SECRETS OF THE SALMON 



hatch at the top. Toward evening the surface of 

 a salmon river is all dappled with the rings and 

 splashes of these parr taking flies. In this way 

 the growing salmon establishes his habits of feed- 

 ing on insect food over a period of eighteen months 

 or so. Brain-tracks so firmly impressed on a grow- 

 ing organism are not likely to be wholly obliterated 

 by a subsequent change of environment, and it 

 may require only a very small stimulus to bring 

 them to the surface of consciousness. As an 

 illustration of the persistence of habits of long 

 standing, I should like to tell of an experience 

 which is somewhat parallel to the early habits of 

 the salmon recurring in later life. For about 

 twenty years I used a foot-power lathe in my work- 

 shop. It was my custom to start this by pulling 

 the belt with my left hand to bring the crank to 

 the upper dead-centre, and then raise my right 

 leg and start the foot pedal. About six years 

 ago I put electricity in my workshop, and placed 

 the switch controlling the power at the right above 

 the lathe. When I came to start the power I 

 invariably raised my right leg as I turned on the 

 switch with my right hand. The motion was 

 involuntary and almost irresistible. This per- 

 sisted for about three years, and I still do it at 



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