518 



contracted into a narrow tube, thick-walled, and somewhat trans- 

 lucent, so that the gastric rugae are visible through its walls. The 

 large quantities of fat stored up around the pyloric appendages and 

 intestine in the sea tend to disappear in the river salmon. The liver 

 loses its soft spongy consistence while the bile assumes a more viscid 

 character. 



2) The Contents of the Gut. 



a) In sea salmon. — In sea salmon at all seasons the gut is 

 frequently found to contain partly digested food materials or indi- 

 gestible substances along with large quantities of fluid. In the stomach 

 the fluid is almost always comparatively clear and is intensely acid. 

 When not in process of digesting food, the stomachic mucous membrane 

 gives a neutral or even faintly alkaline reaction, the alkalinity being 

 in all probability due to the presence of mucin. In the pyloric appen- 

 dages and intestine (in both of which absorption occurs) the fluid 

 contents are tinged with bile or lipochromes from the food. On no 

 occasion have I found in the pyloric appendages any yellow pultaceous 

 matter except as the result of post-mortem digestion. In the intestine 

 large quantities of crystals of carbonate of lime are generally present 

 due to the limy skeletons of the Annimals used as food. 



b) In river salmon. — I have not been able to find any 

 distinct remains of undigested food which are visible to the unaided 

 eye, though there is often clear evidence that food has been recently 

 ingested. In the stomach I have on several occasions obtained an 

 acid reaction, in one case where the genital products (ova) were far 

 advanced in maturity (the yolk spherules of the ova having already 

 partly fused). Save for certain vegetable substances and some parasites, 

 only a clear viscid substance was present in the stomachs of all fishes 

 examined. The intestine in all cases contained more or less of an 

 orange colored substance, semi-solid and viscid in character, and very 

 abundant in the duodenum and rectum. The absence of fluidity is 

 evidently due to the syruppy character of the bile and the diminished 

 exudation of watery fluid from the mucous membrane. 



This orange colored material contains mucin, fats, leucin crystals 

 (often in great abundance), tyrosin, crystals of carbonate of lime, bile- 

 pigments, Cholesterin crystals, a small amount of cellular debris, and 

 certain other small particles which are almost certainly remnants of 

 food materials. As for the pyloric appendages, when they are cut up in 

 the fresh state, no creamy or pus-like substance has ever been observed 

 in their interior by me (except in those cases examined more than 

 30 min. or so after death). A small quantity of the same material as 



