SEWAGE CONTAMINATION OF OYSTER BEDS. 22 
After inoculation the plates were allowed to develop three or four 
days at room temperature and then examined for growths of JL. colz. 
The oysters used were received in the laboratory twice a week during 
October, November, and December of 1902, and the specimens were 
opened within eight hours after they had been taken from the water. 
The intestines of 200 oysters were examined in this manner. After a 
week’s growth all but 3 of the 200 plates remained sterile. The colo- 
nies developing on these 3 were those of a large spore-forming aerobic 
bacillus, which resembled &. vulgatus very closely in cultural features 
and bore no resemblance to 2. colt. Some time after these experi- 
ments were carried on a series of control plates (nutrient gelatin 
containing 0.05 per cent carbolic acid) were inoculated with a known 
culture of £B. col7, and it was found that this organism grew readily 
in the carbo! gelatin. 
The two remaining beds visited in the course of this work are situ- 
ated, one in the entrance to Mount Hope Bay off Bristol Ferry, and 
the other in the Kickemuit River. One examination was made in 
October, 1902, of the oysters from the bed at the entrance to Mount 
Hope Bay. The results of this work are found in Table XV: 
TaBLeE X V.—Analysis of oysters from Bristol Ferry. 
Red colo- 
Dextrose nies on Bo coli Other fecal 
fermented.| litmus lac- JOU bacteria. 
tose agar. 
Specimens and date of collection. 
Oysters, October 30, 1902. 
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in JNMESUIMNG) S 8 Re Mea Soe SE CEGSEOa 5S SESS BeOS aGeESoee 
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LS. coli was found in the juice of but two specimens and in the intes- 
tines of asingle one. The Kickemuit River beds are 43 and the Bristol 
Ferry beds 7 miles from Fall River. Neither ground is contaminated 
by sewage from that city, and the slight pollution found at Bristol 
Ferry is due to local causes. Four batches of oysters were obtained 
from Kickemuit River. In all, 20 oysters were examined, and it was 
found that 2. cold was not present in the intestines or juice of these 
specimens. 
The foregoing analyses demonstrate the following facts: 
Oysters, clams, and mussels taken from the Providence River or its 
shores within half a mile of the Fields Point sewer outlet contain 2. 
coli and other fecal bacteria within their shells. 
