another, and held together by ftrong braces to keep them in their position: then, thirdly, ftrings and wires, i. e. muscles and tendons, artificially inferted for the purpofe of drawing the bones in the directions in which the joints allow them to move. Hitherto we feem to understand the mechanifm pretty well; and understanding this, we poffefs enough for our conclufion : nevertheless we have hitherto only a machine ftanding ftill; a dead organization; an apparatus. To put the fyftem in a state of activity (to fet it at work) a further provision is neceffary, viz. a communication with the brain by means of nerves. We know the existence of this communication, because we can fee the communicating threads, and can trace them to the brain: its neceflity we alfo know, becaufe, if the thread be cut, if the communication be intercepted, the muscle becomes paralytic: but beyond this we know little; the organization being too minute and fubtile for our infpection.

To what has been enumerated, as officiating in the fingle act of a man's raifing his hand to his head, must be added likewife, all that is necellary, and all that contributes, to the growth, nourishment, and fuftentation of the limb,

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limb, the repair of its waste, the preservation of its health: fuch as the circulation of the blood through every part of it; its lymphatics, exhalants, abforbents: its excretions and integuments. All these share in the refult; join in the effect: and how all these, or any of them, come together without a defigning, difpofing intelligence, it is impoffible to con ceive.

CHAP

CHAPTER XI.

OF THE ANIMAL STRUCTURE REGARDED

AS A MASS.

CONTEMPLATI EMPLATING an animal body in its collective capacity, we cannot forget to notice, what a number of inftruments are brought together, and often within how small a compass. In a canary bird, for inftance, and in the ounce of matter which compofes its body (but which feems to be all employed), we have instruments, for eating, for digesting, for nourishment, for breathing, for generation, for running, for flying, for feeing, for hearing, for smelling; each appropriate; each entirely different from all the reft.

The human, or indeed the animal frame, confidered as a mass or affemblage, exhibits in its compofition three properties, which have long ftruck my mind, as indubitable evidences, not only of defign, but of a great deal of attention and accuracy in profecuting the defign.

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1. The

I. The first is, the exact correfpondency of the two fides of the fame animal: the right hand answering to the left, leg to leg, eye to eye, one fide of the countenance to the other, and with a precision, to imitate which in any tolerable degree forms one of the difficulties of ftatuary, and requires, on the part of the artist, a conftant attention to this property of his work, diftin&t 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 fhould not be fo, the anatomy of its bones demonftrates. The upper part of the face is compofed of thirteen bones, fix on each fide, anfwering each to each, and the thirteenth, without a fellow, in the middle: the lower part of the face is in like manner composed of fix bones, three on each fide, refpectively correfponding, and the lower jaw in the centre. In building an arch could more be done in order to make the curve true, i. e. the parts equi-diftant from the middle, alike in figure and position?

The exact refemblance of the eyes, confidering how compounded this organ is in its ftructure, how various and how delicate are the fhades of colour with which its iris is

tinged,.

tinged, how differently, as to effect upon appearance, the eye may be mounted in its focket, and how differently in different heads eyes actually are fet, is a property of animal bodies much to be admired. Of ten thousand eyes, I don't know that it would be possible to match one, except with its own fellow; or to diftribute them into fuitable pairs by any other felection than that which obtains.

This regularity of the animal ftructure is rendered more remarkable by the three following confiderations. First, the limbs, feparately 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 dividę 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 upon the middle or partition line of the body, or which traverfe that line, as the nofe, the tongue, the lips, may be fo divided, or, more properly speaking, are double organs; but other parts cannot. This fhews that the correfpondency which we have been defcribing does not arife by any neceffity in the nature

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