LINE OP DIRECTION. 57 



ing, than if the centre were lower down. Hence such 

 a position as in Fig. 32 would be unsafe. 



The support of the human body, in standing and 

 walking, exhibits some interesting examples in rela- 

 tion to this subject. A child can not learn to walk till 

 he acquhes skill enough to keep his feet always in the 

 line of direction. When he fails to do this, he topples 

 over toward the side that the line falls outside liis feet. 

 A man standing with his heels touching the wash- 

 board of a room can not possibly stoop over without 

 faUing, because, when he bends, the hne of direction 

 falls forward of liis toes, the wall against which he 

 stands preventing the movement of his body backward 

 to preserve the balance. 



In walking, the centre rises and falls shghtly at 

 Pi^ 33 each step, as shown by the waved line 



in Fig. 33. If it were not for the 

 bending of the knee-joints, this exer- 

 cise would be much more laborious, 

 as it would then become needful to 

 tlurow the centre mto an upward curve 

 at every step. For this reason, a wood- 

 en leg is more imperfect than the nat- 

 ural one {Fig. 34). Hence the reason 

 why walking on crutches is laborious and fatiguing, 

 because at every onward step the body must be thrown 

 upward in a curve, like a wagon mounting repeated 

 obstructions. 



"When a load is carried on the shoulder, it should be 



so placed that the Ime of direction may pass directly 



through the shoulder or back down to the feet. Fig. 



35, p. 58. An unskillful person will sometimes place 



C2 



