IN the Bodies of Animals ‘tis oftentimes allowable for a Naturalist, from the manifest and apposite Vses of the Parts, to Collect some of the Particular Ends to which Nature, destinated them. And in some cases we may, from the known Natures as well as from the Structure, of the Parts, ground probable Conjectures (both Affirmative and Negative) about the Particular Offices of the parts,
To obviate mistakes, you may please to take notice, both That in this Proposition, I speak only of those Ends and Uses of the Parts of an Animal, that relate to the Welfare and Propagation of the Animal it self, and which therefore I formerly call’d Animals Ends: and yet that I do not thereby deny any Declaration that is made in the H. Scriptures, That God design’d that the Entire Animals, as well as their Parts, should be in several ways serviceable to Man. And haveing premis’d this to explain my meaning in the Proposition, I shall now consider distinctly the two parts whereof it consists.
And 1. There is no Part of Nature known to us, wherein the Consideration of Final Causes may so justly take place, as in the Structure of the Bodies of Animals. And I confess, that when I assist at a well-administer’d Anatomy, I do so wonder at the admirable Contrivance of a Humane Body, that I cannot but somewhat wonder, that there should be found among Philosophers, men that can ascribe it to blind Chance The Stoick, that in Cicero asked an Epicurean, why Chance did not make Palaces and other Buildings, seems not to me to have made an impertinent Question. For the commodiousest Houses Mens Bodies dwell in, are far less curious Structures, than the Mansions their Souls reside in: which you will not think a groundless Paradox, if you consider, that, whereas even in a Palace, the Materials being Wood, Stone, Brick, Mortar, Glass, and four or five Metals, are but Few in comparison of the Parts of differing Textures, as Bones, Nerves, Ligaments, Membranes, Muscles, Veins, Arteries, Grissels, Glandules, Jellys, Humours, and their Disposition is exceeding Slight, in comparison of the curious and elaborate Contrivance of the numerous Parts, both solid and fluid, of the Human Body: whereof tho’ the Stable Parts alone have been reckon’d to amount to some Hundreds; yet in Every One of these parts, the Bulk, Figure, Consistence, Texture, Situation, Connexion and Aptness for motion, is the most Commodious that can be devised; and All of them are wonderfully Symmetrical, both to, one another and the whole Body; To divers of whose Motions, as Leaping, Running Speaking, Swimming, Sneezing &c. a great Number of them conspire. And this Number of Parts is so artificially contrived and pack’d together, that tho’ in a Body where no room is lost, many Parts do at the same time exercise very differing Motions, yet each of them moves freely, and does not at all Hinder another, but rather they Promote each others Motions.
I will not suffer Indignation to transport me so far as to wish, That those that deny the Usefulness of all the Parts of their Bodys may fall Sick, or receive some Wound, to be thereby at once Convinc’d and Punish’d: But I will venture to say, that Diseases or Hurts alone may shew, how excellently all the Parts of our Bodys are Contriv’d in order to our Welfare. For, if so much as a Finger be made Bigger by Tumors, or Displac’d by being put out of Joynt, or kept in a Wrong Posture by Contractions, or have its Continuity violated by Cutting, or its Tone chang’d by Strains or Contusions, or its Sense or Motion taken away by the Palsey, or its Membranes fretted by Sharp Humors, or its Motions Disorder’d by the Cramp or Convulsions, In any of these Cases we quickly find, how Commodiously the Parts Affected were Framed or Dispos’d, when any Disease or Hurt gives them a Preternatural Constitution; that is, changes that Figure, Connexion, Tone, &c, which, according to the Institution of Nature, whilst the Body is in full Health, does belong to it.
The Eye (to single out again that Part for an Instance) is so little fitted for almost any other Use in the Body, and is so exquisitely adapted for the Use of Seeing, and That Use is so necessary for the welfare of the Animal, that it may well be doubted, whether any Considering Man can really think, that It was not destinated to that Use. The six or seven Muscles that move the whole Bulbe of the Eye, upwards, downwards, to the right Hand, to the left, and to various oblique Positions; and the several Coats and Humors that make up the Sensory, Have not only their Bigness, Shape, Consistence, Situation and Connexion admirably Adapted to that End; but the Transparency of the Cornea and the Humors, the Opacity of the Vvea, and the Semiopacity of the Retina, and the several Motions of the Parts of the Eye, being requisite to Receive, Transmit, Refract, and Dispose the Visive Beams that come from the Object, after the manner requisite to make the Liveliest Picture of it in the Bottom of the Eye, Do no less concur to Compleat this matchless Organ of Vision: which is so rarely Contrived in order to That Use, and comparatively so little to any Other, that there is no more Rashness to say, that an Eye, than that a Telescope, was made for an Instrument to See with; that is, to Discover the Colours, Magnitudes, Shapes and Motions of Distant Objects. And in that admirable Perforation of the Vvea, which we call the Pupil, Nature has much outdone Art. For whereas We are fain to apply to the Object Glasses of Telescopes, Opacous Bodys with several Circular Apertures, that Some may let in less Light, and Others more, according as the Objects are more or less Bright or Inlighten’d; That part of the Vvea that hangs in the Aqueous Humor, is an Aperture, as the Artists call it, that Narrows and Opens it self in a trice, according to the exigency of the Objects we look on; Which if they be so constituted or plac’d, that they Reflect but a Dim Light, the Curtain is presently drawn Open, and the Pupil circularly Widen’d, to let in the more Beams of Light; and the Contrary happens, as often as the Object, being too Luminous or Illustrated, would offend the Organ, or disturb the Sight, if the Contraction of the Pupil did not shut out some of Its Beams. But for the Uses of the several parts of the Eye, I shall referr you to the Industrious Jesuit Scheiner’s Oculus, and Des Cartes his excellent Dioptricks; where you will easily perceive, that, in Framing the Eye, Nature did not only act with Design, but with so much Skill in Opticks, that a more than ordinary insight into that Science, is necessary to Understand the Wisdom of the Contrivances; and perhaps no degree of Skill in it, would enable a man to Alter them for the better. ‘Twere tedious to mention the Other Parts of the Body, that manifestly appear to have been preordain’d to certain Uses. The Books of Anatomists are full of Passages applicable to this purpose; of which I shall say in general, that, tho’ what they deliver suffices to shew, That all the Parts of the Body are the Effects of an Intelligent Cause: yet, unless their Descriptions and Reflexions be improv’d by Men vers’d in Mathematicks and Mechanicks, and, I shall venture to add, in Chymistry too; we shall but imperfectly understand, how Intelligent that Cause is, or how much Wisdom it has display’d, in the Structure of a Human Body and each of its parts.
I know ‘tis objected by the Epicureans,1 that the Parts of Animals were first made, and their Uses afterwards found out by mens Sagacity. But this is a Sophistical Objection. For, first, as to many of the Inner parts, as, the Heart, Liver, Spleen, Kidneys, &c, They perform their Functious without so much as Our Knowledge of their Structure, or perhaps their Situation; so far are they from being applyed to such Uses by Our Sagacity. And as for the Limbs and other Parts, which we can Move at pleasure; ‘tis true, that they cannot be actually Imployed to the respective Uses, till they be actually Form’d; but That hinders not but that in their Formation they were therefore so Formed, that they may be in due time fit for such Uses. And therefore we see, that the Chick is furnished with compleat Eyes, and with Wings and Feathers, before he be Hatch’d; tho’ whilst he is yet inclos’d in the Egg, he can not make use of them to See or Flye. And why was it, do the Epicureans think, that Nature provided a whole Set of Temporary Parts for Pregnant Females, and Animals in the Womb, which, when they are come into a freer state, partly fall away of themselves, and partly turn to a Ligament, fitted no longer for the former, but for a more seasonable Use? And ‘tis to be noted, that the Production of these Umbilical Vessels, and the Placenta or Analogous Body in the Womb to which they are fasten’d, is of no Necessity nor Use to the Female before Conception; and thereby those Temporary Parts appear to have bin Design’d by Nature, not so much for the Personal Preservation of the Female as for the Propagation of the Species: Which Destination not coming to be accomplished, till a Woman, for instance, has attain’d to a competent Age, appears to have been preordain’d by the Author of Mankind for the Continuation of It.
And tho’ it be true, that the Sagacity of men may have found out some Uses of some Parts of their Bodys, that cannot be made appear to have been Primarily Intended by the Author of Nature; yet That is no good Argument, that those Uses were not Intended, which either are made Within us, or do, as it were obtrude themselves Upon Us. And as for other Uses, the Prescience and Goodness of God are such, that it ought not to appear incredible, That He that gave man both the Limbs of his Body, and the Rational Endowments of his Mind, and that has made many Parts, as the Eyes and the Ears, Double, that One may supply the want of the Other; Did both Foresee what Uses men might, according to their Sagacitys and Emergencies, make of these Parts, and so Contrive the Parts that they should be applicable to such Uses. Suppose, a Wise man should send his Son to Travel, and among other things give him a Pocket-Dyal with a Magnetic Needle; and this Traveller having lost his way in some wild Plain, or being at Sea in a Vessel, whose Compass was broken or spoyl’d by a Storm, or some other Mischance: If, I say, in this case tho’ the Traveller Ordinarily Imployed his Dyal only to find the Hour of the Day, He shall now Imploy it to Guide his Course, or Steer the Vessel, by the help of the Needles pointing Northward; tho’ this would be an Effect of His own Sagacity, yet his Father being a Wise and Experienced Man, may reasona bly enough be suppos’d to have Foreseen, that his Son might have need of knowing the Northern and Southern Points of the Horizon. And accordingly may have given him a Dial furnish’d with a Magnetic Needle, rather than an Ordinary Gnomonic Dial. And so a Man that has taught another to Paint Landskips, when he gives him a Pencil and a Pallet furnish’d with Colours, to draw a Particular Prospect, is not to be suppos’d to have Design’d, that he should not Imploy them to any other purpose, if Urgent Circumstances made it requisite for him to do so.
Having insisted longer than I intended upon the former part of my Proposition, I now proceed to the latter; namely, That in some cases we may from the known Ends of Nature, as well as from the Structure of the Parts, ground Probable Conjectures, both Affirmative and Negative, about the particular Offices of the Parts. Which I could not seasonably doe before, because the Arguments, that were founded on the Uses of the Parts of Animals, suppose, not only that those Parts were destinated to Particular Uses knowable by Us, but that the several Parts of the Body were Contrived as Wisely and Commodiously as Men are able to Devise, in order to the Ends of Nature; which is always to be understood to have. United in her Designs, the Uses of the Parts, and the Welfare of the Whole.
And indeed if we consider, how admirable a Fitness there is in the Parts of the Human Body, for instance, to those Particular Ends we can discover them to have been Predesign’d for; it seems allowable to Conjecture, that such a Part was not Primarily Design’d to such an Use, because it is, on the account of its Structure or otherwise, less Fitted for it, than the constant Wisdom of Nature seems to require; especially if there be any Other Parts, by which That Office may be more commodiously perform’d. And on the other side, it may be a Probable Ground, tho’ not altogether so Probable as the former, to Conclude that such a Part was Destinated to such an Use, if the Use it self appear to be necessary, and the Part better fitted for it than any Other is.
Thus, tho’ Anatomical and Optical Writers, as well as the Schools, did for many ages unanimously conclude, the Crystalline Humor to be the Principal Seat of Vision; yet the industrious Scheiner, in his useful Tract intituled Oculus, does Justly enough reject that receiv’d Opinion, by shewing, that it Suits not with the Skill and Providence of Nature, to make that Part the Seat (or chief Organ) of Vision, for which it wants divers requisite Qualifications, especially most of these being to be found in the Retina. And I remember that when I asked our famous Harvey, in the only Discourse I had with him, (which was but a while be fore he dyed) What were the things that induc’d him to think of a Circulation of the Blood? He answer’d me, that when he took notice that the Valves in the Veins of so many several Parts of the Body, were so Plac’d that they gave free passage to the Blood Towards the Heart, but oppos’d the passage of the Venal Blood the Contrary way: He was invited to imagine, that so Provident a Cause as Nature had not so Plac’d so many Valves without Design: and no Design seem’d more probable, than That, since the Blood could not well, because of the interposing Valves, be Sent by the Veins to the Limbs; it should be Sent through the Arteries, and Return through the Veins, whose Valves did not oppose its course that way.
Thus, whereas former Anatomists and Physicians generally believed the Nutrition of the Parts by the Venal Blood, the more Recent Writers are wont to teach, that the Parts are nourish’d by the Blood in its passage through the Arteries. Not that they Think, the Blood that runs through the Veins altogether unfit to Irrigate the Parts with that Vital Liquor; but that they Judge the Veins to be less fit than the Arteries, into which the Blood comes immediately from the left Ventricle of the Heart, Agitated and Spirituous, and with a brisk Impulse, which forces out the Particles of the Blood, at those Pores of the Arteries that they find Congruous to their Shape and Size, and which answer to the several Parts that are to be nourished by Corpuscles so Qualified. ‘Twere not Difficult, if ‘twere Necessary, to accumulate Instances to the same purposes with those already mentioned; there being nothing more frequent in the Books of Anatomists, and those that treat of the Physiological and Pathological parts of Physick, than to draw Arguments, as well Affirmative as Negative, about the Use of the Parts of the Body, from their Fitness or Unfitness, or their greater or lesser Fitness, to attain such Ends as are suppos’d to have been Design’d by Nature. And indeed these Argumentations occur so frequently, that I think there is less need of my Increasing them, than of my Proceeding to give you a Caution about them, which I shall do in the following Proposition.
← Proposition 1 · Contents · Proposition 3 →
Footnotes
-
Illud in his rebus vitium vehementer inesto Effugere, illorumque errorem premeditemur, Lumina qui faciunt Oculorum clara creata Prospicere ut possimus, Lucret. de Nat. l. iv. Nihil ideo quoniam natum est in Corpore ut uti possemus, sed quod natum est, id procreat Vsum. Ibid. ↩