of the Salmon in fresh Water. 73 



KELTS. 



It is a matter of no little interest to trace the changes which take 

 place in the salmon between the time of spawning and their return to 

 the sea. 



It is supposed by some that kelts feed voraciously. Of the two 

 salmon captured at Basel in which Miescher Ruesch found traces of 

 food, both were kelts. 



The evidence adduced by Dr. Gulland shows that the lining membrane 

 of the stomach is regenerated in the kelt stage, while Dr. Gillespie's 

 observations show that the digestive power is greater in kelts than in 

 tmspawned salmon. In the kelts examined by us food was never found 

 in the stomach, but, in nearly all, the gall-bladder contained a greater or 

 less quantity of bile. 



Miescher Ruesch describes the changes in the salmon after spawning 

 as follows : 



After a vivid description of the characters of the fish on the spawning 

 beds, he says (p. 215): 



" How altogether different is the picture if we have the opportunity 

 to see the animal ten days, or, better, two weeks, after spawning. The 

 skin is again blueish, shining and clear, the ulcers cicatrized and healing, 

 the flesh transparent and free of oil granules. The heart fibres also 

 participate in the regenerative change; in the intestine is no trace of food. 

 On the other hand, the ovary contains sometimes more, sometimes fewer 

 eggs, which are embedded in a serous or somewhat purulent effusion of 

 the follicular membrane, and are evidently shrinking and being absorbed. 

 They are thus a sort of nourishment, a provision (Zehrgeld) for 

 the return journey. But I ascribe the chief importance to the pale, 

 shrunken, and folded follicular membrane. The collateral vessels of the 

 ovary are closed through vascular contraction. The salmon is like a 

 patient who has had a leg amputated after the application of an 

 Esmarch's bandage. Its blood courses in a narrow circulation, thus 

 with higher pressure, and supplies a less amount of oxygen-requiring 

 matter than formerly. The circulation is again sufficient for its task, 



and the trunk muscle-; becomes normal The little nutrient 



matter coming from the ovary greatly helps the reconvalescence of the 

 muscle." 



In the spring of 1897, 22 kelts were received from the mouth of the 

 Spey between the 17th March and the 21st May, and other three kelts 

 were procured in 1895-96. 



The weight of muscle, ovaries, etc., was determined in eleven of these, 

 and a detailed analysis was made of four. 



Table XVIII. gives the length, weight, weight per nsh of standard 

 length, weight of musculature total and per fish of standard length, 

 and weight of ovaries total and per fish of standard length. The length 

 is in centimetres and the weight in grammes : 



[TABLK. 



