Were the tips of the fingers of bone, instead of flesh, we could not take up such minute bodies as a millet seed, a thorn, or a hair, which we can now do so readily from their being soft and round. Less soft, or more soft, equal difficulty would arise: the fingers have precisely the degree of consistence which is adapted to their intended use. And that they may hold hard bodies, they are provided with nails, admirable indeed for structure and position: were these placed on the tips of the fingers, power would be lost; but they occupy exactly the situation, and are of just the length, which will insure their utmost efficiency. In almost every art where nicety of execution is required, the nails are continually called into action. Who can, indeed, overrate the value of the hand? Smoothness and roughness, fineness and coarseness, heat and cold, are among the many sensible qualities of matter which it enables us to recognize, from the nerves with which it is so abundantly supplied, while its uses defy enumeration. The cuticle, indeed, becomes hard, thickened, and almost horny, thus suffering a loss of sensibility from years of labor; but in this there is a wise and kind law of Providence, by which the laboring man is fitted for his daily and useful toil. Did his hands thrill with every impression, he would be constantly exposed to pain, and restrained by fear from pursuing as he does now his rugged work. But early use has inured him to labor; he therefore wields the axe, strikes in the spade, or swings over his head the huge hammer, almost unconscious of effort; or, equally unharmed, dips his vessel into the furnace of molten metal when it has attained the intensity of a dazzling and scorching whiteness. Complicated as the mechanism of the hand appears, when the attention is restricted to its surface, it proves still more so when there is a careful examination of its internal structure; while its complexity can only be adequately regarded as other parts of the physical system are duly considered. The wrist, which forms the base of the hand, is composed of eight small bones compacted together; and having little or no motion, they constitute a solid mass. The wrist is joined to the bones of the fore-arm, the radius, and the ulna, which lie alongside each other, and touch only toward the ends. Only one of them is joined to the upper arm, at the elbow; the other only to the hand, at the wrist. The former, by means of a hinge-joint at the elbow, swings backward and forward, carrying with it the whole fore-arm. As often, too, as there is occasion to turn the palm of the hand upward, the radius rolls upon the ulna by the help of a cavity near each end of one bone, to which, in the other, there is a corresponding tubercle.