218 REPORT OF THE COMMISSIONER OF FISHERIES. 



The section of the river 2 to 4 miles below the chief source of con- 

 tamination is much freer from pollution. B. coli was found in 59 per 

 cent of the samples from this area, and the majority of positive tests 

 was obtained from samples collected at low water, while many samples 

 taken on the flood tide did not contain fecal bacteria of any sort. 



Five miles below Fields Point, still fewer samples contain B. coll; 6 

 miles below this organism is rarely found. About 50 per cent of the 

 samples from the Conimicut Point oyster beds and about 31 per cent 

 of those from the Nayatt Point ground contained colon bacilli. The 

 eastern shore of the river is cleaner than the western above Conimicut 

 Point. Below this point reverse conditions are encountered. No fecal 

 bacteria were found in samples collected on the Rocky Point oyster 

 ground, over 7 miles distant from Fields Point. 



But B. coll was isolated from samples taken near buo}' No. 1, 

 marking the entrance of the Warren River channel. This station is 

 a little over 2i miles distant from the town of Warren, and at the 

 same time is far enough out in the Providence River to be just included 

 in the arc which marks the 8-mile limit from Fields Point. No fecal 

 bacteria were found in samples collected near buoy No. 7, however, 

 which is 4 miles distant from Warren and about 8i from the Providence 

 sewer outlet. Thus it may be stated that 8 miles below the Fields 

 Point sewer no colon bacilli have been found in the water of the river, 

 and from this point on till it reaches the headwaters of Narragansett 

 Bay the river is free from sewage bacteria. 



Passing downstream, the number of colon bacilli in the river water 

 decreases gradually from 500 per cubic centimeter one-half mile below 

 Fields Point to 1 per cubic centimeter at Conimicut. Below Conimi- 

 cut no sewage bacteria were found by the plate method employed in 

 this test. 



The water on the Prudence Island and Wickford oyster beds does 

 not contain B. coll. 



The portion of Mount Hope Bay included in the Rhode Island ter- 

 ritory is comparatively free from pollution, and the oyster ground in 

 this bay is located from 4 to 7 miles below Fall River, the chief source 

 of pollution. B. coll was isolated from a single sample taken in the 

 entrance to the bay, but the presence of the organism in this instance 

 was probably due to local contamination, for other samples taken near 

 b^'' did not give reactions for colon bacteria. 



Samples from Kickemuit River did not contain B. coll. 



One sample collected on the oyster bed under Warren Neck con- 

 tained B. coll. 



BACTEETOLOGICAL ANALYSIS OF SHELLFISH FROM NAItRAGANSETT BAY. 



Methods employed. — Much the same plan of work was employed in 

 the examination of the shellfish of Narragansett Baj^ as was used in the 

 water analysis. Oysters, clams, and mussels were first collected on the 



