521 



becomes very distinct , whereas in the sea salmon it is obliterated by 

 the large and swollen glandular cells. 



In the intestine and pyloric appendages of the river salmon the 

 epithelial cells as a whole become more granular than those in the sea 

 salmon, and in many cases, though by no means in all, the calice 

 cells tend to disappear. 



b) The Sub-epithelial Connective Tissue and Stratum 



compactum. 

 The only point that need be mentioned at present with regard to 

 these structures is the fact that the sub-epithelial connective tissue 

 layer in the stomach of the river salmon increases in thickness, while 

 thestratumcompactum sharing in the same increase becomes more 

 contorted than in the stomach of the sea salmon. This increase, how- 

 ever, is probably only apparent, and is in reality due to the constric- 

 tion of the walls of the gut. 



c) The Absorption of Fat as revealed by microscopic 



examination. 

 The process of fat absorption occurs solely in the pyloric appen- 

 dages and intestine. With the necessary microscopic methods (which I 

 need not here detail), it is very easy to demonstrate the paths traversed 

 by the fat particles in their passage from the absorptive surface into 

 the walls of the gut. These methods and the results they bring will be 

 communicated in a future paper by Mr. R. Gl egg, B.Sc, and myself 

 Briefly the appearances presented are as follows: 



In the connective tissue forming the frame-work of the ridges of 

 the pyloric appendages and intestine , there occur a large number of 

 cells in each of which is situated a smaller or larger globule of fat. 

 The nucleus of the cell is spindle-shaped or oval and is pressed to the 

 side of the cell along with the cytoplasm. Thus, in the centre of the 

 ridges and extending a little way into the connective tissue below the 

 level of the epithelial folds, there is found to exist a form of adipose 

 tissue. Along with such , there is always a greater or less amount of 

 ordinary fibrous tissue. Further, the connective tissue below the level 

 of the epithelial folds is crowded with leucocytes of the large eosino- 

 phile variety in all of which may be seen numerous small particles of 

 fat, which they are bearing towards the general lymph stream. Leuco- 

 cytes of the same variety containing fat particles are found also in the 

 connective tissue framework of the ridges between the fat-cells. With 

 regard to the epithelial cells during fat absorption, we find that they can 

 be clearly shown to possess during the process large numbers of fat par- 



