Imágenes de páginas
PDF
EPUB
[ocr errors]

most foolish speculations find a place beside sober and philosophical reasoning.

Aristotle’s ‘History of Animals' forms one of the most important of all his writings. It has occasionally met with adverse criticism, but on the whole the judgment which has been accorded is favourable in the highest degree. Whether Aristotle merits the eulogies which have been very lavishly bestowed upon bim will be seen as we proceed. * Aristotle is proudly regarded by the zoologist as the father of natural history, and with justice; for although it is certain that the various statements and observations recorded in his zoological treatises do not proceed from himself, and that a large proportion of them are erroneous, still, he it is who first produced, so far at least as can be learnt, a compendious work on zoology. In this work will be found truth and error, fact and fable, grain and chaff strangely mingled together; it would indeed have been a wonder had it been otherwise, considering the state of the Greek mind in Aristotle's time, a mind, as we have seen, so generally opposed to the investigation of natural phenomena, And although we must allow that the Stagirite did, 'in an age of universal superstition, discard from his works many popular tales, and fancies, and beliefs which were received by the mass of his countrymen as religious truths, sanctioned by antiquity, interwoven in their history, and consecrated in their poetry,' yet the fact is indisputable that he is found here and there quite as credulous and absurd as he represents both Ctesias and Herodotus to be; sometimes, indeed, seeming to assert in one part of his writings the very things which elsewhere he has ridiculed one of them for believing.f That Aristotle credited the story of the Salamander being able to live in the fire is evident from the following quotation :

In Cyprus, where the stone chalcitis is burnt by men who heap it together, for many days, small winged creatures, a little larger than big flies, are produced, which walk and leap about in the fire. These animals die if taken out of the fire; and that it is possible for

* Compare for instance the exaggerated remark of Buffon, who thus speaks: • Aristotle's “ History of Animals is perhaps even now the best work of its kind; he probably knew animals better, and under more general views, than we do now. Although moderns have added their discoveries to those of the ancients, I do not believe that we have many works on Natural History that we can place above those of Aristotle and Pliny. The language of Cuvier,' says Mr. Lewes, “passes all bounds permissible to sincere enthusiasm.

† Compare v. 4, § 5, with • De Generat. Anim.,' iii. v. How is the opinion of Herodotus (ii. 93), that fish were impregnated by swallowing the milt of the male, more foolish than Aristotle's assertion that the hen-partridge was similarly operated upon by the wind when it blew from the male bird to her; or that his breath was sufficient for the purpose ? (v. 4, $ 7). , Of two ridiculons notions, Aristotle's is the more absurd. Vol. 117.-No. 233.

D

some

6

some living animals to sustain the effects of fire is evident from the case of the salamander, for this animal, it is said, extinguishes the fire as it walks through it.' (V. 17, $$ 12, 13.)

The ‘History of Animals' consists of ten books; the tenth book, however, is supposed by many writers not to be the genuine work of Aristotle ; others again have supposed that it was a continuation of the seventh book. There is certainly some reason to doubt its genuineness. •Aristotle's Natural History' as Külb observes in his introduction, 'formed a connected whole according to its whole philosophical system, but the chain—of whose existence there still is clear evidence-is now broken, and we can with difficulty bring its scattered links together from indications to be gathered from the work itself.' It is quite impossible to fix with any degree of certainty the chronological order of Aristotle's Natural History' treatises. According to Külb they may be arranged in the following series. The first is formed by the History of Animals;' with this treatise the four books on the Parts of Animals' are connected, of which, however, the first book is regarded by Schneider and Külb as a general introduction to the Natural History.'

• The conclusion of this work was, in all probability, a treatise now separated from it, concerning the “Gait of Animals.” Afterwards follow three books “On the Vital Principle," and a few fragments of a similar writing “On the Breath," and the closely-connected treatise “Of Perception and Things perceived,” “ Of Memory and Recollection," " Of Sleep and Waking," " Of Dreams," " Of Prophetic Dreams,"

* “ " “ Of the Motion common to all Animals.” In conclusion come the larger work“ On the Generation of Animals," in five books, and the shorter treatises “ On Long and Short Life,” “On Youth and Age, Life and Death,” and “ On Breathing.”. Moreover, to this series of Aristotle's writings belong several, which we no longer possess, viz. :Eight books on Anatomy, which were furnished with illustrations; a fragment on Anatomy (Ekleyi ávaronwy) in one book; a work on "Made-up Animals" (ure Tūv ovverwy Gów), i. e. figures of animals fantastically formed by poets and artists out of the parts of different real animals; a book “ On Fabulous Animals." Also we may reckon here, as clearly connected, seven books upon “ Medicine.” Thus the sum of the several treatises and books amounts to fifty, a number which answers tolerably well to the declaration of Pliny, that Aristotle had written fifty books about animals.'

A glance at the above-named works, without taking into account his numerous metaphysical writings, will suffice to show in what a vast and comprehensive field the great mind of Aristotle wrought. It is a matter of deep regret that so many of his works have perished, and especially must we deplore the

loss

"66

[ocr errors]
[ocr errors]
[ocr errors]

loss of the Anatomical Illustrations and Diagrams,' to which he frequently refers, and from which much curious and interesting knowledge might have been derived.*

Aristotle's ideas of physiology, which doubtless were generally identical with those taught in the medical schools of Greece about our author's age, were very far from the truth; but considering that he had no knowledge of the circulation of the blood, nor of the nervous system, this is no matter of surprise ; and yet the bold confidence with which he upsets the opinions of his predecessors, and seeks to establish his own—which are nearly always quite as visionary as the others—is very characteristic of the metaphysical mind of ancient Greece. Truly has Dr. Whewell remarked that these early philosophers entered upon the work of physical speculation in a manner which showed the vigour and confidence of the questioning spirit, as yet untamed by labours and reverses. It was for later ages to learn that the man must acquire, slowly and patiently, letter by letter, the alphabet in which nature writes her answers to such inquiries; the first students wished to divine, at a single glance, the whole import of her book.†

Külb, in his recent German translation, has put together some of Aristotle's physiological views in something like the following form. It need hardly be added that the Stagirite's ideas are altogether erroneous.

• The heart is regarded by Aristotle as the source of everything to all living beings; for the blood, the aliment of the whole body, is prepared by it and poured into the vessels that issue from it; but to itself no supply comes from any part. The circulation of the blood was not then thought of; consequently no distinction was made between the veins and the arteries, and very extraordinary were the conjectures touching the course of these vessels through the body. Through the natural heat of the heart, the blood becomes heated, and thus the heart is the source of warmth to the whole body. On this heat of the heart also depends its motion, for as the nourishing juices contained in the blood become warmed, there ensues an evaporation which causes the heart to heave, or, as we say, to beat, and simultaneously the chest is distended. Into the space thus produced the cold external air rushes, and under its condensing influence everything resumes its original smaller size, until a fresh evaporation in the heart again distends the chest, and gives motion to all the vessels, even to the extremities of the body. The heart fulfils another important duty. As it contains numerous sinews, it is the source of all

* It is usually asserted that these diagrams were made by the ph sopher himself; we have been unable to discover the slightest proof that the illustrations to which he alludes were done by his own hand, or under his direction. † History of the Inductive Sciences,' i. p. 25.

the

D 2

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 bloodvessels 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, excep 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

a

a

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 fere 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 frontal 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), ευρέθη κεφαλή ουκ έχουσα ραφήν ουδεμίην, αλλά εξ ενός εούσα οστέου, who speaks of a skull found by the people on the battle-fiel Platæa some years after the battle. There is nothing very remarkable in such a discovery. The sutures are not unfrequently obliterated. 'De Partibas Animalium,' iv. 2.

« AnteriorContinuar »