xvii CARE AND TRAINING OF THE NERVOUS SYSTEM 251 



tobacco must be looked upon as a useless and expensive 

 habit. 



Opium, chloral, and other similar drugs contain nar- 

 cotic poisons, and should never be used by either young 

 or old unless prescribed by a reputable physician and 

 taken under his direction. The moral effect of the use 

 of these narcotics may be even greater than that of 

 alcohol. The only safe rule for a long, healthy, useful, 

 and happy life is never to touch any of these drugs. 



SUMMARY OF THE MAIN POINTS 



1. One eighth of all the blood is used by the brain. It 

 requires a large quantity of nutritious food and pure air to keep 

 the brain in a good, healthy, working condition. 



2. The brain cells should be used regularly and systematically 

 in a large variety of exercises, so as to call into action all the 

 different centers. 



3. When nerve cells function they consume food material, 

 produce waste products, and become fatigued. 



4. Worry, anxiety, and grief are probably more frequently 

 the cause of a nervous breakdown than mental work. 



5. Change of occupation is restful because new nerve centers 

 are called into action, hence we should not continue too long at 

 the same task. 



6. Natural sleep is nature's most powerful reparative agent. 

 The wastes are removed, and the cells repaired and stored with 

 new energy-yielding materials. 



7. An infant sleeps most of the time, a child under five 

 requires about twelve hours, an adult about eight. The brain 

 worker needs a little more sleep than the laboring man. 



8. Regular habits of sleeping are just as important as a regu- 



