THE NERVOUS SYSTEM. 



39 



blood will weaken its action. Hence its dependence 

 on the blood-purify ing system. 



Severe excitement of the mind or long continued 

 anxiety cripple the work of the brain, and finally 

 result in insanity. A cheerful state of the rnind is 

 favorable to healthy nerves and long life. Conse- 

 quently, all proper enjoyments, as the delights of 

 music, pleasant changes of scenery, varied means of 

 recreation and social pleasures, are like tonics to the 

 nervous system first, and through it to the whole body. 



There is no system of the body that is more 

 severely outraged by the habit of drink and the use 

 of narcotics than the nervous system. But this sub- 

 ject is so very important that it will be fully explained 

 in a special chapter, after we are still better 

 acquainted with the structure of the body. 



OUTLINE. 

 THE NERVOUS SYSTEM. 



Consists of brain, spinal cord and nerves. 

 Very soft and delicate in structure. 

 Composed of white and gray matter. 

 The large brain called the cerebrum. 

 The smaller brain the cerebellum. 

 Right and left halves of brain called hemispheres. 

 Nerves of two kinds, nerves of sensation or im- 

 pression and nerves of motion. 



f Brain enclosed in cranium. 

 Spinal cord extends from base of brain through 



the spinal canal of back-bone. 



WHERE. ^ Nerves branch out from the brain, spinal cord and 

 the sympathetic nerve knots, and are distributed 

 to all parts of the body. 



WHAT? 



