130 The Salmon's Insurgence 



They are fastened together by delicate glutinous 

 threads which exude from the kidneys. There are 

 similar pathological products in the kidneys of 

 higher animals, and there can be little doubt that the 

 male stickleback has been able to make a weakness 

 into a strength. Microscopic sections of the kidneys 

 show that considerable changes away from the normal 

 occur at the breeding season, yet these deviations 

 have not crossed the line of safety. Virchow would 

 have said: Here in this fish is a pathological change 

 that has been normalized and turned into an 

 advantage. 



The familiar spectacle of the salmon leaping at 

 the falls is a fine picture of the insurgence of life. 

 They are seeking the spawning-grounds in the higher 

 reaches of the river, and they show an admirable 

 quality of persistence against the stream. It is a great 

 gymnastic feat to hurl the heavy body clean out of 

 the water, sometimes to a considerable height; and 

 our wonder is not lessened by the fact that all the 

 work seems to be done on an empty stomach. For the 

 salmon is one of those creatures that show a very 

 sharply defined alternation or see-saw between feed- 

 ing and breeding. There is the nutritive life in the 

 sea, when vast stores of chemical energy are accumu- 

 lated; there is the adult's reproductive life in the 

 fresh waters, where "hunger" has been eaten up of 

 "love." We are not concerned at present to refute 

 the view that hooked salmon disgorge the contents of 

 their stomach. It is also possible that they may some- 

 times take a larval insect into their mouth, and 



