K JV. Head ley 361 



presses onward, those that, passing all other roads, keep on in 

 a particular direction will at length form a species guided Ijy 

 instincts that seldom swerve. Thus evolution proceeds by 

 Natural Selection, but at the cost of an enormous sacrifice of 

 life, even after instincts come in to reduce it. At the higher 

 level there is intensification of Natural Selection, but the waste 

 of indiscriminate destruction in a great degree comes to an end. 

 Intelligence and plasticity are the order of the day. The 

 monkey is a good representative of the new system : the cater- 

 pillar, with his one accomplishment, of the old. Intelligence 

 enables those who have it to make themselves at home where 

 the creature of instinct would perish. They pass their youth 

 in playing and imitating and thus gain a versatility that protects 

 them amid the shocks of circumstance. They have merit of a 

 kind that must make itself felt. Though they have marked 

 tendencies, strong hkes and dislikes, yet they have with all a 

 certain saving pliancy and elasticity. And greater pliancy in 

 its component individuals leads, as I have tried to show in this 

 section, to greater adaptability in the species. The result is 

 that among the higher plastic classes of animals evolution 

 proceeds more rapidly. 



" But obviously the quickening up of evolution is not all. 

 The individual gains in importance. He improves his powers, 

 is able to face a change of environment that otherwise would 

 have been fatal. He makes an environment for his young in 

 which intelligence can be developed : he chooses the environ- 

 ment which they shall have when out of the nursery, and so 

 decides to some extent what qualities shall be the winning 

 qualities in life. In fact, he is beginning to take the helm and 

 steer the species. Or we may put it in this way: when the 

 individuals of one generation decide the environment in which 

 the next shall grow up, selection ceases to be purely natural : it 

 is in part artificial." 



