scales of fishes, the painted wings of butterflies and beetles, the rich colours and spotted lustre of many tribes of insects. agreeable and disagreeable, no foundation in the sense itself? What is true of the other senses, is most probably true of the eye, (the analogy is ir There are parts also of animals ornamental, resistible,) viz. that there belongs to it an original and the properties by which they are so, not sub-constitution, fitted to receive pleasure from some servient, that we know of, to any other purpose. impressions, and pain from others. The irides of most animals are very beautiful, without conducing at all, by their beauty, to the perfection of vision; and nature could in no part have employed her pencil to so much advantage, because no part présents itself so conspicuously to the observer, or communicates so great an effect to the whole aspect. In plants, especially in the flowers of plants, the principle of beauty holds a still more considerable place in their composition; is still more confessed than in animals. Why, for one instance out of a thousand, does the corolla of the tulip, when advanced to its size and maturity, change its colour? The purposes, so far as we can see, of vegetable nutrition, might have been carried on as well by its continuing green. Or, if this could not be consistently with the progress of vegetable life, why break into such a variety of colours? This is no proper effect of age, or of declension in the ascent of the sap; for that, like the autumnal teints, would have produced one colour on one leaf, with marks of fading and withering. It seems a lame account to call it, as it has been called, a disease of the plant. Is it not more probable, that this property, which is independent, as it should seem, of the wants and utilities of the plant, was calculated for beauty, intended for display. do not however know, that the argument which alleges beauty as a final cause, rests upon this concession. We possess a sense of beauty, however we come by it. It in fact exists. Things are not indifferent to this sense; all objects do not suit it; many which we see, are agreeable to it; many others disagreeable. It is certainly not the effect of habit upon the particular object, because the most agreeable objects are often the most rare; many, which are very common, continue to be of fensive. If they be made supportable by habit, it is all which habit can do; they never become agreeable. If this sense, therefore, be acquired, it is a result; the produce of numerous and compli cated actions of external objects upon the senses, and of the mind upon its sensations. With this result, there must be a certain congruity to enable any particular object to please: and that congruity, we contend, is consulted in the aspect which is given to animal and vegetable bodies. IV. The skin and covering of animals is that upon which their appearance chiefly depends; and it is that part which, perhaps, in all animals is most decorated, and most free from impurities. But were beauty, or agreeableness of aspect, entirely out of the question, there is another purpose answered by this integument, and by the collocation of the parts of the body beneath it, which is of still greater importance; and that purpose is concealment. Were it possible to view through the skin the mechanism of our bodies, the sight would frighten us out of our wits. “Durst we make a single movement," asks a lively French writer, "or stir a step from the place we were in, if we saw our blood circulating, the tendons pulling, the lungs blowing, the humours filtrating, and all the incomprehensible assemblage of fibres, tubes, pumps, valves, currents, pivots, which sustain an existence at once so frail, and so presumptuous?" A ground, I know, of objection, has been taken against the whole topic of argument, namely, that there is no such thing as beauty at all; in other words, that whatever is useful and familiar, comes of course to be thought beautiful; and that things appear to be so, only by their alliance with these qualities. Our idea of beauty is capable of being in so great a degree modified by habit, by fashion, by the experience of advantage or pleasure, and by associations arising out of that experience, that a question has been made, whether it be not altogether generated by these causes, or would have any proper existence without them. It seems, however, a carrying of the conclusion too far, to V. Of animal bodies, considered as masses, deny the existence of the principle, viz. a native there is another property, more curious than it is capacity of perceiving beauty, on account of an generally thought to be; which is the faculty of influence, or of varieties proceeding from that in- standing: and it is more remarkable in two-legfluence, to which it is subject, seeing that princi-ged animals than in quadrupeds, and, most of all, ples the most acknowledged are liable to be affected in the same manner. I should rather argue thus: The question respects objects of sight. Now every other sense hath its distinction of agreeable and disagreeable. Some tastes offend the palate, others gratify it. In brutes and insects, this distinction is stronger and more regular than in man. Every horse, ox, sheep, swine, when at liberty to choose, and when in a natural state, that is, when not vitiated by habits forced upon it, eats and rejects the same plants. Many insects which feed upon particular plants, will rather die than change their appropriated leaf. All this looks like a determination in the sense itself to particuIn like manner, smells affect the nose with sensations pleasurable or disgusting. Some sounds, or compositions of sound, delight the ear; others torture it. Habit can do much in all these cases, (and it is well for us that it can; for it is this power which reconciles us to many necessities:) but has the distinction, in the mean time, of lar tastes. as being the tallest, and resting upon the smallest base, in man. There is more, I think, in the matter than we are aware of. The statue of a man, placed loosely upon its pedestal, would not be secure of standing half an hour. You are obliged to fix its feet to the block by bolts and solder; or the first shake, the first gust of wind, is sure to throw it down. Yet this statue shall express all the mechanical proportions of a living model. It is not, therefore, the mere figure, or merely placing the centre of gravity within the base, that is sufficient. Either the law of gravitation is suspended in favour of living substances, or something more is done for them, in order to enable them to uphold their posture. There is no reason whatever to doubt, but that their parts descend by gravitation in the same manner as those of dead matter. The gift, therefore, appears to me to consist in a faculty of perpetually shifting the centre of gravity, by a set of obscure, indeed, but of quick balancing actions, so as to keep the line of di their own accord. Now let it be remembered, that this is the position of the limbs, in which the bird rests upon its perch. And in this position it sleeps in safety; for the claws do their office in keeping hold of the support, not by any exertion of voluntary power, which sleep might suspend, but by the traction of the tendons in consequence of the attitude which the legs and thighs take by the bird sitting down, and to which the mere weight of the body gives the force that is necessary. VI. Regarding the human body as a mass; regarding the general conformations which obtain in it; regarding also particular parts in respect to those conformations; we shall be led to observe what I call "interrupted analogies." The following are examples of what I mean by these terms; and I do not know how such critical deviations can, by any possible hypothesis, be accounted for without design. 1. All the bones of the body are covered with a periosteum, except the teeth; where it ceases, and an enamel of ivory which saws and files will hardly touch, comes into its place. No one can doubt of the use and propriety of this difference; of the "analogy” being thus “interrupted;" of the rule, which belongs to the conformation of the bones, stopping where it does stop: for had so exquisitely sensible a membrane as the periosteum invested the teeth, as it invests every other bone of the body, their action, necessary exposure, and irritation, would have subjected the animal to continual pain. General as it is, it was not the sort of integument which suited the teeth; what they stood in need of, was a strong, hard, insensible, defensive coat: and exactly such a covering is given to them, in the ivory enamel which adheres to their surface. rection, which is a line drawn from that centre to the ground, within its prescribed limits. Of these actions it may be observed, first, that they in part constitute what we call strength. The dead body drops down. The mere adjustment, therefore, of weight and pressure, which may be the same the moment after death as the moment before, does not support the column. In cases also of extreme weakness, the patient cannot stand upright. Secondly, that these actions are only in a small degree voluntary. A man is seldom conscious of his voluntary powers in keeping himself upon his legs. A child learning to walk is the greatest posture-maker in the world: but art, if it may be so called, sinks into habit; and he is soon able to poise himself in a great variety of attitudes, without being sensible either of caution or effort. But still there must be an aptitude of parts, upon which habit can thus attach; a previous capacity of motions which the animal is thus taught to exercise and the facility with which this exercise is acquired, forms one object of our admiration. What parts are principally employed, or in what manner each contributes its office, is, as hath already been confessed, difficult to explain. Perhaps the obscure motion of the bones of the feet may have their share in this effect. They are put in action by every slip or vacillation of the body, and seem to assist in restoring its balance. Cer tain it is, that this circumstance in the structure of the foot, viz. its being composed of many small bones, applied to and articulating with one another, by diversely shaped surfaces, instead of being made of one piece, like the last of a shoe, is very remarkable. I suppose also that it would be difficult to stand firmly upon stilts or wooden legs, though their base exactly imitated the figure and dimensions of the sole of the foot. The alteration 2. The scarf-skin, which clothes all the rest of of the joints, the knee joint bending backward, the body, gives way, at the extremities of the toes the hip joint forward; the flexibility, in every di- and fingers, to nails. A man has only to look at rection, of the spine, especially in the loins and his hand to observe with what nicety and precineck, appear to be of great moment in preserving sion that covering, which extends over every other the equilibrium of the body. With respect to this part, is here superseded by a different substance, last circumstance, it is observable, that the verte- and a different texture. Now, if either the rule bræ are so confined by ligaments as to allow no had been necessary, or the deviation from it accimore slipping upon their bases, than what is just dental, this effect would not be seen. When I sufficient to break the shock which any violent speak of the rule being necessary, I mean the motion may occasion to the body. A certain de- formation of the skin upon the surface being progree also of tension of the sinews appears to be duced by a set of causes constituted without deessential to an erect posture; for it by the loss sign and acting, as all ignorant causes must act, of this, that the dead or paralytic body drops down. by a general operation. Were this the case, no The whole is a wonderful result of combined account could be given of the operation being suspowers, and of very complicated operations. In-pended at the fingers' ends, or on the back part of deed, that standing is not so simple a business as we imagine it to be, is evident from the strange gesticulations of a drunken man, who has lost the government of the centre of gravity. We have said that this property is the most worthy of observation in the human body: but a bird, resting upon its perch, or hopping upon a spray, affords no mean specimen of the same faculty. A chicken runs off as soon as it is hatched from the egg; yet a chicken, considered geometrically, and with relation to its centre of gravity, its line of direction, and its equilibrium, is a very irregular solid. Is this gift, therefore, or instruction? May it not be said to be with great attention, that nature hath balanced the body upon its pivots ? I observe also in the same bird a piece of useful mechanism of this kind. In the trussing of a fowl, upon bending the legs and thighs up towards the body, the cook finds that the claws close of 3 H the fingers, and not on the fore part. On the other hand: if the deviation were accidental, an error, an anomalism; were it any thing else than settled by intention; we should meet with nails upon other parts of the body. They would be scattered over the surface, like warts or pimples. 3. All the great cavities of the body are enclosed by membranes, except the skull. Why should not the brain be content with the same covering as that which serves for the other principal organs of the body? The heart, the lungs, the liver, the stomach, the bowels, have all soft integuments, and nothing else. The muscular coats are all soft and membranous. I can see a reason for this distinction in the final cause, but in no other. The importance of the brain to life, (which experience proves to be immediate,) and the extreme tenderness of its substance, make a solid case more necessary for it, than for any other part: and such a 36* case the hardness of the skull supplies. When the smallest portion of this natural casket is lost, how carefully, yet how imperfectly, is it replaced by a plate of metal! If an anatomist should say, that this bony protection is not confined to the "brain, but is extended along the course of the spine. I answer that he adds strength to the argument. If he remark, that the chest also is fortified by bones; I reply, that I should have alleged this instance myself, if the ribs had not appeared subservient to the purpose of motion, as well as of defence. What distinguishes the skull from every other cavity is, that the bony covering completely surrounds its contents, and is calculated, not for motion, but solely for defence. Those hollows, likewise, and inequalities, which we observe in the inside of the skull, and which exactly fit the folds of the brain, answer the important design of keeping the substance of the brain steady, and of guarding it against concussions. CHAPTER XII. Comparative Anatomy. When we pass on to smaller animals, or to the inhabitants of a different element, the resemblance becomes more distant and more obscure; but still the plan accompanies us. And, what we can never enough commend, and which it is our business at present to exemplify, the plan is attended, through all its varieties and deflections, by subserviences to special occasions and utilities. 1. The covering of different animals (though whether I am correct in classing this under their anatomy, I do not know,) is the first thing which presents itself to our observation; and is, in truth, both for its variety and its suitableness to their several natures, as much to be admired as any part of their structure. We have bristles, hair, wool, furs, feathers, quills, prickles, scales; yet in this diversity both of material and form, we cannot change one animal's coat for another, without evidently changing it for the worse; taking care however to remark, that these coverings are, in many cases, armour as well as clothing; intended for protection as well as warmth. He What art, however, does for men, nature has, in many instances, done for those animals which are incapable of art. Their clothing, of its own accord, changes with their necessities. This is particularly the case with that large tribe of quadrupeds which are covered with furs. Every dealer in hare skins, and rabbit-skins, knows how much the fur is thickened by the approach of winter. It seems to be a part of the same constitution and the same design, that wool, in hot countries, degenerates, as it is called, but in truth (most happily for the animal's ease) passes into hair; whilst, on the contrary, that hair, in the dogs of the polar regions, is turned into wool, or something very like it. To which may be referred, what naturalists have remarked, that bears, wolves, foxes, hares, which do not take the water, have the fur much thicker on the back than the belly: whereas in the beaver it is the thickest upon the belly; as are the feathers in water fowl. We know the final cause of all this; and we know no other. The human animal is the only one which is naked, and the only one which can clothe itself. This is one of the properties which renders him an animal of all climates, and of all seasons. WHENEVER we find a general plan pursued, can adapt the warmth or lightness of his covering yet with such variations in it as are, in each case, to the temperature of his habitation. Had he required by the particular exigency of the subject been born with a fleece upon his back, although to which it is applied, we possess, in such plan he might have been comforted by its warmth in and such adaptation, the strongest evidence that high latitudes, it would have oppressed him by its can be afforded of intelligence and design; an evi-weight and heat, as the species spread towards dence which most completely excludes every the equator. other hypothesis. If the general plan proceeded from any fixed necessity in the nature of things, how could it accommodate itself to the various wants and uses which it had to serve under different circumstances, and on different occasions? Arkwright's mill was invented for the spinning of cotton. We see it employed for the spinning of wool, flax, and hemp, with such modifications of the original principle, such variety in the same plan, as the texture of those different materials rendered necessary. Of the machine's being put together with design, if it were possible to doubt, whilst we saw it only under one mode, and in one form; when we came to observe it in its different applications, with such changes of structure, such additions and supplements, as the special and particular use in each case demanded, we could not refuse any longer our assent to the proposition, "that intelligence, properly and strictly so called, (including under that name, foresight, consideration, reference to utility,) had been employed, as well in the primitive plan, as in the several changes and accommodations which it is made to undergo." Very much of this reasoning is applicable to what has been called Comparative Anatomy. In their general economy, in the outlines of the plan, in the construction as well as offices of their principal parts, there exists between all large terrestrial animals a close resemblance. In all, life is sustained, and the body nourished, by nearly the same apparatus. The heart, the lungs, the stomach, the liver, the kidneys, are much alike in all. The same fluid (for no distinction of blood has been observed) circulates through their vessels, and nearly in the same order. The same cause therefore, whatever that cause was, has been concerned in the origin, has governed the production, of these different animal forms. The covering of birds cannot escape the most vulgar observation. Its lightness, its smoothness, its warmth;-the disposition of the feathers all inclined backward, the down about their stem, the overlapping of their tips, their different configuration in different parts, not to mention the variety of their colours, constitute a vestment for the body, so beautiful, and so appropriate to the life which the animal is to lead, as that, I think, we should have had no conception of any thing equally perfect, if we had never seen it, or can now imagine any thing more so. Let us suppose (what is possible only in supposition) a person who had never seen a bird, to be presented with a plucked pheasant, and bid to set his wits to work, how to contrive for it a covering which shall unite the qualities of warmth, levity, and least resistance to the air, and the highest degree of each; giving it also as much of beauty and ornament as he could afford. He is the person to behold the work of the Deity, in this part of his creation, with the sentiments which are due to it. as if nothing had happened to it. Draw your finger down the feather, which is against the grain, and you break, probably, the junction of some of the contiguous threads; draw your finger up the feather, and you restore all things to their former state. This is no common contrivance: and now for the mechanism by which it The commendation, which the general aspect is effected. The threads or laminæ above-menof the feathered world seldom fails of exciting, tioned are interlaced with one another: and the will be increased by farther examination. It is interlacing is performed by means of a vast number one of those cases in which the philosopher has of fibres, or teeth, which the lamina shoot forth on more to admire, than the common observer. Every each side, and which hook and grapple together. feather is a mechanical wonder. If we look at A friend of mine counted fifty of these fibres in the quill we find properties not easily brought one twentieth of an inch. These fibres are together-strength and lightness. I know few crooked; but curved after a different manner: for things more remarkable than the strength and those which proceed from the thread on the side lightness of the very pen with which I am writing. towards the extremity of the feather, are longer, If we cast our eye to the upper part of the stem, more flexible, and bent downward; whereas those we see a material made for the purpose, used in which proceed from the side towards the beginno other class of animals, and in no other part of ning, or quill-end of the feather, are shorter, firmer, birds; tough, light, pliant, elastic. The pith, also, and turn upwards. The process then which takes which feeds the feathers, is, amongst animal sub-place, is as follows: when two laminæ are pressstances, sui generis; neither bone, flesh, mem-ed together, so that these long fibres are forced brane, nor tendon.* But the artificial part of the feather is the beard, or, as it is sometimes, I believe, called, the vane. By the beards are meant, what are fastened on each side of the stem, and what constitute the breadth of the feather; what we usually strip off from one side or both, when we make a pen. The separate pieces or lamine, of which the beard is composed, are called threads, sometimes filaments, or rays. Now the first thing which an attentive observer will remark is, how much stronger the beard of the feather shows itself to be, when pressed in a direction perpendicular to its plane, than when rubbed, either up or down, in the line of the stem; and he will soon discover the structure which occasions this difference, viz. that the lamina whereof these beards are composed, are flat, and placed with their flat side towards each other; by which means, whilst they easily bend for the approaching of each other, as any one may perceive by drawing his finger ever so lightly upwards, they are much harder to bend out of their plane, which is the direction in which they have to encounter the impulse and pressure of the air, and in which their strength is wanted, and put to the trial. This is one particularity in the structure of a feather; a second is still more extraordinary. Whoever examines a feather, cannot help taking notice, that the threads or lamina of which we have been speaking, in their natural state, unite; that their union is something more than the mere apposition of loose surfaces; that they are not parted asunder without some degree of force; that nevertheless there is no glutinous cohesion between them; that therefore, by some mechanical means or other, they catch or clasp among themselves, thereby giving to the beard or vane its closeness and compactness of texture. Nor is this all when two lamine, which have been separated by accident or force, are brought together again, they immediately reclasp: the connexion, whatever it was, is perfectly recovered, and the beard of the feather becomes as smooth and firm The quill part of a feather is composed of circular and longitudinal fibres. In making a pen you must scrape off the coat of circular fibres, or the quill will split in a ragged, jagged manner, making what boys call cat's teeth. far enough over the short ones, their crooked parts fall into the cavity made by the crooked parts of the others; just as the latch that is fastened to a door, enters into the cavity of the catch fixed to the door-post, and there hooking itself, fastens the door; for it is properly in this manner, that one thread of a feather is fastened to the other. This admirable structure of the feather, which it is easy to see with the microscope, succeeds perfectly for the use to which nature has designed it; which use was not only that the laminæ might be united, but that when one thread or lamina has been separated from another by some external violence, it might be reclasped with sufficient facility and expedition.* In the ostrich, this apparatus of crochets and fibres, of hooks and teeth, is wanting: and we see the consequence of the want. The filaments hang loose and separate from one another, forming only a kind of down; which constitution of the feathers, however it may fit them for the flowing honours of a lady's head-dress, may be reckoned an imperfection in the bird, inasmuch as wings, composed of these feathers, although they may greatly assist it in running, do not serve for flight. But under the present division of our subject, our business with feathers is, as they are the covering of the bird. And herein a singular circumstance occurs. In the small order of birds which winter with us, from a snipe downwards, let the external colour of the feathers he what it will, their Creator has universally given them a bed of black down next their bodies. Blak, we know, is the warmest colour: and the purpose here is, to keep in the heat, arising from the heart and circulation of the blood. It is farther likewise remarkable, that this is not found in larger birds; for which there is also a reason:-small birds are much more exposed to the cold than large ones; forasmuch as they present, in proportion to their bulk, a much larger surface to the air. If a turkey were divided into a number of wrens (supposing the shape of the turkey and the wren to be simi *The above account is taken from Memoirs for a Natural History of Animals, by the Royal Academy of Paris, published in 1701, p. 219. lar,) the surface of all the wrens would exceed the surface of the turkey, in the proportion of the length, breadth (or, of any homologous line,) of a turkey to that of a wren; which would be, perhaps, a proportion of ten to one. It was necessary therefore that small birds should be more warmly clad than large ones: and this seems to be the expedient by which that exigency is provided for. moist earth, which is the bed in which the food of that species is lodged. This is exactly the instrument which the animal wanted. It did not want strength in its bill, which was inconsistent with the slender form of the animal's neck, as well as unnecessary for the kind of aliment upon which it subsists; but it wanted length to reach its object. But the species of bill which belongs to the birds that live by suction, deserves to be described in its relation to that office. They are what naturalists call serrated or dentated bills; the inside of them towards the edge, being thickly set with parallel or concentric rows of short, strong, sharp pointed prickles. These, though they should be called teeth, are not for the purpose of mastication, like the teeth of quadrupeds; nor yet, as in fish, for the seizing and retaining of their prey; but for a quite different use. They form a filter. The duck by means of them discusses the mud; exa II. In comparing different animals, I know no part of their structure which exhibits greater variety, or in that variety, a nicer accommodation to their respective conveniency, than that which is seen in the different formations of their mouths. Whether the purpose be the reception of aliment merely, or the catching of prey, the picking up of seeds, the cropping of herbage, the extraction of juices, the suction of liquids, the breaking and grinding of food, the taste of that food, together with the respiration of air, and, in conjunction with it, the utterance of sound; these various offices are as-mining with great accuracy the puddle, the brake, signed to this one part, and in different species, provided for, as they are wanted, by its different constitution. In the human species, forasmuch as there are hands to convey the food to the mouth, the mouth is flat, and by reason of its flatness, fitted only for reception; whereas the projecting jaws, the wide rictus, the pointed teeth of the dog and his affinities, enable them to apply their mouths to snatch and seize the objects of their pursuit. The full lips, the rough tongue, the corrugated cartilaginous palate, the broad cutting teeth of the ox, the deer, the horse, and the sheep, qualify this tribe for browsing upon their pasture; either gathering large mouthfuls at once, where the grass is long, which is the case with the ox in particular; or biting close, where it is short, which the horse and the sheep are able to do, in a degree that one could hardly expect. The retired under-jaw of a swine works in the ground, after the protruding snout, like a prong or plough-share, has made its way to the roots upon which it feeds. A conformation so happy, was not the gift of chance. In birds, this organ assumes a new character; new both in substance and in form: but in both, wonderfully adapted to the wants and uses of a distinct mode of existence. We have no longer the fleshy lips, the teeth of enamelled bone; but we have, in the place of these two parts, and to perform the office of both, a hard substance (of the same nature with that which composes the nails, claws, and hoofs, of quadrupeds,) cut out into proper shapes, and mechanically suited to the actions which are wanted. The sharp edge and tempered point of the sparrow's bill picks almost every kind of seed from its concealment in the plant; and not only so, but hulls the grain, breaks and shatters the coats of the seed, in order to get at the kernel. The hooked beak of the hawk tribe separates the flesh from the bones of the animals which it feeds upon, almost with the cleanness and precision of a dissector's knife. The butcher-bird transfixes its prey upon the spike of a thorn, whilst it picks its bones. In some birds of this class, we have the cross-bill, i. e. both the upper and lower bill hooked, and their tips crossing. The spoon-bill enables the goose to graze, to collect its food from the bottom of pools, or to seek it amidst the soft or liquid substances with which it is mixed. The long tapering bill of the snipe and woodcock, penetrates still deeper into every mixture which is likely to contain her food. The operation is thus carried on:-The liquid or semi-liquid substances, in which the animal has plunged her bill, she draws, by the action of her lungs, through the narrow interstices which lie between these teeth; catching, as the stream passes across her beak, whatever it may happen to bring along with it, that proves agreeable to her choice, and easily dismissing all the rest. Now, suppose the purpose to have been out of a mass of confused and heterogeneous substances, to separate for the use of the animal, or rather to enable the animal to separate for its own, those few particles which suited its taste and digestion; what more artificial, or more commodious, instrument of selection, could have been given to it, than this natural filter? It has been observed also (what must enable the bird to choose and distinguish with greater acuteness, as well, probably, as what greatly increases its luxury,) that the bills of this species are furnished with large nerves,—that they are covered with a skin,-and that the nerves run down to the very extremity. In the curlew, woodcock, and snipe, there are three pairs of nerves, equal almost to the optic nerve in thickness, which pass first along the roof of the mouth, and then along the upper chap down to the point of the bill, long as the bill is. But to return to the train of our observations.The similitude between the bills of birds and the mouths of quadrupeds, is exactly such, as, for the sake of the argument, might be wished for. It is near enough to show the continuation of the same plan: it is remote enough to exclude the supposi tion of the difference being produced by action or use. A more prominent contour, or a wider gap, might be resolved into the effect of continued efforts, on the part of the species, to thrust out the mouth, or open it to the stretch. But by what course of action, or exercise, or endeavour, shall we get rid of the lips, the gums, the teeth; and acquire, in the place of them, pincers of horn? By what habit shall we so completely change, not only the shape of the part, but the substance of which it is composed? The truth is, if we had seen no other than the mouths of quadrupeds, we should have thought no other could have been formed: little could we have supposed, that all the purposes of a mouth, furnished with lips, and armed with teeth, could be answered by an instrument which had none of these; could be supplied, |