USE OF PYLORIC FAT. 805 



worm-like, fleshy offshoots from the intestine, situated 

 immediately helow the true stomach. In the salmon 

 there are forty-five to sixty-five pyloric apx^endages. 

 Although they may be subservient in secreting a fluid 

 connected with digestion, yet there can be no doubt in 

 my mind (and I venture to claim this as a discovery of 

 my own) that they act as a convenient depository for fat, 

 even if this be not their princii3al function. Analogous 

 cases may be found in the hump of the camel, in bears, 

 marmots, &c. 



The process of developing the ova and milt is a great 

 tax upon the system of the salmon ; thus, in a Tweed 

 fish (January 14, 1869) just ready to spawn, the ova 

 in weight amounted to a little over one-fifth of the entire 

 weight of the fish itself ; and in a Tay fish (December 

 11, 1868) the weight of the eggs amounted to a little 

 over one-quarter the weight of the entire fish. The oily 

 matter in the eggs and milt of a salmon is very great. 

 I believe it, therefore, sound physiology to say that the 

 use of the fat stored up in the pyloric appendages and 

 under the skin is : first, to supply nutrition to the fish 

 during its sojourn in fresh water; and, second, to 

 afford materials for the development of the milt and 

 ova. 



The blocks, which I have caused to be engraved, will 

 illustrate what I have endeavoured to explain above : — 

 a', the oesophagus ; i, the intestines ; p, the i)ylorics ; W7, 

 the milt. In the case of the "clean rmi" sahnon the 

 2)ylorics can hardly be distinguished, on account of 

 the mass of fat which envelopes them, while it will be 

 remarked that the milt is very small. This specimen 

 is from a clean " fi-esh-run " salmon from the Avon, 

 Hants; it weighed 35lbs., and was caught March 14, 

 1871. It was, in fact, an '♦ up " fish. 



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