168 APPENDIX. 



Almighty Power that created the animal exercised an equal 

 amount of omniscient knowledge in devising an instinct for its 

 guidance and functions. Instinct is, therefore, unerring, or the 

 word should be expunged from our dictionaries. 



M. I am perfectly satisfied with your definition of instinct ; 

 tell me now how it influences salmon differently from grilse ? 



H. As the human eye cannot follow the motions of fish 

 while in the sea, their habits can only be ascertained by watch- 

 ing them during their annual migrations to the rivers, where 

 they are completely withiu the reach of our observation. Ex- 

 perience then shows us that salmon, impelled by their instinct, 

 leave the sea for their home or rivers in winter and spring ; 

 whereas the grilses do not leave the sea for the rivers until 

 summer, clearly showing that the one is a spring, and the other 

 a summer fish. Another difference, which I shall explain 

 more fully hereafter, is, that although I have a hundred times 

 made inquiry on the subject, I have never yet heard any old 

 Highland poacher assert that he had seen salmon and grilse 

 spawn promiscuously ; but, on the contrary, that he invari- 

 ably found either two grilse or two salmon performing that 

 operation. My own experience as a fisherman for thirty years 

 goes to corroborate the same fact. 



M. If instinct is unerring, how do you account for some 

 rivers producing salmon earlier than others ? 



H. Instinct has nothing to do with the nature or the circum- 

 stances connected with early or late rivers ; but in the seasons 

 of their migrations, instinct directs the fish of each river to 

 itself ; and were all the fish in the sea suddenly to become 

 blind, every fish would proceed directly to its own natal river, 

 passing all others, regardless of their taste or temperature, still 

 impelled onwards by its instinct, which does not cease operat- 

 ing from the time the fish left the ocean until it had reached 

 its destination ; the only inconvenience it would experience 

 from blindness being, that it could not escape from its enemies, 

 or procure its food. 



M. If, then, the instinct in salmon leads them to return to 

 their natal river, passing all others, how do you account for the 

 fact of fish, recognised as belonging to a certain river, being 



