128 Instinct, 



tion and Instinct to harmonize In every one of the 

 hundreds of thousands of species, — and each indi- 

 vidual, through these combined agencies, into the 

 best relations with the world in which it lives. 



In addition to this, before we can accept Natur- 

 al Selection as the chief agency in the production 

 of species, we must see how all the species were 

 kept in existence while those slow changes were 

 taking place which now give the species character 

 and upon which their existence seems to depend. 

 The explanations of the best masters, after giving 

 them the benefit of every fact they present, leave 

 many, perplexing difficulties, in regard to such re- 

 lationships as we have already referred to. The 

 problem will become more difficult as we advance. 

 Some of its difficulties are well illustrated by the 

 examples under the next topic, — 



The Relatio7t of histinct to special structure and 

 function. 



If we accept Natural Selection as the means of 

 securing the special adaptations of Instincts and in- 

 struments which we see among animals, we must 

 grant that in every case, there was at the beginning, 

 an Instrument and an instinct to use it effectively ; 

 because an instrument without the corresponding 

 instinct would be of no advantage to the animal, 

 but a damage. Where we find special structures 

 or special functions and corresponding instincts, we 

 must grant the co-existence of both and the con- 

 joined action of both, before Natural Selection 

 could possibly have any influence to preserve either 



