48 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS. 
The examination made of water and food samples for B. coli has 
resulted in diagnosing the presence of this organism only after iso- 
lation and making a thorough study of its morphological and bio- 
logical characters; even under these conditions many minor differ- 
ences are found as to the quantity and character of gas produced, 
the time required for coagulating milk, the amount of indol and 
nitrites formed, its reaction on various culture media, and other 
detailed considerations. 
Unless isolated and carefully studied in pure culture, no reliable 
means are yet available for distinguishing the true colon bacillus, 
by presumptive tests alone, from other gas-forming organisms, such 
as B. lactis aerogenes, B. cloace, etc. However, the presence of any 
of these organisms in water is indicative of fecal matter. 
There seems to be no question regarding the undesirability of the 
presence of the colon bacillus and allied organisms in water used in 
any way for food purposes. The relation of this germ to the pollu- 
tion or purity of water supplies seems to be now pretty well established 
and there can be no doubt that water harboring this germ may be a 
constant source of great danger, for where #. coli is found the spe- 
cific cause of enteric fever, namely, B. typhosus, and also the cholera 
spirillum, etc., may be present in sufficient numbers to produce infec- 
tion when introduced into susceptible individuals. 
SUMMARY. 
(1) There is undisputed evidence to show that shellfish become 
contaminated when placed in sewage-polluted water, and that B. cola 
and B. typhosus will survive for variable lengths of time im the liquor 
and the body contents of such shellfish after their removal from 
infected water. 
(2) The presence of sewage organisms in oysters and other shell- 
fish, even in small numbers, may be indicative of great danger; for, 
where such organisms exist, the specific cause of enteric fever and 
allied disorders may also be found. 
(3) The results of many investigators show that sewage-polluted 
shellfish have been responsible for the production of typhoid fever 
and other intestinal diseases. The most noteworthy cases appear to 
have occurred from eating oysters which had been floated in sewage-_ 
polluted water, although instances are cited where shellfish infected 
by polluted water, either in their natural or artificial beds, have also 
been the vehicle of disease transmission. 
(4) The shellfish industries of this country are extensive and 
important, comparing favorably with other imdustries concerned 
with the production of food materials. A valuable article of food is 
furnished to millions of people by these industries, and thousands of 
mae ter aes 
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