He a.s.serts that all of the globe which is now covered by the waters of the sea was formerly dry land; and that what is now dry land will be again converted into water. The reason is this: the rivers and torrents are continually carrying along sand and earth, which causes the sh.o.r.es gradually to advance, and the sea gradually to retire; so that in the course of innumerable ages the alleged vicissitudes necessarily take place. He adds, that in several parts which are considerably inland, and even of great elevation, the sea, when retiring, left sh.e.l.ls, and that, on digging in the ground, anchors and fragments of ships are sometimes found. Ovid attributes the same opinion to Pythagoras.

Aristotle farther remarks, that these conversions of sea into land, and of land into sea, which gradually take place in the long lapse of ages, are in a great measure the cause of our ignorance of past occurrences.

He adds, that besides this other accidents happen, which give rise even to the loss of the arts; and among these he enumerates pestilences, wars, famines, earthquakes, burnings, and desolations, which exterminate all the inhabitants of a country, excepting a few who escape and save themselves in the deserts, where they lead a savage life, and where they give origin to others, who in the progress of time cultivate the ground, and invent or rediscover the arts; and that the same opinions recur, and have been renewed times without number. In this manner, he maintains that, notwithstanding these vicissitudes and revolutions, the machine of the world always remains indestructible.

If an apology were necessary for the brevity of the above sketch, it might be urged, that it probably contains all that is authentic respecting the life of this eminent philosopher; and that our object is to condense, not to expand; to direct the attention to characteristic features, not to lead the mind to expatiate vaguely upon the general surface.

SECTION II.

_Account of Aristotle's History of Animals._

Aristotle's Ideas respecting the Soul--His Views of Anatomy and Physiology--Introduction to his History of Animals, consisting of Aphorisms or general Principles--His Division of Animals; their external Parts; their Arrangement into Families; their internal Organs; Generation, &c.

Of all the sciences, it has been remarked, that which owes most to Aristotle is the natural history of animals. Not only was he acquainted with numerous species, he also described them according to a comprehensive and luminous method, which perhaps none of his successors have approached; arranging the facts observed, not according to the species, but according to the organs and functions, which affords the only means of establishing comparative results. It may in fact be said, that besides being the oldest author on comparative anatomy whose writings we possess, he was likewise one of those who have treated that part of natural history with most genius, and best deserves to be taken as a model. The princ.i.p.al divisions which are still adopted by naturalists in the animal kingdom are those of Aristotle, and he proposed some which have been resumed after having been unjustly rejected. If we examine the foundation of these great labours, we shall find that they all rest on the same method, which is itself derived from the theory respecting the origin of general ideas. He always observes facts with attention, compares them with great precision, and endeavours to discover the circ.u.mstances in which they agree. His style, moreover, is suited to his method: simple, precise, unstudied, and calm, it seems in every respect the reverse of Plato's; but it has also the merit of being generally clear, except in some places where his ideas themselves were not so.[C]

In one of his treatises, Aristotle divides natural bodies into those possessing life, and those dest.i.tute of that principle,--into animate and inanimate. He considers soul as the vital energy or vivifying principle common to all organized bodies; but distinguishes in it three species. Thus, in plants there is a vegetative, in animals a vegetative and a sentient, in man a vegetative, a sentient, and a rational soul.

The functions of nutrition and generation in plants and animals he attributes to the vegetative soul; sense, voluntary motion, appet.i.te, and pa.s.sion, to the sentient soul; the exercise of the intellectual faculties, to the rational soul.

His ideas of anatomy and physiology were extremely imperfect. Thus, he supposed the brain to be a cold spongy ma.s.s, adapted for collecting and exhaling the superfluous moisture, and intended for aiding the lungs and trachea in regulating the heat of the body. The heart is the seat of the vital fire, the fountain of the blood, the organ of motion, sensation, and nutrition, as well as of the pa.s.sions, and the origin of the veins and nerves. The blood is confined to the veins; while the arteries contain an aerial spirit; and by nerves he means tendons, nerves, and arteries,--in short, strings of all kinds, as the name implies. The heart has three cavities; in the larger animals it communicates with the windpipe, or the ramifications of the pulmonary artery receive the breath in the lungs and carry it to the heart. Respiration is performed by the expansion of the air in the lungs, by means of the internal fire, and the subsequent irruption of the external air to prevent a vacuum.

Digestion is a kind of concoction or boiling, performed in the stomach, a.s.sisted by the heat of the neighbouring viscera.

It is perhaps impossible at the present day, when the investigation of nature is so much facilitated by the acc.u.mulated knowledge of ages in every department of physical science, by the commercial relations existing between countries in all parts of the globe, by a tried method of observation, experiment, and induction, and finally, by the possession of the most ingenious instruments, to form any adequate idea of the numerous difficulties under which the ancient naturalist laboured. On the other hand, he had this great advantage, that almost every thing was new; that the most simple observation correctly recorded, the most trivial phenomenon truly interpreted, became as it were his inalienable property, and was handed down to succeeding ages as a proof of his talents,--a circ.u.mstance which must have supplied a great motive to exertion.

The History of Animals is undoubtedly one of the most remarkable performances of which physical science can boast. It must not, however, be imagined that it is a work which, replete with truth and exhibiting the well-arranged results of accurate observation and laborious investigation, is calculated to afford material aid to the modern student. To him more recent productions are the only safe guides; nor is it until he has studied them, and interrogated nature for himself, that he can derive benefit from the perusal of the treatise which we now proceed to examine.

The first book contains a brief description of the parts of which the bodies of animals are composed. The introduction consists of general propositions; of which we shall present a few of the more remarkable as a specimen.

Some parts, he observes, are simple, and divided into similar particles; while others are compound, and consist of dissimilar elements. The same parts in different animals vary in form, proportion, and other qualities; and there are many creatures which, although they have the same parts, have them in different situations. Animals differ in their mode of living, actions, and manners: thus, some reside on land, others in water; and of the latter some breathe water, others air, and some neither. Of aquatic animals, some inhabit the sea, others the rivers, lakes, or marshes. Of those which live in the sea, some are pelagic, others littoral, and others inhabit rocks. Of land-animals, some respire air, as man; others, although they live on the land and obtain their food there, do not breathe air, as wasps, bees, and other insects.

We know no animal, says he, that flies only, as the fish swims; for those which have membranous wings walk also; and bats have feet, as have seals, although imperfect. But some birds have the feet weak; in which case the defect is compensated by the superior action of the wings, as in swallows. There are many species which both walk and swim. Animals also differ in their habits; thus, some are gregarious, others solitary,--a distinction applicable to them whether they walk, fly, or swim. Some obey a leader, others act independently; cranes and bees are of the former, ants of the latter kind. Some feed on flesh, others on fruits, while others feed indiscriminately; some have homes, others use no covering of this kind, but reside in the open air. Some burrow, as lizards and snakes; others, as the horse and the dog, live above ground.

Some animals seek their food at night, others by day; some are tame, others wild; some utter sounds, others are mute, and some sing; all of them, however, sing or cry in some way at the season of pairing.

In this way he proceeds, stating briefly the various circ.u.mstances in which animals differ from each other, and in conclusion a.s.serting that man is the only one capable of design; for, says he, although many of them have memory and docility, none but man have the faculty of reflection.

These general propositions or aphorisms are not so simple or so easily attained as one might imagine on reading them inattentively. Let any person who has a tolerably comprehensive idea of the series of animated beings reflect a little, and he will perceive, that such as the following must be derived from the observation of a great number of facts:--Those parts which seize the food, and into which it is received, are found in all animals. The sense of touch is the only one common to all. Every living creature has a humour, blood or sanies, the loss of which produces death. Every species that has wings has also feet.

In this chapter Aristotle divides animals into such as have blood, and such as have it not. Of the former (the red-blooded) some want feet, others have two of these organs, and others four. Of the latter (the white-blooded) many have more than four feet. Of the swimming-animals, which are dest.i.tute of feet, some have fins, which are two or four; others none. Of the cartilaginous cla.s.s, those which are flat have no fins, as the skate. Some of them have feet, as the mollusca. Those which have a hard leathery covering swim with their tail. Again, some animals are viviparous, others produce eggs, some worms. Man, the horse, the seal, and other land-animals, bring forth their young alive; as do the cetacea and sharks. Those which have blow-holes have no gills, as the dolphin and whale. In this department, the observations of the great philosopher are often minute, and generally accurate, although usually too aphoristic and unconnected to be of much use to the student.

Of flying-animals, some, as the eagle and hawk, have wings; others, in place of wings, have membranes, as the bee and the beetle; others a leathery expansion, as the bat. Those which have feathered or leathery wings are blooded (red-blooded); but those which have membranous wings, as insects, are bloodless (white-blooded). Those which fly with wings or with leathery expansions, either have two feet or none; for, says he, it is reported that there are serpents of this kind in Ethiopia. Of the flying bloodless animals, some have their wings covered by a sheath, as beetles; others have no covering, and of these some have two, others four wings. Those which are of large size, or bear a sting behind, have four; but the smaller and stingless, two only. Those which have sheaths to their wings, have no sting; but those which have two wings are furnished with a sting in their fore part, as the gnat.

Animals are distinguished from each other, so as to form kinds or families. These, according to our author, are quadrupeds, birds, fishes, cetacea, all which he says have (red) blood. There is another kind, covered with a sh.e.l.l, such as the oyster; and another, protected by a softer sh.e.l.l, such as the crab. Another kind is that of the mollusca, such as the cuttlefish; and lastly, the family of insects. All these are dest.i.tute of (red) blood.

Here, then, we have a general cla.s.sification of animals, which it is important to notice, as we may have occasion afterwards to compare it with arrangements proposed by other naturalists. It may be reduced to the following form:--

_Red-blooded Animals._

QUADRUPEDS, SERPENTS, BIRDS, FISHES, CETACEA.

_White-blooded Animals._

TESTACEA, CRUSTACEA, MOLLUSCA, INSECTS.

It must, however, be understood, that Aristotle proposes no formal distribution of animals, and that his ideas respecting families, groups, or genera, such as those of our present naturalists, are extremely vague.

His quadrupeds include the mammalia and the quadrupedal reptiles. He divides them into those which are viviparous, and those which are oviparous; the former covered with hair, the latter with scales.

Serpents are also scaly, and, excepting the viper, oviparous. Yet all viviparous animals are not hairy; for some fishes, he remarks, likewise bring forth their young alive. In the great family of viviparous quadrupeds also, he says, there are many species (or genera), as man, the lion, the stag, and the dog. He then mentions, as an example of a natural genus, those which have a mane, as the horse, the a.s.s, the mule, and the wild-a.s.s of Syria, which are severally distinct species, but together const.i.tute a genus or family.

This introduction to the History of Animals the philosopher seems to have intended, less as a summary of his general views respecting their organization and habits, than as a popular exordium, calculated to engage the attention of the reader, and excite him to the study of nature. Whatever errors it may contain, and however much it may be deficient in strictly methodical arrangement, it is yet obviously the result of extensive, and frequently accurate observation. He then proceeds to the description of the different parts of the human body, first treating of what anatomists call the great regions, and the exterior generally, and then pa.s.sing to the internal organization. His descriptions in general are vague, and often incorrect. As an example, we may translate the pa.s.sage that refers to the ear.

This organ, he says, is that part of the head by which we hear; but we do not respire by it, for Alcmeon's opinion, that goats respire by the ears, is incorrect. One part of it has no name, the other is called lobos; it consists entirely of cartilage and flesh. The internal region is like a spiral sh.e.l.l, resembling an auricle at the extremity of the bone, into which as into a vessel the sound pa.s.ses. Nor is there any pa.s.sage from it to the brain, but to the palate; and a vein stretches from the brain to it. But the eyes belong to the brain, and each is placed upon a small vein. Every animal that has ears moves them, excepting man; for of those which are furnished with the sense of hearing, some have ears, others none, but an open pa.s.sage; of which kind are feathered animals, and all that are covered with a scaly skin. But those which are viviparous, the seal, the dolphin, and other cetacea excepted, have external ears, as well as the viviparous cartilaginous animals. The seal has a manifest pa.s.sage for hearing; but the dolphin, although it hears, yet has no ears. The ears are situated at the same level as the eyes, but not higher, as in certain quadrupeds. The ears of some persons are smooth, of others rough, or partly so; but this furnishes no indication of disposition. They are also large, small, or of moderate size, projecting, or flat, or intermediate. The latter circ.u.mstance indicates the best disposition. Large and projecting ears are indicative of a fool and babbler.

From this pa.s.sage we perceive that Aristotle was acquainted with the Eustachian tube; although his anatomical knowledge of the ear is certainly of the most superficial kind, and his physiognomical notions respecting it sufficiently ludicrous. He divides the body into head, neck, trunk, arms, and legs, much as we do at the present day. The head consists of the calvaria, or part covered with hair, which is divided into three regions, the bregma or fore part, the crown, and the occiput.

Under the bregma is the brain; but the back part of the head is empty.

When speaking of the face, he remarks, that persons having a large forehead are of slow intellect, that smallness of that part indicates fickleness, great breadth stupidity, and roundness irascibility. The physiognomists of our day have a different opinion. The neck contains the spine, the gullet, and the arteria (or windpipe). The trunk consists of the breast, the belly, &c.;--and in this manner he pa.s.ses over the different external regions.

In describing the brain, he states that all red-blooded animals have that organ, as have also the mollusca, and that in man it is largest and most humid. He had observed its two membranes, as well as the hemispheres and cerebellum; but he a.s.serts that it is bloodless, that no veins exist in it, and that it is naturally cold to the touch. He was ignorant of the distribution of the nerves, was not aware that the arteries contain blood, imagined that the heart being connected with the windpipe is inflated through it, and, in a word, manifests extreme ignorance of every thing that relates to the internal organization.

Judging from this specimen, the reader may suspect that his time would not be profitably employed in separating the few particles of wheat from the great ma.s.s of chaff which the writings of Aristotle present to us.

Nor must it be concealed that the modern naturalist does not consult his volumes for information, but merely to gratify curiosity. There is to be found, indeed, in the most imperfect of our elementary works on anatomy, whether human or comparative, more knowledge than was probably contained in the Alexandrian library.

In his second book, he treats more particularly of animals. At its commencement we unfortunately meet with a stumbling-block, in the shape of an a.s.sertion, that the neck of the lion has no vertebrae, but consists of a single bone. In speaking of limbs, he takes occasion to describe the proboscis of the elephant, and to enter generally into the history of that gigantic quadruped. He then speaks with reference to the distribution of hair, remarking, that the hair of the human head is longer than that of any other animal; that some are covered all over with long hair, as the bear; others on the neck only, as the lion; and others only along the back of the neck, as the horse and the bonasus. He describes the buffalo and the camel; of the latter of which he mentions the two species, the Arabian and the Bactrian. The subject of claws, hoofs, and horns, is next discussed. He states that some quadrupeds have many toes, as the lion; while others have the foot divided into two, as the sheep; and others again have a single toe or hoof, as the horse. His aphorisms on the subject of horns are in general correct. Thus, he states that most creatures furnished with them have cloven hoofs, and that no single-hoofed animal has two horns.

He then proceeds to speak of teeth, which he says are possessed by all viviparous quadrupeds. Some have them in both jaws, others not; for horned animals have teeth in the lower jaw only, the front ones being wanting in the upper. Yet all animals which have no teeth above are not horned; the camel, for example. Some have projecting teeth, as the boar; others not. In some they are jagged, as in the lion, panther, and dog; in others even, as in the horse and cow. No animal has horns and protruded teeth; nor is there any having jagged teeth that has either horns or projecting teeth. The greater part have the front teeth sharp, and those behind broad; but the seal has them all jagged for it partakes of the nature of fishes, which have that peculiarity. His remarks on the shedding of the teeth are in general erroneous. The elephant, he says, has four grinders, together with two others, the latter of which are of great size and bent upwards in the male, but small and directed the contrary way in the female. This circ.u.mstance Cuvier states to be correct with respect to the African variety, although the case is different in the Asiatic. His account of the hippopotamus, however, is inaccurate in almost every particular. Thus, he says it has a mane like a horse, cloven feet like an ox, and is of the size of an a.s.s,--a description which answers better to the gnu. In speaking of monkeys, of which he mentions several kinds, he remarks their resemblance to the human species, and the peculiar formation of their hind feet, which may be used as hands.

He then gives a general account of the oviparous quadrupeds, particularly of the Egyptian crocodile and the chameleon, concerning which he relates many interesting circ.u.mstances.

In treating of birds, he remarks that they are bipedal, like man, dest.i.tute of anterior limbs, but furnished with wings, and having a peculiar formation in the legs. Those birds which have hooked claws, he says, have the breast more robust than others. He then describes the differences in the structure of their feet; remarking, that most of them have three toes before and one behind, although a few, as the wryneck, have two only before. Birds, he adds, have the place of lips and teeth supplied by a bill; and instead of external ears and nostrils properly so called, they have pa.s.sages for hearing and smelling in different parts of the head. The eyes have no lashes, but are furnished with a membrane like lizards. The other remarkable peculiarities, such as the feathers and the form of the tongue, are then mentioned. No birds, he observes, that have hooked claws are furnished with spurs. In his remarks on this family he is generally correct; though here, as elsewhere, he is not merely brief, but vague and superficial. His division of birds would seem to be the following:--Those with hooked claws; those with separated toes; and such as are web-footed.

Fishes are next discussed with nearly equal brevity. He remarks, that they have a peculiar elongated form, are dest.i.tute of mammae, emit by their gills the water received at the mouth, swim by means of fins, are generally covered with scales, and are dest.i.tute of the organs of hearing and smelling.

His description of the internal parts of these tribes of animals contains a mixture of truth and error. This book terminates with remarks on the structure of serpents.

The third commences with observations on those parts of animals which are h.o.m.ogeneous, such as the blood, the fibres, the veins, the nerves, and the hair. Under the general t.i.tle of nerve, he confounds the columnae carneae of the heart, the tendons and fasciae; and it does not appear that he had any idea of what modern anatomists call nerves. In speaking of hair, he remarks that it grows in sick persons, especially those labouring under consumption, in old people, and even in dead bodies. The same remark applies to the nails. The blood is contained in the veins and heart, is, like the brain, insensible, flows from a wound in any part of the flesh, has a sweet taste and a red colour, coagulates in the air, palpitates in the veins, and when vitiated is productive of disease. On the subject of milk, his observations deserve attention.

Thus, he says that all viviparous animals which have hair are furnished with mammae, as are also the whale and the dolphin; but those which are oviparous are not so provided. All milk has a watery fluid, called serum, and a thick part, called cheese; while that produced by animals which are dest.i.tute of fore teeth in the upper jaw coagulates. On this subject he mentions some curious circ.u.mstances. Some kinds of food occasion the appearance of a little milk in women who are not pregnant.

There have even been instances of it flowing from the b.r.e.a.s.t.s of elderly females. The shepherds about Mount Oeta rub the udders of unimpregnated goats with nettles, and thus obtain abundance of milk from them. It sometimes happens that male animals secrete the same fluid; thus, there was a he-goat in the island of Lemnos, which yielded so much that small cheeses were made of it. A little may be pressed from the b.r.e.a.s.t.s of some men after the age of p.u.b.erty; and there have been individuals who on being sucked have yielded a large quant.i.ty. Instances of this have been recorded by other observers; and Humboldt met with a similar case in South America.[D]

In the fourth book, Aristotle treats of the animals which are dest.i.tute of red blood. Of these, he says there are several genera: the mollusca, such as the cuttlefish, which is externally soft with an internal firm part; the crustacea, internally soft and covered with a firm integument, such as the crab; the testacea, internally soft and externally hard and solid, as the limpet and oyster. The insects form the fourth genus; and are distinguished by their being externally and internally formed of a hardish or cartilaginous substance, and divided into segments; some of them having wings, as the wasp; while others have none, as the centipede. He then gives a pretty full account of the cuttlefish and nautilus, treats of the crustaceous animals generally, and enters into details respecting the other two cla.s.ses. After this he enumerates the organs of sensation, stating that man, and all the red-blooded and viviparous animals, possess five senses, although in the mole vision is deficient. He describes correctly the eye of that creature, showing that it is covered by a thickish skin, but presents a conformation similar to that of other animals, and is furnished with a nerve from the brain. He shows that although fishes have no visible organs of smelling or hearing, they yet possess both senses, and, in treating of this subject, states many interesting facts relative to the mode employed in catching dolphins. He also shows that insects have the faculty of hearing and smelling. The testacea, he says, besides feeling, which is common to all animals, have smell and taste; but he also a.s.serts that some of them, the solen and pecten, are capable of seeing, and others of hearing.

All viviparous quadrupeds not only sleep, but also dream; but whether the oviparous dream is uncertain; although it is plain that they sleep, as do the aquatic animals, fishes, mollusca, testacea, and crustacea. A transition is then made to the subject of s.e.x, for the purpose of showing that in the mollusca, crustacea, testacea, and eels, there is no difference in that respect between individuals of the same species.

The subjects of generation and parturition occupy the fifth, sixth, and seventh books. From the comparatively large s.p.a.ce which he has devoted to the result of his inquiries in these departments, the minuteness with which he describes the phenomena presented by them in man and the domestic animals, and the accurate knowledge which he frequently exhibits, it may be inferred that they were favourite subjects with Aristotle. It is sufficient for our purpose to mention some of the cases in which he attained the truth, and others in which he failed.

He describes the membranes with which some of the mollusca envelope their eggs, mentions the changes through which insects pa.s.s before they acquire the perfect state, and speaks with tolerable accuracy of the economy of bees and wasps. He states, however, that the former make wax from flowers, but gather their honey from a substance which falls from the air upon trees. The eggs of tortoises, he says, are hard, like those of birds, and are deposited in the ground. His remarks on those of lizards and the crocodile are also correct. He states accurately that some serpents bring forth their young enclosed in a soft membrane, which they afterwards burst; but that sometimes the little animals escape from the egg internally, and are produced free. Other serpents, he observes, bring forth eggs cohering in the form of a necklace. On the eggs of birds his observations are nearly as correct as those which we find in books at the present day. He was acquainted with their general structure, and the development of the chick, which he minutely describes. He remarks of the cuckoo, that it is not a changed hawk, as some have a.s.serted; that, although certain persons have alleged that its young have never been seen, it yet certainly has young; that, however, it does not construct a nest, but deposites its eggs in the nest of other birds, after eating those which it finds there.

He remarks that the cartilaginous fishes are viviparous, but that the other species bring forth eggs, and states correctly that they have no alantoid membrane. He then pa.s.ses to the cetacea, with which he seems to be nearly as well acquainted as modern naturalists, and reverts to the oviparous fishes, respecting which he presents numerous details. He maintains, however, that the eel is produced spontaneously, and that no person had ever detected eggs or milt in it.

Having discussed the subject of generation, he proceeds, in the eighth book, to treat of the food and actions of animals, their migrations, and other circ.u.mstances. The ninth consists of a mult.i.tude of topics without any direct relation to each other, but apparently treated as they had successively presented themselves to the author. Thus, at the commencement we find remarks on the peculiarities of disposition observed in the males and females of different animals, the combats of hostile species, the actions of animals, nidification, generation, and other matters. Several species of different cla.s.ses are then described, such as the kingfisher, the black-bird, the cuckoo, the marten, eagles, owls, fishes, insects, and quadrupeds.