Every horse, ox, sheep, swine, when at liberty to choose, and when in a natural state, that is, when not vitiated by habits forced upon it, eats and rejects the same plants. Many insects which feed upon particular plants, will rather die than change their appropriate leaf. All this looks like a determination in the sense itself to particular tastes. In like manner, smells affect the nose with sensations pleasurable or disgusting. Some sounds, or compositions of sound, delight the ear; others torture it. Habit can do much in all these cases, (and it is well for us that it can; for it is this power which reconciles us to many necessities); but has the distinction, in the mean time, of agreeable and disagreeable, no foundation in the sense itself? What is true of the other senses, is most probably true of the eye, (the analogy is irresistible,) viz. that there belongs to it an original constitution, fitted to receive pleasure from some impressions and pain from others.

I do not however know, that the argument which alleges beauty as a final cause, rests upon this concession. We possess a sense of beauty, however we come by it. It in fact exists. Things are not indifferent to this sense; all objects do not suit it; many, which we see, are agreeable to it; many others disagreeable. It is certainly not the effect of habit upon the particular object, because the most agreeable objects are often the most rare; many which are very common, continue to be offensive. If they be made supportable by habit, it is all which habit can do; they never become agreeable. If this sense, therefore, be acquired, it is a result; the produce of numerous and complicated actions of external objects upon the senses, and of the mind upon its sensations. With this result, there must be a certain congruity to enable any particular object to

please; and that congruity, we contend, is consulted in the aspect which is given to animal and vegetable bodies.

IV. The skin and covering of animals is that upon which their appearance chiefly depends; and it is that part which, perhaps, in all animals, is most decorated and most free from impurities. But were beauty, or agreeableness of aspect, entirely out of the question, there is another purpose answered by this integument, and by the collocation of the parts of the body beneath it, which is of still greater importance; and that purpose is concealment.* Were it possible to view

through the skin the mechanism of our bodies, the sight would frighten us out of our wits. "Durst we make a single movement," asks a lively French writer, "or stir a step from the place we were in, if we saw our blood circulating, the tendons pulling, the lungs blowing, the humours filtrating, and all the incomprehensible assemblage of fibres, tubes, pumps, valves, currents, pivots, which sustain an existence at once so frail, and so presumptuous ?"

V. Of animal bodies, considered as masses, there is another property, more curious than it is generally thought to be; which is the faculty of standing: and it is more remarkable in two-legged animals than in quadrupeds, and, most of all, as being the tallest, and resting upon the smallest base, in man.† There is more,

*The purpose of integuments is, we conceive, protection rather than concealment; it is an elastic medium resisting every violence better than any other medium. See also preceding note, p. 168.

+Anatomy explains the mode in which the weight of the body is transmitted to the feet, and we have seen that the muscles which prevent the head from falling forward in standing, have their fixed point in the neck; that those which perform the same office with regard to the vertebral column, have theirs in the pelvis; that those which preserve the pelvis in equilibrium

I think, in the matter than we are aware of. The statue of a man, placed loosely upon its pedestal, would not be secure of standing half an hour. You are obliged to fix its feet to the block by bolts and solder; or the first shake, the first gust of wind, is sure to throw it down. Yet this statue shall express all the mechanical proportions of a living model. It is not, therefore, the mere figure, or merely placing the centre of gravity within the base, that is sufficient. Either the law of gravitation is suspended in favour of living substances, or something more is done for them, in order to enable them to uphold their posture. There is no reason whatever to doubt, but that their parts descend by gravitation in the same manner as those of dead matter. The gift, therefore, appears to me to consist in a faculty of perpetually shifting the centre of gravity, by a set of obscure, indeed, but of quick-balancing actions, so as to keep the line of direction, which is a line drawn from that centre to the ground, within its prescribed limits. Of these actions it may be observed, first, that they in part constitute what we call strength. The dead body drops down. The mere adjustment, therefore, of weight and pressure, which may be the same the moment after death as the moment before, does not support the column. In cases also of extreme weakness, the patient cannot stand upright. Secondly, that these actions are only in a small degree voluntary. A man is seldom conscious of his voluntary powers in keeping himself upon his legs. A child learning to walk is the greatest posture-master in the world: but art, if it may be so

are attached to the thighs, or to the bones of the legs; that those which prevent the thighs from falling backward are inserted into the tibia; and, lastly, that those that preserve the tibia in their vertical position have their fixed point in the feet; these preserve us firm in a standing position.

called, sinks into habit; and he is soon able to poise himself in a great variety of attitudes, without being sensible either of caution or effort. But still there must be an aptitude of parts, upon which habit can thus attach; a previous capacity of motions which the animal is thus taught to exercise: and the facility with which this exercise is acquired, forms one object of our admiration. What parts are principally employed, or in what manner each contributes to its office, is, as hath already been confessed, difficult to explain. Perhaps the obscure motion of the bones of the feet may have their share in this effect. They are put in action by every slip or vacillation of the body, and seem to assist in restoring its balance. Certain it is, that this circumstance in the structure of the foot, viz. its being composed of many small bones, applied to and articulating with one another, by diversely shaped surfaces, instead of being made of one piece, like the last of a shoe, is very remarkable.*

See Tab. XI. There is no part of the human frame which is more wonderfully constructed than the foot. It has the requisite strength to support the weight of the body, and often an additional burden: flexibility, that it may be adapted to the inequalities of the surface on which we tread; and elasticity, to assist in walking, running, and springing from the ground. This advantage we possess from the number of joints, the

I suppose, also, that it would be difficult to stand firmly upon stilts or wooden legs, though their base exactly imitated the figure and dimensions of the sole of the foot. The alternation of the joints-the knee-joint bending backward, the hip-joint forward; the flexibility, in every direction, of the spine, especially in the loins and neck, appear to be of great moment in preserving the equilibrium of the body. With respect to this last circumstance, it is observable, that the vertebræ are so confined by ligaments, as to allow no more slipping upon their bases, than what is just sufficient to break the shock which any violent motion may occasion to the body. A certain degree also of tension of the sinews appears to be essential to an erect posture; for it is by the loss of this, that the dead or paralytic body drops down. The whole is a wonderful result of combined powers, and of very complicated operations. Indeed, that standing is not so simple a business as we imagine it to be, is evident from the strange gesticulations of a drunken man, who has lost the government of the centre of gravity.

We have said that this property is the most worthy of observation in the human body; but a bird, resting upon its perch, or hopping upon a spray, affords no mean specimen of the same faculty. A chicken runs. off as soon as it is hatched from the egg; yet a chicken, considered geometrically, and with relation to its centre of gravity, its line of direction, and its equilibrium, is a arch of the foot being composed of twenty-six bones: a, the metatarsus ; b, c, the phalanges of the foot and toes; d, e, f, g, h, the bones of the tarsus or instep. These bones have a considerable play on each other and as each articulating surface is covered with cartilage, the essential property of which is elasticity, the jarring is thus prevented which would result from a contact of the bones.

;

"The first question which naturally arises is, Why there should be so many bones? the answer is-In order that there may be so many joints: for the structure of a joint not only permits motion but bestows elasticity."