156 THE HUMAN BODY. 



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 commencing manhood or maidenhood any kind of out- 

 door 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; and the day, which fortunately seems approaching, 

 which will see dolls as unknown to or as despised by healthy 

 girls as by healthy boys will see the beginning of a great im- 

 provement in the stamina of the female portion of our popu- 

 lation. 



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 vigorous muscular work often unadvisable, especially 

 under conditions 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- 

 advisable. The frame is still not firmly knit or as capable of 

 endurance as it will subsequently become. 



Girls should be allowed to ride or play out-door games in 

 moderation, and in any case should not be cribbed in tight 

 stays or tight boots. A flannel dress and proper lawn tennis 

 shoes are as necessary for the healthy and safe enjoyment of an 

 afternoon at that game by a girl as they are for her brother in the 

 baseball field. Eowing is excellent for girls if there be any 

 one to teach them to do it properly with the legs and back, 

 and not with the arms only, as women are so apt to row. 

 Properly practised it strengthens the back and improves the 

 carriage. 



Exercise in Adult Life. Up to forty a man may carry on 

 safely the exercises of youth, but after that sudden efforts 



