THE EVOLUTION OF THE MIND. 439 



as the race exists, for general inadequacy would mean extinction of 

 the species. 



The intellect, as distinguished from lower mental operations, is 

 the choice among responses to external conditions. Complex con- 

 ditions permit a variety of responses. Varying conditions demand 

 a change of response. This demand is met by the intellect. The 

 intellect rises with a complex or changing environment. The 

 greater the stress on a race of thinking creatures, the more active and 

 effective their thoughts. The growth of man has been a succession 

 of triumphs over hard conditions. The races which have been 

 successful have arisen from adversity. Prosperity has been the con- 

 quest of hard times. Human progress in general has come through 

 the falling away of the ineffective. The " fool-killer " has been its 

 most active agent. " The goodness and the severity of God " are in 

 science one and the same thing, as they were in the thought of the 

 prophet. Its essence is the survival of those who can live and act 

 effectively and happily in the conditions which surround human and 

 animal life. The power of safe and accurate response to external 

 conditions is the essential feature of sanity. The inability to adapt 

 action to need is a character of insanity. Insanity, except as pro- 

 tected by human altruism, means death. 



The difference between intellect and instinct in lower animals 

 may be illustrated by the conduct of certain monkeys brought into 

 relation with new experiences. At one time I had two adult 

 monkeys, " Bob " and " Jocko," belonging to the genus Macacus. 

 Neither of these possessed the egg-eating instinct. At the same 

 time I had a baby monkey, " Mono," of the genus Cercopithecus. 

 Mono had never seen an egg, but his inherited impulses bore a direct 

 relation to feeding on eggs, as the heredity of Macacus taught the 

 others how to crack nuts or to peel fruit. 



To each of these monkeys I gave an egg, the first that any of 

 them had ever seen. 



The baby monkey, Mono, being of an egg-eating race, devoured 

 his eggs by the operation of instinct. On being given the egg for the 

 first time, he cracked it against his upper teeth, making a hole in it, 

 sucked out all the substance, then, holding the eggshell up to the 

 light and seeing that there was no longer anything in it, he threw it 

 away. All this he did mechanically, automatically, and it was just as 

 well done with the first egg he ever saw as with any other he ate. All 

 eggs since offered him he has treated in the same way. 



The monkey Bob took the egg for some kind of nut. He broke 

 it against his upper teeth and tried to pull off the shell, when the 

 inside ran out and fell on the ground. He looked at it for a moment 

 in bewilderment, and then took both hands and scooped up the yolk 



