ABSORPTION OF NUTRIMENT BY MUSSELS 413 



and distortion of the cells, the differences in the depth of stain 

 taken being less exactly represented by the stippling. In figures 

 13 and 14 are shown respectively filaments of a mussel which 

 had been subjected to filtered water and of one which had been 

 in the solution for fifty-eight days. The same differences were 

 found in this case as in the former. The pair killed at the end 

 of forty-five days also manifested these differences. 



The above facts leave little doubt that the mussels in the 

 solutions make use of the albumin as food. The mussel that 

 died during the course of the experiment was one of the lot 

 in filtered water and its death was probably due to starvation. 



Efforts were made, however, to devise methods whereby the 

 albumin might actually be seen in the cells. Experiments 

 were carried out in which some mussels were kept in solutions 

 of albumin and others in tap or spring water. Sections of those 

 in the albumin solutions were mounted on s'ides with corre- 

 sponding sections of individuals which had been in water only. 

 These were stained with eosin or Bordeaux red and a study of 

 the minute structure of the cytoplasm was made. In general 

 the cytoplasm of the mussels which had been in the solutions 

 was of a moi'e granular nature than that of the other mussels. 

 The granules were not only more numerous but many of them 

 were larger. For example, in one case where 100 cc. of albumin 

 in 5000 cc. of water had been used in an experiment of twenty-one 

 days' duration the difference was quite marked. The effect 

 of the fixing sgents is ' to precipitate the proteins of the cell. 

 Apparently there was a greater quantity of protein present in 

 the case of the mussels which had been in the solutions of ablumin. 



In an effoi't to discover whether or not the same result could 

 be obtained if the alimentary canal were eliminated, the mouths 

 of some of the mussels were plugged with dumbbeU-shaped 

 pieces of partiffin. In many cases the mussels died due to in- 

 jury incident to the operation. If no injury was inflicted the 

 mussels often lived for a week or two. If the mussel did not 

 die in the couise of one or two days it might be assumed that 

 no injury had been inflicted and that the mussel would live for 

 at least eight days, which w^as the length of time it was desired 



