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doable, and, consequently, the nostrils quadruple, a pair for each snout. This powerful inlet of pleasure to fishes often proves fatal to them from its very perfection; for several kinds are so strongly allured by the odour of majorum, asafetida, and other aromas, that by smearing the hand over with these substances, and immersing it in the water, they will often flock towards the fineers, and in their intoxication of delight may easily be laid hold of. And hence the angler frequently overspreads his baits with the same substances, and thus arms himself with a double decoy. There can be no doubt of the existence of the same sense in insects; for they possess a very obvious power of distinguishing the odorous properties of bodies, even at a considerable distance beyond the range of their vision; but the organ in which this sense resides has not been satisfactorily pointed out: Reimar supposes it to exist in their stigmata, and Knoch in their ante rior pair of feelers. The general organ of Hearing is the ear, but not always so; for in most of those who hear by the Eustachian tube only, it is the mouth, and in the whale tribes the nostrils or blow-hole. It is so, however, in all the more perfect animals, which usually for this purpose possess two distinct entrances into the organ; a larger and external, surrounded by a lobe; and a smaller and internal, opening into the mouth. It is this last which is denominated the Eustachian tube. The shape of the lobe is seldom found even in mammals similar to that in man, excepting among the monkey and the porcupine tribes. In many kinds there is neither external lobe nor external passage. Thus, in the frog, and most amphibious animals, the only entrance is the internal, or that from the mouth; and in the cetaceous tribes the only effective entrance is probably of the same kind; for, though these may be said to possess an external aperture, it is almost imperceptibly minute. It is a curious fact, that, among the serpents, the blind-worm or common harmless snake is the only species that appears to possess an aperture of either sort; the rest have a rudiment of the organ within, but we are not acquainted with its being pervious to sound. Fishes are well known to possess a hearing organ, and the skate and shark have the rudiment of an external ear; but, like other fishes, they seem chiefly to receive sound by the internal tubule alone. That insects in general hear is unquestionable, but it is highly questionable by what organ they obtain the sense of hearing. The antennas, and perhaps merely because we do not know their exact use, have been supposed by many naturalists to furnish the means; it appears fatal, however, to this opinion to observe, that spiders hear, though they have no true antennas, and that other insects which possess them naturally seem to hear as correctly after they are cut off. The sense of Vision exhibits perhaps more variety in the different classes of animals than any of the external senses. In man, and the greater number of quadrupeds, it is guarded by an upper and lower eyelid; both of which in man, but neither of which in most quadrupeds, are terminated by the additional defence and ornament of cilia or eyelashes. In the elephant, opossum, seal, cat-kind, and various other mammals, all birds, and all fishes, we find a third eyelid, or nictitating membrane, as it is usually called, arising from the internal angle of the eye, and capable of covering the pupil with a thin transparent veil, either wholly or in part, and hence of defending the eyes from danger in their search after food. In the dog this membrane is narrow; in oxen and horses it will extend over half the eyeball; in birds it will easily cover the whole; and it is by means of this veil, according to Cuvier, that the eagle is capable of looking directly against the noonday sun. In fishes it is almost always upon the stretch, as in their uncertain element they are exposed to more dangers than any other animal. Serpents have neither this nor any other eyelid; nor any kind of external defence whatever but the common integument of the skin. The largest eyes in proportion to the size of the animal belong to the bird tribes, and nearly the smallest to the whale; the smallest altogether to the shrew and mole; in the latter of which the eye is not larger than a pin's head. The iris, with but few exceptions, partakes of the colour of the hair, and is hence perpetually varying in different species of the same genus. The pupil exhibits a very considerable, though not an equal, variety in its shape. In man it is circular; in the lion, tiger, and indeed all the cat-kind, it is oblong; transverse in the horse and in ruminating animals; and heart-shaped in the dolphin. In man, and the monkey tribes, the eyes are placed directly under the forehead; in other mammals, birds, and reptiles, more or less laterally; in some fishes, as the genus pleuronectes, including the turbot and flounder tribes, both eyes are placed on the same side of the head; in the snail they are situated on its horns, if the black points on the extremities of the horns of this worm be real eyes, of which, however, there is some doubt; in spiders the eyes are distributed over different parts of the body, and in different arrangements, usually eight in number, and never less than six. The eyes of the sepia have lately been detected by M. Cuvier: their construction is very beautiful, and nearly as complicated as that of vertebrated animals.* Polypes and several other zoophytes appear sensible of the presence of light, and yet have no eyes; as the nostrils are not in every animal necessary to the sense of smell, the tongue to that of taste, or the ears to that of sound. A distinct organ is not always requisite for a distinct sense. In man himself we have already seen this in regard to the sense of touch, which exists both locally and generally: the distinct organ of touch is the tips of the tongue and of the fmgers, but the feeling is also diffused, though in a subordinate and less precise degree, over every part of the body. It is possible, therefore, in animals that appear endowed with particular senses, without particular organs for their residence, that these senses are diffused, like that of touch, over the surface generally; though there can be no doubt that, for want of such appropriate organs, they must be less acute and precise than in animals that possess them.f But who of us can say what is possible? who of us can say what has actually been done? After all the assiduity with which this attractive science has been studied, from the time of Aristotle to that of Lucretius, or of Pliny, and from these periods to the present day,—after all the wonderful and important discoveries which have been developed in it, natural history is even yet but little more than in its infancy, and zoonomy is scarcely entitled to the name of a science in any sense. New varieties and species, and even kinds of beings, are still arising to our view among animals, among vegetables, among minerals :—new structures are detecting in those already known, and new laws in the application of their respective powers. But the globe has been upturned from its foundation; and with the wreck of a great part of its substance has intermingled the wreck of a great part of its inhabitants. It is a most extraordinary fact, that of the five or six distinct layers or strata of which the solid crust of the earth is found to consist, so far as it has ever been dug into, the lowermost, or granitic, as we observed on a former occasion,*, contains not a particle of animal or vegetable materials of any kind; the second, or transition formation, as Werner has denominated it, is filled, indeed, with fossil relics of animals, but of animals not one of which is to be traced in a living state in the present day; and it is not till we ascend to the third, or floetz stratification, that we meet with a single organic remain of known animal structures. M. Cuvier has been engaged for the last fifteen years in forming a classification, and establishing a museum of non-descript animal fossils, for the purpose of deciding, as far as may be, the general nature and proportion of those tribes that are now lost to the world: and in the department of quadrupeds alone, his collection of unknown species amounted in the year 1810 to not less than seventy-eight, some of which he has been obliged to arrange
* Lc Regno Animate distribue d'apres son Organization, 4 tomes, 8vo. Paris, 1817.
t Study of Med. vol. iv. p. 14,2d edil 1829. } Series i. Lecture vi p. 69
under new genera, as we shall have occasion to notice still farther in a subsequent study. In the new and untried soil of America, the bones of unknown kinds and species lie buried in profusion; and my late friend Professor Barton, of Philadelphia, one of our first transatlantic physiologists, informed me by letter a short time before his death, that they are perpetually turning up skeletons of this description, whose living representatives are nowhere to be met with. In few words, every region has been enriched with wonders of animal life that have long been extinct for ever. Where is now that enormous mammoth, whose bulk outrivalled the elephant's where that gigantic tapir, of a structure nearly as mountainous,* whose huge skeleton has been found in a fossil state in France and Germany; while its only living type, a pigmy of what has departed, exists in the wilds of America? where is now the breathing form of the fossil sloth of America, the magaloninx of Cuvier, whose size meted that of the ox ?* where the mighty moniter,* outstripping the lengthened bulk of the crocodile? itself, too, a lord of the ocean, and yet, whose only relics have been traced in the quarries of Maestricht; to which, as to another leviathan, we may well apply the forcible description of the Book of Job, "at whose appearing the mighty were afraid, and who made the deep to boil as a caldron: who esteemed iron as straw, and brass as rotten wood; who had not his like upon the earth, and was a king amid the children of pride."f
Over this recondite and bewildering subject skeptics have laughed and critics have puzzled themselves; it is natural history alone that can find us a clew to the labyrinth, that enables us to repose faith in the records of antiquity, and that establishes the important position, that the extravagance of a description is no argument against the truth of a description, and that it is somewhat too much to deny that a thing has existed formerly, for the mere reason that it does not exist now.
SERIES II. LECTURE I. ON ZOOLOGICAL SYSTEMS, AND THE DISTINCTIVE CHARACTERS OP ANIMALS.
While every department of nature displays an unbounded scope to the contemplative mind,—a something on which it may perpetually dwell with new and growing delight, and new and growing improvement; we behold in the great division of the animal kingdom a combination of allurements that draw us, and fix us, and fascinate us with a sort of paramount and magical captivity, unknown to either of the other branches of natural history; and which seem to render them chiefly or alone desirable and interesting, m proportion as they relate to animal life. There is, indeed, in the mineral domain, an awe, and a grandeur, and a majesty, irresistibly impressive and sublime; and that cannot fail to lift up the heart to an acknowledgment of the mighty Power which piled the massy cliffs upon each other, and rent the mountains asunder, and flung their scattered fragments over the valleys. There is in the realm of vegetables an immeasurable profusion of bounty and of beauty, of every thing that can delight the external eye, and gratify the desire; simple, splendid, variegated, exquisite. But the moment we open the gates of the animal kingdom a new world pours upon us, and a new train of affections take possession of the bosom; it is here, for the first time, that we behold the nice lineaments of feeling, motion, spontaneity; we associate and sympathize with every thing around us, we insensibly acknowledge an approximation (often indeed very remote, but an approximation nevertheless) to our own nature, and run over with avidity the vast volume that lies before us, of tastes, and customs, and manners, and propensities, and passions, and consummate instincts. But where shall we commence the perusal of this volume' the different pages of which, though each intrinsically interesting, lie scattered, like the sibyl leaves of antiquity, over every part of the globe, and require to be collected and arranged in order, to give us a just idea of their relative excellence, and to enable us to contemplate them as a whole. The difficulty has been felt in all ages; and hence multiplied classifications, or schemes for assorting, and grouping into similar divisions, such individuals as indicate a similar structure, or similar habits, or similar powers,have been devised in different periods of the world, and especially in modern times, in which the study of zoology has been pursued with a searching spirit, unknown to the sages of antiquity.—And well has it deserved to be so pursued. "This subject," observes M. Biberg, "is of so much importance, and of such an extent, that if the ablest men were to attempt to treat it thoroughly, an age would pass away before they could explain completely the admirable economy, habits, and structure even of the most imperceptible insect. There is not a single species that does not, of itself, deserve an historian."* Before we gird ourselves then to a critical indagation into any particular part of the immense theatre which this study presents to us, it may be convenient to contemplate it upon that general survey which it is the object of such schemes or classifications to lay down; to travel over it and mark its more prominent characters by a map, anterior to our entering upon the country itself. And such are the humble pretensions of the present lecture; which will merely attempt to place before you a brief sketch of zoology, in
* Amcenilatca Academics Saccics, vol. li, art. 19, CEconomia Naturat.
regard to its bare outlines; for such a sketch is the whole that our time will allow; yet if it be found faithful, it will assuredly be found beneficial; for if the outlines be correctly laid down, the picture may be filled up at our leisure. That most sublime and magnificent of all poems, ancient or modern, the Book of Job, establishes, in the most satisfactory manner, that the study of natural history, and especially the history of the animal kingdom, was cultivated at a very early period of the world,—in all probability as early, at least, as the Mosaic epoch,—with a considerable degree of minute attention in regard to various kinds and species; and the detailed references to the habits and manners of other animals that lie scattered through almost every part of the Hebrew Scriptures, and especially through the book of Psalms, and those of the Prophecies, and the distinct historical notice which is given of the scientific acquaintance of Solomon with this attractive study,* establish, not only that it was attended to at a very early period, but that it was a very favourite and fashionable pursuit for many ages throughout Egypt, Syria, and Arabia. But the first physiologist who, we can say, with any degree of certainty, pointed out the expediency of a methodical arrangement of animals was Aristotle. His works upon this subject have reached us; yet while they prove that he took the same extensive and scientific view of it which he did of all other subjects, to which he directed the wonderful powers of his comprehensive mind, they prove also, that the study of natural history in Greece had by no means, in his day, kept pace with a variety of other studies; and that he did not conceive, aided as he was by all the mighty patronage of Alexander the Great, and the concurrent exertions of every other physiolo
fist, that he was in possession of a sufficiency of facts to attempt the same kind of systematic arrangement here, which he is so celebrated for having effected almost every where else. He modestly contented himself, therefore, with pointing out the important use of such an arrangement as soon as it could be accomplished, and with suggesting a few hints as to the principles upon which it should be constructed. He observes, that the distinctive characters of animals might be taken from the nature of their food, from their actions, their manners, or their different structures. That their inhabiting land or water, offers a distinction of another sort: and that of land animals, there are some kinds that respire by lungs, as quadrupeds, and others that have no such kind of respiration; that some are winged, and others wingless; that some possess proper blood, while others are exsanguineous; that some produce their young by eggs, and these he named oviparous, while others bring them forth naked, and these he called viviparous; that quadrupeds, again, may, perhaps, be distinguished by the make of the foot, as being of three kinds, undivided, cloven, and digitated, or severed into toes or claws.f These, indeed, were mere hints, and only intended as such; but they were truly valuable and important; for they roused zoologists to that general comparison of animal with animal, which could not fail of very essentially advancing the cause of natural history; and have, in different degrees, laid the foundation of almost every methodical arrangement which has since been offered to the world. To run over a list of these arrangements would be equally useless and jejune. The writers who have chiefly signalized themselves in this department, are Gesner, Aldrovandi, Johnston, Ray, Linnaeus, Klein, Lacgpede, Blnmenbach, and Cuvier; and in particular sections of it, Lamarck, Bloch, Fabricius, Latreille, and Brogniart; all of whom have flourished since the middle of the sixteenth century; most of whom have contributed something of importance to a scientific method of studying and distributing animals; and the most celebrated of whom are Ray, Linnaeus, and Cuvier. The system of Ray is derived, in its first outlines, from that recommendation of Aristotle, which suggests an attention to the different structures of different descriptions of animal life; and his observation, that one of these
* 1 Kings, It. 33. t Arte. Hist. Aniin. lib. i. cap. 1, cap. 3, cap. 8.