144 ANIMAL LIFE 



in fish when the water of their aquarium has become 

 partly exhausted. In short, whilst the movements 

 of an animal are stimulated by light, heat, and outer 

 agencies, they are controlled by a nervous mechanism 

 that is not only related to that control, but is also 

 concerned in satisfying the inner desires by those 

 movements. 



Gradually these adjustments become not only 

 automatic in their working, but by their repetition 

 induce a second self, a periodic heightening and lowering 

 of the central governing control, through which the 

 rate of automatic working is rendered steady for long 

 intervals and is protected from becoming spasmodic 

 and from changing with each change of scene. Thus 

 we find choice becoming obedience and obedience 

 becoming tradition, giving, as it were, a direction 

 which the answer may take, though not determining 

 the intensity of its response. 



The warm blood of the higher animals creates a 

 further buffer between them and the changing con- 

 ditions around their bodies ; it wards oft from them 

 those changes of temperature which sink their less 

 fortunate relations into stupor or death. 



The value of this mechanical and traditional tend- 

 ency is easily misunderstood. We need not look upon 

 it as necessarily converting the whole life of an animal 

 into a scries of purely automatic actions. For if we 

 steadily keep our outlook on the gradual evolution 

 of self-consciousness, we shall see in this stiffening 

 of action the necessary prelude to advance in the 



