OPINIONS ON SEWAGE CONTAMINATION. 43 



That broadly speaking, a fall in the ratio between organisms growing at 20 C. and 

 those at 37 0. 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 69 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, 33 failed to show the presence of B. coli or coZi-like organ- 

 isms in quantities as large as 100 cc of the sample. 



Evidence is produced from Fuller's 25 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, 63 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 59 says that "mud samples yield more reliable bacterio- 

 logical evidence of the degree of contamination of a tidal river 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 from 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? li 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 iuices 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 

 thjeir country for human consumption had been procured from locali- 

 ties where they were not liable to contamination by sewage or other 

 objectionable filth. 



In their work on the study of shellfish Clark and Gage 14 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 



