THE NERVOUS SYSTEM 359 



endowment is useless to it. It can be useful only by directing 

 activity towards the attainment of pleasure and the avoidance 

 of pain. This admitted, the mechanical theory falls to the 

 ground. There is an " It " which feels, selects feelings, chooses 

 those which have a pleasant tone, wills to perform the acts by 

 which they are attained. It follows that the value of conscious- 

 ness lies in the prerogative which it confers of adapting action, 

 within certain limits, to circumstance. An animal succeeds 

 in life in proportion as the nervous system which it inherits 

 reacts satisfactorily to its environment. A chick which, after 

 being hatched in an incubator, has been isolated for twelve 

 hours without food, seizes a grain of corn the instant that it 

 sees it. Its brain contains ready-made sensori-motor arcs 

 connecting the spot in its cortex in which the visual impression 

 of the grain is perceived and the motor neurones which control 

 the pecking muscles. A sheep-dog is quickly broken to sheep, 

 because its ancestors have been selected by mankind from 

 amongst dogs that readily adapted themselves to this work. 

 The breeder has selected a pattern of brain with the same 

 success with which, when appearance is the only desideratum, 

 he selects a pattern of coat. Beavers set to work at construct- 

 ing a dam at the only spot in a valley at which it is possible 

 to create an artificial lake, because for countless ages Nature 

 has ruled out the animals which constructed their dams in 

 unsuitable places. Man also inherits a brain-pattern ; but, not 

 being required to shift for himself soon after birth, he goes 

 through a long period of infancy and tutelage, during which, 

 by force of circumstance and his own Will, the pattern is 

 elaborated. His supreme success is due to his capacity for 

 adapting means to ends. He inherits very few instincts. 

 Except as regards organic functions, his spinal cord is sub- 

 servient in almost all respects to his brain. Most of the actions 

 of an animal are instinctive a word which has been sadly mis- 

 applied. Its connotation is negative rather than positive. 

 Owing to the marked pattern of its brain, an animal finds it 

 difficult to avoid acting in a particular way. As the nights 

 grow longer and its hours for feeding are curtailed, a swallow 

 is impelled by its instinct to go South. It makes the same use 

 of its sensations during its migration, and is as completely 

 dependent upon them for its guidance as a man would be. 



