Instinctive Behaviour 181 



surrounding conditions brought these faculties 

 into play. 



The instinctive powers displayed by this lad, 

 in conjunction with the previous histories of 

 the deaf and dumb children, strengthens the 

 idea we have advocated, that the brain of human 

 beings contains a nervous mechanism possess- 

 ing innate qualities which, when stimulated by 

 appropriate energy, become manifest in instinc- 

 tive action. The evolution of this mechanism 

 can be traced upwards through the ascending 

 classes of animals, and constitutes a prominent 

 feature of the human brain. We thus come to 

 realise the fact that the animal side of man's 

 nature results from a specific arrangement of 

 elements entering into the formation of his 

 central nervous system which he has inherited 

 from his. progenitors, and cannot therefore get 

 rid of or permanently alter. Nevertheless, it 

 seems possible to modify the kind of work 

 which the nervous substance of the basal 

 ganglia performs by educating or influencing 

 its action through means of the sensory organs, 

 and still more directly, by energy derived from 

 association areas of the brain. We know that 



