451 



The mass in the tube is made up mainly of rounded cells staining 

 deeply with eosin, and having their nucleus rounded, somewhat vary- 

 ing in size, but always staining deeply and uniformly with hsematoxylin 

 — no chromatin network can be made out. In addition a few leuco- 

 cytes may be present and one or two shrunken goblet cells. The 

 main mass of cells are certainly derived from the degeneration of the 

 columnar epithelium, which in these cases is shed almost entirely from 

 the folds of the mucous membrane. It is almost always easy to find 

 some spot between the folds where this epithelium remains unaltered, 

 and within quite a short distance one can trace every stage of degener- 

 ation until the same form as that lying free in the lumen is reached. 

 Fig. 7 will make this clearer than any description. 



Sometimes the d6bris in the tube is more granular and the cellular 

 structure less easily made out, but that is evidently merely a later 

 stage of the same process. 



I have never found a salmon in whose intestine and pyloric 

 appendages (for the two are always at the same stage of the process, 

 another proof of their identity of function) this change was not present 

 to a greater or less extent. The pyloric appendages and intestine of 

 the seven Berwick salmon were examined, and as these had all been 

 fixed immediately after death with sublimate, there could be no question 

 of post-mortem change. In four out of the seven the change was 

 practically complete, either the entire epithelium was degenerated, or 

 only a little was left deep down between the folds. In the remaining 

 three the change, though present, was less marked, being confined 

 mainly to the apices of the folds ; in one there was very little catarrhal 

 change. In all the fish from the higher reaches, from the sea, and 

 in the kelts from the river the change was complete. It is very 

 curious to see the connective tissue framework of the folds, with its 

 blood vessels much congested as a rule, lying absolutely bare of 

 epithelium in this pus-hke mass. 



This change must certainly be a pathological, catarrhal, or sea- 

 sonal one, for in the trout we see nothing of it. There the columnar 

 epithelium everywhere covers the folds, both in the specimens fixed 

 immediately after death, and in those fixed at varying times post- 

 mortem, except in the intestine of the specimen fixed six hours after 

 death. Here there is indeed a considerable desquamation of epithehum, 

 which is lying free in the lumen of the gut, but the cells are not 

 degenerated in any way. They still exhibit the characteristic bar, 

 their nuclei show the chromatin network, and the desquamation is 



