188 CELL INTELLIGENCE THE CAUSE OF EVOLUTION 



problem, or if with a friend we can carry on conversation 

 without having to give any attention to the movements 

 of the limbs. Even talking can become an automatic af- 

 fair of this kind, as when we recite a poem without think- 

 ing of each word, and what comes after it, as we had to do 

 when we learnt it originally. Habit is the popular word 

 for all these activities which may or may not have been 

 originally learned, but which are now all relegated to the 

 subconscious sphere. 'Instinct' is the popular term for 

 habit as found congenitally present. We say that a child 

 knows how to suck by instinct ; certainly it is not by con- 

 sciousness, for children without brains at all (acephalic 

 monsters) can suck perfectly. The child inherits the 

 capability of carrying out the co-ordinated movements of 

 sucking; it does not require to learn these, they are poten- 

 tially present in its nervous system. We shall later see 

 that this sort of thing is only an example of a certain kind 

 of reflex action. 



"One of the best illustrations of how the nerves work 

 is the one so often given, the telephone exchange. What 

 is a telephone exchange for? To put two people into 

 (verbal) communication with each other." 



This statement will illustrate what we mean by a nerve 

 centre. It is as Prof. Harris states, a collection of cells, 

 set apart f.or superintending, looking after or having to do 

 with a particular function or activity of the body. We 

 have collections of cells looking after breathing, if we de- 

 stroy them the breathing stops. To illustrate, if the 

 continual pumping of air into the submarine was neces- 

 sary to the lives of its inhabitants, the same as it is in the 

 animal, a number of individuals would be placed in charge 

 cf that work, and if those individuals were killed, the 

 pumping of air into the submarine would stop and the 

 submarine would be killed all life in the submarine 



