Introductory, 29 



tions that never could have been suggested to us 

 by the study of the structure or function of organs. 

 It is a function of the salmon as of the codfish to 

 bring forth eggs. But why does not the salmon 

 deposit her eggs in the salt waters where she loves 

 to swim ? While the codfish finds her breeding 

 place in the ocean, the salmon leaves the ocean and 

 seeks the clear cold waters of the fresh streams as 

 the place for depositing her eggs. She selects the 

 best place in the stream, and after covering her 

 eggs with gravel she leaves them to the care of the 

 elements. She has done the best in her power for 

 them and in all this work we say she is guided by 

 Instinct. But in due time by the same sort of spon- 

 taneous impulse and knowledge or guidance, her 

 young find the pathway to the ocean feeding 

 grounds without the parent's aid. These are fair 

 examples of instinctive action, or of spontaneous 

 impulse, knowledge and skill, which are generally 

 spoken of as the operations of some distinct princi- 

 ple in the animal. 



The impulse^ that arises in every one of the spe- 

 cies at a given season of the year, or at a given pe- 

 riod of its own development, to do the same 

 thing — the apparent knowledge by which acts are per- 

 formed to meet coming emergencies, the like of 

 which the animals have never witnessed-the skill 

 in working that comes without instruction or expe- 

 rience — all these are inscrutible. So much of all 

 of these, as is needful for the preservation of each 

 species, it seems to have as an original outfit, and 



