Tis often allowable for a naturalist, from the manifeft and appofite uses of the parts of animal bodies, to collect fome of the particular ends for which the creator defign'd them: and in fome cafes we may, from the known nature and structure: of the parts, draw probable conjectures about the particular offices of them.

To obviate miftakes, it must be here obferv'd, that I fpeak only of those ends and uses of the parts of an animal, that relate to the welfare and propagation of the animal itself, and which, therefore, I call animal ends; tho' I do not thereby deny any declaration made in the holy fcriptures, that 'God defign'd the entire animals, as well as their parts, to be ferviceable many ways to man. This premifed, I come to confider diftinctly the two parts of the propofition.

And, firft, there is no work of nature known to us, wherein the confideration of final caufes may fo juftly take place, as in the ftructure of animal bodies. For my own part, I confefs, that when I affift at a skil-, ful diffection, I cannot but wonder there fhould be philofophers, who afcribe the admirable contrivance of a human body to blind chance. The Stoic, who in Cicero, ask'd an Epicurean why chance did not make palaces, and erect other buildings, feems to have propofed a pertinent question. But the most commodious houfes are far lefs curious ftructures than the human machine for the materials of a palace are few, in comparison to the parts of an animal body; and their difpofition exceeding flight, compared to the curious and elaborate contrivance of the numerous folids and fluids of the human ftructure: the former whereof, alone, are above some hundreds; yet in every one of these parts, the bulk, figure, confiftence, texture, fituation, connexion, and aptnefs for motion, are the most commodious that can poffibly be devifed; whilft all of them are wonderfully fymmetrical, both to one another, and the whole body. And this number of parts is fo artificially contrived and fet together, that tho' no room be loft, many of them, at the fame time, exercife very different motions, while each moves freely, and rather promotes than hinders the motion of others.

Hurts or diseases may fhew how excellently all the parts of our bodies are contrived, in order to our welfare. For if even a finger be fwell'd, difplaced, kept in a wrong pofture by contractions, have its continuity violated, its tone chang'd by ftrains or contufions, its fenfe or motion taken away, its membranes fretted by fharp humours, or its motions dif order'd by convulfions; we quickly find, how commodioufly the parts affected were framed or difpofed; their natural figure, connexion, tone, &c. being now alter'd.

PHYSICS.

The eye, to fingle out again that part for an inftance, is fo exquifitely adapted for feeing, and fo little fitted for almoft any other office in the body and that ufe is fo neceffary for the welfare of the animal, that it may well be doubted, whether any confidering man can really think it not defigned for that ufe. The fix or feven mufcles, which move the whole ball VOL. II.

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PHYSICS. of the eye upwards, downwards, to the right-hand, to the left, and to va rious oblique pofitions; and the several coats and humours that make up the organ, have not only their magnitude, figure, confiftence, fituation, and connexion, admirably adapted to that end; but the transparency of the cornea, and the three humours, the opacity of the uvea, the femi-opacity of the retina, and the feveral motions of the parts of the eye, which are requifite to receive, tranfmit, refract, and dispose the visual rays, that come from the object, after the manner neceffary to make the livelieft piЄture of it in the bottom of the eye, wonderfully confpire to compleat this matchless instrument of vision: whence we may as properly conclude, that an eye, as that a telescope, is made to view objects with. But in that admirable perforation of the uvea, which we call the pupil, nature has greatly exceeded art. For tho' we are obliged to employ opake bodies, with fe veral circular apertures, to the object-glaffes of telescopes, that fome may let in lefs light, and others more, according as the objects require to be illumin'd; that part of the uvea which is fufpended in the aqueous humour, is an aperture that widens and contracts itself in an inftant, according to the exigency of the object.

But for the uses of the feveral parts of the eye, I refer my reader to Scheiner's Oculus, and Des Cartes's Dioptrics; whence it will appear, that, in forming this part, nature not only acted with defign, but with fo great skill in optics, that a more than ordinary acquaintance with that science is neceffary to understand the wisdom of the feveral contrivances, which perhaps no degree of skill whatever in it would enable a man to alter for the better.

"Twere tedious to mention other parts of the body that manifeftly appear to have been ordain'd to certain ufes. The books of anatomists are Full of paffages to this purpose, of which I fhall only fay in general, that tho' what they deliver is fufficient to fhew all the parts of the body to be the effects of an intelligent caufe, yet unless their defcriptions and refleЄtions be improved by mathematics, mechanics, and chymistry, we shall have but an imperfect notion how intelligent that caufe is, or how much wisdom is difplay'd in the ftructure of a human body, and its feveral parts.

I know 'tis objected by the Epicureans, that the parts of animals were First made, and their ufes afterwards difcover'd, by the fagacity of men; but this is a fophiftical objection: for, firft, many of the internal parts perform their functions, without our having any knowledge of their ftruture or fituation; fo far are they from being applied to fuch ufes by our fagacity. And as for the limbs and other parts, which we move at pleasure, 'tis true, they cannot be employ'd to their respective ufes, till actually form'd; nevertheless, they might be originally fo form'd, as in due time to be fit for fuch ufes. And, in effect, we fee that a chick is furnish'd with compleat eyes and wings, before it be hatch'd, tho' whilft inclofed in the egg it can make no ufe of them, either to fee or fly. And why was it, do the Epicureans think, that nature provided a whole fert of

temporary parts for pregnant females, and animals in the womb; which, PHYSICS. when they are come into a freer ftate, partly fhrink away of themselves, and partly turn to a ligament, fitted no longer for the former, but for a more feasonable ufe? And 'tis to be noted, that thefe umbilical veffels, and the placenta to which they are faften'd, is of no neceffity or use to the female before conception; and therefore those temporary parts appear to have been defign'd by nature for the propagation of the fpecies.

And tho' the fagacity of men may have found out fome uses of the particular parts of their bodies, which feem not to have been primarily intended by the author of nature; yet this does not prove that those uses were undefign'd: for the prefcience and goodness of God are fufficient to render it probable that he who gave man both the limbs of his body, and the endowments of his mind, did both foresee what ufes men might, according to their fagacities and emergencies, make of thefe parts, and fo contrive the parts, that they fhould be applicable to fuch uses.

And we may now proceed to the latter part of our propofition, which afferts, that, in some cases, from the known ends of nature, as well as from the ftructure of the parts, probable conjectures may be form'd about the particular offices of them.

This could not have been seasonably spoken to before, because the arguments that were founded on the ufes of the parts of animals fuppofe thofe parts to have been deftin'd to particular ufes, knowable by us; and that the feveral parts of the body were contrived as wifely and commodiously as men are able to devife, in order to the ends of nature; which must always be understood to have united in her defigns the ufes of the parts, and the welfare of the whole.

And indeed if we confider how admirable a fitness there is in the parts of a human body, to those particular ends we can difcover them to have been defign'd for; it feems allowable to conjecture, that such a part was not primarily defign'd to fuch an ufe, if it is, on the account of its ftru&ture, or otherwife, lefs fitted for it than the conftant wifdom of nature feems to require; efpecially if there be any other parts by which the office may be more commodioufly performed. And, on the other fide, it feems probable, that fuch a part was deftin'd to fuch an ufe, if the ufe itfelf appear to be neceffary, and the part better fitted for it than any

other.

Thus, tho' anatomical and optical writers, for many ages, unanimoufly concluded the cryftalline humour to be the principal feat of vifion, yet the industrious Scheiner justly rejects that receiv'd opinion, upon fhewing, that it fuits not with the skill and providence of nature, that it fhould be fo, fince it wants many requifite qualifications for that purpofe; and efpecially fince most of these are to be found in the retina. And I remember, upon asking our famous Harvey what induced him to think of a circulation of the blood; he faid, that obferving the valves in the veins of many parts of the body, fo placed, as to give free paffage to the blood towards the heart; but to oppofe the paffage of the venal blood, the contrary way; he

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PHYSICS. imagin'd that fo provident a cause, as nature, had not thus placed fo many valves without defign: and as no defign feem'd more probable than that, fince the blood could not well, because of the interpofing valves, be fent by the veins, to the limbs, it should be sent thro' the arteries, and return through the veins, whofe valves did not oppofe its course that way.

Thus, tho' the ancient anatomifts, and phyficians, believ'd the parts were nourished by the venal blood; the modern writers teach them to be nourifhed by the blood, in its paffage thro' the arteries. Not that they think the blood, which runs thro' the veins, altogether unfit to fupply the parts with that vital liquor; but because they judge the veins to be Jefs fit for this purpofe, than the arteries; into the latter whereof the blood comes immediately from the left ventricle of the heart, agitated, and fpirituous, and, by a brisk impulfe, better fuited to answer this end. But the writings of phyficians, and anatomists, being filled with inftances of this kind, I forbear to mention any more.

PROP. III.

It is rational, from the manifeft fitness of fome things, to cofmical, or animal ends, to infer, that they were thereto ordained by an intelligent agent.

Care seems to have been taken, that the body of an animal fhould be provided not only with all things that are ordinarily neceffary, and convenient: but with fome super-abundant provision against accidents. Thus, tho' a man may live, and propagate his fpecies, after the lofs of an eye; yet nature furnishes us with two, that, in cafe one be destroy'd, the other may fuffice for vifion. And the like may be faid of the ears. In short, nature has furnish'd men with double parts of the fame kind, where it is highly useful, and may be permitted without prejudice, to the rest of the body. And this is the more confiderable, because, in other parts, nature appears to husband things fo, as to avoid doing what is fuperfluous. Thus, within the skull, fome veffels, that would, in other parts of the body, have double coats, are very thin; the skull being ordinarily fufficient to defend them from external injuries.

Another argument, that nature acts with defign, about animals, may be drawn from what anatomifts obferve of thofe parts of the womb, or the foetus, that are to be found but at certain times, when there is need of them; and not at others, when they would be ufelefs. Thus, when a woman is with child, the Vafa umbilicalia are produced to be canals, either for the blood, or alimental juice, and fpirits, that then ought to pafs between the womb and the foetus, by means of the placenta. And tho', as long as the child continues in the womb, these temporary parts continue with him; yet, as foon as he comes into the world, the umbilical veffels, particularly the two arteries, and the vein, together with the membranes they are wrapp'd up in, with the chorion, and the amnios, that involve the foetus, are thrown off, as unneceffary, and expell'd in the after-birth; there remaining only that part of the umbilical veffels that

Fes within the child's abdomen, between the navel and the liver where PHYSICS its ufe is confiderable, tho' new; for it ferves: now no longer to convey blood, or an aliniental liquor, to and fro, but degenerates into a liga

ment.

Thus, alfo, the Foramen ovale, gives paffage to the blood from the right ventricle of the heart to the left, that the circulation of it may be maintain'd; for it cannot in the embryo, as in a born child, pafs thro' the veffels of the lungs, from one of the ventricles to the other: whence this contrivance feems to be an expedient that nature employs, till the fœtus is excluded; when that temporary conformation is obliterated... For the child, now breathing the free air, is in a condition to make the blood circulate thro' the pulmonic vessels, according to the primary intention of nature. From which, and the like inftances, we may infer, that these temporary parts were framed by a fore-knowing, as well as a defigning agent; who intended they should ferve for fuch a purpose, and then be laid a fide: for 'tis utterly improbable, that an undefigning agent should fo appofitely, and exquifitely, frame fcaffolds for a future building, if he did not, before-hand, deftine both the one and the other, to concur to the fame ultimate effect.

Another argument, for our prefent purpose, may be drawn from the confideration of what, in animals, is commonly call'd inftinct: which, in fome cafes, more directly regards the welfare of the creature; in others, the propagation of the fpecies; and, fometimes again, refpects both. The writers of voyages, and natural hiftory, recount ftrange inftances of the inftinct obfervable in certain animals. But we need not lay the ftrefs of our argument upon dubious, or fufpected relations; fince what I have met with, in authors of good authority, or receiv'd from the mouths of credible travellers, may ferve my prefent turn; efpecially, if we may take the word inftinct in a latitude, fo as to comprize thofe untaught methods, and expedients, that are made ufe of by fome animals, to avoid dangers, provide for their future neceffities, or to catch their prey.

Surprizing things are related, not only by poets, but by more credible writers, about the fagacity and government of bees; in point, both of œconomy, and politics. But tho' I fhall not build any thing upon fufpected authorities, yet, having long kept a transparent hive, and thereby gained the opportunity to make frequent obfervations of the actions of thefe little animals; I confefs, I difcover'd fome things that I did not believe before: which induced me to look upon them, as very fit inftances of creatures endow'd with natural inftinct and providence. For, 'twere hard for a mathematician, in contriving fo many cells as bees make in the area of one of their combs, to husband fo little space more skilfully than these animals. And they not only carefully, and seasonably, lay up their ho ney, to serve them all the winter; but, curioufly, close the particular cells with covers of wax, that keep the included liquor from fpilling, and from external injuries. I do not here mention the prognoftication of weather that may be made in the morning, by their keeping within their