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a green-colored body, the source of this substance in a clear 

 water must be the minute vegetable organisms suspended in it. 

 It cannot be traced to the coating on the larger aquatic plants, 

 because it can be separated from them by chemical operations 

 only, in which about one hundred parts, by weight, of green 

 plants are required to furnish one of the green wax. Chlorophyl 

 cannot give the peculiar flavor to the water, as it has neither odor 

 nor taste^ and cannot be dissolved in water. 



If mucilaginous and albuminous matters, in a state of decay, 

 could exist in the water at the freezing point, and be the cause 

 of its odor and taste, it would be impossible to render the water 

 pure by the use of filters of coarse texture, as is every day done. 

 The hundreds of cooks who every day use the stone-ware filters, 

 purify the water by a sponge, which must be daily cleaned, by 

 the removal of the bodies of crustaceans containing oil. No 

 other substance, having taste and odor, is separated from the 

 water in this operation. Very few confervse or other vegetable 

 organisms are found at the present low temperature, while the 

 taste and odor were never more offensive at the localities from 

 which we take the water. The varying intensity of taste and 

 odor, in different parts of the city, and also at different points in 

 the lake, is alone a sufficient refutation of the hypothesis of a 

 vegetable impregnation. The constant circulation due to chang- 

 ing temperature, can have no effect to remove from one portion 

 of the water its dissolved matter and transfer it to another. There 

 has been constant reference to the sudden local changes of 

 laste within the city, which find a probable explanation in the 

 occasional swarming of the crustaceans, which is a matter of 

 observation. Any hypothesis resting upon the presence of an 

 unusual quantity of autumnal leaves in the lake, would be met by 

 the observed fact, that the trees still retain their leaves to an extra- 

 ordinary amount. It would also have the obstacle to overcome, 

 that the taste and odor of the water are the same as are afforded 

 by the oil and crustaceans found in it. 



We are able to report some further observations, which bear 

 on points of scientific interest. Through the kindness of Prof. 

 William B. Rogers, Dr. Bacon has examined the crustaceans 

 from Fresh Pond, where the water has not been affected, and 



