EXERCISE. 53 



stronger. Frequent exercise carried on to the point of 

 great fatigue, leads to wasting away and weakness of the 

 muscles as surely as does continued idleness. It also 

 enfeebles the whole body and makes it more liable to 

 many diseases. 



Action and repose in turn, and neither in excess, are the 

 conditions necessary for healthy muscles. In those whose 

 action we cannot control by the will, we find this illus- 

 trated. The heart is a muscle which contracts seventy 

 times or more every minute, in its work of pumping the 

 blood all over the body. Yet the heart beats on year 

 after year and feels no fatigue. The secret of this is that 

 after every contraction it rests before it makes the next 

 one. The muscles which cause the movements of breath- 

 ing, teach us the same lesson. If they stopped their work 

 for five minutes, we should die for want of fresh air in 

 our lungs. After each breath we draw, they take their 

 rest, and so keep at work fifteen or sixteen times a min- 

 ute all life long. 



10. The Proper Amount of Exercise is not the same 

 for all persons. A strong healthy boy or girl runs about 

 until pretty thoroughly tired, then goes home, eats a 

 good supper, sleeps soundly, and wakes in the morning 

 feeling all the better for the exercise. One who is deli- 

 cate, should always rest as soon as the least fatigue is felt. 

 Being delicate means, in most cases, that the organs of 

 the body, the muscles along with the rest, only nourish 

 themselves slowly; short exercise and long rest are there- 

 fore necessary. If a person who is not strong becomes 



10. When should a delicate person stop exercising ? Why ? What 

 is the result if a delicate person overexerts himself? How may 

 healthful games be made injurious ? What is about sufficient regu- 

 lar exercise for a healthy adult of sedentary habits ? 



