The Brain. 235 



Summary. i . The outside of the brain consists of gray matter, the 

 inside of white matter. 



2. The twelve pairs of cranial nerves are distributed to the head, with 

 the exception of the tenth and part of the eleventh. 



3. The cranial nerves include the senses of sight, smell, taste, and 

 hearing. 



4. Each hemisphere of the brain is connected with, and has chief 

 control of, the opposite half of the body. 



5. The gray matter of the cerebrum is the seat of the will, sensation, 

 thought, and emotion. 



6. The cerebellum regulates voluntary motion. 



7. Many of the cerebral functions have been located. 



8. The brain needs rest. In sleep less blood flows through the 

 brain. 



9. Work reduces the size of nerve cells. During rest they increase 

 again. 



Questions. i . Is there any special reason why the "speech center " 

 should be in the left cerebral hemisphere ? 



2. Why does a light lunch sometimes enable one to go to sleep after 

 mental work ? 



3. Why is it uncomfortable to hold the head down ? 



4. How does the nervous system resemble a telegraph system ? In 

 what respects are the two unlike ? 



5. Name some remedies for sleeplessness. 



