198 REPORT OF THE COMMISSIOI^EK OF FISHERIES. 



ence of B. coll in shellfish can be considered an index of fecal con- 

 tamination there seems to be considerable difference of opinion. On 

 the one hand Klein asserts this to be the case, and states that "the 

 presence of B. coll in the oyster is strongly suggestive of fouling of 

 the particular sample with material of excremental origin," while, on 

 the other hand, Herdman and Boyce are inclined to accept the state- 

 ment with reserve. From the results of the experiments recorded in 

 this paper, however, it seems to me that the presence of this organism 

 in oysters is a certain indication of sewag-e contamination. 



It was partially due to the interest stimulated by the splendid paper 

 on "Oysters and Disease," b}" Prof. W. A. Herdman and Rupert 

 Boyce, of Liverpool, England, that the present investigations were 

 undertaken. At that time the city of Providence was discharging, 

 daily, large quantities of "untreated" sew^age into the Providence 

 Ri^-er. It is in this body of water that most of the so-called "Provi- 

 dence River oysters " are raised for market. Besides the sewage of 

 Providence, the drains of numerous summer residences and shore 

 resorts located on the river banks also contribute to the g'enenxl pollu- 

 tion of these waters, and the sewage of the cit}' of Fall River is a 

 possible source of contamination to certain oyster beds situated in 

 Mount Hope Bay. 



Here, then, was an interesting and practically unexplored field for 

 research, the careful stuc\y of which might throv\' some light oo the 

 question of sewage pollution of tidal waters and the contamination of 

 shellfish growing therein. The experiments were begun in the fall of 

 1899, and continued through a period of about three years. The end 

 in view was twofold: First, to obtain by bacteriological examination 

 some definite knowledge of the extent of the pollution of these waters, 

 and, second, to determine, also by bacteriological methods, the pres- 

 ence of sewage in oysters and other sbelifish from various regions of 

 the bay. Bacillus coli was taken as an indicator of sewage pollution, 

 and samples containing this organism were considered to be contami- 

 nated by sewage. 



The work was carried on at the Anatomical Laboratory of Brown 

 Universit}", under the direction of Prof. F. P. Gorhum, to whom I 

 desire to express especial gratitude for assistance and guidance 

 throughout the entire investigation. I wish also to express my sincere 

 thanks to Dr. A. D. Mead, of Brown University, and to Dr. H. C. 

 Bumpus, director of the American Museum of Natural History, for 

 material assistance and many kindnesses shown me during the prepa- 

 ration of this work. 



DESCRIPTION OF XAREAGAN8ETT BAY. 



The state of Rhode Island has an actual land area of 1,051.6 square 

 miles. The waters of Narragansett Bay, with its tributaries, comprise 



