Generally speaking we may say that deep sea water dis- 
tant from local sources is unpolluted according to Bacillus coli 
tests.”’ 
Dr. Soper, in reporting the Lawrence, Long Island, outbreak, 
found that while 20 per cent of oysters were certainly polluted on 
the inside, as many as 70 per cent were polluted on the outside. 
Dr. Savage * says that ‘‘mud samples yield more reliable bacterio- 
logical evidence of the degree of contamination of a tidal mver than 
either water or oyster samples. Muds which show high relative 
purity are safe for oysters.” 
Professor Huxley is quoted as saying in the report of the Royal 
Commission on Sewage Disposal: 
I do not see how it can be doubted that oysters taken trom a bed irrigated with 
sewage and eaten uncooked would be dangerous articles of diet. Does anybody 
pretend that it would be safe to take drinking water (unfiltered and otherwise unpu- 
rified) from a body ot fresh water, of similar dimensions to any estuary which may 
be under consideration, at a point equally near a sewage discharge? It such a pro- 
ceeding is safe, our sanitary authorities are taking a great deal of trouble in vain; 
if it is not safe neither is it desirable to eat oysters the juices of which are impregnated 
with sewage in however dilute a condition. 
This commission further recommends that each Government should 
require a guarantee that all oysters or other shellfish imported into 
their country for human consumption had been procured from locali- 
ties where they were not hable to contamination by sewage or other 
objectionable filth. 
In their work on the study of shellfish Clark and Gage “ state: 
Enough study has been made by many investigators to show that B. coli is not a 
normal inhabitant of the intestines of clams or oysters, and that its presence in the 
intestines or juice in the shell must be due to contamination, either by drainage and 
sewage flowing over the clam and oyster beds, or by careless and uncleanly handling 
of the shellfish between the time of collecting and placing upon the market. In this 
