150 THE HUMAN BODY. 



7. Many actions which must, at first, be attended to by 

 the cerebrum, may, after a time, be handed over to the 

 offices lower down. For example, in learning to play on 

 the piano, it is necessary, at first, to give the whole mind 

 to every touch. After a while, difficult music can be 

 played with little thought. 



If we were not made so that we could act in this way, 

 our whole time and attention would be taken up in doing 

 the things which now seem the simplest. Our minds would 

 be worn out in making the movements, and combinations 

 of movements, necessary in eating and breathing and 

 walking. 



8, The nerve-fibers which carry messages in to the 

 centers are called sensory fibers. The nerve fibers which 

 carry messages out to the muscles are called motor fibers. 



9. The messages do not all come from the outside, as in 

 the case of the mosquito-bite. A wish or thought may 

 start in the cerebrum, without any impression from out- 

 side, and cause an order to be sent out to the muscles. 



10, The nervous system connects the different parts of 

 the body, and makes them work together. 



THE CEREBRUM THE SEAT OP THE HIGHER FACULTIES. 



SECTION III. 1, We have taken it for granted, that 

 the cerebrum is the seat of the higher faculties, the 

 memory, the reason, the will, the feelings. This is proved 

 in two ways : 



i. If this portion of the brain be diseased or injured, 

 these faculties are affected. 



g. The more of the higher faculties an animal has, the 

 larger is the cerebrum in proportion to the rest of the 

 brain. Man has the largest cerebrum proportionally. 



