280 



EEPORT OF THE COMMISSIONER OF FISHERIES. 



The above results are condensed in the following table: 



Table XVI. — Correlation of the results of water and sJiellfish analyses. 



Locality. 



Providence River: 



Fields Point 



Pawtuxet 



Sabins Point oyster bed 



Bullock Point bed 



Conimicut Point 



Nayatt Point 



( Warren River) 



Bayside 



Warwicli Neck 



Narragansett Bay: 



Prudence Island 



Wickford 



Mount Hope Bay (Fall River sewer) 



Kickemuit River 



Bristol Ferrv 



Distance 

 from the 

 Providence 

 sewer out- 

 let. 



Miles 



B. coll in 

 water. 



Per cent. 



100 



100 



74 



59 



50 



31 



100 



6 1 









 





 20 



B. coll in 

 oysters. 



B. coll in 

 clams. 



Per cent. 

 100 



Per cent. 



100 



66S 



70 

 63 

 32 

 23 

 67i 



3} 









 





 20 



B. coH in 

 mussels. 



Per cent. 



100 



75 



THE BACTERIOLOGY OF OYSTERS FROM UNPOLLUTED SOURCES. 



Before commencing the sj^stematic examination of shellfish from 

 different sections of the bay for sewage contamination an attempt was 

 made to gain some knowledge of the bacterial content of oysters from 

 sources known to be free from all sewage contamination. Inocula- 

 tions were made from the juice, intestines, and stomachs of these 

 specimens, nutrient gelatin, reaction 1.5+, being used in this work. 

 Plates were allowed to develop for two or three days at room tem- 

 perature, and the colonies were fished out and studied in pure cul- 

 ture. As man}' as possible of these cultures were identified, and a 

 few which did not appear to be identical with species already described, 

 yet were frequentl}' found in the oysters examined, are described in 

 this paper. For convenience I have prepared the accompanying chart, 

 similar to one proposed by the American Public Health Association 

 for use in the description of water bacteria, and have relied princi- 

 pally upon the list of reactions given in this table for the description 

 of these forms. Gelatin plate cultures were also made from water 

 samples collected at the same places from which the oysters were 

 obtained, in order to make a comparison between the bacterial content 

 of the oyster and the water in which it lives. 



For this purpose 03'sters and water samples were collected at Kicke- 

 muit River, Wickford Harbor, and the shores of Greenwich Bay. 

 Twenty young native oysters growing on a mud flat left uncovered at 

 low water were obtained frohi the last-named locality. Plates were 

 inoculated with scrapings from the stomachs of 5 of these specimens 

 and with samples of juice from 20. 



Of the 5 plates inoculated with material taken from the stomach, 3 

 remained sterile and 2 developed but a few scattered colonies, which, 



