and general qualities of bodies. The whole of the palmar surface is exquisitely sensitive, but it is on the pulpy tips of the fingers that the greatest sensibility resides. There the multitudinous nerves form a congeries of papillæ, supported on cushions of cellular tissue, and protected by the nails. These latter add firmness to the tips of the fingers, and serve not only as a support, but also as a barrier between external bodies and the nerves beneath them, thereby intercepting the communication of definite impressions, in order that the nervous energy may be more fully concentrated on the pulpy portion appropriated to touch, and that the impressions there received may be the more definite and vivid. The nails arise out of the true skin, and grow from a pulpy root; they are closely attached to the soft parts, which they cover, and cannot be torn away without intense pain. From the arrangement of the muscles of the palm, which bend the thumb and fingers, the centre of the palm is concave, and by this provision the hand is more efficient under many circumstances as an instrument of prehension. this, also, the roughness, or rigid linear markings of the cuticle of the palm and inside of the

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fingers contributes, no less than to nicety of perception in testing the quality of the surface of objects, and which, had the cuticle been smoothly polished, would have been at a much lower ratio. To persons accustomed to heavy labour as the blacksmith and ploughman-the cuticle becomes much thickened, and operates as a defence to the nervous tissue, though at the same time it interferes with delicacy of tact. "The hand of little labour has the nicer sense."

Such is a general sketch of the human hand considered restrictively; and conformable to it is the arm, according to that principle of harmony which ever prevails in organic bodies. The peculiar flexibility of the wrist joint, the power of flexure, and of pronation and supination enjoyed by the fore-arm, and the amazing freedom of the shoulder-joint, which permits the arms to be whirled about, are all essential to the efficacy of the hand, and the multitude of purposes to which it is applied. It is in a shallow socket of the bladebone (scapula) that the shoulder-bone (humerus) moves freely; and the blades are kept in their position by two clavicles, or collar-bones, which extend between them and the top of the breast-bone. Thus are the shoulders kept

apart from the chest, and the arms, instead of being drawn to the latter by muscular exertion, thereby interfering with its due expansion, and their own freedom, are at full liberty.

Let us now turn to the analogous parts of the lower animals,-and first let us take the ape tribe, which are called quadrumanous, that is, four-handed, because all four extremities are constructed as graspers. In man alone, of all the mammalia, is the erect bipedous attitude easy and natural. The structure of the spine and trunk, the bony and muscular development of the lower limbs, and the balance of the skull on the top of the vertebral column, combine to necessitate such an attitude. In the ape tribe, animals for the most part of arboreal habits, their progression on the ground is on all fours, and their attitude is crouching, or more or less diagonal-a posture intermediate between the upright and horizontal. The lower part of the trunk is contracted and slender - there is no development of the haunch bones and their muscles-the thighs are meagre and ordinarily drawn up to the body, with the knees acutely bent, a position favourable for sudden and vigorous leaps, which these animals execute with great address.

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In the chimpanzee and orang, however, there is, to a certain extent, a greater approximation to the human form and attitude; these animals can with some difficulty, and by the aid of their long arms balancing themselves, proceed for a short distance in an erect posture; but the gait is an unsteady hobblethey cannot walk with a firm step, nor run, nor leap, like man. If we rigorously scrutinize the hands of the ape tribe, we shall soon perceive that they are instruments for grasping, rather than organs structurally adapted for tact and nice manipulation. They are narrow and elongated; the palm is flat, and in many species-as, for example, the long-armed gibbons of the Indian islands-linear, expanding from the wrist to the base of the fingers. In all, the thumb is short and feeble; in none is it a fair antagonist to the fingers, though, in some species, it is better developed than in others. In the gibbons, the short thumb is divided down to the wrist, or nearly so, and is not opposable to the fingers; the ball formed by the adductor muscles is very trifling, but in the feet, or hinder graspers, the thumb is greatly developed, and forms an equal antagonist to the other toes conjointly-and,

indeed, as a general rule, the hinder graspers of these animals approach nearer to the human hand, as far as the development of the thumb is concerned, than do the fore-hands, or graspers. In some of the American monkeys, the thumb is wanting, or reduced to a mere rudiment beneath the skin, and in those which possess it, it is on the same plane with the fingers, or utterly uncpposable to them, and bends like the fingers in the same direction. A true thumb, however, exists in the hinder graspers; and it is remarkable that among certain groups of the American monkeys, we meet with an accessory organ for grasping, namely, a strongly prehensile tail, by which they can suspend themselves head downwards from the branches. The prehensile tail of the spider-monkeys, of the opossums, and some other quadrupeds, may indeed be regarded as an accessory hand, or grasper, not only from the power of clinging tenaciously with which it. is endowed, but also from the sense of touch which it possesses; apparently in as high a degree, or even perhaps higher, than the paws themselves. Indeed, the extremity of the tail, in the spider-monkey, is finger-like, and is capable of seizing small objects with great