THE NERVOUS SYSTEM 283 



as much as by what he does. Education, even, has been 

 partially denned as the "training of inhibitions and the 

 control of reflexes." 



16. The cerebrum the chief organ for the acquisition of new 

 coordinations and associations. It would, however, be taking 

 too narrow a view of the functions of the cerebrum to regard 

 it simply as the seat of consciousness and volition. In 

 Chapter VII, 15, we saw that hi addition to definite in- 

 herited reflex mechanisms, such as those of winking, the 

 so-called unconditioned reflexes, new paths of conduction 

 from the afferent to the efferent side are acquired during 

 life by the repeated association of two acts. Doubtless all 

 parts of the brain and spinal cord possess in some degree 

 this power of making new associations like those concerned 

 in the conditioned reflexes ; but the cerebrum is certainly 

 the organ in which they are made most readily, and there 

 can be no doubt that one of its chief functions is the acqui- 

 sition of such new paths of conduction as the experience 

 and activities of life first blaze within its nervous substance 

 and subsequently, by the repeated passage of nervous im- 

 pulses over the " blazed trail," change to " beaten paths " of 

 easy conduction. Here every act and experience of life may 

 leave its record, and here good and bad habits are acquired. 



17. Use and disuse as factors in individual development, 

 training, and efficiency. When we consider the marvelously 

 complicated character of the nervous mechanisms which 

 control our actions, we naturally wonder how this intricate 

 machinery can be built and why it does not more frequently 

 get out of order. We cannot say that a simple and compre- 

 hensive answer will not some day be given to these ques- 

 tions, but to-day we have no adequate answer whatever. 

 The neurones with which we must work in life are born with 

 us ; but in most cases efficient connections must subsequently 

 be made between them, thus perfecting the mechanisms they 

 compose ; and this perfecting of the nervous machine comes 



