RECENT RESEARCH UPON SALMON 231 



of their stomachs has been accounted for by a hypothetical 

 power of ejecting the contents when they are netted or hooked. 

 But to found on such a hypothesis would be childish, seeing 

 that the ejecting power cannot be limited to the period when 

 the fish are in fresh water, and that the stomachs of salmon 

 taken at sea are often found gorged with food. I have 

 given below (page 238) some evidence tending to show 

 that, should the period between entering the river and the 

 maturation of the ovaries be so prolonged as to cause a return 

 of appetite consequent upon the necessity for nutriment, the 

 fish will revisit the sea before spawning. 



For some time after spawning the salmon remains in the 

 river as a " kelt," or spent fish. The investigations conducted 

 in the Rhine by Dr. Hock and the late Professor Miescher 

 Ruesch led them to the conclusion that during this period also 

 the digestive tract of the salmon remains functionless, or, at 

 most, capable of very feeble action. This has since been con- 

 firmed in the course of investigations upon British salmon 

 conducted in the Research Laboratory of the Royal College 

 of Physicians of Edinburgh in co-operation with the Fishery 

 Board for Scotland. The observations of these gentlemen all 

 tend to establish the fact that, although traces of food may 

 occasionally be detected in the stomachs of spent fish, especially 

 after they have reached the tidal water, the true feeding-ground 

 of the salmon is the sea, and that it performs a physiological 

 fast as long as it remains in fresh water. 



It is to be noted that the conclusions of the Edinburgh 

 Committee, as reported upon in 1898,* have been checked by 

 an independent biologist, Dr. Kingston Barton, who detected a 

 very serious error in one of their processes. The Committee 

 were led to believe that, so soon as the salmon entered fresh 

 water, its digestive tract underwent a morbid change, described 

 as " desquamative catarrh," rendering the organ functionless 



* Report upon Investigations on the Life-History of the Salmon, H.M. 

 Stationery Office, 1898. 



