468 Edivard Livingston Youmans. 



co-ordinated with the movements of locomotion and utter- 

 ance. Repetition strengthens association and facilitates 

 action ; that which is difficult at first, requiring a large 

 expenditure of voluntary effort, at last seems " to go of 

 itself." Upon this point Dr. Carpenter remarks: " There 

 can be no doubt that the nerve force is disposed to pass in 

 special tracks, and it seems probable that while some are 

 originally marked out for the automatic movements, others 

 may be gradually worn in by the habitual action of the 

 will, and that thus when a train of sequential actions origi- 

 nally directed by the will has been once set in operation, 

 it may continue without any further influence from that 

 source." * 



Thus, in committing to memory a poem, or in learning 

 a piece of music, voluntary effort wears a path of asso- 

 ciation, so that each word or sound automatically suggests 

 the next, and we can either repeat the words or hum the 

 air in silence, or link on the automatic movements of ex- 

 pression : but by sufficient repetition the words and sounds 

 become so closely associated, that when the first bar of the 

 melody or the first stanza of the poem is awakened, it will 

 cost an effort to prevent running through with them. In 

 this way, as the child grows to maturity, brain connections 

 are established between sensations, ideas, and movements ; 

 they become automatic and powerful, and give rise to fixed 

 habits. Peculiarities of gait, attitude, gesture, and speech, 

 and the iteration of set phrases, become partially auto- 

 matic, their paths of discharge getting so deeply worn that 

 repetition occurs involuntarily. The same thing is seen 

 also in the higher region of ideas and beliefs. Long-es- 

 tablished associations and opinions survive their rejection 

 by reason : convince a man of his lifelong errors to-day, 

 and he reasserts them to-morrow, so strong is the tend- 



* Principles of Human Physiology. Fifth edition, p. 699. 



