THE ABSORPTION OF FAT BY FRESH-WATKK Ml'SSELS. 77 



of the mantle. No fat was found in the cells of the side of the 

 mantle next to the shell. 



The observations made on the mussels which were kept in fat 

 solution for the periods of 4, 7, 18 and 24 hours may be sum- 

 marized as follows: 



1. More fat was found in the epithelium of the mantle, gills 

 and foot than in that of the intestine. 



2. In the case of the mussels which were kept in fat solution 

 for 4 and 7 hours, fat was found only in the various epithelia. 



3. In the mussel which remained in fat solution for 18 hours, 

 much more fat than in the two above cases was found in the 

 epithelium and a small amount was observable at various points 

 beneath the epithelium, but none could be discerned distributed 

 throughout the deeper body tissues. 



4. In the mussel which had remained in fat solution for 24 

 hours, a very marked quantity of fat was found in the epithelium 

 and a considerable amount appeared beneath the epithelium, 

 diminishing in quantity, however, toward the interior of the 

 body so that there was none distributed throughout the deeper 

 body tissues. 



5. No fat could be seen in the epithelium of the side of the 

 mantle next to the shell but an abundance was present on the 

 side which had been in contact w'th the solution. 



6. Scarcely any fat was found in the cells of the liver. 



From these facts it is probable that fat is absorbed by the 

 , outer epithelium of the body as well as by that of the intestine. 

 Unless such were the case it would be very difficult to account 

 for the presence of as much fat in the epithelium of the gills, 

 mantle and foot as in that of the intestine, taking into considera- 

 tion the fact that the mussels had been kept in the fat solution 

 for such short periods, viz., intervals varying from 4 to 24 hours. 

 It would also be difficult to account for the fact that such a 

 very small amount of fat appeared within the deeper body tissues 

 of these mussels while a very marked quantity was found in the 

 epithelium of the outer body walls. It is very unlikely that the 

 blood carried such a large amount of fat from the intestine to 

 the outer epithelium in such a short time and during the same 

 time carried none to the muscle fibers, mesenchyme cells or 



