230 Human Physiology. 



self-acting work automatically, or without any apparent effort 

 of the will. We walk, we sing, we play on instruments, we 

 write, without any consciousness of effort. Habit fixes what 

 exercise has gained. 



With a little trouble, we can form habits in our bodies of 

 great importance to health. We can practice deep breathing 

 until it becomes a habit, and our blood is always well supplied 

 with oxygen. We can habituate ourselves to the kinds and 

 quantities of food, and times of eating, which are best for us, 

 and to the proper period of sleep. Even the evacuations of the 

 body may be brought under the law of habit. 



We are continually forming bad habits; habits of using stimu- 

 lants and intoxicants ; of taking brandy and tobacco ; of relying 

 on tea and coffee ; of depending upon cathartic medicines ; of 

 eating high-seasoned food, or eating too much or too often. It 

 costs much sometimes to break off a bad habit ; but how easy 

 not to form them ! And it is easier to form good habits than 

 bad ones. The quantity of food is so much a matter of habit, 

 that two persons of equal weight, and mental and bodily activity, 

 will consume widely different quantities of food one eating, 

 four times as much as the other, the surplus being of no pos- 

 sible advantage, but the reverse. So habit makes five meals 

 a-day seem necessary to some persons ; while others live equally 

 well perhaps, far better on two meals a-day. It is a matter 

 of habit whether a man sleep six hours or nine hours a-day; and 

 ihree hours a-day is one-eighth of life. It is therefore of great 

 importance that we form simple, natural, and healthful habits, 

 and in all ways order our lives to the highest uses. There is 

 no tyranny so odious as that of a bad habit, no blessing so great 

 as that of having formed good ones. 



And the law of habit applies to the moral and spiritual life 

 of man as much as to his intellect and muscles. We can 

 acquire habits of feeling as well as of thought and action. One 

 has but to watch over impatience and irritability of temper to 



