THE NERVOUS SYSTEM AND ORGANS OF SENSIO 405 



" The hell to be endured hereafter, of which theology tells, is no worse 

 than the hell we make for ourselves in this world by habitually fashioning 

 our characters in the wrong way. Could the young but realize how soon 

 they will become mere walliing bundles of habits, they wculd give more 

 heed to their conduct while in the plastic state. We are spinning our 

 own fates, good or evil, and never to be undone. Every smallest stroke 

 of virtue or of vice leaves its never-so-little scar. The drunken Rip Van 

 Winkle, in Jefferson's play, excuses himself for every fresh dereliction by 

 saying, ' I won't count this time ! ' Well ! he may not count it, and a 

 kind Heaven may not count it ; but it is being counted none the less. 

 Down among his nerve cells and fibers the molecules are counting it, regis- 

 tering and storing it up to be used against him when the next temptation 

 conies. Nothing we e\-er do is, in strict scientific literalness, wiped out. 

 Of course this has its good side as well as its bad one. As we become per- 

 manent drunkards by so many separate drinks, so we become saints in the 

 moral, and authorities in the practical and scientific, spheres by so many 

 separate acts and hours of work. Let no youth have any anxiety about 

 the upshot of his education, whatever the line of it may be. If he keep 

 faithfully busy each hour of the working day, he may safely leave the final 

 result to itself. He can with perfect certainty count on waking up some 

 fine morning, to find himself one of the competent ones of his generation, 

 in whatever piursuit he may have singled out." — James, Psychology. 



Necessity of Food, Fresh Air, and Rest. — The nerve cells, like 

 all other cells in the body, are continually wasting away and being 

 rebuilt. Oxidation of food material is more rapid when we do 

 mental work. The cells of the brain, hke muscle cells, are not 

 only capable of fatigue, but show this in changes of form and of 

 contents. Food brought to them in the blood, plenty of fresh 

 air, especially when engaged in active brain work, and rest at 

 proper times, are essential in keeping the nervous system in con- 

 dition. One of the best methods of resting the brain cells is a 

 change of occupation. Tennis, golf, baseball, and other outdoor 

 sports conibine muscular exercise with brain activity of a different 

 sort from that of business or school work. 



Necessity of Sleep. — Sleep is an essential factor in the health of 

 the brain, especially for growing children. Most brain cells attain 

 their growth early in life. Changes occur, however, until some 

 time after the school age. Ten hours of sleep should be allowed 

 for a child, and at least eight hours for an adult. At this time, 

 only, do the brain cells have opportunity to rest and store food and 

 energy for their working period. 



