THE Structure of the Ani­mal Body, whether we con­sider the Size, Situation and Uses of its larger and more complex Parts, with relation to each other, and their Subservience to the whole, or by diving deeper into the secret and [Page]more mysterious Parts of Nature, we scrutinize the several Parts of which these are composed, exhibits to our View such an amazing Scene of un­bounded Power and Wisdom, as in­finitely exceeds all the Contrivance of the rest of the visible Creation, how great the Bodies, or astonishing soever their Motions and Revolutions may upon a strict Enquiry appear to us.

But tho' this Position is sufficiently evident from the Structure of every Organ in the Animal Body, yet it is in no Part so singularly astonishing, as in the Growth of Animals, from their first original Stamina in the Ani­malcule, [Page 3]till they arrive at their ap­pointed Size.

That every Vessel and Fibre in the Body is contained in Miniature in an Animalcule, few, I believe, will dis­pute, it being absolutely impossible, that mere Matter and Motion, with­out its being conducted by the Vessels proper to an Animal, should produce an Animal at all; and still more ab­surd, if there can be Degrees in Ab­surdity, to suppose such a Cause ca­pable of producing that Variety of Species, in their regular Order, which, we see, is constantly kept up thro' so great a Series of Years and Genera­tions; but that instead of a Calf, a Cow might as naturally produce a Lion, Camel, or any other Creature, [Page 4]as frequently as its own proper Spe­cies.

Besides, could the Parts or Limbs, or even the most minute Organ be produced by the Motion of the Fluids, without their being conducted by the Vessels of the Organ itself already latent in the Stamina, what should hinder, why any Part taken away by Amputation should not again be perfectly formed and restored, since all the adductory Vessels continue in their former State, and are capable of supplying the same Fluids as be­fore? Consequently since the most minute Organ cannot be supplied by any other than the forementioned Method, can any thing be so absurd, as to suppose that all the regular Or­der [Page 5]of Vessels necessary to compose the whole Bodily Machine should be pro­duced by such a Cause, as is utterly incapable of forming the least Part imaginable in a regular Manner? This is no less exemplified in the Seeds or proper Embryos of Plants. Thus the Seed of the Fir-tree, whose Bulk with all its Integuments scarce equals the Head of the smallest Pin, has its Fibres and Vessels so enlarged by the Addition of fresh Particles, as to grow to an enormous Size, without ever de­viating (in whatever Soil it grows) from its own Species into any other kind of Tree. Which can be owing to no other Cause than the original Stamina latent in its Seed; which not only separate, but conduct the Parti­cles proper for its Nourishment, each [Page 6]to its proper Place in a manner pecu­liar to itself, thereby distinguishing it from all other Vegetables of what kind soever. But a Branch once lop­ped off can no more be restored by the Gardener's Art, than an amputa­ted Limb by the Surgeon's: 'Tis true, indeed, new Buds may be thrust forth by the redundant Nourishment, both in the adjacent and more remote Parts, to compensate in some measure this Defect: but whether this Mutila­tion of the Plant be of its Summit, or of a lateral Branch, the Extremity must shrivel and dry up, and will bud and blossom no more.

If therefore mere Matter, altho' supposed to be in Motion, must be thus conducted by the Vessels of an [Page 7]Animal, it must be conducted by the Animal itself, no Application of dif­ferent Forces ab extra to the Vessels (was there any such thing, as it is evi­dent from the Structure of the Uterus, there is not) being capable of regula­ting and directing such an innumera­ble Variety of Motions, or indeed of contributing to its Operations, any farther than supplying it with a pro­per Nidus, and furnishing it with Materials ready prepared for the Pur­pose, as sufficiently appears, not only from the Observations of the accurate Malpighi, Bellini, Redi, Merian and others, but discovers itself to our Sen­ses, in the Generation of innumerable other Species of Animals, some depo­siting their Eggs on Vegetables, or in the Earth, to be brought to Light by [Page 8]the genial Warmth of the Sun, others in Dunghills, and other putrefying Substances, and others in Streams of Water, where it is impossible for any such Force to be applied.

Hence then Nutrition must consist not only in the mere Distension, but in the Apposition of new Particles into such Parts of the Animal Body, as by the Enlargement of the Pores, and Vacuities in the Solids, are fitted to receive them, as I have elsewhere shewn by Experiment ^(a): And, in­deed, was it otherwise, the Animal would have a Power of making its own Fibres and Vessels, and conse­quently of producing itself; nay the [Page 9]Circulation of the Fluids must be per­formed in Vessels, before the Vessels themselves, thro' which it is to be conveyed, have a Being; which are such Absurdities, as I shall not give myself the Trouble of confuting.

That these new Particles by adhe­ring firmly to the original Stamina in­crease the Bulk of the Animal, till such time as it arrives at the Perfec­tion its Structure is capable of, needs no Proof; but that the Strength of the original Animal owes its gradual Improvement to the same Cause, is likewise evident from the common Practice of several of our mechanic Workmen, who by steeping and satu­rating porous Woods, or the like light and brittle Substances in glutinous [Page 10]Decoctions, vastly increase their na­tural Strength, without any Addition to their external Bulk, which would be still farther increased, was that also enlarged by a regular Distension of Parts, as in the Case of Animal Bodies.

Hence then it will follow, that these adventitious Particles, which by their Cohesion with the original Sta­mina, increase the Bulk and Strength of the Body, and thereby enable it to perform the proper Offices, for which it was created, are not really any Part of the Body itself, but extraneous to it, actuated and regulated intirely by it, and consequently contribute no farther to its exercising the Powers, it is designed to exert when perfect, than would be performed by a strong [Page 11]Lever acting with such a Power, as would be impossible for a weak one to sustain, tho' in all other Respects the Case might be exactly parallel.

Nor is this less true with regard to the Sensations, than Strength of the Body. A proper Tension in the nervous Fibres being as requisite in this Case, as Strength in those design­ed for Muscular Motion, as appears from the pernicious Effects of too great Laxity, as well as Rigidity, in several Diseases, the one rendering the Sen­sations so languid and slow thro' their weak Vibrations, as not to affect the Animal with sufficient Force and Vi­vacity; whilst the other, thro' too great Stiffness and Inflexibility, scarce allows them to vibrate at all, as is the [Page 12]Case in old Age; or lastly by being too springy and elastic, and thence exciting too strong and frequent Vi­brations in such as are younger, ei­ther renders their Sensations painful and uneasy, or so quick in their Suc­cessions to each other, as to prove useless, nay often prejudicial to the Animal, as is the Case in Phrensies, Maniacal Persons, and the like.

How far the Strength of the Body depends upon the adventitious Parti­cles derived to it by Nutrition has been explained above, and it is hence no less evident, that they cannot pos­sibly contribute farther to its Sensa­tions, than as they add such a Degree of Firmness, as may prevent any ex­ternal Species from acting upon the [Page 13]nervous Fibrils so forcibly, as to in­jure them; whilst at the same time by their intimate Adhesion with the original sensitive Organs, they cannot act upon the one, without exciting a proper Degree of Motion in the other; and consequently the real Sensitive Part of an Animal can contain no greater Quantity of Matter, than is included in the Nervous Parts of the Animalcule.

This then being the State of an Animal when arrived at its Perfection, how amazing must it be to consider, how small and weak Organs do really actuate the whole Machine! But that this may more fully appear, and also afford us some determinate Idea of their extream Tenuity, I shall endea­vour [Page 14]to reduce such Microscopical Ob­servations as are of best Credit to a cer­tain Standard; that by comparing them with each other, and reducing them to Numbers, our Notions of them may not be altogether so vague and indeterminate as at present they are.

Leeuwenhoek, that curious and di­ligent Inquirer into those Works of Nature, which till his Time had by their Minuteness escaped all Discove­ry, has by his repeated Microscopical Observations on the Semen Masculi­num of Animals, not only shewn, that it abounds with Animalcula proper to each Species, but that, according to his Judgment, a thousand of them would scarce be equal in Thickness [Page 15]to a Grain of Sand ^(a); and conse­quently that a cubical Inch would contain a thousand Millions of Mil­lions of these little Beings. Professor Keil indeed, in his elegant Inquiry into the actual Divisibility of the Particles of Matter, has from a Principle of Dioptrics computed their Magnitude to be somewhat greater than that just now mention­ed; but he has however demon­strably shewn, that the Length of a single Animalculum cannot possi­bly exceed the 3 (divisor)100000 ^th Part of an Inch ^(b). That our present Enquiry may therefore be wholly confined within the Limits of Truth, rather than proceed upon probable Conjec­ture, [Page 16]we will make Choice of this latter Estimate, and for the further Conveniency of Calculation, take it for granted, that when the Foot is decimally divided, even such a Cubi­cal Inch will exceed the Bulk of a single Animalculum, in no greater a Proportion, than that of a thousand Millions of Millions to 27.

Now the specific Weight of the various Parts of an Animal Body re­duced to a Medium amounts to a lit­tle more than the Weight of an equal Bulk of Water; if therefore we suppose one of these Animalcula to be to Wa­ter, as the other Parts of young Ani­mals are, (and greater it cannot be, as appears from what I have elsewhere demonstrated with relation to the in­creased [Page 17]specific Gravity in the Arte­ries of aged Animals ^(a), it follows, that as a Cubical Inch of Water is equivalent to 0.5271 parts of an Ounce Troy, the Weight of a single Animalcule will be equal to the 1 (divisor)140391450739 ^th part of a Grain nearly.

But by the Experiments of the in­genious Dr. Keil it appears, that in a Man of 12 Stone-weight, the Fluids are to the Solids when taken at a Me­dium, at the least in the Proportion of 8 to 3 ^(b), exclusive of those, which by the Help of Fire and a Chymical Process may be extracted without the Destruction of a single Fibre, which amounts to no small Quantity. It has [Page 18]also been farther shewn by Experi­ment, that the Vessels in young Ani­mals bear a much less Proportion to their Cavities, than the like Vessels in old ones of the same Species bear to theirs ^(a); consequently, since the Density of any Body is as the Weight of the Body directly, and its Magni­tude inversely, we shall find, by com­paring the foregoing Proportions of the Fluids and Solids together in each different State of the Animal, as well before its Birth, as after it has arrived at full Maturity, that all the Stamina, from which so noble a Being as Man himself was at first derived, could not contain so much solid Matter as would be equal in Bulk, to that of a Quan­tity of Water, of no greater a Weight [Page 19]than the 1 (divisor)92408129934910602442073752000 ^th part of a Grain.

If the preceding Exility of the Solids in general be so surpizingly small, That of the Sensitive Parts alone, could their Relation to the rest be once adjusted, would doubtless, to speak in the Language of the Mathe­maticians, appear a mere Infinitesimal. For even Leeuwenhoek has declared in express Words, that ‘" Hae Cerebri Fibrillae, tenuibus puto amiciuntur Membranulis, quae ob insignem Exilitatem nunquam sese nuda­bunt conspectui nostro: Quod nisi statuamus, quo pacto Fibrillarum Disparationem vel Distinctionem Oculis assequeremur? ^(a)"’ To [Page 20]which he might have added our Intel­lectual Faculties also, it being scarce possible to conceive Fibres always growing and encreasing in Bulk, should be kept separate, and perform their various Operations, but must soon prove immoveable, without be­ing divided from each other by these slender Partitions.

This is not only evident from the Nature of the Fibres, but demonstra­ble from Fact in the larger Parts even of full-grown Animals; which, when contiguous and deprived of their proper Integuments, never fail to ad­here and unite firmly to each other, as is sufficiently known to the Prac­titioners in Surgery. How much sooner then would this Adhaesion be [Page 21]produced in growing Animals, where the Fibres are not only more supple, and thence more easily united, but if deprived of these Membranes, would daily as they increase in Bulk, press more strongly against each other?

The Writers in Geometry have laid it down as an established Maxim, that ubicunque deficit Modulus, in aeternum latebit Mensura; on which account, tho' we may rest satisfied, that the Subtility of the sensitive Parts in an Animal Body must neces­sarily so far surpass the Extent of hu­man Abilities, as to put their Bulk beyond a Possibility of being ever de­termined to a Mathematical Exact­ness; yet even the Nerves themselves, those delicate Instruments of all our [Page 22]Knowledge, may be brought under such an Examination, as to afford us a much clearer Idea of their exqui­site Minuteness, than what can be obtained from those conjectural De­scriptions, the Anatomists have hi­therto given us concerning it.

For it is evident, that all the Mem­branes of an Animal Body have Mus­cular Fibres, and that even the great­est Number of them are principally made up of such; consequently we could not err very far from the Truth, were we to estimate the Bulk of the Membranous Fibres in the same Pro­portion with the Muscular ones. But we shall examine the Bulk and Pro­portion they bear to each other a lit­tle more distinctly.

Now Leeuwenhoek in his Observa­tions on the Muscular Fibres has shewn, that some of them were equal to the 1/9th, others to the 1/16th part of a Hair ^(a); consequently supposing each Fibre to be the Length of a Decimal Inch, there will be contained in such a Cubic Inch seven Millions two hundred ninety thousand of the for­mer, and twenty-three Millions forty thousand of the latter Kind. But these Muscular Fibres are by later Observations found to be really small Muscles, consisting of Parts similar to the large one, which they consti­tute, and terminating in Tendons after the same Manner as the former; and consequently the Fibres, of which [Page 24]the more lax and cavernous Parts of the Muscle are composed, must be much smaller than the muscular Fi­bres rendered visible by his Glasses. Whether these be the same individual Fibres, which constitute the Tendon, by being more closely compacted in their Parts, I shall not undertake to determine; but this we learn from the forecited Author, that a hundred of these exceed not the Bulk of a Hair ^(a), and consequently nine hun­dred Millions of them will be con­tained in the forementioned Cubic Inch.

But these are far from being the smallest Fibres in the Body. For that the pellucid Membranes consist [Page 25]of Fibres of still smaller Dimensions, decreasing probably to the 1 (divisor)300 ^th part of a Hair, or upwards, is evident from the Structure of those fine Capillary Arteries, which are destined to con­vey a Fluid to them. For the whole Diameter of such an extream Artery does not exceed the 1 (divisor)1620 ^th part of an Inch ^(a) that is, the 1 (divisor)5th of a Hair nearly, and yet the Coat of this Ves­sel is made up of at least three distinct Species of Membranes, each of them furnished with Vessels peculiar to it­self. And farther, if we consider, that the transverse Section of every Vessel is of a circular Form, we must necessarily allow, that the Longitudi­nal Fibres must be much smaller than any of those abovementioned; other­wise [Page 26]instead of a Circle, a Polygon would be produced, as is evident from Geometry.

Now even these are bulky Sub­stances, when compared with the nervous Fibrils destined to Sensation, as appears from those which form the Retina. For these Fibres were manifestly before their Expansion into this Membrane collected within the Bulk of what is styled by Anatomists the Optic Nerve, and are, as the in­genious Professor Monro assures us, so extreamly small, that it is demon­strable, they cannot exceed the Thick­ness of the 1 (divisor)32400th part of a Hair ^(a). If therefore we reject the odd four hundred in the foregoing Fraction, [Page 27]and suppose, that no more than 32000 of these Nervous Fibrils are necessary to make up a Thickness equal to that abovementioned, and also set the Muscular, Tendinous, and Membra­nous Fibres to be at a Medium, of no greater a Thickness than the 1 (divisor)200th Part of a Hair, (which, from what has been just now explained above, is apparently a very large Allowance with respect to the Subtility of the Fibres in general) it will then follow, that the Thickness of one of these Fibrils in the Retina will be to that of such Fibres, as constitute the other Membranes and Organs of the Body, in the proportion of 1 to 160. But we have already shewn, that all the Sta­mina in an Animalcule could not con­tain so much solid Matter, as is equal [Page 28]in Bulk to a Particle of Water weigh­ing the 1 (divisor)92408129934910602442073752000 ^th part of a Grain; consequently, if we suppose, that a Nervous Fibril does accompany every individual Fibre in the Animal System, and compare the Proportions they bear to each other as given above, we shall find, that the whole sensitive Parts in the Animalcule taken together could not amount to a greater Bulk than that of the 1 (divisor)3764060396563654679984851840619241 ^th part of a cubical Inch, or that all the solid Matter of the Nerves, by which the Sensations in the human System are actually communicated to the Mind, cannot possibly weigh the 1 (divisor)14877708919520606993173874072000 ^th part of a Grain.

That the stupendous Expansion and Action of the Fibres and Vessels of an Animalcule up to that of a full grown Man should be owing to an Entity like this, a mere fluxionary Increment with respect to Quantity and Magnitude, will, I doubt not, to many appear impossible, to all incom­prehensible; but are not all other of the Creator's Works equally so? Or is this more than infinite Power act­ing on Matter infinitely divisible is capable of, whose Particles must be still higher subtilised, and spun into Fibres inconceivably more minute in the Bodies of Insects, than is here spe­cified of the human, as they are all furnished with Arteries, Veins, Nerves, Muscles, Bones, and Tendons suitable [Page 30]to their various Structures, and Man­ner of subsisting.

The incomparable Mr. Locke, speaking of the Identity of the same Person, resolves it wholly into its Con­sciousness, even though the whole Substance, material or immaterial, should be intirely changed. Many Physicians have also been of opinion, and some even laid it down as a Maxim, that the whole Substance of the BOdy, during the Length of an ordinary Life, is several times so in­tirely changed, as to consist wholly of new Particles, of the same Nature and Kind as the preceeding. How far these Opinions may agree with what is taught by Divine Revelation, where this very Sameness, in its [Page 31]strictest Acceptation, seems to be ex­pressly declared, is not my province to determine. But this we may plainly deduce from what has been premised, that the whole Substance of the Body, except these original Stamina of the Animalcule, may be many times changed, and yet the real Body continue the same, and be pos­sessed of the same personal Identity, with regard both to Body and Mind, at the End of the longest Life, as it was at the instant of its Birth; nay even in the Animalcule itself.

That these original Stamina should all remain unhurt, and fit to perform their several Functions to the End of Life, is a Position not to be admitted; but that without a competent Num­ber [Page 32]of them so remaining, the Animal will decline both in its vital and in­tellectual Faculties, notwithstanding the Body be replenished with a suf­ficient Number of homogeneous Par­ticles to supply the Place of such Parts as are abraded and worn away, or otherwise hindered from performing their natural Functions, seems equally certain; both from the Decay of our intellectual Faculties, and the gradual Loss of Vigour in the Body, even whilst the Force of the vital Organs seems no ways impaired. Conse­quently something more must be ne­cessary, than the mere Application of homogeneous Matter to supply this Demand. But that can be no other, than that particular Texture, with which they were originally formed, [Page 33]and by which they become capable of transmitting the Effects of exter­nal Agents to the Mind.

It may possibly be objected, that all Matter being equally incapable of Sensation, no Reason can possibly be assigned, why such homogeneous Matter, as supplies the constant Loss, the Body sustains by the Attrition of its Parts on each other, and serves for its Accretion, Strength, and Nutri­tion, may not be equally capable of conveying our Sensations to the Mind, as the original Stamina above men­tioned. But if we may reason from what ensues in the larger Parts, which are compounded of these very Sta­mina, upon their being wounded, or broken with Loss of Substance, 'tis [Page 34]evident, that though by the Addi­tion of homogeneous Matter to the different Species of Vessels, the Body to Appearance, may have received no great Detriment, and be sufficient for the principal Purposes of Life; yet are such Parts of very dull and ob­scure Sensation, if they may be said to enjoy it in any other manner, than by their Union with the original Sta­mina. So that could we suppose these Stamina quite destroyed, and the Body so far changed, as to consist only of such homogeneous Matter, though with Vessels in Form and Bulk simi­lar to the former, yet these united by a Texture different from that of the original Fibres; 'tis evident from what ensues upon a like Change in the Fibres constituting the larger [Page 35]Parts, that such a Person, if he had either Sensitive or Intellectual Facul­ties at all, must have them in a man­ner vastly different from those of the former. And consequently this Same­ness or Identity must remain in a great Measure fixed and unalterable in the Body from its Birth to its Dissolution.

Nor is this Difference in the ori­ginal Stamina confined in its Effects to the fibrous Parts of the Body only, but communicates them to the circu­lating Juices themselves, distinguish­ing thereby the different Kinds of Flesh of each Species of Animals from each other, even where they are su­stained by the same Kind of Food. Otherwise it would happen in Cases of this Kind, that the Taste, Com­plexion, [Page 36]Odour, and Cohesion of the Flesh would of Necessity be nearly the same in all.

The same would be the Conse­quence with regard to the Glands of the same Body, which would sepa­rate nearly the same Kind of Juice, and consequently be useless, or per­haps prejudicial, was it not prevented by the different Structure both of the Strainer itself, and the Preparatory Vessels. For howsoever we may imagine the Juice to be separated from the circulating Mass, we cannot with any Colour of Reason suppose such a various and exquisite Contri­vance, as is discovered not only in the Formation of the Gland itself, but also in that of the Vessels leading to [Page 37]and from it, so widely differing among themselves in their Structure, Texture, and Capacity ^(a), should ever be designed only to perform what any one Species of them was capable of.

Hence then it must follow, that the principal Differences in Animal Bodies are owing to the different Structure of the original Stamina, with regard not only to their exterior Shape and Actions, but that even the Fluids themselves, and that solid Part called the Flesh, derive their chief and principal Difference from this Source; and consequently, that there is a real Identity of Animal [Page 38]Bodies incommunicable to any other, depending on this very Cause.

Nor is this relating to the Fluids a mere Conjecture, but a real Fact, as appears from those morbid Cases, where either the Glands, Preparatory Vessels, or even the fleshy Parts are vitiated and depraved; which never fail to separate unnatural Juices, tho' derived from the most healthful Blood.

Analogous to this we see in the Vegetable World, that it is not the Root, or even Trunk of the Tree, tho' all the Juices are thereby sup­plied, but the Bud or Scion only, which governs the whole, and pro­duces the Species of Blossoms and [Page 39]Fruit peculiar to itself. In like manner the Vessels of the Animalcule, of what Species soever it be, convert the Juices designed for its Nourish­ment, each, into such as are suitable to their different Structures; and thence keep up an infinite Variety in Animals, tho' supplied by the same kind of Food, according to the dif­ferent Vessels by whose means it is elaborated and perfected, being in some highly volatilised and attenuat­ed, which gives the high Taste; in others more viscous and inactive, which produces the opposite, and are therefore less pleasing to a volup­tuous Appetite.

I am not here supposing, that the Qualities of the circulating Juices of [Page 40]Animals depend so intirely upon the Structure of the Solids, that the Di­versity of Food is herein of no Con­sequence, daily Experience sufficiently confuting so absurd an Opinion. But only that in those of a different Spe­cies, the Taste, Odour, and other Qualities of their Juices, are princi­pally owing to this different Struc­ture; as is manifest from hence, viz. that the Qualities of the Juices of differing Animals, though sustained with the same Kind of Food, are more dissonant to each other, than are those of the same Species, though sustained with Food of a very differ­ent Nature; and consequently, this Identity in the various Species of Animals, must principally consist in the Structure of the Solids, or, in [Page 41]other Words, in the original Stamina of each individual Species.

Thus has our Reasoning at length led us to the Discovery and Demon­stration of a Truth, which at first Sight must appear beyond all Proba­bility, and we can now with Cer­tainty affirm, that from so simple a Cause as the different Modification of the same Matter, the wise Author of Nature has produced not only one kind of Flesh of Men, another of Beasts, another of Fishes, and another of Birds; but these also infinitely dif­ferent in the different Species of each.

Hence we may see, why some Ani­mals shall necessarily require such a [Page 42]Degree of Warmth, to preserve their Juices sufficiently exalted and attenu­ated for their comfortable Subsistence, as others cannot sustain without Pre­judice, even scarcely without a Dis­solution; and vice versa, why such a Degree of Cold, as is only agree­able, or perhaps necessary to the Health of these, should prove so far destructive of others, as on the least Condensation of the Fluids from that Cause, to render them torpid, mo­tionless, and seemingly dead, till re­stored by the kindly Influence of the approaching Summer.

Hence also it is obvious, why the Blood and Juices of some particular Species of Animals shall be affected with Diseases of a Pestilential Nature [Page 43]with regard to them, from such Causes, as shall produce very few In­conveniences to many other Kinds.

Hence also we may see the Reason, why each individual Person has some Particularities in his Constitution pe­culiar to himself, not to be found in the Generality of the Species, nor de­pending on his Manner of Life, by which he is as it were distinguished from the rest: Which also probably may sometimes be the Case in Brutes, tho' more rarely than in Men, could we equally arrive at the Knowledge of it, as is manifest from the different Sprightliness, Vigour, and Activity of some compared with others of the same Species.

Lastly, hence we may see, why an intire Change of the Constitution should be attended with almost insu­perable Difficulties: Why great Al­terations require a long and gradual Process, nor are to be attempted by hasty Methods, lest the Patient, in­stead of Relief, meet with certain Ruin and Destruction.