ABSORPTION OF NUTRIMENT BY MUSSELS 405 



Knorrich ('10), working with Daphnia, which Hved 14 days 

 in sterihzed hay solution, concluded that nutriment was absorbed 

 from the solution. 



Kerb ('10) kept eels in sugar solutions and noted no diminu- 

 tion in the amount of sugar from day to day. He obtained 

 similar results while working with Corethra larvae in sugar 

 solutions. Also he found that Daphnia lost in dry body weight 

 as rapidly in solutions of peptones as in tap water. 



Wolff ('10), working with Simocephalus, found that it lived 

 twice as long in bacteria-free water, which contained some dis- 

 solved carbon compounds, as it did in tap water. He made no 

 observations as to body weight lost or gained. 



Several American investigators of the question of the nutri- 

 tion of the oyster have felt that the amount of material found in 

 the alimentary canal was not large enough to account for the 

 growth of the oyster to the relatively large size which it attains 

 in the first two years of its existence. 



Grave ('12) in particular suggested that in the oyster food 

 may be taken in by means other than that of the alimentary 

 canal. 



Moore, Whiteley, Edie and Dakin ('12) investigated the rate 

 of oxidation and the output of carbon dioxide by aquatic inverte- 

 brates in relation to the available food supply in sea-water. 

 They also made chemical analyses of samples of sea-water from 

 various regions. Their general conclusion was that sea-water 

 does not contain any appreciable amount of dissolved organic 

 matter capable of acting as a nutrient medium for animals 

 living in it. 



Lipschutz ('13) reviewed almost the entire subject including 

 his own previously published experiments along that line and 

 offered criticism of Putter's work. Lipschutz noted that fish 

 and eels when kept in nutrient solutions lost as much body weight 

 as in tap water. He also thought Putter had overestimated 

 the amount of material in solution in the water and underesti- 

 mated the carbon content of the plankton. His general con- 

 clusions are the opposite of those of Putter. 



