of the Fishery Board for Scotland. 



39 



THE COD. 



A glycerine, or other extract of the mucous membrane of the stomach 

 of the cod, is possessed of powerful peptic properties. The gastric glands 

 contain plenty of pepsin, and the reaction of the mucous membrane is 

 distinctly acid. This result is what one would expect. It is no uncom- 

 mon thing to find fish, such as haddock, in every stage of disintegra- 

 tion in the stomach of the cod. One frequently fiuds crustaceans, molluscs, 

 holothurians, and sometimes great quantities of aphrodite. The aphro- 

 dite I have found very abundant in the cod's stomach during May. The 

 calcareous coverings of the Crustacea and the bones of fishes are rapidly 

 decalcified by the gastric juice. Only the very indigestible portions of 

 the food seem to pass unchanged through the comparatively narrow 

 pylorus into the duodenum. 



The pyloric appendages, when extracted with glycerine or weak spirit, 

 yield a solution which, in the presence of a 1 per cent, solution of sodium 

 carbonate, has distinct digestive properties, indicating the presence of 

 trypsin. As far as my experiments go, they lead one to believe that the 

 spirit extract is more powerful than that obtained by glycerine. Such 

 an extract acts upon fibrin at the ordinary temperature of a room, but 

 more rapidly at 38° C. 



The Bile has a beautiful green colour, and can usually be obtained in 

 sufficient quantities for experiments. It is neutral or very feebly alkaline 

 in reaction. In testing for the presence of a diastatic ferment, one is apt 

 to commit an error, unless he adopts the precaution of testing the bile 

 itself for the presence of sugar. In one case, at least, I found that the 

 bile of the cod contained a considerable quantity of a substance which 

 reduced Fehling's solution, thus exhibiting the ordinary reaction for sugar. 

 To ascertain the presence of a diastatic ferment in bile, over and above 

 the sugar, one must of course get rid of the sugar either by dialysis or 

 estimate the amount of sugar in a given amount of bile, and ascertain if 

 the sugar is increased on the addition of starch. In most of the other 

 samples of bile which I analysed, there was no sugar, but distinct evidence 

 of a diastatic ferment. 



The Liver. — Extracts were made of the liver by means of water and 

 a solution of sulphate of soda. The results as regards the presence of 

 glycogen and sugar varied in different specimens. In one cod's liver 

 which I examined in this way in January, I found no glycogen, and with 

 difficulty traces of sugar. This fish had plenty of partially-digested food 

 in its stomach. In two other specimens examined early in May abundant 

 evidence of glycogen was obtained. From a comparatively small piece of 

 liver I obtained a highly opalescent solution of glycogen, after precipitat- 

 ing the proteids by potassio-mercuric iodide and hydrochloric acid by 

 the method of Briicke. As in the extract of a mammal's liver, glycogen 

 is thereafter precipitated by alcohol from the opalescent solution. The 

 same extract showed the presence of a large amount of sugar. In this 

 case the fish was digesting also. The difference in regard to the extracts 

 of the liver in these two cases was certainly very great — in one no 

 glycogen and mere traces of sugar, in the other plenty of glycogen and 

 sugar ; while in both cases the stomach contained food, and in both cases 

 the food consisted of crustaceans and fishes. The one fish was examined 

 in the end of January, when the ova were large, and the others in May, 

 when the reproductive products were shed. Obviously, a more extended 

 analysis as to the food and other conditions must be made, before one can 

 give a satisfactory statement as to the relation of the glycogen and sugar in 



