146 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



the liver, however, goes into the intestiual canal, as well as does a juice 

 secreted by the x^ancreas and the appendages of the coecum. Both the 

 pancreas and the appendages of the cajcum are wanting in many fish. 

 The appendages referred to, which in varying number are attached to 

 the front part of the intestinal canal (3 in the perch, ] 9 to 150 in the sal- 

 monoids, and upwards of 200 in the mackerel), are often connected into 

 a glandular mass by a loose tissue. 



The gall-bladder does not digest albuminous matter, but contains a 

 so-called "diastatic" ferment which transforms soaked starch to sugar, 

 and thus renders it fit to be received in the organism. The liquids 

 secreted by the pancreas and the appendages of the caecum react in a 

 neutral or alkalic manner, digest albumen, and to a limited extent possess 

 the faculty of transforming soaked starch to sugar. Like the gall-blad- 

 .der they also possess the faculty of changing fatty substances to an 

 emulsion, and thus preparing them for absorption by the intestinal 

 canal. 



Matters are very different in those fish which have no stomach, for 

 instance, in the carp and bleak. Here the entire intestiual canal, from 

 the throat to the anus (though to a much greater extent in the front 

 than in the back part), secretes a liquid, which in its effect resembles 

 that secreted by the i)ancreas, and which therefore digests both albu- 

 minous matter and soaked starch, as well as fatty substances. These 

 fish have no appendages to the caecum, but the liver pours a consider- 

 able quantity of gall into the intestinal canal, immediately back of the 

 throat. These fish, therefore, are capable of digesting albuminous mat- 

 ter, carbohydrates, and fatty substances. 



It is wtU known that fish do not masticate their food, as the teeth of 

 predatory fish serve only to take hold of and to retain food. Even in 

 those fish which possess strong teeth, worms and the larvaj of insects are 

 only squeezed somewhat. Kor do fish euveloi) their food in saliva while 

 in the mouth, as is done by mammals, as fish have no salivary glands. 



Although the food, therefore, reaches the alimentary canal without 

 any preparation favoring digestion, the alimentary canal in the majority 

 of our fish is comparatively short. While in the cat, for instance, it is 3 

 times the length of the body, in man C times, in the horse 12 times, and 

 in the goat even 26 times, we find that, according to numerous measure- 

 ments, the proportion of the length of the body and the length of the 

 alimentary canal is in the pike, hake, whiting, and tench, as 1:1; in 

 the bass, perch, and eel it is as 3 : 2; in the crucian carp as 2:3; and 

 in the u-els, as 11 : 8. Only in a few species of fish does the length 

 of the alimentary canal exceed that of the body to any great extent. 

 A notable example is the lump-fish {Cyc1oj)terus liimpus) of the Baltic, 

 whose alimentary canal is from G to 10 times as long as tlie body. 



The rapidity of digestion depends very much on the quantity of Ibod 

 taken at one tiiiu^ Sm:dl «iuantities are, of course, digested quicker 

 jhan large ones. II' :i j)ike swallows a fish half ils own size, so that in 



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