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living animal, the opening can scarcely he discern-
We now come to particularities strictly so called, as being limited to a single species of animal. Of these, I shall take one from a quadruped, and
one from a bird.
and, in the third place, (which appears to me the most remarkable property of all,) this tip is dentated on both sides, like the beard of an arrow or the barb of a hook. The description of the part declares its uses. The bird, having exposed the retreats of the insects by the assistance of its bill, with a motion inconceivably quick, launches out at them this long tongue; transfixes them upon the barbed needle at the end of it; and thus draws its prey within its mouth. If this be not mechanism, what is? Should it be said, that, by continual endeavours to shoot out the tongue to the stretch, the woodpecker species may by degrees have lengthened the organ itself, beyond that of other birds, what account can be given of its form, of its tips? how, in particular, did it get its barb, its dentation? These barbs, in my opinion, wherever they occur, are decisive proofs of me
*Goldsmith's Nat. His. vol. iv. p. 244.
III. I shall add one more example, for the sake of its novelty. It is always an agreeable discovery, when, having remarked in an animal an extraordinary structure, we come at length to find out an unexpected use for it. The following narrative furnishes an instance of this kind. The baby rouessa, or Indian hog, a species of wild boar, found in the East Indies, has two bent teeth, more than half a yard long, growing upwards, and (which is the singularity) from the upper jaw.
These instruments are not wanted for offence: that service being provided for by two tusks issuing from the upper jaw, and resembling those of the common boar: nor does the animal use them for defence. They might seem therefore to be both a superfluity and an encumbrance. But observe the event:-the animal sleeps standing; and, in order to support its head, hooks its upper tusks upon the branches of trees.
I. The stomach of the camel is well known to retain large quantities of water, and to retain it unchanged for a considerable length of time. This property qualifies it for living in the desert. Let us see, therefore, what is the internal organization, upon which a faculty so rare, and so beneficial, depends. A number of distinct sacks or bags (in a dromedary thirty of these have been counted) are observed to lie between the membranes of the second stomach, and to open into the stomach near the top by small square apertures. Through these orifices, after the stomach is full, the annexed bags are filled from it: and the water so deposited is, in the first place, not liable to pass into the intestines; in the second place, is kept separate from the solid aliment; and, in the third place, is out of the reach of the diges-guishing mark, and, consequently, a more certain tive action of the stomach, or of mixture with the proof of design, than preparation, i. e. the progastric juice. It appears probable, or rather cer-viding of things before-hand, which are not to be tain, that the animal, by the conformation of its used until a considerable time afterward: for this muscles, possesses the power of squeezing back implies a contemplation of the future, which bethis water from the adjacent bags into the sto- longs only to intelligence. mach, whenever thirst excites it to put this power
I CAN hardly imagine to myself a more distin
Of these prospective contrivances, the bodies of animals furnish various examples.
II. The tongue of the woodpecker is one of those singularites which nature presents us with, when a singular purpose is to be answered. It is a particular instrument for a particular use: and what, except design, ever produces such? The woodpecker lives chiefly upon insects, lodged in the bodies of decayed or decaying trees. For the purpose of boring into the wood, it is furnished with a bill, straight, hard, angular, and sharp. When, by means of this piercer, it has reached the cells of the insects, then comes the office of its tongue: which tongue is, first, of such a length that the bird can dart it out three or four inches from the bill-in this respect differing greatly from every other species of bird; in the second place, it is tipped with a stiff, sharp, bony thorn;
I. The human teeth afford an instance, not only of prospective contrivance, but of the completion of the contrivance being designedly suspended. They are formed within the gums, and there they stop: the fact being, that their farther advance to maturity would not only be useless to the new-born animal, but extremely in its way; as it is evident that the act of sucking, by which it is for some time to be nourished, will be performed with more ease both to the nurse and to the infant, whilst the inside of the mouth, and edges of the gums, are smooth and soft, than if set with hard pointed bones. By the time they are wanted, the teeth are ready. They have been lodged within the gums for some months past, but detained, as it were, in their sockets, so long as their farther protrusion would interfere with the office to which the mouth is destined. Nature,
namely, that intelligence which was employed in us: and they are all indications of design. The creation, looked beyond the first year of the in- last circumstance is the strongest of any. If I fant's life; yet, whilst she was providing for func- had been to guess beforehand, I should have contions which were after that terin to become neces-jectured, that at the time when there was an exsary, was careful not to incommode those which traordinary demand for nourishment in one part preceded them. What renders it more probable of the system, there would be the least likelihood that this is the effect of design, is, that the teeth of a redundancy to supply another part. The are imperfect, whilst all other parts of the mouth advanced pregnancy of the female has no intelliare perfect. The lips are perfect, the tongue is gible tendency to fill the breast with milk. The perfect; the cheeks, the jaws, the palate, the lacteal system is a constant wonder; and it adds pharynx, the larynx, are all perfect: the teeth to other causes of our admiration, that the num alone are not so. This is the fact with respect to ber of the teats or paps in each species is found the human mouth: the fact also is, that the parts to bear a proportion to the number of the young. above enumerated are called into use from the be- In the sow, the bitch, the rabbit, the cat, the rat, ginning; whereas the teeth would be only so which have numerous litters, the paps are numer many obstacles and annoyances, if they were ous, and are disposed along the whole length of there. When a contrary order is necessary, a the belly; in the cow and mare, they are few. contrary order prevails. In the worm of the beetle, The most simple account of this is to refer it to as hatched from the egg, the teeth are the first a designing Creator. things which arrive at perfection. The insect begins to gnaw as soon as it escapes from the shell, though its other parts be only gradually advancing to their maturity.
But, in the arguinent before us, we are entitled to consider not only animal bodies when framed, but the circumstances under which they are framed: and in this view of the subject, the constitution of many of their parts is most strictly prospective. }
But in the case of the teeth,-of the human teeth at least, the prospective contrivance looks still farther. A succession of crops is provided, and provided from the beginning; a second tier being originally formed beneath the first, which do not come into use till several years afterward. And this double or suppletory provision meets a difficulty in the mechanism of the mouth, which would have appeared almost insurmountable. The expansion of the jaw, (the consequence of the proportionable growth of the animal, and of its skull,) necessarily separates the teeth of the first set, however compactly disposed, to a distance from one another, which would be very inconvenient. In due time, therefore, i. e. when the jaw has attained a great part of its dimensions, a new set of teeth springs up, (loosening and pushing out the old ones before them,) more exactly fitted to the space which they are to occupy, and rising also in such close ranks, as to allow for any extension of line, which the subsequent enlargement of the head may occasion. II. It is not very easy to conceive a more evi-ing and considering the defect of vision to which dently prospective contrivance, than that which, advanced age is subject? Would not the precise in all viviparous animals, is found in the milk of suitableness of the instrument to its purpose, of the female parent. At the moment the young the remedy to the defect, of the convex lens to the animal enters the world, there is its maintenance flattened eye, establish the certainty of the concluready for it. The particulars to be remarked in sion, that the case, afterward to arise, had been conthis economy, are neither few nor slight. We sidered beforehand, speculated upon, provided for? have, first, the nutritious quality of the fluid, un- All which are exclusively the acts of a reasoning like, in this respect, every other excretion of the mind. The eye formed in one state, for use only body; and in which nature hitherto remains un- in another state, and in a different state, affords a imitated, neither cookery nor chymistry having proof no less clear of destination to a future purbeen able to make milk out of grass: we have, pose; and a proof proportionably stronger, as the secondly, the organ for its reception and reten- machinery is more complicated, and the adaptasion we have, thirdly, the excretory duct, an- tion more exact. nexed to the organ and we have, lastly, the determination of the milk to the breast, at the particular juncture when it is about to be wanted. We have all these properties in the subject before
What has been observed of the teeth, is true of the horns of animals; and for the same reason. The horn of a calf or a lamb does not bud, or at III. The eye is of no use, at the time when it least does not sprout to any considerable length, is formed. It is an optical instrument made in a until the animal be capable of browsing upon its dungeon; constructed for the refraction of light pasture; because such a substance upon the fore-to a focus, and perfect for its purpose, before a ray head of the young animal would very much in- of light has had access to it; geometrically adaptcommode the teat of the dam in the office of giv-ed to the properties and action of an element, ing suck. with which it has no communication. It is about indeed to enter into that communication: and this is precisely the thing which evidences intention. It is providing for the future, in the closest sense which can be given to these terms: for it is providing for a future change; not for the then subsisting condition of the animal; not for any gra dual progress or advance in that same condition but for a new state, the consequence of a great and sudden alteration, which the animal is to undergo at its birth. Is it to be believed that the eye was formed, or, which is the same thing, that the series of causes was fixed by which the eye is formed, without a view to this change; without a prospect of that condition, in which its fabric, of no use at present, is about to be of the greatest; without a consideration of the qualities of that element, hitherto entirely excluded, but with which it was hereafter to hold so intimate a relation? A young man makes a pair of spectacles for himself against he grows old; for which spectacles he has no want or use whatever at the time he makes them. Could this be done without know
IV. What has been said of the eye, holds equally true of the lungs. Composed of air-vessels, where there is no air; elaborately constructed for the alternate admission and expulsion of an elastic
As part and parcel of the same plan ought to be mentioned, in speaking of the lungs, the provisionary contrivances of the foramen orale and ductus arteriosus. In the fœtus, pipes are laid for the passage of the blood through the lungs; but until the lungs be inflated by the inspiration of air, that passage is impervious, or in a great degree obstructed. What then is to be done? What would an artist, what would a master, do upon the occasion? He would endeavour, most probably, to provide a temporary passage, which might carry on the communication required, until the other was open. Now this is the thing which is actually done in the heart:Instead of the circuitous route through the lungs, which the blood afterward takes, before it get from one auricle of the heart to the other: a portion of the blood passes immediately from the right auricle to the left, through a hole placed in the partition, which separates these cavities. This hole, anatomists call the foramen ovale. There is likewise another cross cut, answering the same purpose, by what is called the ductus arteriosus, lying between the pulmonary artery and the aorta. But both expedients are so strictly temporary, that, after birth, the one passage is closed, and the tube which forms the other shrivelled up into a ligament. If this be not contrivance, what is?
to one another, for the purpose of producing, by their united action, the effect, is what I call relation; and wherever this is observed in the works of nature or of man, it appears to me to carry along with it decisive evidence of understanding, intention, art. In examining, for instance, the several parts of a watch, the spring, the barrel, the chain, the fusee, the balance, the wheels of various sizes, forms, and positions, what is it which would take an observer's attention, as most plainly evincing a construction, directed by thought, deliberation, and contrivance? It is the suitableness of these parts to one another; first, in the succession and order in which they act; and secondly, with a view to the effect finally produced. Thus referring the spring to the wheels, our observer sees in it, that which originates and upholds their motion; in the chain that which transmits the motion to the fusee; in the fusee, that which communicates it to the wheels; in the conical figure of the fusee, if he refer to the spring, he sees that which corrects the inequality of its force. Referring the wheels to one another, he notices, first, their teeth, which would have been without use or meaning, if there had been only one wheel, or if the wheels had had no connexion between themselves, or common bearing upon some joint effect; secondly, the correspondency of their position, so that the teeth of one wheel catch into the teeth of another; thirdly, the proportion observed in the number of teeth of each wheel, which determines the rate of going. Referring the balance to the rest of the works, he saw, when he came to understand its action, that which rendered their motions equable. Lastly, in looking upon the index and face of the watch, he saw the use and conclusion of the mechanism, viz. marking the succession of minutes and hours; but all depending upon the motions within, all upon the system of intermediate actions between the spring and the pointer. What thus struck his attention in the several parts of the watch, he might probably designate by one general name of "relation;" and observing with respect to all cases whatever, in which the origin and formation of a thing could be ascertained by evidence, that these relations were found in things produced by art and design, and in no other things, he would rightly deem of them as characteristic of such productions.
But, forasmuch as the action of the air upon the blood in the lungs, appears to be necessary to the perfect concoction of that fluid, i. e. to the life and health of the animal, (otherwise the shortest-To apply the reasoning here described to the route might still be the best,) how comes it to pass that the fetus lives, and grows, and thrives, without it? The answer is, that the blood of the foetus is the mother's; that it has undergone that action in her habit; that one pair of lungs serves for both. When the animals are separated, a new necessity arises; and to meet this necessity as soon as it occurs, an organization is prepared. It is ready for its purpose; it only waits for the atmosphere; it begins to play, the moment the air is admitted to it.
fluid, where no such fluid exists; this great organ, with the whole apparatus belonging to it, lies collapsed in the fatal thorax; yet in order, and in readiness for action, the first moment that the occasion requires its service. This is having a machine locked up in store for future use; which incontestably proves, that the case was expected to occur, in which this use might be experienced: but expectation is the proper act of intelligence. Considering the state in which an animal exists before its birth, I should look for nothing less in its body than a system of lungs. It is like finding a pair of bellows in the bottom of the sea; of no sort of use in the situation in which they are found; formed for an action which was impossible to be exerted; holding no relation or fitness to the element which surrounds them, but both to another element in another place.
works of nature.
The animal economy is full, is made up, of these relations:
I. There are, first, what, in one form or other belong to all animais, the parts and powers which successively act upon their food. Compare this action with the process of a manufactory. In men and quadrupeds, the aliment is, first, broken and bruised by mechanical instruments of mastication, viz. sharp spikes or hard knobs, pressing against or rubbing upon one another; thus ground and comminuted, it is carried by a pipe into the stomach, where it waits to undergo a great chymical action, which we call digestion: when digested, it is delivered through an orifice, which opens and shuts as there is occasion, into the first intestine: there, after being mixed with certain other ingredients, poured through a hole in the side of the vessel, it is farther dissolved: in this state, the milk, chyle, or part which is wanted, and which is
WHEN several different parts contribute to one effect; or, which is the same thing, when an effect is produced by the joint action of different in-suited for animal nourishment, is strained off by struments; the fitness of such parts or instruments the mouths of very small tubes, opening into the
cavity of the intestines: thus freed from its grosser | Nothing about these animals is fitted for the parts, the percolated fluid is carried by a long, pursuit of living prey. Accordingly it has been winding, but traceable course, into the main stream found by experiments, tried not many years ago, of the old circulation; which conveys it in its with perforated balls, that the gastric juice of progress, to every part of the body. Now I say ruminating animals, such as the sheep and the again, compare this with the process of a manu- ox, speedily dissolves vegetables, but makes no factory; with the making of cider, for example; impression upon animal bodies. This accordancy with the bruising of the apples in the mill, the is still more particular. The gastric juice, even squeezing of them when so bruised in the press, of granivorous birds, will not act upon the grain, the fermentation in the vat, the bestowing of the whilst whole and entire. In performing the exliquor thus fermented in the hogsheads, the draw-periment of digestion with the gastric juice in ing off into bottles, the pouring out for use into vessels, the grain must be crushed and bruised, the glass. Let any one show me any difference before it be submitted to the menstruum, that is between these two cases, as to the point of contri- to say, must undergo by art without the body, the vance. That which is at present under our con- preparatory action which the gizzard exerts upon sideration, the "relation" of the parts successively it within the body; or no digestion will take place. employed, is not more clear in the last case than So strict, in this case, is the relation between the in the first. The aptness of the jaws and teeth offices assigned to the digestive organ, between to prepare the food for the stomach, is, at least, as the mechanical operation and the chymical promanifest as that of the cider-mill to crush the cess. apples for the press. The concoction of the food II. The relation of the kidneys to the bladder, in the stomach is as necessary for its future use, and of the ureters to both, i e. of the secreting as the fermentation of the stum in the vat is to the organ to the vessel receiving the secreted liquor, perfection of the liquor. The disposal of the ali- and the pipe laid from one to the other for the ment afterward; the action and change which it purpose of conveying it from one to the other, is undergoes; the route which it is made to take, in as manifest as it is amongst the different vessels order that, and until that, it arrive at its destina-employed in a distillery, or in the communications tion, is more complex indeed and intricate, but in between them. The animal structure, in this the midst of complication and intricacy, as evident case, being simple, and the parts easily separated, and certain, as is the apparatus of cocks, pipes, it forms an instance of correlation which may be tunnels, for transferring the cider from one vessel presented by dissection to every eye, or which, into another; of barrels and bottles for preserving it deed, without dissection, is capable of being appretill fit for use; or of cups and glasses for bringing hended by every understanding. This correlation it, when wanted, to the lip of the consumer. The of instruments to one another fixes intention character of the machinery is in both cases this; somewhere. that one part answers to another part, and every part to the final result.
This parallel between the alimentary operation and some of the processes of art, might be carried farther into detail. Spallanzani has remarked* a circumstantial resemblance between the stomachs of gallinaceous fowls and the structure of cornmills. Whilst the two sides of the gizzard perform the office of the mill-stones, the craw or crop supplies the place of the hopper.
Especially when every other solution is negatived by the conformation. If the bladder had been merely an expansion of the ureter, produced by retention of the fluid, there ought to have been a bladder for each ureter. One receptacle, fed by two pipes, issuing from different sides of the body, yet from both conveying the same fluid, is not to be accounted for by any such supposition as this.
III. Relation of parts to one another accompanies us throughout the whole animal economy. When our fowls are abundantly supplied with Can any relation be more simple, yet more conmeat, they soon fill their craw: but it does not vincing than this, that the eyes are so placed as immediately pass thence into the gizzard; it al- to look in the direction in which the legs move ways enters in very small quantities, in proportion and the hands work? It might have happened to the progress of trituration; in like manner as, very differently if it had been left to chance. in a mill, a receiver is fixed above the two large There were, at least, three quarters of the comstones which serve for grinding the corn; which pass out of four to have erred in. Any considerreceiver, although the corn be put into it by bush-able alteration in the position of the eye, or the els, allows the grain to dribble only in small quan- figure of the joints, would have disturbed the line. tities, into the central hole in the upper mill- and destroyed the alliance between the sense and the limbs.
But we have not done with the alimentary history. There subsists a general relation between the external organs of an animal by which it procures its food, and the internal powers by which it digests it. Birds of prey, by their talons and beaks, are qualified to seize and devour many species, both of other birds, and of quadrupeds. The constitution of the stomach agrees exactly with the form of the members. The gastric juice of a bird of prey, of an owl, a falcon, or a kite, acts upon the animal fibre alone; it will not act upon seeds or grasses at all. On the other hand, the conformation of the mouth of the sheep or the ox is suited for browsing upon herbage.
Dis. I. sect. liv.
IV. But relation perhaps is never so striking as when it subsists, not between different parts of the same thing, but between different things. The relation between a lock and a key is more obvious, than it is between different parts of the lock. A bow was designed for an arrow, and an arrow for a bow: and the design is more evident for their being separate implements.
Nor do the works of the Deity want this clearest species of relation. The seres are manifestly made for each other. They form the grand relation of animated nature; universal, organic, mechanical: subsisting like the clearest relations of art, in different individuals; unequivocal, inexpli cable without design.
So much so, that, were every other proof of
contrivance in nature dubious or obscure, this alone would be sufficient. The example is complete. Nothing is wanting to the argument. I see no way whatever of getting over it.
V. The teats of animals which give suck, bear a relation to the mouth of the suckling progeny; particularly to the lips and tongue. Here also, as before, is a correspondency of parts; which parts
subsist in different individuals.
THESE are general relations, or the relations of parts which are found, either in all animals, or in large classes and descriptions of animals. Particular relations, or the relations which subsist between the particular configuration of one or more parts of certain species of animals, and the particular configuration of one or more other parts of the same animal, (which is the sort of relation that is, perhaps, most striking,) are such as the following:
II. This natural relation, arising from a subserviency to a common purpose, is very observable also in the parts of a mole. The strong short legs of that animal, the palmated feet armed with sharp nails, the pig-like nose, the teeth, the velvet coat, the small external ear, the sagacious smell, the sunk, protected eye, all conduce to the utilities or to the safety of its under-ground life. It is a special purpose, especially consulted throughout. The form of the feet fixes the character of the animal. They are so many shovels; they determine its action to that of rooting in the ground; and every
thing about its body agrees with its destination. The cylindrical figure of the mole, as well as ine compactness of its form, arising from the terseness of its limbs, proportionably lessens its labour; because, according to its bulk, it thereby requires the least possible quantity of earth to be removed for its progress. It has nearly the same structure of the face and jaws as a swine, and the same office for them. The nose is sharp, slender, tendinous, strong; with a pair of nerves going down to the end of it. The plush covering, which, by the smoothness, closeness, and polish, of the short piles that compose it, rejects the adhesion of almost every species of earth, defends the animal from cold and wet, and from the impediment which it would experience by the mould sticking to its body. From soils of all kinds the little pioneer comes forth bright and clean. Inhabiting dirt, it is, of all animals, the neatest.
But what I have always most admired in the mole is its eyes. This animal occasionally visiting the surface, and wanting, for its safety and direcI. In the swan; the web-foot, the spoon-bill, tion, to informed when it does so, or when it the long neck, the thick down, the graminivorous approaches it, a perception of light was necessary. stomach, bear all a relation to one another, inas- I'do not know that the clearness of sight depends much as they all concur in one design, that of at all upon the size of the organ. What is gained supplying the occasions of an aquatic fowl, float- by the largeness or prominence of the globe of the ing upon the surface of shallow pools of water, eye, is width in the field of vision. Such a capaand seeking its food at the bottom. Begin with city would be of no use to an animal which was any one of these particularities of structure, and ob- to seek its food in the dark. The mole did not serve how the rest follow it. The web-foot quali-want to look about it; nor would a large adfies the bird for swimming; the spoon-bill enables vanced eye have been easily defended from the it to graze. But how is an animal, floating upon annoyance to which the life of the animal must the surface of pools of water, to graze at the bot- constantly expose it. How indeed was the mole, tom, except by the mediation of a long neck? A working its way under ground, to guard its eyes long neck accordingly is given to it. Again, a at all? In order to meet this difficulty, the eyes warm-blooded animal, which was to pass its life are made scarcely larger than the head of a corkupon water, required a defence against the cold-ing pin; and these minute globules are sunk so ness of that element. Such a defence is furnished deeply in the skull, and lie so sheltered within to the swan, in the muff in which its body is the velvet of its covering, as that any contraction wrapped. But all this outward apparatus would of what may be called the eye-brows, not only have been in vain, if the intestinal system had not closes up the apertures which lead to the eyes, but been suited to the digestion of vegetable sub- presents a cushion, as it were, to any sharp or stances. I say, suited to the digestion of vegeta-protruding substance which might push against ble substances for it is well known, that there them. This aperture, even in its ordinary state, are two intestinal systems found in birds: one is like a pin-hole in a piece of velvet, scarcely perwith a membranous stomach and a gastric juice, vious to loose particles of earth. capable of dissolving animal substances alone: the other with a crop and gizzard, calculated for the moistening, bruising, and afterward digesting, of vegetable aliment.
Observe then, in this structure, that which we call relation. There is no natural connexion between a small sunk eye and a shovel palmated foot. Palmated feet might have been joined with Or set off with any other distinctive part in the goggle eyes; or small eyes might have been joined body of the swan; for instance, with a long neck. with feet of any other form. What was it thereThe long neck, without the web-foot, would have fore which brought them together in the mole? been an incumbrance to the bird; yet there is no That which brought together the barrel, the necessary connexion between a long neck and a chain, and the fusee, in a watch; design and web-foot. In fact, they do not usually go toge-design, in both cases, inferred, from the relation ther. How happens it, therefore, that they meet, which the parts bear to one another in the proseonly when a particular design demands the aid cution of a common purpose. As hath already of both. been observed, there are different ways of stating the relation, according as we set out from a different part. In the instance before us, we may either consider the shape of the feet, as qualifying the animal for that mode of life and inhabitation to which the structure of its eyes confines it; or we may consider the structure of the eye, as the only one which would have suited with the action to which the feet are adapted. The relation is manifest, whichever of the parts related we place first in the order of our consideration. In a word; the feet of the mole are made for digging; the neck, nose, eyes, ears, and skin, are peculiarly