SEWAGE CONTAMINATION OF OYSTER BEDS. 



225 



Table XIII. — Analysis of oysters from the Nayait ^eds-- Continued. 



These results show a still further decrease in the infection. About 

 23 per cent of the specimens examined contained B. coll. It is possi- 

 ble, however, to demonstrate the presence of sewage bacteria in oysters 

 living- from 5 to 6 miles distant from the sewer outfall. 



Passing- now from the western side of the river below Conimicut 

 Point, a number of samples — four batches, making 32 oj^sters in all — 

 were taken from the Rocky Point oyster ground. Two batches were 

 obtained from the beds off Bayside, and two from the beds off" War- 

 wick Neck, below Eocky Point. No one of the tubes inoculated with 

 material from the intestines of these specimens gave reactions for 

 B. coJl. This organism was, however, found in the juice of a single 

 oyster from the Bayside beds. The stomachs of 10 of the specimens 

 were examined, but B. coll was not found in any of these analyses. 

 These lots were taken from the river at a distance of 6 and 7i miles, 

 respectively, from the Fields Point sewer outfall. 



Oysters from the AVarren River grounds, on the other hand, were 

 more or less contaminated by sewage. Table XIV gives the results 

 of the analyses of 8 oysters dredged off the mouth of this river. 



F. C. 1904—15 



