Greene. — Absorption of Fats in Salmon 267 



small. Aside from these facts the coeca have a structure 

 comparable to that of the adult salmon. 



The epithelial layer of the coecum of this salmon fed 19 

 hours before with oil was found to be simply crowded with 

 fat droplets. With the low power magnification this coat in 

 which the fat is stained with scarlet red is so full of oil 

 that it appears of almost a uniform scarlet color. In the 

 portions of the epithelial coat lying nearer the deeper grooves 

 in which the adjacent mucous surfaces are more or less in 

 contact, thus preventing free contact with the fat within 

 the lumen of the cecum, the epithelium was not always 

 filled with fat. This fact was more prominent in the more 

 sparingly fed fish no. 46. In other words, considering the 

 picture as a whole, it was found that there was not a uni- 

 form filling of the epithelial cells with fat in all portions 

 of the coecum. In those portions of the epithelium in which 

 the sections showed the presence in the lumen of the ccecum 

 of large quantities of free fat in close contact with the 

 epithelial coat, the coat itself was so gorged with fat droplets 

 as to make it difficult to determine the cellular outlines. In 

 fat-stained frozen sections that were counterstained with 

 hematoxylin the nuclei are shown as a layer at about the 

 basal third of the cells. At the stage in the process of 

 absorption represented by no. 45 the greater masses of the 

 fat are in droplets in the outer two-thirds of the epithelial 

 cells. In this young specimen the fat drops seem unusually 

 large, much larger than those observed in the ordinary 

 course of absorption shown by the pyloric mucous epithe- 

 lium of adult fish caught in the sea. The bases of the 

 epithelial cells in those regions where active absorption is 

 taking place contain fat droplets, but the droplets are 

 smaller and not so numerous. Also, in such regions fat 

 was found to have penetrated into the tunica propria where 

 droplets of considerable size are distributed along the strands 

 of connective tissue of the tunica. The fat droplets in the 

 tunica propria are comparatively numerous in the three 

 experimental specimens of this group. On the whole, the 



