the sinews that put the various joints in motion. Furthermore, the heart as being the seat of the sentient soul is regarded as the source of all sensation. The importance of the heart in having so many functions to perform is very obvious, and Aristotle therefore considers it the fortress of the body; hence it lies in the middle, the most protected spot, with a slight direction forwards. Life begins with its action and ceases with it. Next to the heart ranks the brain, and the efficiency of the brain lies in its antagonism to the heart, for the latter is warm, the former cold; but as nature universally produces her perfect harmonies by means of antagonism, so she formed the brain to correct the heat of the heart, out of earth and water, and suffered no blood to pour into it, in order that the work of cooling might go on undisturbed, and only sent a few slender branches of blood vessels into the enclosing skin, in order that circling there they might serve to modify such an overpowering mass of coolness. Aristotle expressly denies that the brain has anything to do with sensation, and rests upon the fact that the brain by its motion produces no kind of sensation. As relates to the senses, man is principally distinguished from other animals by his greater delicacy of touch, the other senses being often possessed by animals in greater perfection than by him. Touch and taste are the only senses absolutely essential to animal existence; the noblest of the senses are sight and hearing;-sight, because of the needful and instantaneous service it renders,-hearing, because it takes in sounds which warn of danger.

In addition to the brain, another means of cooling the heart's heat is the act of breathing. The greater or less importance of this function depends on the greater or less degree of the natural temperature of the animals. Hence the breathing organs are made proportionate to the animal's necessities, the bloodless or cold animals requiring them smaller, those provided with blood, or the warm animals, requiring them larger. Fish which have little blood are sufficiently cooled by the water. The rest of the animal creation, which have much blood, need a lighter medium and one which shall permeate the whole body and extend its influence even to the heart; and such a medium is air. This is inspired and exspired by all creatures, and hence they all require a lung, and an air-tube. The inspired air is cold, and thus acts upon the heart in the manner mentioned before. In this operation the lung does exactly the work of a pair of bellows, except that, in the latter case, the incoming and outgoing air has not one and the same passage. A difference in the form of the air-tube produces difference of sound. On breathing motion also, that is, motion within the body itself, depends. Locomotion Aristotle makes subject to volition and predetermination, and only in this sense ascribes voluntary motion to a living animal. As the heart is the seat of sensation it naturally must be regarded as the centre whence issue volition and desire. But the mechanical media by which such will or desire is carried out are not hinted at; and it must be confessed that Aristotle was totally uninformed concerning the mechanism of regulated motion by means of muscles, bones, and nerves. Whether he perceived

that

that the nerves formed a distinct portion of the animal economy remains at most very doubtful. The muscles he included under the general name of flesh, and his representation of the bony system is a curious mixture of perfect adaptation and great inefficiency.'*

Aristotle held some peculiar notions with respect to the skull. He says, that part of the head which is covered with hair is called the cranium; the fore part of this is called the sinciput; this is the last formed, being the last part in the body which becomes hard.' He correctly alludes here to the opening in the frontab bone of a young infant, which gradually becomes hardened by ossification; the hinder part is the occiput, and between the occiput and sinciput is the crown of the head. The brain is placed beneath the sinciput, and the occiput is empty (!) the skull has sutures; in women there is but one placed in a circle (!) men have generally three joined in one, and a man's skull has been seen without any sutures at all. The often repeated question as to how far Aristotle's observations are the result of his own investigation naturally suggests itself again here; had Aristotle ever dissected a human body, he never would have asserted a proposition so manifestly false as that the back of the head is empty, or that women have only one suture placed in a circle. It would be easy to adduce many other passages in proof that Aristotle very often borrowed his statements from others, or that he generalised hastily. 'The dog's cranium,' he says, 'consists of a single bone.' It is probable that Aristotle had got hold of the cranium of an old individual in which the sutures had become obliterated. 'There is a kind of ox which has a bone in its heart, though it is not found in all oxen; the horse also has a bone in its heart.' It would seem that Aristotle supposed every horse had a bone in its heart; indeed, from a comparison of another passage, he appears to regard the bone as a necessary part of the animal's heart; for, he says, 'the heart in all animals which we have considered is without bone, with the exception of horses and a certain kind of oxen, which, on account of their great size, have a bone for the sake of support.' The bones to which Aristotle refers are abnormal osseous depositions in the valves of the heart, which occur in many of the mammalia, and indicate a diseased state. The seal and the pig are said to have no gall, though Aristotle correctly attributes the nonexistence of a gall to the stag, elephant, horse, &c.

* Külb's Einleitung.'

† This seems to be copied from Herodotus ix. 83), εὑρέθη κεφαλὴ οὐκ ἔχουσα ῥαφὴν οὐδεμίην, ἀλλὰ ἐξ ἑνὸς ἐοῦσα ὀστέου, who speaks of a skull found by the people on the battle-field of Platea some years after the battle. There is nothing very remarkable in such a discovery. The sutures are not unfrequently obliterated.

De Partibus Animalium,' iv. 2.

It

It is impossible to study Aristotle's Natural History Treatises and not be convinced that he borrowed largely from his predecessors. It is probable that his observations on human anatomy and physiology were derived in great measure from the writings of the illustrious Hippocrates, the Father of Medicine, and from the information, whether oral or written, obtained from his own father Nicomachus, who was physician in ordinary to the King of Macedon, Amyntas II., and who was himself, as Stahr informs us, the author of several treatises on subjects connected with natural science.'

6

Do we detract aught from the fame of Aristotle when we assert that his History of Animals' is largely indebted to the labours of others? Did not Cuvier acknowledge his obligations to his predecessors in the field of zoological science, to Lacépède, Levaillant, Blainville, Geoffroy St. Hilaire, and a host of others? Has Cuvier's fame thereby decreased? Is it possible that the life of a man, the author of so many and various learned works, who died at sixty-two, could have sufficed for the observation of such a mass of recorded facts? Does the evidence of the existence of much error and want of investigation in Aristotle's Natural History writings close our eyes to the greatness of his intellect, and to the fact that those very writings contain vast stores of interesting matter which evince the brilliancy of his genius, the originality of his mind, and the philosophic combination of his ideas?

With regard to the question of the formation of a systematic classification by Aristotle, people's views differ so widely as to be almost irreconcilable; for while some maintain, as Külb has remarked, that Aristotle purposely abstained from forming any system, in order not to prejudice the more accurate conclusions of better and later wisdom, or at least laid down no such marked distinctions, as we fancy we perceive in his writings, and had merely a vague general idea of classification, which as little resembled a system as a mere jotting down of all the letters of the alphabet would resemble an essay; others are resolved to discover a system so perfect that it leaves to us little to alter in it.' Nothing can be more erroneous than this latter view, which has been so successfully combated by Dr. Whewell more than twenty years ago, that it is a wonder to find it still maintained by some writers. Were it a fact that Aristotle's classification is in many respects superior to some of the most admired and recent attempts of modern times,' the law of evolution, upon which we have laid so much stress, would be materially interfered with, or indeed completely destroyed. But in reality,' we now quote Dr. Whewell's words

"The

'The statements to which we refer respecting the scientific character of Aristotle's zoological system are altogether without foundation, and this science confirms the lessons taught us by all the others. . . Aristotle's nine books "On Animals are a work enumerating the differences of animals in almost all conceivable respects; the organs of sense, of motion, of nutrition, the interior anatomy, the exterior covering, the manner of life, growth, generation, and many other circumstances. These differences are very philosophically estimated. . . . . Aristotle proceeds to state his object, which is, to describe the differences of animals in their structure and habits. He then observes that for structure we may take man for our type, as being best known to us. . . The authors of this "Systema Aristotelicum " have selected, I presume, the following passages from the work "On Animals," as they might have selected any other; and by arranging them according to a subordination unknown to Aristotle himself, have made for him a scheme which undoubtedly bears a great resemblance to the most complete system of modern times:

'Book I. chap. v.-" Some animals are viviparous, some oviparous, some vermiparous. The viviparous are such as man, and the horse and all those animals which have hair; and of aquatic animals, the whale-kind, as the dolphin and cartilaginous fishes."

'Book II. chap. vii.—“ Of quadrupeds which have blood and are viviparous, some are (as to their extremities) many-cloven, as the hands and feet of man. For some are many-toed, as the lion, the dog, the panther; some are bifid, and have hoofs instead of nails, as the sheep, the goat, the elephant, the hippopotamus; and some have undivided feet, as the solid-hoofed animals, the horse and the ass. The swine-kind share both characters."

Chap. ii.-" Animals have also great differences in the teeth, both when compared with each other and with man. For all quadrupeds which have blood and are viviparous have teeth; and, in the first place, some are ambidental (having teeth in both jaws), and some are not so, wanting the front-teeth in the upper jaw. Some have neither front-teeth nor horns, as the camel; some have tusks, as the boar, some have not. Some have serrated teeth, as the lion, the panther, the dog; some have the teeth unvaried, as the horse and the ox; for the animals which vary their cutting teeth have all serrated teeth. No animal has both tusks and horns; nor has any animal with serrated teeth either of those weapons. The greater part have the front-teeth cutting and those within broad."

'These passages undoubtedly contain most of the differences on which the asserted Aristotelian classification rests; but the classification is formed by using the characters drawn from the teeth, in order to subdivide those taken from the feet, whereas, in Aristotle, these two sets of characters stand side by side, along with dozens of others; any selection of which, employed according to any arbitrary method of subordination, might with equal justice be called Aristotle's system. Why, for instance, in order to form subdivisions of animals, should we not go on with Aristotle's continuation of the second of the above

quoted

quoted passages, instead of capriciously leaping to the third. "Of these some have horns, some have none. . . Some have a fetlockjoint, some have none. . . Of those which have horns, some have them solid throughout, as the stag; others, for the most part, hollow.

. . Some cast their horns, some do not." If it be replied, that we could not by means of such characters form a tenable zoological system, we again ask by what right we assume Aristotle to have made or attempted a systematic arrangement, when what he has written, taken in its natural order, does not admit of being construed into a system?

Again, what is the object of any classification? This, at least, among others:-To enable the person who uses it to study and describe more conveniently the objects thus classified. If, therefore, Aristotle had formed or adopted any system of arrangement, we should discover it in the order of the subjects in his work. Accordingly, so far as he has a system, he professes to make use of it. At the beginning of the fifth book, where he is proceeding to treat of the different modes of generation of animals, he says, "As we formerly made a division of animals according to their kinds, we must now in the same manner give a general survey of their history. Except, indeed, that in the former case we made our commencement by a description of man; but in the present instance we must speak of him last, because he requires most study. We must begin, then, with those animals which have shells (testaceous molluscs); we must go on to those which have softer coverings (crustacea), then to the cephalopoda and annulose animals; after this to fishes, both viviparous and oviparous, then to birds, then to land-animals, both viviparous and oviparous."

'It is clear,' Dr. Whewell continues, that Aristotle had certain wide and indefinite views of classification, which, though not very exact, are still highly creditable to him; but it is equally clear that he was quite unconscious of the classification that has been ascribed to him.... The honour due to the stupendous accumulation of zoological knowledge, which Aristotle's works contain, cannot be tarnished by our denying him the credit of a system which he never dreamt of, and which from the nature of the progress of science could not possibly be constructed at that period. But, in reality, we may exchange the mistaken claims which we have been contesting for a better, because a truer, praise. Aristotle does show, as far as could be done at his time, a perception of the need of groups, and of names of groups, in the study of the animal kingdom: and thus may justly be held up as the great figure in the prelude to the formation of systems which took place in more advanced scientific times.'*

We have given at some length Dr. Whewell's remarks on this point. They evince great powers of discernment, and are incontrovertible. But although we deny to Aristotle the formation of any grand philosophical system of classification, we must not

*See History of Inductive Sciences,' iii. pp. 344-355.

suppose