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OF THE ANIMAL STRUCTURE REGARDED AS A MASS.
Contemplating an animal body in its collective capacity, we cannot forget to notice, what a number of instruments are brought together, and often within how small a compass. In a canary bird, for instance, and in the ounce of matter which composes its body (but which seems to be all employed), we have instruments, for eating, for digesting, for nourishment, for breathing, for generation, for running, for flying, for seeing, fdr hearing, for smelling; each appropriate; each entirely different from all the rest.
The human, or indeed the animal frame, considered as a mass or assemblage, exhibits in its composition three properties, which have long struck my mind, as indubitable evidences, not only of design, but of a great deal of attention and accuracy in prosecuting the design.
04 I. The
I. The first is, the exact correspondency of the two sides of the fame animal; the right hand answering to the left, leg to leg, eye to eye, one side of the countenance to the other; and with a precision, to imitate which in any tolerable degree forms one of the difficulties of statuary, and requires, on the part of the artist, a constant attention to this property of his work, distinct from every other.
It is the most difficult thing that can be to get a wig made even; yet how seldom is the face awry? And what care is taken that it should not be so, the anatomy of its bones demonstrates. The upper part of the face is composed of thirteen bones, six on each side, answering each to each, and the thirteenth, without a fellow, in the middle: the lower part of the face is in like manner compo sed of six bones, three on each side, respectively core responding, and the lower jaw in the centra. In building an arch could more be done in order to make the curve true, i. e. the parts equi-difiant from the middle, alike in figure and position?
The exact resemblance of the eyes, considering how compounded this organ is in its structure, how various and how delicate are the shades of colour with which its iris is
tinged, tinged, how differently, as to effect upon appearance, the eye may be mounted in its socket, and how differently in different heads eyes actually are set, is a property of animal bodies much to be admired. Of ten thoufand eyes, I don't know that it would be possible to match one, except with its own fellow ; or to distribute them into suitable pairs by any other selection than that which obtains.
This regularity of the animal structure is rendered more remarkable by the three following considerations. First, the limbs, separately taken, have not this correlation of parts; but the contrary of it. A knife drawn down the chine cuts the human body into two parts, externally equal and alike; you cannot draw a straight line which will divide a hand, a foot, the leg, the thigh, the cheek, the eye, the ear, into two parts equal and alike. Those parts which are placed Report the middle or partition line of the body, or which traverse that line, as the nose, the tongue, the lips, may be so divided, or, more properly speaking, are double organs; but other parts cannot. This shews that the correspondency which we have been describing does not arise by any necessity in the nature
of of the subject; for, if necessary, it would be univerfal, whereas it is observed only in the system or assemblage: it is not true of the separate parts: that is to fay, it is found where it conduces to beauty or utility; it is not found, where it would subsist at the expence of both. The two wings of a bird always correspond; the two sides of a feather frequently do not. In centipedes, millepedes, and that whole tribe of insects, no two legs on the same side are alike; yet there is the most exact parity between the legs opposite to one another.
2. The next circumstance to be remarked, is, that, whilst the cavities of the body are so configurated, as, externally, to exhibit the most exact correspondency of the opposite sides, the contents of these cavities have no such correspondency. A fine drawn down the middle of the breast divides the thorax into two sides exactly similar; yet these two sides inclose very different contents. The heart lies on the left side; a lobe of the lungs on the right; balancing each other, neither in size nor shape. The fame thing holds of the abdomen. The liver lies on the right side, without any similar viscus opposed to it on the left. The 6 spleen spleen indeed is situated over against; the liver; but agreeing with the liver, neither in bulk nor form. There is no equipollency between these. The stomach is a vessel, both irregular in its shape, and oblique in its position. The foldings and doublings of the intestines do not present a parity of sides. Yet that symmetry which depends upon the correlation of the sides, is externally preserved throughout the whole trunk: and is the more remarkable in the lower parts of it, as the integuments are soft; and the shape, consequently, is not, as the thorax is by its ribs, reduced by natural stays. It is evident, therefore, that the external proportion does not arise from any equality in the shape or pressure of the internal contents. What is it indeed but a correction of inequalities? an adjustment, by mutual compenfation of anomalous forms into a regular congeries? the.effect, in a word, of artful, and, if we might be permitted so, to speak, of studied collocation?