INTRODUCTION 7 



the seed of a great unlikeness, of very new things, in that his 

 desires had an element of the unlimited which was to orow 

 apace, and in time to make him greedy of on-going. As this 

 innovating creature sought for agents of power in the wilder- 

 ness about him, he blindly laid hands upon such of the fellow 

 tenants of the wilds as might serve his immediate needs. 

 This species, both animals and plants, endowed with the 

 capacity for variation, the plasticity which is in general a 

 characteristic of all organic forms, were early led by their 

 new master, as of old they had been guided by the old 

 organic laws. They changed according to his choice, aban- 

 doning their ancient ways for the novel paths of civilization. 

 With this association of the higher forms of the earth under 

 the leadership of man, there began an entirely new and 

 unprecedented condition of the world's affairs. In place of 

 the ancient law of nature there came the control of our spe- 

 cies which had been, in a way, chosen to be the overlord of 

 life. 



At first, the number of species of animals and plants which 

 man brought under his control was very limited ; it was 

 indeed confined to those which might readily be subjugated 

 to meet immediate needs. Gradually, however, the list has 

 been extended until it included thousands of forms, which, 

 while they meet no need such as the savage recognizes, are 

 gratifying to the taste or the ambitions of civilized peoples. 

 These aesthetic devices, or those of necessity, are advancing 

 so rapidly that each generation sees hundreds of new animal 

 and plant species added to our living collections, so that our 

 plant and animal gardens now contain a large share of the 

 more attractive forms which are to be found in the various 

 geographical realms. Our tilled fields yield perhaps a 



