ABSORPTION OF NUTRIMENT BY MUSSELS 415 



parted to the albumin was that of a weak bluish-browTi it proved 

 to be of no great value. When fixed tissues of the mussels 

 which had been in the albumin solutions were treated with 

 haematoxylin, it was found impossible to distinguish any gran- 

 ules in the general mass of the cytoplasm that might have been 

 stained with the haematoxylin. The cytoplasm in unstained 

 fixed tissues is of a brownish color and it was difficult accurately 

 to determine the color of the small opaque granules found in 

 these sections. 



Albumin solutions were stained by dissolving haematoxylin 

 in them. Mussels were kept in such solutions and control in- 

 dividuals were allowed to remain in tap water in which haema- 

 toxylin had been dissolved. The mouths of the mussels were 

 plugged as described above. The experiment was continued 

 for five days. At the close of that time portions of the gills 

 were fixed in absolute alcohol and embedded in paraffin. As abso- 

 lute alcohol precipitates albumin and does not dissolve haema- 

 toxylin from tissues, it was considered a favorable fixative for 

 this purpose. The sections were mounted unstained and search 

 was made for blue granules which might have been taken up 

 from the solution by the cells. The results of such a study were 

 of a negative nature. The same difficulty was experienced as 

 described above in regard to the fixed tissues. While some of 

 the granules in the cells which had been in the solutions seemed 

 to have a bluish tint, in general it was impossible to be certain 

 of the matter. In other words, haematoxylin does not impart 

 to albumin a stain sufficiently characteristic to permit of its 

 being distinguished from the unstained gi'anules about it. 



However, another result was obtained which confirmed the 

 results of an earlier experiment. The cytoplasm of the cells 

 of mussels which had been in the solutions was of a much more 

 granular nature than that of the cells of the individuals which 

 had not. The granules were both more numerous and larger. 

 Also, many could be seen adhering to the outer ends of the cells 

 or entangled in the cilia. Appearances indicated that these 

 granules were particles of albumin and that some had been 

 taken into the cells. The gill filaments of mussels which had 



