253 PROCEEDINGS OF THE AMERICAN ACADEMY 



At the request of Professor Horsford, Dr. Charles T. Jack- 

 son stated that, in his recent examinations of Cochituate wa- 

 ter, he had found the Crustacea, to which the impurity of that 

 water in 1855 was attributed by some, quite numerous. A 

 month since the Cyclops were as abundant as at any time, ex- 

 cept when the water was first introduced into the city. They 

 always contain more or less oil, of various colors. Dr. J. had 

 collected a teaspoonful of them, and observed, on boiling, that 

 they became of a bright orange-red color. He could perceive 

 no disagreeable odor or taste to the oil ; but when the mouth 

 was rinsed with water containing it, it left a peculiar stinging 

 sensation in the throat, resembling what Professor Horsford 

 and himself had noticed in tasting the water of the lake in 

 situ. The oil was always found in these Crustacea. 



Dr. A. A. Gould remarked, that other observers had stated to 

 him that the Crustacea are far less numerous this year than last, 

 and contain much less oil. The number is found, as then, to 

 vary very much at different times and places. He doubted if 

 oil was found in them at all times. It was his impression, also, 

 that it had been but recently noticed. In the figures and de- 

 scriptions of them by European observers, he believed no 

 delineation or mention of its existence occurred. On the au- 

 thority of Professor Jeff'ries Wyman, who had been recently 

 studying those found in the wells of the College yard, Cam- 

 bridge, he stated that there was abundance of oil in the bodies 

 of the specimens from that locality. 



Dr. Jackson mentioned that one European observer had re- 

 corded its existence, namely, Kulliker. 



In reply to a question of Professor Horsford, whether the 

 animals in question ever feed on anything but vegetable food, 

 Dr. Gould said that the Crustacea in general are known to be 

 carnivorous. He could not speak positively with reference to 

 the microscopic species. 



Dr. Pickering said that no Crustacean had ever been known 

 to feed on vegetable matter. 



Professor Levering exhibited and explained Wheatstone's 

 photometer. 



