228 REPORT OF THE COMMISSIONER OF FISHERIES. 
Practically all of the clams and mussels analyzed as representing the 
condition of shellfish on the Pawtuxet shore, 2 miles below the city 
sewer, were infected with colon bacilli; but 70 per cent, however, of 
the oysters taken on the Sabins Point oyster ground, which lies directly 
across the river from Pawtuxet Neck, were thus infected. 
Fifty-three per cent of the oysters collected from the Bullock Neck 
layings, about + miles south of Fields Point, contained LB. col. 
Thirty-two per cent of the oysters obtained from the Conimicut 
Point ground, 1; miles below the locality where the oysters from the 
Bullock Neck layings were dredged, contained colon bacilli. 
Twenty-three per cent of the specimens dredged on the Nayatt Point 
oyster beds were infected. 
On the other hand, oysters from the Rocky Point ground, 6 to 8 
miles below the chief source of sewage contamination of the river, are 
practically free from pollution. . coli was isolated from but one 
specimen of a lot of 82 oysters which were obtained from these grounds. 
A sharp rise in the percentage of oysters infected with sewage 
forms was noticed when specimens from the Warren River were ana- 
lyzed. Five out of a total of 8 oysters examined were infected with 
B. coli. 
Oysters from Prudence Island and Wickford Harbor do not con- 
tain B. coli or other sewage bacteria. 
Oysters from the Kickemuit River were not infected with these 
organisms. Only a small percentage of the specimens taken from the 
layings in the entrance of Mount Hope Bay contain any trace of sew- 
age bacteria. 
COMPARISON OF RESULTS OF WATER ANALYSIS AND SHELLFISH ANALYSIS. 
If we consider the presence of 4. cold in waters and food stuffs an 
indication of sewage contamination, we may trace the distribution of 
sewage in the Providence River and Narragansett Bay as follows: 
Starting in the neighborhood of Fields Point and proceeding grad- 
ually down the river to the bay below, we find that all water samples 
taken within a radius of one-half to three-quarters of a mile from the 
Providence city sewer outlet contain 2. col/, and often other species 
of bacteria commonly found in sewage. £. cold was abundant, not 
only in the water about Fields Point, but was readily isolated from 
samples of sand taken from the beaches near by; also oysters col- 
lected from these highly polluted waters, and clams and mussels from 
the shores within half a mile from the sewer outlet, without exception, 
contained £4. coli, and in many cases other sewage bacteria, within 
their shells. 
Nearly all the water samples collected at Pawtuxet Neck, about 2 
miles below Fields Point, were found to contain 2. cold; also most 
of the shellfish (clams and mussels) obtained from this section of the 
