书城教材教辅科学读本(英文原版)(套装1-6册)
47723000000364

第364章 第四册(20)

The palm of the hand corresponds to the sole of the foot, and each of them has five bones running through it, which carry the fingers and toes respectively.

The hand has four fingers and a thumb-each finger being formed of three bones, the thumb of two. Thefoot, in its turn, has four toes and a great toe; the great toe having two bones, each of the others three.

We have only to consider the purposes for which the hand and the foot are respectively designed, and we must be at once struck with admiration for themanner in which each is adapted to its work. In the hand, flexibility andea sy rapid mo vement, delicate touch, and firmgra sping powers ha ve

to be secured. Hence the wrist bones are small, those of the fingers very long, while the thumb is placed so as to be able to move in the opposite direction to the fingers. In the foot, we need strength and solidity of support, consequently the whole of the bones are short, thick, heavy, and clumsy in appearance. The great toe has no grasping power, corresponding to that of the thumb.