ALIMENTARY CANAL, ETC., OF AMIURUS CATUS. 415 



A glycerine extract of the liver digests fibrin in a 05 % solution 

 of sodium bicarbonate, requiring but a few hours for a piece of 

 moderate size. 



In young cat-fishes, of from one to two inches in length, and from 

 which I made a series of sections in the neighbourhood of the liver and 

 midgut, I was unable to find a trace of pancreas. This is possibly to 

 be explained, as Bernard suggested, by the supposition that digestion 

 by the stomach is quite sufficient for the food of young fishes. It is 

 also to be observed that hepatic tissue does not penetrate between all 

 the capillary vessels of the liver. It is quite safe to say that the 

 pancreas is of later development, and is connected with the portal 

 vein in some such way as to be dragged by it into the liver when the 

 latter increases in size. 



The fact discovered by Krukenberg that the extracts of the livers 

 of different fishes accomplished a tryptic digestion may be explained 

 by the possible distribution of the pancreas in the liver in the way 

 that is describe! above. Among those fishes studied by this physi- 

 ologist, were Perca fluviatilis, Labrax lupus, Belone rostrata, Crenila- 

 ibrus pavo, Dentex vulgaris, Trigla hirundo, Sargus Rondeletii, Gobius 

 niger, &c. In Perca fluviatilis, according to Cajetan, the pancreatic 

 ducts entwine about the portal branches till they sink into the liver. 

 It may be added that it is possible in this fish, as well as in those given 

 above, that the pancreas follows the portal vein as it does in the cat- 

 fish. The organs so affected are, however, by no means to be denomi- 

 nated a hepato-panci^eas. as that name is understood in invertebrate 

 anatomy. 



A more careful study of the pancreatic tubules in the cat-fish 

 shows that it undergoes the ordinary changes effected during diges- 

 tion. In a fasting condition the cells are filled with granules, the 

 round nucleus situated near the outer part of the cell, and the whole 

 stains feebly in carmine. When the liver is cut out four or five 

 hours after the fish has been feeding, the granules are gathered into 

 a region adjacent to the lumen of the gland, and this portion stains 

 feebly, the rest of the cell strongly, in carmine. Fig. 11 gives a 

 representation of this stage. 



I could observe a membrana propria for these gland tubules as 

 little as in those of the gastric glands. The fibres of the connective 

 tissue surrounding them are arranged in a dense sheath which serves 

 .all the purposes of membrane. 



