Ki2 THE HUMAN BODY 



ing and similar pursuits do not. For the same reasons baseball, 

 cricket, and boxing are excellent. 



Exercise in Infancy and Childhood. Young children have not 

 only to strengthen their muscles by exercise, but also to learn 

 to use them. Watch an infant trying to convey something to its 

 mouth, and you will see how little control it has over its muscles. 

 On the other hand, the healthy infant is never at rest when awake; 

 it constantly throws its limbs around, grasps at all objects within 

 its reach, coils itself about, and so gradually learns to exercise its 

 powers. It is a good plan to leave every healthy child more than 

 a few months old several times daily on a large bed, or even on a rug 

 or carpeted floor, with as little covering as is safe, and that as loose 

 as possible, and let it wriggle about as it pleases. In this way it 

 will not only enjoy itself thoroughly, but gain strength and a 

 knowledge of how to use its limbs. To keep a healthy child 

 swathed all day in tight and heavy clothes is cruelty. 



When a little later the infant commences to crawl it is safe to 

 permit it to as much as it wishes, but unwise to tempt it to do 

 so when disinclined: the bones and muscles are still feeble and 

 may be injured by too much work. The same is true of learning 

 to walk. 



From four or five to twelve years of age almost any form of 

 exercise should be permitted, or even encouraged. During this 

 time, however, the epiphyses of many bones are not firmly united 

 to their shafts, and so anything tending to throw too great a 

 strain on the joints should be avoided. After that up to com- 

 mencing manhood or maidenhood any kind of outdoor exercise 

 for healthy persons is good, and girls are all the better for being 

 allowed to join in their brothers' sports. Half of the debility and 

 general ill-health of so many of our women is the consequence of 

 deficient exercise during early life. 



Exercise in Youth should be regulated largely by sex; not that 

 women are to be shut up and made pale, delicate, and unfit to 

 share the duties or participate fully in the pleasures of life; but 

 the other calls on the strength of the young woman render vig- 

 orous muscular work often unadvisable, especially under con- 

 ditions where it is apt to be followed by a chill. 



A healthy boy or young man may do nearly anything; but 

 until twenty-two or twenty-three very prolonged effort is un- 



