252 HUMAN PHYSIOLOGY CHAP, xvn 



lated life in other matters. Sleeping, eating, and working 

 should all be carefully regulated as to time and amount. 



9. Education is designed to exercise and develop all the 

 brain cells, and to create a wide range of sympathies and inter- 

 ests in early life. 



10. When brain cells act they become so changed as to make 

 it easier to act the same way a second time. This we call 

 habit. Habits are due to changes in the brain structure. 



11. The two important principles are : (i) Habits are most 

 easily formed in early life. (2) Habits are most easily formed 

 during periods of rapid growth and great nutrition. 



12. Good habits become our strongest friends and allies, 

 while bad habits are our worst enemies and most hostile foes. 



13. Alcohol affects the nerve tissues more profoundly than 

 the other tissues. It tends to destroy the cell protoplasm and 

 increase the amount of connective tissue and fat. 



14. Alcohol weakens the moral sense, destroys the will, 

 impairs the intellect, and causes poverty, crime, suffering, 

 immorality, debauchery, and insanity. 



15. Tobacco and other narcotic drugs are harmful to the 

 nervous system, and should never be used unless prescribed by 

 a reputable physician. 



