422 E. p. CHURCHILL, JR. 



Ill into the cell. Therefore there may exist the possibility that 

 the sodium oleate, stearate and palmitate from the soap may 

 have entered the cell as such, the radical carrying the stain. 

 The sodium may then have been separated leaving the radical 

 free to unite with any glycerin which may have been absorbed. 



In regard to the absorption of albumin it is necessary to as- 

 sume either a power on the part of the cell to split the protein 

 into its amino acids and the absorption of these as in the ali- 

 mentary canal, or the direct taking in by the cells of the col- 

 loidal particles of albumin by means of something analogous 

 to phagocytic action. The fact that the Janus green stain was 

 carried into the cell offers some evidence that the albumin 

 entered the cell as such without being previously split into the 

 amino acids. 



In the case of starch it seems probable also that the granules 

 entered the cell by amoeboid or phagocytic action. The presence 

 of the definite blue granules within the cells would somewhat 

 oppose the theory of any conversion of the starch previous to 

 absorption. 



The present investigations demonstrate only the ability of 

 the mussels to make use of nutriment which is in solution in 

 the water by the twofold means cited above. They do not deal 

 with the possible amount of nutriment present in various bodies 

 of water in which aquatic animals are found. The investiga- 

 tions show that if dissolved material is present the mussels 

 can make use of it. After the ability of the animal to make use 

 of food in such form is proved, the question of whether or not, 

 in any particular case, it does do so, depends upon the presence 

 or absence of such food in the water. It is too sweeping a 

 statement to assert that aquatic animals in general do not or 

 can not make use of nutriment which is in solution in the water 

 merely because no dissolved compounds are found in certain 

 analyses of water taken from a more or less limited region. Nor 

 is the fact of the presence of an amount of detritus, apparently 

 adequate for the nourishment of a bottom-living animal, suffi- 

 cient proof that all its nutriment is made up of such detritus. 



