ABSORPTION OF NUTRIMENT BY MUSSELS 419 



complications, however, in the search for any red granules that 

 may have been present owing to the conversion of starch to 

 dextrin and to its subsequent staining with iodine. No satis- 

 factory evidence of the absorption of starch was disclosed by 

 the above riiethods. 



The experiment of keeping the mussels in a starch solution 

 wliich had been stained blue "wdth iodine was then tried. The 

 mouths of the mussels were plugged wdth pieces of paraffin as 

 described above. After the expiration of four days the mus- 

 sels were killed and sections were made of their tissues by the 

 freezing method. The sections were mounted at once in gly- 

 cerin without staining. In the cells of the gill filaments some 

 granules were found that were blue in color, though the obser- 

 vation was made with difficulty owing to the opacity of the 

 granules. Similar granules were found within the corpuscles 

 and also chnging to the outer ends of the cells and to the cilia. 

 They were quite irregular in shape and varied from one to three 

 microns in diameter. The gill filaments of a mussel which 

 had remained in the stained starch solution for four days are 

 represented in figures 28 and 29. Figure 30 is a representation 

 of the gill filament of a mussel kept in tap water. 



These results present some evidence that starch may be 

 taken up directly from a starch solution by the epithelial cells 

 of the gills of the mussel. Since fewer experiments were carried 

 out with starch than with fat and protein, the results can not 

 be considered to be as conclusive as were those attained in the 

 work with the latter. 



Behavior of the corpuscles 



An interesting point in connection with the behavior of the 

 corpuscles of the blood was noted. In the author's previous 

 paper dealing with the absorption of fat, mention was made of 

 the fact that the corpuscles were often found pressed closely 

 against the bases of the epithelial cells of the gills and that the 

 corpuscles carried some of the fat droplets from the cells to the 

 other parts of the body. Some of the fat droplets were appar- 



