III. But to proceed with our compensations.-A very numerous and comprehensive tribe of terrestrial animals are entirely without feet; yet locomotive and in a very considerable degree swift in their motion. How is the want of feet compensated? It is done by the disposition of the muscles and fibres of the trunk. In consequence of the just collocation, and by means of the joint action of longitudinal and annular fibres, that is to say, of strings and rings, the body and train of reptiles are capable of being reciprocally shortened and lengthened, drawn up and stretched out. The result of this action is a progressive, and in some cases, a rapid movement of the whole body, in any direction to which the will of the animal determines it. The meanest creature is a collection of wonders. The play of the rings in an earth-worm, as it crawls; the undulatory motion propagated along the body; the beards or prickles with which the annuli are armed, and which the animal can either shut up close to its body, or let out to lay hold of the roughnesses of the surface upon which it creeps; and the power arising from all these, of changing its place and position, afford, when compared with the provisions for motion in other animals, proofs of new and appropriate mechanism. Suppose that we had never seen an animal move upon the ground without feet, and that the problem was; Muscular action, i. e. reciprocal contraction and relaxation being given, to describe how such an animal might be constructed, capable of voluntarily changing place. Something, perhaps, like the organization of reptiles, might have been hit upon by the ingenuity of an artist: or might have been exhibited in an automaton, by the combination of springs, spiral wires, and ringlets: but to the solution of the problem would not be denied, surely, the praise of invention and of successful thought: least of all could it ever be questioned, whether intelligence had been employed about it, or not. CHAPTER XVII. THE RELATION OF ANIMATED BODIES TO INANIMATE NATURE. We have already considered relation, and under different views; but it was the relation of parts to parts, of the parts of an animal to other parts of the same animal, or of another individual of the same species. But the bodies of animals hold, in their constitution and properties, a close and important relation to natures altogether external to their own: to inanimate substances, and to the specific qualities of these; e. g. they hold a strict relation to the ELEMENTS by which they are surrounded*. been found in the gizzard of a turkey-hen, and more than one thousand in that of a goose. However varying in size and number, some are invariably found there. Spallanzani could never procure a bird so young that it had not some pebbles in its gizzard, and to obtain them with that deficiency, he was obliged to rear turkeys and pigeons even from the shell. The parent bird always supplies its young with appropriately-sized pebbles, even whilst they are in the nest. All the varieties in the structure of the digestive organs of birds, whether living on animal or vegetable substances, appear adapted to their food and mode of life. All the varieties of structure in the attached glands are calculated to produce a secretion appropriate to their food; and any complexity in such structures is only for the purpose of economising the food. Nothing in nature, concludes sir E. Home, can be more beautiful, nothing can show more conspicuously the dispensing hand of an all-wise Creator, than the means with which different birds are provided, to enable them to subsist in the best possible manner in the situations upon the globe for which they were destined. The cassowary of Java may devour the stores so lavishly provided for it, without injury to its health, since its means of retaining and digesting its food are so small; whilst the African ostrich, whose provision is so scanty, has such large means of economizing it, that, circumstanced as it is, it yet can procure a subsistence. The power possessed by man, of inhabiting all parts of the earth, bearing all degrees of heat and cold, and differences in atmospheric pressure, is another instance of the adaptation of animated bodies to inanimate nature, worthy of particular consideration; this natural power is alone possessed by man, who, having by the will of his creator dominion over the earth, and over all animals, was of necessity obliged to be endowed with superior powers to resist the extremes of heat and cold in all parts of the globe. He is accordingly constituted in a manner different from all other animals: he can dwell in all climates, and at all elevations of the earth's surface. "The situations occupied by our species," says Mr. Lawrence, "extend as far as the known surface of the earth. The Greenlanders and the Esquimaux have reached between 70° and 80° of north latitude, and Danish settlements have been formed in Greenland. "Three Russians lived between six and seven years on Spitzbergen, between 77° and 80°. The Negro lives I. Can it be doubted, whether the wings of birds bear a relation to air, and the fins of fish to water? They are instruments of motion, severally suited to the properties of the medium in which the motion is to be performed: which properties are different. Was not this difference contemplated, when the instruments were differently constituted? II. The structure of the animal ear depends for its use, not simply upon being surrounded by a fluid, but upon the specific nature of that fluid. Every fluid would not serve; its particles must repel one another; it must form an elastic medium: for it is by the successive pulses of such a medium, that the undulations excited by the surrounding body are carried to the organ; that a communication is formed between the object and the sense; which must be done, before the internal machinery of the ear, subtile as it is, can act at all. III. The organs of speech and voice and respiration are, no less than the ear, indebted, for the success of their operation, to the peculiar qualities of the fluid in which the animal is immersed. They, therefore, as well as the ear, are constituted upon the supposition of such a fluid, i. e. of a fluid with such particular properties, being always present. Change the properties of the fluid, and the organ cannot act : change the organ, and the properties of the fluid would be lost. The structure, therefore, of our organs, and the properties of our atmosphere, are made for one another. Nor does it alter the relation, whether you allege the organ to be made for the element (which seems the most natural way of considering it), or the element as prepared for the organ. IV. But there is another fluid with which we have to do; with properties of its own; with laws of acting, and of being acted upon, totally different from those of air and water: under the equator, and all America is inhabited even to Terra del Fuego. Thus we find that man can exist and propagate his species in the hottest and coldest countries of the earth." M. Gmelin in 1735 observed the greatest natural cold; the quicksilver froze in the thermometer, the sparrows and other birds were all killed. The same was observed by Pallas. At the English settlements in Hudson's Bay, the cold is just as extreme; brandy freezes even in rooms where there is a fire. Yet in such a temperature as this, the Canadian savages hunt and fish. "Some of the Dutch," continues Mr. Lawrence, "who wintered in Nova Zembla, under Heemskerk, perished; but those who moved enough, and were in good health at first, withstood the dreadful cold, which the Polar bear (Ursus maritimus) apparently born for these climes, seems to have been incapable of supporting, for their journal states, that as soon as the sun sinks below the horizon, the cold is so intense, that the bears are no longer seen, and the white fox (Isatis Canis Lagopus) alone braves the weather." "The power of the human body to withstand severe cold, will seem the more remarkable when we observe what heat it is capable of bearing. The mean temperature of Sierra Leone is 84°. The thermometer is frequently at 100, and even 102, and 103° in the shade. Adanson saw it at 1080 in the sun, at Senegal; and, according to Buffon, it has been seen at 117°. When the sirocco blows in Sicily, the thermometer rises to 112o. Dr. Chalmers saw it at 115o in the shade, in South Carolina; and Humboldt, at 110 to 115o in the deserts, on the banks of the Orinoco." In some experiments of Dr. Fordyce, Sir Joseph Banks, and others, a room was artificially heated to 260°; into this room these gentlemen walked, in company with several others, and remained some time, without inconvenience, although their watch chains were too much heated to be touched without pain; and eggs were cooked in a few minutes by merely remaining on a plate in the room. The oven girls of Germany sustain even still higher temperatures, and this is the true secret of many a feat of legerdemain. Then, again, as regards resisting diminutions of atmospheric pressure, man is singularly endowed. The ordi nary pressure upon the surface of an adult's body, is calculated by Mr. Lawrence to be equal to 32,325 lbs. on a level with the sea, when the barometer is at 30 inches: but at a height of twelve thousand feet, or that of many inhabited plains in South America, the barometer sinks to 20 inches, and the pressure is then only equal to 21,750 lbs.: yet Condamine and Bouguer lived for three weeks more than two thousand feet higher than this. The city of Mexico is 7475, and Quito 9550 feet above the level of the ocean; the hamlet of Antisana, in South America, is supposed to be the most elevated inhabited spot in the world, being 13,500 feet above the sea. Humboldt ascended Chimborazo, to more than 19,000 feet. Gay Lussac, in a balloon, attained to 23,000; and yet some of the peaks of the Himalaya Mountains in India exceed even this great elevation. M. The power of the human body to withstand increased pressure, is equally extraordinary, the barometer often ranges considerably above 30°; and in diving into deep waters, as, for instance, in the diving bell, a pressure is sustained equal to several atmospheres. Thus is man unrestrained by temperature, or atmospheric pressure to any particular section of the globe; a freedom which no other being possesses even vegetation is located to particular spots-the fruits and palms of the equator gradually disappear as we approach the temperate regions of the earth, as those of our climate are equally unknown in the tropics-and as we still progress in a northerly direction, we find one vegetable product leaves us after another. The rose and the violet, the oak and the elm speedily depart; the pine and the birch cling to us much longer; but as we travel northward, these are no longer seen. The heath and the arctic raspberry (the Rubus Arcticus), at last are our only vegetable companions; but even they cannot live beyond a certain latitude they, too, disappear; and yet man is still seen hunting and fishing, as if in defiance of the climate, and triumphing over all the obstacles of nature. Lawrence's Lectures, p. 189; Phil. Trans. 1775, p. 111, 484; Dr. Aiken, Manchester, S. M., vol. 1, p. 95; Barrow's Voyages, chap. 2; Chalmers on the Diseases of South Carolina; Winterbottom on the Native Africans, vol. 1, p. 32; Mémoires de l'Acad. 1744, p. 262. and that is light. To this new, this singular element; to qualities perfectly peculiar, perfectly distinct and remote from the qualities of any other substance with which we are acquainted, an organ is adapted, an instrument is correctly adjusted, not less peculiar amongst the parts of the body, not less singular in its form, and in the substance of which it is composed, not less remote from the materials, the model, and the analogy, of any other part of the animal frame, than the element to which it relates, is specific amidst the substances with which we converse. If this does not prove appropriation, I desire to know what would prove it. Yet the element of light and the organ of vision, however related in their office and use, have no connexion whatever in their original. The action of rays of light upon the surfaces of animals, has no tendency to breed eyes in their heads. The sun might shine for ever upon living bodies, without the smallest approach towards producing the sense of sight. On the other hand also, the animal eye does not generate or emit light. V. Throughout the universe there is a wonderful proportioning of one thing to another. The size of animals, of the human animal especially, when considered with respect to other animals, or to the plants which grow around him, is such, as a regard to his conveniency would have pointed out. A giant or a pigmy could not have milked goats, reaped corn, or mowed grass; we may add, could not have rode a horse, trained a vine, shorn a sheep, with the same bodily ease as we do, if at all. A pigmy would have been lost amongst rushes, or carried off by birds of prey. It may be mentioned likewise, that the model and the materials of the human body being what they are, a much greater bulk would have broken down by its own weight. The persons of men who much exceed the ordinary stature, betray this tendency. VI. Again (and which includes a vast variety of particulars, and those of the greatest importance); how close is the suitableness of the earth and sea to their several inhabitants; and of these inhabitants, to the places of their appointed residence! Take the earth as it is; and consider the correspondency of the powers of its inhabitants with the properties and condition of the soil which they tread. Take the inhabitants as they are; and consider the substances which the earth yields for their use. They can scratch its surface; and its surface supplies all which they want. This is the length of their faculties: and such is the constitution of the globe, and their own, that this is sufficient for all their occasions. When we pass from the earth to the sea, from land to water, we pass through a great change; but an adequate change accompanies us, of animal forms and functions, of animal capacities and wants, so that correspondency remains. The earth in its nature is very different from the sea, and the sea from the earth: but one accords with its inhabitants as exactly as the other. VII. The last relation of this kind which I shall mention, is that of sleep to night; and it appears to me to be a relation which was expressly intended. Two points are manifest, first, that the animal frame requires sleep; secondly, that night brings with it a silence, and a cessation of activity, which allows of sleep being taken without interruption, and without loss. Animal existence is made up of action and slumber; nature has provided a season for each. An animal which stood not in need of rest, would always live in day-light. An animal, which, though made for action, and delighting in action, must have its strength repaired by sleep, meets, by its constitution, the returns of day and night. In the human species, for instance, were the bustle, the labour, the motion of life, upheld by the constant presence of light, sleep could not be enjoyed without being disturbed by noise, and without expense of that time which the eagerness of private interest would not contentedly resign. It is happy therefore for this part of the creation, I mean that it is conformable to the frame and wants of their constitution, that nature, by the very disposition of her elements, has commanded, as it were, and imposed upon them, at moderate intervals, a general intermission of their toils, their occupations, and pursuits. But it is not for man, either solely or principally, that night is made. Inferior, but less perverted natures, taste its solace, and expect its return, with greater exactness and advantage than he does. I have often observed, and never observed but to admire, the satisfac tion, no less than the regularity, with which the greatest part of the irrational world yield to this soft necessity, this grateful vicissitude; how comfortably the birds of the air, for example, address themselves to the repose of the evening; with what alertness they resume the activity of the day. Nor does it disturb our argument to confess, that certain species of animals are in motion during the night, and at rest in the day. With respect even to them, it is still true, that there is a change of condition in the animal, and an external change corresponding with it. There is still the relation, though inverted. The fact is, that the repose of other animals sets these at liberty, and invites them to their food or their sport. If the relation of sleep to night, and, in some instances, its converse, be real, we cannot reflect without amazement upon the extent to which it carries us. Day and night are things close to us; the change applies immediately to our sensations; of all the phenomena of nature, it is the most obvious and the most familiar to our experience; but, in its cause, it belongs to the great motions which are passing in the heavens. Whilst the earth glides round her axle, she ministers to the alternate necessities of the animals dwelling upon her surface, at the same time that she obeys the influence of those attractions which regulate the order of many thousand worlds. The relation therefore of sleep to night, is the relation of the inhabitants of the earth to the rotation of their globe; probably it is more; it is a relation to the system of which that globe is a part: and, still farther, to the congregation of systems, of which theirs is only one. If this account be true, it connects the meanest individual with the universe itself; a chicken roosting upon its perch, with the spheres revolving in the firmament. VIII. But if any one object to our representation, that the succession of day and night, or the rotation of the earth upon which it depends, is not resolvable into central attraction, we will refer him to that which certainly is,-to the change of the seasons. Now the constitution of animals susceptible of torpor, bears a relation to winter, similar to that which sleep bears to night. Against not only the cold, but the want of food, which the approach of winter induces, the Preserver of the world has provided in many animals by migration, in many others by torpor. As one example out of a thousand; the bat, if it did not sleep through the winter, must have starved, as the moths and flying insects upon which it feeds disappear. But the transition from summer to winter carries us into the very midst of physical astronomy, that is to say, into the midst of those laws which govern the solar system at least, and probably all the heavenly bodies.* The relation of animals to inanimate nature, the suiting the first to the circumstances by which they are surrounded, the provisions for their comfort, are striking in some instances, not noticed by Paley. The wool of the sheep would be much too warm a clothing for it in climates nearer the equator than our own, and in those its fleece is exchanged for a fine and much more scanty covering of hair. In the arctic regions, the fur of the bear and the plumage of the birds is chiefly white. Some of the animals of those northern climates even shed their summer furs, and acquire a white one as the winter approaches. Is not this a kind provision of Providence, to render them less conspicuous objects in the snow, which is the almost perpetual covering of the zone they inhabit? The migration of birds deserves a fuller notice than that in the text, for it is one of the most surprising instances of God's providence for preserving animals in circumstances most conducive to their welfare. This remarkable phenomenon early attracted attention, for fiveand-twenty hundred years ago it was remarked, "the stork knoweth her appointed times; the turtle, and the crane, and the swallow, observe the time of their coming." (Jerem. viii. 7.) It is certain that a deficiency of food, a painful alteration of temperature, may render their present abiding place to them uncomfortable; these circumstances might gradually drive them, without any cause for wonder, from one extremity of a continent to another; but what has taught them that a happier state of things exists at a distance of hundreds of miles, across the ocean ?—a distance that they traverse with wearied wing, and which proves fatal to many of the companions of their flight. What informed the swallow at Senegal that a genial and desirable climate was at a particular period, and that period only, to be found in Britain? How came the Soland Goose to conceive, in its high northern home, that there was one diminutive island, that of the Bass, in the Solway Firth, and that only, to be found upon our shores that would be favourable for its residence during the time of incubation? Who, to use our Homer's verse, "Who bids the stork, Columbus-like, explore Reason raise o'er instinct as you can CHAPTER XVIII. INSTINCTS. THE order may not be very obvious, by which I place instincts next to relations. But I consider them as a species of relation. They contribute, along with the animal organization, to a joint effect, in which view they are related to that organization. In many cases, they refer from one animal to another animal; and, when this is the case, become strictly relations in a second point of view. An INSTINCT is a propensity prior to experience, and independent of instruction. We contend, that it is by instinct that the sexes of animals seek each other; that animals cherish their offspring that the young quadruped is directed to the teat of its dam; that birds build their nests, and brood with so much patience upon their eggs; that insects which do not sit upon their eggs, deposit them in those particular situations, in which the young, when hatched, find their appropriate food: that it is instinct which carries the salmon, and some other fish, out of the sea into rivers, for the purpose of shedding their spawn in fresh water. We may select out of this catalogue the incubation of eggs. I entertain no doubt, but that a couple of sparrows hatched in an oven, and kept separate from the rest of their species, would proceed as other sparrows do, in every office which related to the production and preservation of their brood. Assuming this fact, the thing is inexplicable, upon any other hypothesis than that of an instinct, impressed upon the constitution of the animal. For, first, what should induce the female bird to prepare a nest before she lays her eggs? It is in vain to suppose her to be possessed of the faculty of reasoning: for no reasoning will reach the case. The fulness or distention which she might feel in a particular part of her body, from the growth and solidity of the egg within her, could not possibly inform her that she was about to produce something, which, when produced, was to be preserved and taken care of. Prior to experience, there was nothing to lead to this inference, or to this suspicion. The analogy was all against it: for, in every other instance, what issued from the body, was cast out and rejected. But, secondly, let us suppose the egg to be produced into day; how should birds know that their eggs contain their young? There is nothing, either in the aspect or in the internal composition of an egg, which could lead even the most daring imagination to conjecture, that it was hereafter to turn out from under its shell, a living, perfect bird. The form of the egg bears not the rudiments of a resemblance to that of the bird. Inspecting its contents, we find still less reason, if possible, to look for the result which actually takes place. If we should go so far, as, from the appearance of order and distinction in the disposition of the liquid substances which we noticed in the egg, to guess that it might be designed for the abode and nutriment of an animal (which would be a very bold hypothesis), we should expect a tadpole dabbling in the slime, much rather then a dry, winged, feathered creature; a compound of parts and properties impossible to be used in a state of confinement in the and bearing no conceivable relation, either in quality or material, to any thing observed in it. From the white of an egg, would any one look for the feather of a goldfinch? or expect from a simple uniform mucilage, the most complicated of all machines, the most diversified of all collections of substances? Nor would the process of incubation, for some time at least, lead us to suspect the event. Who that saw red streaks, shooting in the fine membrane which divides the white from the yolk, would suppose that these were about to become bones and limbs? Who, that espied two discoloured points first making their appearance in the cicatrix, would have had the courage to predict, that these points were to grow into the heart and head of a bird? It is difficult to strip the mind of its experience. It is difficult to resuscitate surprise, when familiarity has once laid the sentiment asleep. egg, |