254 PHYSIOLOGY AND HEALTH. 



not immovably. The arch, therefore, is not unyielding like 

 the skull, but it is somewhat loose, and allows a little spring 

 to the foot when the body rests upon it. This arrangement 

 gives to the foot both strength arid elasticity. It admits great 

 ease of motion, and saves the jar that would otherwise hap- 

 pen, when we step upon the ground. The foot rests, not 

 upon its whole under surface, but upon the heel and the ball 

 near the toes, which are the ends of the arch. The hollow 

 of the foot bears none of the weight. The bones of the leg 

 (Fig. XLI. a) rest upon the top of the arch, b. 



603. When we step the hollow of the foot upon a round 

 stick, so that the ends of the arch do not support the weight 

 of the body, as when walking on the round steps of a ladder, 

 or when a boy walks on stilts, we feel an unpleasant jar, and 

 the want of that elasticity and ease in the step which we 

 feel when we walk naturally on a flat surface. When we 

 walk, we first place the heel upon the ground ; this receives 

 a part of the shock ; next, the ball comes to the ground, and 

 the force or weight comes upon the arch. Thus the shock 

 is so divided that it is hardly felt. 



604. When we jump down from any high place, we throw 

 the toes downward, 'so' that the first force of the blow is re- 

 ceived upon the ball of the foot. The ankle then bends, and 

 the second force is received upon the heel ; and again these 

 two, being the ends of the arch, yield, and thus the force is 

 divided into three portions, and is received in part upon the 

 ball, the heel, and the arch; and thus no violent jar is com- 

 municated to the general frame above. A sailor, falling from 

 the mast in a rolling ship, struck the hollow of his foot upon 

 the railing, and- received a very severe shock and much injury. 

 But another, falling the same distance, struck with the ball 

 of his foot upon the level surface of the deck, and received 

 no great shock and suffered no material damage. 



605. The natural shape, of the foot is somewhat broad in 

 front, with the toes spread, or, at least, lying loosely, and the 

 inner side of the great toe in a line with the heel and the 

 ball. The greatest length of the foot is along this lane, 



