The Legacy of GREECE

Essays by Gilbert Murray, W. R. Inge, J. Burnet, Sir T. L. Heath, D’Arcy W. Thompson, Charles Singer, R. W. Livingston, A. Toynbee, A. E. Zimmern, Percy Gardner, Sir Reginald Blomfield

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PRINTED IN ENGLAND AT THE
UNIVERSITY PRESS, OXFORD
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[137]

NATURAL SCIENCE

Aristotle

There is a little essay of Goethe’s called, simply, Die Natur. It comes among those tracts on Natural Science in which the poet and philosopher turned his restless mind to problems of light and colour, of leaf and flower, of bony skull and kindred vertebra; and it sounds like a prose-poem, a noble paean, eulogizing the love and glorifying the study of Nature. Some twenty-five hundred years before, Anaximander had written a book with the same title, Concerning Nature, περι φυσεως: but its subject was not the same. It was a variant of the old traditional cosmogonies. It told of how in the beginning the earth was without form and void. It sought to trace all things back to the Infinite, το απειρον—to That which knows no bounds of space or time but is before all worlds, and to whose bosom again all things, all worlds, return. For Goethe Nature meant the beauty, the all but sensuous beauty of the world; for the older philosopher it was the mystery of the Creative Spirit.

Than Nature, in Goethe’s sense, no theme is more familiar to us, for whom many a poet tells the story and many a lesser poet echoes the conceit; but if there be anywhere in Greek such overt praise and worship of Nature’s beauty, I cannot call it to mind. Yet in Latin the divini gloria ruris is praised and Natura daedala rerum worshipped, as we are wont to praise and worship them, for their own sweet sakes. It is one of the ways, one of the simpler ways, in which the Roman world seems nearer to us than the Greek: and not only seems, but is so. For compared with the great early civilizations, [138] Rome is modern and of the West; while, draw her close as we may to our hearts, Greece brings along with her a breath of the East and a whisper of remote antiquity. A Tuscan gentleman of to-day, like a Roman gentleman of yesterday, is at heart a husbandman, like Cato; he is ruris amator, like Horace; he gets him to his little farm or vineyard (O rus, quando te aspiciam!), like Atticus or the younger Pliny. As Bacon praised his garden, so does Pliny praise his farm, with its cornfields and meadowland, vineyard and woodland, orchard and pasture, bee-hives and flowers. That God made the country and man made the town was (long before Cowper) a saying of Varro’s; but in Greek I can think of no such apophthegm.

As Schiller puts it, the Greeks looked on Nature with their minds more than with their hearts, nor ever clung to her with outspoken admiration and affection. And Humboldt, asserting (as I would do) that the portrayal of nature, for her own sake and in all her manifold diversity, was foreign to the Greek idea, declares that the landscape is always the mere background of their picture, while their foreground is filled with the affairs and actions and thoughts of men. But all the while, as in some old Italian picture—of Domenichino or Albani or Leonardo himself—the subordinated background is delicately traced and exquisitely beautiful; and sometimes we come to value it in the end more than all the rest of the composition.

Deep down in the love of Nature, whether it be of the sensual or intellectual kind, and in the art of observation which is its outcome and first expression, lie the roots of all our Natural Science. All the world over these are the heritage of all men, though the inheritance be richer or poorer here and there: they are shown forth in the lore and wisdom of hunter and fisherman, of shepherd and husbandman, of artist and poet. The natural history of the ancients is not enshrined in Aristotle and Pliny. It pervades the vast literature of classical antiquity.[139] For all we may say of the reticence with which, the Greeks proclaim it, it greets us nobly in Homer, it sings to us in Anacreon, Sicilian shepherds tune their pipes to it in Theocritus: and anon in Virgil we dream of it to the coo of doves and the sound of bees’ industrious murmur.

Not only from such great names as these do we reach the letter and the spirit of ancient Natural History. We must go a-wandering into the by-ways of literature. We must eke out the scientific treatises of Aristotle and Pliny by help of the fragments which remain of the works of such naturalists as Speusippus or Alexander the Myndian; add to the familiar stories of Herodotus the Indian tales of Ctesias and Megasthenes; sit with Athenaeus and his friends at the supper table, gleaning from cook and epicure, listening to the merry idle troop of convivial gentlemen capping verses and spinning yarns; read Xenophon’s treatise on Hunting, study the didactic poems, the Cynegetica and Halieutica, of Oppian and of Ovid. And then again we may hark back to the greater world of letters, wherein poet and scholar, from petty fabulist to the great dramatists, from Homer’s majesty to Lucian’s wit, share in the love of Nature and enliven the delicate background of their story with allusions to beast and bird.

Such allusions, refined at first by art and hallowed at last by familiar memory, lie treasured in men’s hearts and enshrine themselves in our noblest literature. Take, of a thousand crowding instances, that great passage in the Iliad where the Greek host, disembarking on the plains of the Scamander, is likened to a migrating flock of cranes or geese or long-necked swans, as they fly proudly over the Asian meadows and alight screaming by Cayster’s stream—and Virgil echoes more than once the familiar lines. The crane was a well-known bird. Its lofty flight brings it, again in Homer, to the very gates of heaven. Hesiod and Pindar speak of its far-off cry, heard from above the clouds: and that it ‘observed the time of its [140] coming’, ‘intelligent of seasons’, was a proverb old in Hesiod’s day—when the crane signalled the approach of winter, and when it bade the husbandman make ready to plough. It follows the plough, in Theocritus, as persistently as the wolf the kid and the peasant-lad his sweetheart. The discipline of the migrating cranes, the serried wedge of their ranks in flight, the good order of the resting flock, are often, and often fancifully, described. Aristotle records how they have an appointed leader, who keeps watch by night and in flight keeps calling to the laggards; and all this old story Euripides, the most naturalistic of the great tragedians, puts into verse:

Lastly, Milton gathers up the spirit and the letter of these and many another ancient allusion to the migrating cranes:

But the natural history of the poets is a story without an end, and in our estimation, however brief it be, of ancient knowledge, there are other matters to be considered, and other points of view where we must take our stand.

When we consider the science of the Greeks, and come quickly to love it and slowly to see how great it was, we likewise see that it was restricted as compared with our own, curiously partial or particular in its limitations. The practical and ‘useful’ sciences of chemistry, mechanics, and engineering, which in our modern world crowd the others to the wall, are absent altogether, or so concealed that we forget and pass them[141] by. Mathematics is enthroned high over all, as it is meet she should be; and of uncontested right she occupies her throne century after century, from Pythagoras to Proclus, from the scattered schools of early Hellenic civilization to the rise and fall of the great Alexandrine University. Near beside her sits, from of old, the daughter-science of Astronomy; and these twain were worshipped by the greatest scientific intellects of the Greeks. But though we do not hear of them nor read of them, we must not suppose for a moment that the practical or technical sciences were lacking in so rich and complex a civilization. China, that most glorious of all living monuments of Antiquity, tells us nothing of her own chemistry, but we know that it is there. Peep into a Chinese town, walk through its narrow streets, thronged but quiet, wherein there is neither rumbling of coaches nor rattling of wheels, and you shall see the nearest thing on earth to what we hear of Sybaris. To the production of those glowing silks and delicate porcelains and fine metal-work has gone a vast store of chemical knowledge, traditional and empirical. So was it, precisely, in ancient Greece; and Plato knew that it was so—that the dyer, the perfumer, and the apothecary had subtle arts, a subtle science of their own, a science not to be belittled nor despised. We may pass here and there by diligent search from conjecture to assurance; analyse a pigment, an alloy or a slag; discover from an older record than the Greeks’, the chemical prescription wherewith an Egyptian princess darkened her eyes, or study the pictured hearth, bellows, oven, crucibles with which the followers of Tubal-Cain smelted their ore. Once in a way, but seldom, do we meet with ancient chemistry even in Greek literature. There is a curious passage (its text is faulty and the translation hard) in the story of the Argonauts, where Medea concocts a magic brew. She put divers herbs in it, herbs yielding coloured juices such as safflower and alkanet, and soapwort and fleawort to give consistency or[142] ‘body’ to the lye; she put in alum and blue vitriol (or sulphate of copper), and she put in blood. The magic brew was no more and no less than a dye, a red or purple dye, and a prodigious deal of chemistry had gone to the making of it. For the copper was there to produce a ‘lake’ or copper-salt of the vegetable alkaloids, which copper-lakes are among the most brilliant and most permanent of colouring matters; the alum was there as a ‘mordant’; and even the blood was doubtless there incorporated for better reasons than superstitious ones, in all probability for the purpose of clarifying (by means of its coagulating albumen) the seething and turbid brew.

The ‘Orphic’ version of the story, in which this passage occurs, is probably an Alexandrine compilation, and whether the ingredients of the brew had been part of the ancient legend or were merely suggested to the poet by the knowledge of his own day we cannot tell; in either case the prescription is old enough, and is at least pre-Byzantine by a few centuries. Such as it is, it does not stand alone. Other fragments of ancient chemistry, more or less akin to it, have been gathered together; in Galen’s book on The making of Simples, in Pliny, in Paulus Aegineta, and for that matter in certain Egyptian papyri (especially a certain very famous one, still extant, of which Clement of Alexandria speaks as a secret or ‘hermetic’ book), we can trace the broken and scattered stones of a great edifice of ancient chemistry.

Nevertheless, all this weight of chemical learning figures scantily in literature, and is conspicuously absent from our conception of the natural genius of the Greeks. We have no reason to suppose that ancient chemistry, or any part of it, was ever peculiarly Greek, or that this science was the especial property of any nation whatsoever; moreover it was a trade, or a bundle of trades, whose trade-secrets were too precious to be revealed, and so constituted not a science but a mystery.[143] So has it always been with chemistry, the most cosmopolitan of sciences, the most secret of arts. Quietly and stealthily it crept through the world; the tinker brought it with his solder and his flux; the African tribes who were the first workers in iron passed it on to the great metallurgists who forged Damascan and Toledan steel.

This ‘trade’ of Chemistry was never a science for a Gentleman, as philosophy and mathematics were; and Plato, greatest of philosophers, was one of the greatest of gentlemen. Long, long afterwards, Oxford said the same thing to Robert Boyle—that Chemistry was no proper avocation for a gentleman; but he thought otherwise, and the ‘brother of the Earl of Cork’ became the Father of scientific Chemistry.

Now I take it that in regard to biology Aristotle did much the same thing as Boyle, breaking through a similar tradition; and herein one of the greatest of his great services is to be found. There was a wealth of natural history before his time; but it belonged to the farmer, the huntsman, and the fisherman—with something over (doubtless) for the schoolboy, the idler, and the poet. But Aristotle made it a science, and won a place for it in Philosophy. He did for it just what Pythagoras had done (as Proclus tells us) for mathematics in an earlier age, when he discerned the philosophy underlying the old empirical art of ‘geometry’, and made it the basis of ‘a liberal education’.[5]

The Mediterranean fisherman, like the Chinese fisherman or the Japanese, has still, and always has had, a wide knowledge of all that pertains to and accompanies his craft. Our Scottish fishermen have a limited vocabulary, which scarce extends beyond the names of the few common fishes with which the market is supplied. But at Marseilles or Genoa or in the Levant[144] they have names for many hundreds of species, of fish and shell-fish and cuttle-fish and worms and corallines, and all manner of swimming and creeping things; they know a vast deal about the habits of their lives, far more, sometimes, than do we ‘scientific men’; they are naturalists by tradition and by trade. Neither, by the way, must we forget the ancient medical and anatomical learning of the great Aesculapian guild, nor the still more recondite knowledge possessed by various priesthoods (again like their brethren of to-day in China and Japan) of the several creatures, sacred fish, pigeons, guinea-fowl, snakes, cuttlefish, and what not, which time out of mind they had reared, tended, and venerated.

Of what new facts Aristotle actually discovered it is impossible to be sure. Could it ever be proved that he discovered many, or could it even be shown that of his own hand he discovered nothing at all, it would affect but little our estimate of his greatness and our admiration of his learning. He was the first of Greek philosophers and gentlemen to see that all these things were good to know and worthy to be told. This was his great discovery.

I have sought elsewhere to show that Aristotle spent two years, the happiest years perhaps of all his life—a long honeymoon—by the sea-side in the island of Mytilene, after he had married the little Princess, and before he began the hard work of his life: before he taught Alexander in Macedon, and long before he spoke urbi et orbi in the Lyceum. Here it was that he learned the great bulk of his natural history, in which, wide and general as it is, the things of the sea have from first to last a notable predominance.

I have tried to illustrate elsewhere (as many another writer has done) something of the variety and the depth of Aristotle’s knowledge of animals—choosing an example here and there, but only drawing a little water from an inexhaustible well.

A famous case is that of the ‘molluscs’, where either [145] Aristotle’s knowledge was exceptionally minute, or where it has come down to us with unusual completeness.

These are the cuttle fish, which have now surrendered their Aristotelian name of ‘molluscs’ to that greater group which is seen to include them, together with the shell-fish or ‘ostracoderma’ of Aristotle. These cuttle-fishes are creatures that we seldom see, but in the Mediterranean they are an article of food and many kinds are known to the fishermen. All or wellnigh all of these many kinds were known to Aristotle. He described their form and their anatomy, their habits, their development, all with such faithful accuracy that what we can add to-day seems of secondary importance. He begins with a methodical description of the general form, tells us of the body and fins, of the eight arms with their rows of suckers, of the abnormal position of the head. He points out the two long arms of Sepia and of the calamaries, and their absence in the octopus; and he tells us, what was only confirmed of late, that with these two long arms the creature clings to the rock and sways about like a ship at anchor. He describes the great eyes, the two big teeth forming the beak; and he dissects the whole structure of the gut, with its long gullet, its round crop, its stomach and the little coiled coecal diverticulum: dissecting not only one but several species, and noting differences that were not observed again till Cuvier re-dissected them. He describes the funnel and its relation to the mantle-sac, and the ink-bag, which he shows to be largest in Sepia of all others. And here, by the way, he seems to make one of those apparent errors that, as it happens, turn out to be justified: for he tells us that in Octopus, unlike the rest, the funnel is on the upper side; the fact being that when the creature lies prone upon the ground, with all its arms outspread, the funnel-tube (instead of being flattened out beneath the creature’s prostrate body) is long enough to protrude upwards between arms and head, and to appear on one[146] side or other thereof, in a position apparently the reverse of its natural one. He describes the character of the cuttle-bone in Sepia, and of the horny pen which takes its place in the various calamaries, and notes the lack of any similar structure in Octopus. He dissects in both sexes the reproductive organs, noting without exception all their essential and complicated parts; and he had figured these in his lost volume of anatomical diagrams. He describes the various kinds of eggs, and, with still more surprising knowledge, shows us the little embryo cuttle-fish, with its great yolk-sac attached, in apparent contrast to the chick’s, to the little creature’s developing head.

But there is one other remarkable feature that he knew ages before it was rediscovered, almost in our own time. In certain male cuttle-fishes, in the breeding season, one of the arms develops in a curious fashion into a long coiled whip-lash, and in the act of breeding may then be transferred to the mantle-cavity of the female. Cuvier himself knew nothing of the nature or the function of this separated arm, and indeed, if I am not mistaken, it was he who mistook it for a parasitic worm. But Aristotle tells us of its use and its temporary development, and of its structure in detail, and his description tallies closely with the accounts of the most recent writers.

A scarcely less minute account follows of the ‘Malacostraca’ or crustaceans, the lobsters and the crabs, the shrimps and the prawns, and others of their kind, a chapter to which Cuvier devoted a celebrated essay. There be many kinds of crabs—the common kind, the big ‘granny’ crabs, the little horsemen-crabs, that scamper over the sand and which are for the most part empty, that is to say, whose respiratory cavities are exceptionally large; and there are the freshwater crabs. There are the little shrimps and the big hump-backed fellows, or prawns; there are the ‘crangons’ or squillae; and the big lobsters and the crawfish or ‘langoustes’, their spiny cousins. We read about their beady eyes, which turn every way; about their[147] big rough antennae and the smaller, smoother pair between; the great teeth, or mandibles; the carapace with its projecting rostrum, the jointed abdomen with the tail-fins at the end, and the little flaps below on which the female drops her spawn. In more or less detail these things are severally described, and the many limbs severally enumerated, in one kind after another. The descriptions of the lobster and the langouste are particularly minute, and the comparison or contrast between the two is drawn with elaborate precision. In the former, besides other differences between male and female, the female is said to have the ‘first foot’ (or leg) bifurcate, while in the male it is undivided. It seems a trifling matter, but it is true; it is so small a point that I searched long before at last I found mention made of it in a German monograph. The puzzling thing is that it is (as we should say) the last and not the first leg which is so distinguished; but after all, it is only a convention of our own to count the limbs from before backwards. To inspect a lobster’s limbs, we lay it on its back (as Aristotle did), and see the legs overlapping, each hinder one above the one before; the hindmost is the first we see, and the one we must first lift up to inspect the others.

Aristotle’s account of fishes is a prodigious history of habits, food, migrations, modes of capture, times and ways of spawning, and anatomical details; but it is not here that we can elucidate or even illustrate this astonishing Ichthyology. It is not always easy to understand—but the obstacle lies often, I take it, in our own ignorance. The identification of species is not always plain, for here as elsewhere Aristotle did not reckon with a time or place where the familiar words of Greek should be unknown or their homely significance forgotten. Among the great host of fish-names there are several referring, somehow or other, to the Grey Mullet, which puzzle both naturalist and lexicographer. A young officer told me the other day how he had watched an Arab fisherman emptying out his creel of Grey [148] Mullet on some Syrian beach, and the Arab gave four if not five names to as many different kinds, betwixt which my friend could see no difference whatsoever. Had my friend been an ichthyologist he would doubtless have noticed that one had eyelids and the others none; that one had little brushes on its lips, another a small but wide-open slit under the jaw, another a yellow spot on its gill-covers, and so on. The Mullets are a difficult group, but Aristotle, like the Arab fisherman, evidently recognized their fine distinctions and employed the appropriate names. Again, Aristotle speaks of a certain nest-building fish, the ‘phycis’, and regarding this Cuvier fell into error (where once upon a time I followed him). In Cuvier’s time there was but one nest-building fish known such as to suit, apparently, the passage, namely the little black goby; but after Cuvier’s day the nest-building habits of the ‘wrasses’ became known to naturalists, as they had doubtless been known ages before to the fishermen—and to Aristotle.

Like almost every other little point on which we happen to touch, we might make this one the starting-point (here comes in the delight and fascination of the interpreter’s task!) for other stories.

Speusippus, Plato’s successor in the Academy, was both philosopher and naturalist, and we may take it, if we please, that his leaning towards biology, and the biological trend which at this time became more and more marked in Athenian philosophy, were not unconnected with the great impulse which Aristotle had given. However this may be, Speusippus wrote a book περι Ὁμοιων ‘Concerning Resemblances’; and this, of which we only possess a few fragmentary sentences, must have been a very curious and an interesting book. He mentions, among other similar cases, that our little fish phycis has a close outward semblance to the sea-perch; and this is enough to clinch the proof that Aristotle’s nest-building fish was not a goby but a wrasse. The whole purport of [149] Speusippus’s book seems to have been to discuss how, or why, with all Nature’s apparently infinite variety, certain animals have a singularly close resemblance to certain others, though they be quite distinct in kind. It is a problem which perplexes us still, when we are astonished and even deluded by the likeness between a wasp and a hover-fly, a merlin and a cuckoo. In certain extreme cases we call it ‘mimicry’, and invoke hypotheses to account for this ‘mimetic’ resemblance; and those of us who reject these hypotheses must fain take refuge in others, as far-reaching in their way. This at least we know, that Speusippus seized upon a real problem of biology, of lasting interest and even of fundamental importance.

To come back to Aristotle and his fishes, let us glance at one little point more. The reproduction of the eel is an ancient puzzle, which has found its full solution only in our own day. While the salmon, for instance, comes up the river to breed and goes down again to the sea, the eel goes down to the ocean to spawn, and the old eels come back no more but perish in the great waters. The eel’s egg develops into a little flattened, transparent fish, altogether different in outward appearance from an eel, which turns afterwards into a young eel or ‘elver’; and Professor Grassi, who had a big share in elucidating the whole matter, tells us the curious fact that he found the Sicilian fishermen well acquainted with the little transparent larva (the Leptocephalus of modern naturalists), that they knew well what it was, and that they had a name for it—Casentula. Now Aristotle, in a passage which I think has been much misunderstood (and which we must admit to be in part erroneous), tells us that the eel develops from what he calls γης εντερα, a word which we translate, literally, the ‘guts of the earth’, and which commentators interpret as ‘earthworms’! But in Sicilian Doric, γης εντερα would at once become γας εντερα; and between ‘Gasentera’ and the modern Sicilian ‘Casentula’ there is scarce a hairbreadth’s[150] difference. So we may be permitted to suppose that here again Aristotle was singularly and accurately informed; and that he knew by sight and name the little larva of the eel, whose discovery and identification is one of the modest triumphs of recent investigation.

Aristotle’s many pages on fishes are delightful reading. The anatomist may read of such recondite matters as the placenta vitellina of the smooth dog-fish, whereby the viviparous embryo is nourished within the womb, after a fashion analogous to that of mammalian embryology—a phenomenon brought to light anew by Johannes Müller, and which excited him to enthusiastic admiration of Aristotle’s minute and faithful anatomy. Again we may read of the periodic migration of the tunnies, of the great net or ‘madrague’ in which they are captured, and of the watchmen, the θυννοσκοποι, the ‘hooers’ of our ancient Cornish fishery, who give warning from tower or headland of the approaching shoal. The student may learn what manner of fish it was (the great Eagle-ray) with whose barbed fin-spine—most primitive of spear-heads—Ulysses was slain; and again, he may learn not a little about that ναρκη, or torpedo, to which Meno compared his master Socrates, in a somewhat ambiguous compliment.

In rambling fashion Aristotle has a deal to tell us about insects, and he has left us a sort of treatise on the whole natural history of the bee. He knew the several inmates of the hive, though like others of his day (save, perhaps, only Xenophon), and like Shakespeare too, he took the queen-bee for a king. He describes the building of the comb, the laying of the eggs, the provision of the larvae with food. He discusses the various qualities of honey and the flowers from which these are drawn. He is learned in the diseases and the enemies of bees. He tells us many curious things about the economy of the hive and the arts of the bee-keeper, some of which things have a very modern and familiar look about them: for[151] instance, the use of a net or screen to keep out the drones, a net so nicely contrived that these sturdy fellows are just kept out, while the leaner, slenderer workers are just let in. But it would be a long, long story to tell of Aristotle’s knowledge of the bee, and to compare it with what is, haply, the still deeper skill and learning of that master of bee-craft, Virgil.

Then, having perfect freedom to go whithersoever we chose and to follow the bees across the boundless fields of ancient literature, we might read of the wild bees and of their honey out of a rock, and of the hive-bees too, in Homer; follow them to their first legendary home in Crete, where the infant Jupiter was fed on honey—as a baby’s lips are touched with it even unto this day; trace their association with Proserpine and her mother, or their subtler connexion with Ephesian Diana; find in the poets, from Hesiod to the later Anthology, a hundred sweet references—to the bee-tree in the oak-wood, to the flowery hill Hymettus. Perhaps, at last, we might even happen on the place where Origen seems so strangely to foreshadow Shakespeare—speaking of the king of the bees with his retinue of courtiers (his officers of sorts), the relays of workmen (the poor mechanic porters crowding in), the punishment of the idle (where some, like magistrates, correct at home), the wars, the vanquished, and the plunder (which pillage they with merry march bring home To the tent-royal of their Emperor).

Go back to Aristotle, and we may listen to him again while he talks of many other kindred insects: of the humble-bee and its kind, of the mason-bee with its hard round nest of clay, of the robber-bees, and of the various wasps and hornets; or (still more curiously and unexpectedly) of the hunter-wasp or ‘ichneumon’, and how it kills the spider, carries it home to its nest, and lays its eggs in its poor body, that the little wasp-grubs may afterwards be fed. Or again of the great wasps which he calls Anthrenae, and how they chase the big flies, and cut off their heads, and fly away with [152] the rest of the carcass—all agreeing to the very letter with what Henri Fabre tells us of a certain large wasp of Southern Europe, and how it captures the big ‘taons’ or horse-flies: ‘Pour donner le coup de grâce à leurs Taons mal sacrifiés, et se débattants encore entre les pattes du ravisseur, j’ai vu des Bembex mâchonner la tête et le thorax des victimes.’ Verily, there is nothing new under the sun.

With the metamorphoses of various insects Aristotle was well acquainted. He knew how the house-fly passes its early stages in a dung-hill, and how the grubs of the big horse-flies and Tabanids live in decayed wood; how certain little flies or gnats are engendered (as he calls it) in the slime of vinegar. He relates with great care and accuracy the life-history of the common gnat, from its aquatic larva, the little red ‘blood-worm’ of our pools; he describes them wriggling about like tiny bits of red weed, in the water of some half-empty well; and he explains, finally, the change by which they become stiff and motionless and hard, until a husk breaks away and the little gnat is seen sitting upon it; and by and by the sun’s heat or a puff of wind starts it off, and away it flies.

Some of these stories are indeed remarkable, for the events related are more or less hidden and obscure; and so, with all this knowledge at hand, it is not a little strange that Aristotle has very little indeed to tell us about the far more obvious phenomena of the life-history of the butterfly, and of the several kinds of butterflies and moths. He does tell us briefly that the butterfly comes from a caterpillar, which lives on cabbage-leaves and feeds voraciously, then turns into a chrysalis and eats no more, nor has it a mouth to eat withal; it is hard and, as it were, dead, but yet it moves and wriggles when you touch it, and after a while the husk bursts and out comes the butterfly. The account is good enough, so far as it goes, but nevertheless Aristotle shows no affection for the butterfly, does not linger and dally over it, tells no stories about it. This is[153] all of a piece with the rest of Greek literature, and poetry in particular, where allusions to the butterfly are scanty and rare. I think the Greeks found something ominous or uncanny, something not to be lightly spoken of, in that all but disembodied spirit which we call a butterfly, and they called by the name of ψυχη, the Soul. They had a curious name (νεκυδαλλος) for the pupa. It sounds like a ‘little corpse’ (νεκυς); and like a little corpse within its shroud or coffin the pupa sleeps in its cocoon. A late poet describes the butterfly ‘coming back from the grave to the light of day’; and certain of the Fathers of the Church, St. Basil in particular, point the moral accordingly, and draw a doubtless time-honoured allegory of the Resurrection and the Life from the grub which is not dead but sleepeth, and the butterfly which (as it were) is raised in glory.

Of one large moth, Aristotle gives us an account which has been a puzzle to many. This begins as a great grub or caterpillar, with (as it were) horns; and, growing by easy stages, it spins at length a cocoon. There is a class of women who unwind and reel off the cocoons, and afterwards weave a fabric with the thread; and a certain woman of Cos is credited with the invention of this fabric. This is, at first sight, a plain and straightforward description of the silkworm; but we know that it was not till long afterwards, nearly a thousand years after, in Justinian’s reign, that the silkworm and the mulberry-tree which is its food were brought out of the East into Byzantine Greece. We learn something of this Coan silkworm from Pliny, who tells us that it lived on the ash and oak and cypress tree; and from Clement of Alexandria and other of the Fathers we glean a little more—for instance, that the larva was covered with thick-set hairs, and that the cocoon was of a loose material something like a spider’s web. All this agrees in every particular with a certain large moth (Lasiocampa otus), which spins a rough cocoon not unlike that of our Emperor moth, and lives in south-eastern Europe, feeding on the cypress and the oak. [154] Many other silkworms besides the true or common one are still employed, worms which yield the Tussore silks of India and other kindred silks in Japan; and so likewise was this rough silky fabric spun and woven in Hellas, until in course of time it was surpassed and superseded by the finer produce of the ‘Seric worm’, and the older industry died out and was utterly forgotten.

Ere we leave the subject of insects let us linger a moment over one which the Greeks loved, and loved most of all. When as schoolboys we first began to read our Thucydides, we met in the very beginning with the story of how rich Athenians wore Golden Grasshoppers (as the schoolmaster calls them) in their hair. These golden ornaments were, of course, no common grasshoppers, but the little Cicadas, whose sharp chirrup seemed delightful music to the Greeks. It is unpleasant to our ears, as Browning found it; but in a multitude of Greek poets, in Alcaeus and Anacreon and all through the whole Anthology, we hear its praise. We have it, for instance, in the Birds:

Of this familiar and beloved insect Aristotle gives a copious account. He describes two separate species, which we still recognize easily; a larger one and the better singer, the other smaller and the first to come and last to go with the summer season. He recognized the curious vocal organ, or vibratory drum, at the cicada’s waist, and saw that some cicadas possessed it and others not; and he knew, as the poets also knew, that it was the males who sang, while their wives listened and were silent. He tells how the cicada is absent from treeless countries, as, for instance, from Cyrene (and why, I wonder, does he go all the way to Cyrene for his illustration?), neither is it heard in deep and sunless woods; but in the olive-groves you hear it at its best, for an olive-grove is sparse[155] and the sun comes through. Then he tells us briefly, but with remarkable accuracy, the story of the creature’s life: how the female, with her long ovipositor, lays her eggs deep down in dead, hollow twigs, such as the canes on which the vines are propped; how the brood, when they escape from the egg, burrow underground; how later on they emerge, especially in rainy weather, when the rains have softened the soil; how then the larva changes into another form, the so-called ‘nymph’; and how at last, when summer comes, the skin of the nymph breaks and the perfect insect issues forth, changes colour, and begins to sing. In Aristophanes, in Theocritus, in Lucretius, Virgil, Martial, and in the Anthology, we may gather up a host of poetical allusions to the natural history thus simply epitomized.

The Book about Animals, the Historia Animalium as we say, from which I have quoted these few examples of Aristotle’s store of information, may be taken to represent the first necessary stage of scientific inquiry. There is a kind of manual philosophy (as old Lord Monboddo called it) which investigates facts which escape the vulgar, and may be called the anecdotes or secret history of nature. In this fascinating pursuit Gilbert White excelled, and John Ray and many another—the whole brotherhood of simple naturalists. But such accumulated knowledge of facts is but the foundation of a philosophy; and ‘nothing deserves the name of philosophy, except what explains the causes and principles of things’. Aristotle would have done much had he merely shown (as Gilbert White showed to the country gentlemen of his day) that the minute observation of nature was something worth the scholar and the gentleman’s while; but, far more than this, he made a Science of natural knowledge, and set it once for all within the realm of Philosophy. He set it side by side with the more ancient science of Astronomy, which for many hundred years in Egypt and the East, and for some few centuries in Hellas, had occupied the mind of philosophers[156] and the attention of educated men. I have quoted before a great sentence in which he explains his purpose, and makes excuse for his temerity. ‘The glory, doubtless, of the heavenly bodies fills us with more delight than the contemplation of these lowly things; for the sun and stars are born not, neither do they decay, but are eternal and divine. But the heavens are high and afar off, and of celestial things the knowledge that our senses give us is scanty and dim. The living creatures, on the other hand, are at our door, and if we so desire it we may gain ample and certain knowledge of each and all. We take pleasure in the beauty of a statue, shall not then the living fill us with delight; and all the more if in the spirit of philosophy we search for causes and recognize the evidences of design. Then will nature’s purpose and her deep-seated laws be everywhere revealed, all tending in her multitudinous work to one form or another of the Beautiful.’

Aristotle’s voluminous writings have come down to us through many grave vicissitudes. The greatest of them all are happily intact, or very nearly so; but some are lost and others have suffered disorder and corruption. The work known as the ‘Parts of Animals’ opens (as our text has it) with a chapter which seems meant for a general exordium to the whole series of biological treatises; and I know no chapter in all Aristotle’s books which better shows (in plainer English or easier Greek) the master-hand of the great Teacher and Philosopher. He begins by telling us (it has ever since been a common saying) that every science, every branch of knowledge, admits of two sorts of proficiency—that which may properly be termed scientific knowledge, and that which is within the reach of ordinary educated men. He proceeds to discuss the ‘method’ of scientific inquiry, whether we should begin with the specific and proceed to the general, or whether we are to deal first with common or generical characters and thereafterward with special peculiarities. Are we entitled to treat of animals, as is done in mathematical astronomy, by [157] dealing first with facts or phenomena and then proceeding to discover and relate their several causes? At once this leads to a brief discussion (elaborated elsewhere) of the two great Causes, or aspects of cause—the final cause and the ‘moving’ or efficient cause—the reason why or the purpose for which, and the antecedent cause which, of necessity, brings a thing to be such as it is. Here is one of the great crucial questions of philosophy, and Aristotle’s leaning to the side of the Final Cause has been a dominant influence upon the minds of men throughout the whole history of learning. Empedocles had taken another view: he held that the rain comes when it listeth, or ‘of necessity’; that we have no right to suppose it comes to make the corn grow in spring, any more than to spoil the autumn sheaves: that the teeth grow by the operation of some natural (or physical) law, and that their apparent and undoubted fitness for cutting and grinding is not purposeful but coincident; that the backbone is divided into vertebrae because of the antecedent forces, or flexions, which act upon it in the womb. And Empedocles proceeds to the great evolutionary deduction, the clear prevision of Darwin’s philosophy, that fit and unfit arise alike, but that what is fit to survive does survive and what is unfit perishes.

The story is far too long and the theme involved too grave and difficult for treatment here. But I would venture to suggest that Aristotle inclined to slur over the physical and lean the more to the final cause, for this simple reason (whatever other reasons there may be), that he was a better biologist than a physicist: that he lacked somewhat the mathematical turn of mind which was intrinsic to the older schools of philosophy. For better for worse the course he took, the choice he made, was of incalculable import, and had power for centuries to guide (dare we say, to bias) the teaching of the schools, the progress of learning, and the innermost beliefs of men.

In this one short but pregnant chapter of Aristotle’s there is far more than we can hope even to epitomize. He has much [158] to say in it of ‘classification’, an important matter indeed, and he discusses it as a great logician should, in all its rigour. Many commentators have sought for Aristotle’s ‘classification of animals’; for my part I have never found it, and, in our sense of the word, I am certain it is not there. An unbending, unchanging classification of animals would have been something foreign to all his logic; it is all very well, it becomes practically necessary, when we have to arrange our animals on the shelves of a museum or in the arid pages of a ‘systematic’ catalogue; and it takes a new complexion when, or if, we can attain to a real or historical classification, following lines of actual descent and based on proven facts of historical evolution. But Aristotle (as it seems to me) neither was bound to a museum catalogue nor indulged in visions either of a complete scala naturae or of an hypothetical phylogeny. He classified animals as he found them; and, as a logician, he had a dichotomy for every difference which presented itself to his mind. At one time he divided animals into those with blood and those without, at another into the air-breathers and the water-breathers; into the wild and the tame, the social and the solitary, and so on in endless ways besides. At the same time he had a quick eye for the great natural groups, such ‘genera’ (as he called them) as Fish or Bird, Insect or Mollusc. So it comes to pass that, while he fashioned no hard and fast scheme of classification, and would undoubtedly (I hold) have thought it vain to do so, the threads of his several partial or temporary classifications come together after all, though in a somewhat hazy pattern, yet in a very beautiful and coherent parti-coloured web. And though his order is not always our order, yet a certain exquisite orderliness is of the very essence of his thought and style. It is the characteristic which Molière hits upon in Les Femmes savantes,—‘Je m’attache pour l’ordre au péripatétisme’.

Before he finishes the great chapter of which we have begun to speak he indicates that there are more ways than one of [159] relating, or classifying, our facts; that, for instance, it may be equally proper and necessary to deal now with the animals and their several parts or properties, and at another time with the parts or properties as such, explaining and illustrating them in turn by the several animals which display or possess them. The ‘Parts of Animals’ is, then, a corollary, a necessary corollary, to the more anecdotal Historia Animalium. And yet again, there is a third alternative—to discuss the great functions or actions or potentialities of the organism, as it were first of all in the abstract, and then to correlate them with the parts which in this or that creature are provided and are ‘designed’ to effect them. This involves the conception and the writing of separate physiological treatises on such themes as Respiration, Locomotion, on Sleeping and Waking, and lastly (and in some respects the most ambitious, most erudite, and most astonishing of them all) the great account of the Generation of Animals.

So the whole range, we might say the whole conceivable range, of biological science is sketched out, and the greater part of the great canvas is painted in. But to bring it into touch with human life, and to make good its claim to the high places of philosophy, we must go yet farther and study Life itself, and what men call the Soul. So grows the great conception. We begin with trivial anecdote, with the things that fisherman, huntsman, peasant know; the sciences of zoology, anatomy, physiology take shape before our very eyes; and by evening we sit humbly at the feet of the great teacher of Life itself, the historian of the Soul. It is not for us to attempt to show that even here the story does not end, but the highest chapters of philosophy begin. Then, when we remember that this short narrative of ours is but the faintest adumbration of one side only of the philosopher’s many-sided task and enterprise, we begin to rise towards a comprehension of Roger Bacon‘s saying, that ‘although Aristotle did not arrive at the end of knowledge, he set in order all parts of [160] philosophy’. In the same spirit a modern critic declares: ‘Il n’a seulement défini et constitué chacune des parties de la science; il en a de plus montré le lien et l’unité’.

Aristotle, like Shakespeare, is full of old saws, tags of wisdom, jewels five words long. Here is such a one, good for teacher and pupil alike—Δει πιστευειν τον μανθανοντα. It tells us that the road to Learning lies through Faith; and it means that to be a scholar one should have a heart as well as brains.

By reason partly of extraneous interpolation, but doubtless also through a lingering credulity from which even philosophers are not immune, we find in Aristotle many a strange story. The goats that breathe through their ears, the vulture impregnated by the wind, the eagle that dies of hunger, the stag caught by music, the salamander which walks through fire, the unicorn, the mantichore, are but a few of the ‘Vulgar Errors’ or ‘Received Tenents’ (as Sir Thomas Browne has it) which are perpetuated, not originated, in the Historia Animalium. Some of them come, through Persia, from the farther East: and others (we meet with them once more in Horapollo the Egyptian priest) are but the exoteric or allegorical expression of the arcana of ancient Egyptian religion.

So it comes to pass that for two thousand years and throughout all lands men have come to Aristotle, and found in him information and instruction—that which they desired. Arab and Moor and Syrian and Jew treasured his books while the western world sat in darkness; the great centuries of Scholasticism hung upon his words; the oldest of our Universities, Bologna, Paris, Oxford, were based upon his teaching, yea, all but established for his study. Where he has been, there, seen or unseen, his influence remains; even the Moor and the Arab find in him, to this day, a teacher after their own hearts: a teacher of eternal verities, telling of sleep and dreams, of youth and age, of life and death, of generation and corruption, of growth and of decay: a guide to the book of Nature, a revealer of the Spirit, a prophet of the works of God.

[161] The purpose of these little essays, I have been told (though I had half forgotten it), is to help though ever so little to defend and justify the study of the language and the vast literature of Greece. It is a task for which I am unfitted and unprepared. When Oliver Goldsmith proposed to teach Greek at Leyden, where he ‘had been told it was a desideratum’, the Principal of that celebrated University met him (as we all know) with weighty objections. ‘I never learned Greek’, said the Principal, ‘and I don’t find that I have ever missed it. I have had a Doctor’s cap and gown without Greek. I have ten thousand florins a year without Greek; and, in short’, continued he, ‘as I don’t know Greek, I do not believe there is any good in it.’—I have heard or read the story again and again, for is it not written in the Vicar of Wakefield? But I never heard that any man, not Goldsmith himself, attempted to confute the argument. I agree for the most part with the Principal, and can see clearly that all the Greek that Goldsmith knew, and all the Greek in all the world, would have meant nothing and done nothing for him. But there is and will be many another who finds in Greek wisdom and sweet Hellenic speech something which he needs must have, and lacking which he would be poor indeed: something which is as a staff in his hand, a light upon his path, a lantern to his feet.

In this workaday world we may still easily possess ourselves, as Gibbon says the subjects of the Byzantine Throne, even in their lowest servitude and depression, were still possessed, ‘of a golden key that could unlock the treasures of antiquity, of a musical and prolific language that gives a soul to the objects of sense, and a body to the abstractions of philosophy’.

Our very lives seem prolonged by the recollection of antiquity; for, as Cicero says, not to know what has been transacted in former times is to continue always a child. I borrow the citation from Dr. Johnson, who reminds us also of a saying of Aristotle himself, that as students we ought first to examine[162] and understand what has been written by the ancients, and then cast our eyes round upon the world. And Johnson prefaces both quotations by another:

But now I, who have dared to draw my tiny draft from Aristotle’s great well, seem after all to be seeking an excuse, seeking it in example and precept. Precept, at least, I know to be of no avail. My father spent all the many days of his life in the study of Greek; you might suppose it was for Wisdom’s sake,—but my father was a modest man. The fact is, he did it for a simpler reason still, a very curious reason, to be whispered rather than told: he did it for love.

Nigh forty years ago, I first stepped out on the east-windy streets of a certain lean and hungry town (lean, I mean, as regards scholarship) where it was to be my lot to spend thereafter many and many a year. And the very first thing I saw there was an inscription over a very humble doorway, ‘Hic mecum habitant Dante, Cervantes, Molière’. It was the home of a poor schoolmaster, who as a teacher of languages eked out the scanty profits of his school. I was not a little comforted by the announcement. So the poor scholar, looking on the ragged regiment of his few books, is helped, consoled, exalted by the reflection: Hic mecum habitant ... Homerus, Plato, Aristoteles. And were one in a moment of inadvertence to inquire of him why he occupied himself with Greek, he might perchance stammer (like Dominie Sampson) an almost inarticulate reply; but more probably he would be stricken speechless by the enormous outrage of the request, and the reason of his devotion would be hidden from the questioner for ever.

D’Arcy Wentworth Thompson.

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[163]

BIOLOGY

Before Aristotle

What is science? It is a question that cannot be answered easily, nor perhaps answered at all. None of the definitions seem to cover the field exactly; they are either too wide or too narrow. But we can see science in its growth and we can say that being a process it can exist only as growth. Where does the science of biology begin? Again we cannot say, but we can watch its evolution and its progress. Among the Greeks the accurate observation of living forms, which is at least one of the essentials of biological science, goes back very far. The word Biology, used in our sense, would, it is true, have been an impossibility among them, for bios refers to the life of man and could not be applied, except in a strained or metaphorical sense, to that of other living things.[6] But the ideas we associate with the word are clearly developed in Greek philosophy and the foundations of biology are of great antiquity.

The Greek people had many roots, racial, cultural, and spiritual, and from them all they inherited various powers and qualities and derived various ideas and traditions. The most suggestive source for our purpose is that of the Minoan race whom they dispossessed and whose lands they occupied. That highly gifted people exhibited in all stages of its development a marvellous power of graphically representing animal forms, of which the famous Cretan friezes, Vaphio cups (Fig. 5), and [164] Mycenean lions provide well-known examples. It is difficult not to believe that the Minoan element, entering into the mosaic of peoples that we call the Greeks, was in part at least responsible for the like graphic power developed in the Hellenic world, though little contact has yet been demonstrated between Minoan and archaic Greek Art.

For the earliest biological achievements of Greek peoples we have to rely largely on information gleaned from artistic remains. It is true that we have a few fragments of the works of both Ionian and Italo-Sicilian philosophers, and in them we read of theoretical speculation as to the nature of life and of the soul, and we can thus form some idea of the first attempts of such workers as Alcmaeon of Croton (c. 500 B. C.) to lay bare the structure of animals by dissection.[7] The pharmacopœia also of some of the earliest works of the Hippocratic collection betrays considerable knowledge of both native and foreign plants.[8] Moreover, scattered through the pages of Herodotus and other early writers is a good deal of casual information concerning animals and plants, though such material is second-hand and gives us little information concerning the habit of exact observation that is the necessary basis of science.

Something more is, however, revealed by early Greek Art. We are in possession of a series of vases of the seventh and sixth centuries before the Christian era showing a closeness of observation of animal forms that tells of a people awake to the study of nature. We have thus portrayed for us a number of animals—plants seldom or never appear—and among the best rendered are wild creatures: we see antelopes quietly feeding or startled at a sound, birds flying or picking worms from the ground, fallow[165] deer forcing their way through thickets, browsing peacefully, or galloping away, boars facing the hounds and dogs chasing hares, wild cattle forming their defensive circle, hawks seizing their prey. Many of these exhibit minutely accurate observation. The very direction of the hairs on the animals’ coats has sometimes been closely studied, and often the muscles are well rendered. In some cases even the dentition has been found[166] accurately portrayed, as in a sixth-century representation on an Ionian vase of a lioness—an animal then very rare on the Eastern Mediterranean littoral, but still known in Babylonia, Syria, and Asia Minor. The details of the work show that the artist must have examined the animal in captivity (Figs. 1 and 2).

Animal paintings of this order are found scattered over the Greek world with special centres or schools in such places as Cyprus, Boeotia, or Chalcis. The very name for a painter in Greek, zoographos, recalls the attention paid to living forms. By the fifth century, in painting them as in other departments of Art, the supremacy of Attica had asserted itself, and there are many beautiful Attic vase-paintings of animals to place by the side of the magnificent horses’ heads of the Parthenon (Fig. 6). In Attica, too, was early developed a characteristic and closely accurate type of representation of marine forms, and this attained a wider vogue in Southern Italy in the fourth century. From the latter period a number of dishes and vases have come down to us bearing a large variety of fish forms, portrayed with an exactness that is interesting in view of the attention to marine creatures in the surviving literature of Aristotelian origin (Fig. 3).

These artistic products are more than a mere reflex of the [167] daily life of the people. The habits and positions of animals are observed by the hunter, as are the forms and colours of fish by the fisherman; but the methods of huntsman and fisher do not account for the accurate portrayal of a lion’s dentition, the correct numbering of a fish’s scales or the close study of the lie of the feathers on the head, and the pads on the feet, of a bird of prey (Fig. 4). With observations such as these we are in the presence of something worthy of the name Biology. Though but little literature on that topic earlier than the writings of Aristotle has come down to us, yet both the character of his writings and such paintings and pictures as these, suggest the existence of a strong interest and a wide literature, biological in the modern sense, antecedent to the fourth century.

Greek science, however, exhibits throughout its history a peculiar characteristic differentiating it from the modern scientific standpoint. Most of the work of the Greek scientist was done in relation to man. Nature interested him mainly in relation to himself. The Greek scientific and philosophic world was an anthropocentric world, and this comes out in[168] the overwhelming mass of medical as distinct from biological writings that have come down to us. Such, too, is the sentiment expressed by the poets in their descriptions of the animal creation:

It is thus not surprising that our first systematic treatment of animals is in a practical medical work, the περι διαιτης, On diet, of the Hippocratic Collection. This very peculiar treatise dates from the later part of the fifth century. It is strongly under the influence of Heracleitus (c. 540-475) and contains many points of view which reappear in later philosophy. All animals, according to it, are formed of fire and water, nothing is born and nothing dies, but there is a perpetual and eternal revolution of things, so that change itself is the only reality. Man’s nature is but a parallel to that of the universal nature, and the arts of man are but an imitation or reflex of the natural arts or, again, of the bodily functions. The soul, a mixture of water and fire, consumes itself in infancy and old age, and increases during adult life. Here, too, we meet with that singular doctrine, not without bearing on the course of later biological thought, that in the foetus all parts are formed simultaneously. On the proportion of fire and water in the body all depends, sex, temper, temperament, intellect. Such speculative ideas separate this book from the sober method of the more typical Hippocratic medical works with which indeed it has little in common.

[169] After having discussed these theoretical matters the work turns to its own practical concerns, and in the course of setting out the natures of foods gives in effect a rough classification of animals. These are set forth in groups, and from among the larger groups only the reptiles and insects are missing. The list has been described, perhaps hardly with justification, as the Coan classificatory system. We have here, indeed, no system in the sense in which that word is now applied to the animal kingdom, but we have yet some sort of definite arrangement of animals according to their supposed natures. The passage opens with mammals, which are divided into domesticated and wild, the latter being mentioned in order according to size, next follow the land-birds, then the water-fowl, and then the fishes. These fish are divided into (1) the haunters of the shore, (2) the free-swimming forms, (3) the cartilaginous fishes or Selachii, which are not so named but are placed together, (4) the mud-loving forms, and (5) the fresh-water fish. Finally come invertebrates arranged in some sort of order according to their structure. The characteristic feature of the ‘classification’ is the separation of the fish from the remaining vertebrates and of the invertebrates from both. Of the fifty animals named no less than twenty are fish, about a fifth of the number studied by Aristotle, but we must remember that here only edible species are mentioned. The existence of the work shows at least that in the fifth century there was already a close and accurate study of animal forms, a study that may justly be called scientific. The predominance of fish and their classification in greater detail than the other groups is not an unexpected feature. The Mediterranean is especially rich in these forms, the Greeks were a maritime people, and Greek literature is full of imagery drawn from the fisher’s craft. From Minoan to Byzantine times the variety, beauty, and colour of fish made a deep impression on Greek minds as reflected in their art.

Much more important, however, for subsequent biological [170] development than such observations on the nature and habits of animals, is the service that the Hippocratic physicians rendered to Anatomy and to Physiology, departments in which the structure of man and of the domesticated animals stands apart from that of the rest of the animal kingdom. It is with the nature and constitution of man that most of the surviving early biological writings are concerned, and in these departments are unmistakable tendencies towards systematic arrangement of the material. Thus we have division and description of the body in sevens from the periphery to the centre and from the vertex to the sole of the foot,[9] or a division into four regions or zones.[10] The teaching concerning the four elements and four humours too became of great importance and some of it was later adopted by Aristotle. We also meet numerous mechanical explanations of bodily structures, comparisons between anatomical conditions encountered in related animals, experiments on living creatures,[11] systematic incubation of hen’s eggs for the study of their development, parallels drawn between the development of plants and of human and animal embryos, theories of generation, among which is that which was afterwards called ‘pangenesis’—discussion of the survival of the stronger over the weaker—almost our survival of the fittest—and a theory of inheritance of acquired characters.[12] All these things show not only extensive knowledge but also an attempt to apply such knowledge to human needs. When we consider how even in later centuries biology was linked with medicine, and how powerful and fundamental was the influence of the Hippocratic writings, not only on their immediate successors in antiquity, but also on the Middle Ages and right into the nineteenth century, we shall recognize the significance of these developments.

 

[171] Such was the character of biological thought within the fifth century, and a generation inspired by this movement produced some noteworthy works in the period which immediately followed. In the treatise περι τροφης, On nourishment, which may perhaps be dated about 400 B. C., we learn of the pulse for the first time in Greek medical literature, and read of a physiological system which lasted until the time of Harvey, with the arteries arising from the heart and the veins from the liver. Of about the same date is a work περι καρδιης, On the heart, which describes the ventricles as well as the great vessels and their valves, and compares the heart of animals with that of man.

A little later, perhaps 390 B. C., is the treatise περι σαρκων, On muscles, which contains much more than its title suggests. It has the old system of sevens and, inspired perhaps by the philosophy of Heracleitus (c. 540-475), describes the heart as sending air, fire, and movement to the different parts of the body through the vessels which are themselves constantly in movement. The infant in its mother’s womb is believed to draw in air and fire through its mouth and to eat in utero. The action of the air on the blood is compared to its action on fire. In contrast to some of the other Hippocratic treatises the central nervous system is in the background; much attention, however, is given to the special senses. The brain resounds during audition. The olfactory nerves are hollow, lead to the brain, and, convey volatile substances to it which cause it to secrete mucus. The eyes also have been examined, and their coats and humours roughly described; an allusion, the first in literature, is perhaps made to the crystalline lens, and the eyes of animals are compared with those of man. There is evidence not only of dissection but of experiment, and in efforts to compare the resistance of various tissues to such processes as boiling, we may see the small beginning of chemical physiology.

[172] An abler work than any of these, but exhibiting less power of observation is a treatise, περι γονης, On generation, that may perhaps be dated about 380 B. C.[13] It exhibits a writer of much philosophic power, very anxious for physiological explanations, but hampered by ignorance of physics. He has, in fact, the weaknesses and in a minor degree the strength of his successor Aristotle, of whose great work on generation he gives us a fore-taste. He sets forth in considerable detail a doctrine of pangenesis, not wholly unlike that of Darwin. In order to explain the phenomena of inheritance he supposes that vessels reach the seed, carrying with them samples from all parts of the body. He believes that channels pass from all the organs to the brain and then to the spinal marrow (or to the marrow direct), thence to the kidneys and on to the genital organs; he believes, too, that he knows the actual location of one such channel, for he observes, wrongly, that incision behind the ears, by interrupting the passage, leads to impotence. As an outcome of this theory he is prepared to accept inheritance of acquired characters. The embryo develops and breathes by material transmitted from the mother through the umbilical cord. We encounter here also a very detailed description of a specimen of exfoliated membrana mucosa uteri which our author mistakes for an embryo, but his remarks at least exhibit the most eager curiosity.[14]

The author of this work on generation is thus a ‘biologist’ in the modern sense, and among the passages exhibiting him in this light is his comparison of the human embryo with the chick. ‘The embryo is in a membrane in the centre of which is the navel through which it draws and gives its breath, and the[173] membranes arise from the umbilical cord.... The structure of the child you will find from first to last as I have already described.... If you wish, try this experiment: take twenty or more eggs and let them be incubated by two or more hens. Then each day from the second to that of hatching remove an egg, break it, and examine it. You will find exactly as I say, for the nature of the bird can be likened to that of man. The membranes [you will see] proceed from the umbilical cord, and all that I have said on the subject of the infant you will find in a bird’s egg, and one who has made these observations will be surprised to find an umbilical cord in a bird’s egg.’[15]

The same interest that he exhibits for the development of man and animals he shows also for plants.

‘A seed laid in the ground fills itself with the juices there contained, for the soil contains in itself juices of every nature for the nourishment of plants. Thus filled with juice the seed is distended and swells, and thereby the power (= faculty ἡ δυναμις) diffused in the seed is compressed by pneuma and juice, and bursting the seed becomes the first leaves. But a time comes when these leaves can no longer get nourished from the juices in the seed. Then the seed and the leaves erupt below, for urged by the leaves the seed sends down that part of its power which is yet concentrated within it and so the roots are produced as an extension of the leaves. When at last the plant is well rooted below and is drawing its nutriment from the earth, then the whole grain disappears, being absorbed, save for the husk, which is the most solid part; and even that, decomposing in the earth, ultimately becomes invisible. In time some of the leaves put forth branches. The plant being thus produced by humidity from the seed is still soft and moist. Growing actively both above and below, it cannot as yet bear fruit, for it has not the quality of force and reserve (δυναμις ισχυρη και πιαρα) from which a seed can be precipitated. But when, with time, the plant becomes firmer and better rooted, it develops veins as passages both[174] upwards and downwards, and it draws from the soil not only water but more abundantly also substances that are denser and fatter. Warmed, too, by the sun, these act as a ferment to the extremities and give rise to fruit after its kind. The fruit thus develops much from little, for every plant draws from the earth a power more abundant than that with which it started, and the fermentation takes place not at one place but at many.’[16]

Nor does our author hesitate to draw an analogy between the plant and the mammalian embryo. ‘In the same way the infant lives within its mother’s womb and in a state corresponding to the health of the mother ... and you will find a complete similitude between the products of the soil and the products of the womb.’

The early Greek literature is so scantily provided with illustrations drawn from botanical study, that it is worth considering the remarkable comparison of generation of plants from cuttings and from seeds in the same work.

‘As regards plants generated from cuttings ... that part of a branch where it was cut from a tree is placed in the earth and there rootlets are sent out. This is how it happens: The part of the plant within the soil draws up juices, swells, and develops a pneuma (πνευμα ισχει), but not so the part without. The pneuma and the juice concentrate the power of the plant below so that it becomes denser. Then the lower end erupts and gives forth tender roots. Then the plant, taking from below, draws juices from the roots and transmits them to the part above the soil which thus also swells and develops pneuma; thus the power from being diffused in the plant becomes concentrated and budding, gives forth leaves.... Cuttings, then, differ from seeds. With a seed the leaves are borne first, then the roots are sent down; with a cutting the roots form first and then the leaves.’[17]

But with these works of the early part of the fourth century the first stage of Greek biology reaches its finest development. [175] Later Hippocratic treatises which deal with physiological topics are on a lower plane, and we must seek some external cause for the failure. Nor have we far to seek. This period saw the rise of a movement that had the most profound influence on every department of thought. We see the advent into the Greek world of a great intellectual movement as a result of which the department of philosophy that dealt with nature receded before Ethics. Of that intellectual revolution—perhaps the greatest the world has seen—Athens was the site and Socrates (470-399) the protagonist. With the movement itself and its characteristic fruit we are not concerned. But the great successor and pupil of its founder gives us in the Timaeus a picture of the depth to which natural science can be degraded in the effort to give a specific teleological meaning to all parts of the visible Universe. The book and the picture which it draws, dark and repulsive to the mind trained in modern scientific method, enthralled the imagination of a large part of mankind for wellnigh two thousand years. Organic nature appears in this work of Plato (427-347) as the degeneration of man whom the Creator has made most perfect. The school that held this view ultimately decayed as a result of its failure to advance positive knowledge. As the centuries went by its views became further and further divorced from phenomena, and the bizarre developments of later Neoplatonism stand to this day as a warning against any system which shall neglect the investigation of nature. But in its decay Platonism dragged science down and destroyed by neglect nearly all earlier biological material. Mathematics, not being a phenomenal study, suited better the Neoplatonic mood and continued to advance, carrying astronomy with it for a while—astronomy that affected the life of man and that soon became the handmaid of astrology; medicine, too, that determined the conditions of man’s life was also cherished, though often mistakenly, but pure science was doomed.

[176] But though the ethical view of nature overwhelmed science in the end, the advent of the mighty figure of Aristotle (384-322) stayed the tide for a time. Yet the writer on Greek Biology remains at a disadvantage in contrast with the Historian of Greek Mathematics, of Greek Astronomy, or of Greek Medicine, in the scantiness of the materials for presenting an account of the development of his studies before Aristotle. The huge form of that magnificent naturalist completely overshadows Greek as it does much of later Biology.

Charles Singer.

After Aristotle

All Aristotle’s surviving biological works refer primarily to the animal creation. His work on plants is lost or rather has survived as the merest corrupted fragment. We are fortunate, however, in the possession of a couple of complete works by his pupil and successor Theophrastus (372-287), which may not only be taken to represent the Aristotelian attitude towards the plant world, but also give us an inkling of the general state of biological science in the generation which succeeded the master.

These treatises of Theophrastus are in many respects the most complete and orderly of all ancient biological works that have reached our time. They give an idea of the kind of interest that the working scientist of that day could develop when inspired rather by the genius of a great teacher than by the power of his own thoughts. Theophrastus is a pedestrian where Aristotle is a creature of wings, he is in a relation to the master of the same order that the morphologists of the second half of the nineteenth century were to Darwin. For a couple of generations after the appearance of the Origin of Species in 1859 the industry and ability of naturalists all over the world were occupied in working out in detail the structure[177] and mode of life of living things on the basis of the Evolutionary philosophy. Nearly all the work on morphology and much of that on physiology since his time might be treated as a commentary on the works of Darwin. These volumes of Theophrastus give the same impression. They represent the remains—alas, almost the only biological remains—of a school working under the impulse of a great idea and spurred by the memory of a great teacher. As such they afford a parallel to much scientific work of our own day, produced by men without genius save that provided by a vision and a hope and an ideal. Of such men it is impossible to write as of Aristotle. Their lives are summed up by their actual achievement, and since Theophrastus is an orderly writer whose works have descended to us in good state, he is a very suitable instance of the actual standard of achievement of ancient biology. ‘Without vision the people perish’ and the very breath of life of science is drawn, and can only be drawn, from that very small band of prophets who from time to time, during the ages, have provided the great generalizations and the great ideals. In this light let us examine the work of Theophrastus.

In the absence of any adequate system of classification, almost all botany until the seventeenth century consisted mainly of descriptions of species. To describe accurately a leaf or a root in the language in ordinary use would often take pages. Modern botanists have invented an elaborate terminology which, however hideous to eye and ear, has the crowning merit of helping to abbreviate scientific literature. Botanical writers previous to the seventeenth century were substantially without this special mode of expression. It is partly to this lack that we owe the persistent attempts throughout the centuries to represent plants pictorially in herbals, manuscript and printed, and thus the possibility of an adequate history of plant illustration.

Theophrastus seems to have felt acutely the need of botanical [178] terms, and there are cases in which he seeks to give a special technical meaning to words in more or less current use. Among such words are carpos = fruit, pericarpion = seed vessel = pericarp, and metra, the word used by him for the central core of any stem whether formed of wood, pith, or other substance. It is from the usage of Theophrastus that the exact definition of fruit and pericarp has come down to us.[18] We may easily discern also the purpose for which he introduces into botany the term metra, a word meaning primarily the womb, and the vacancy in the Greek language which it was made to fill. ‘Metra,’ he says, ‘is that which is in the middle of the wood, being third in order from the bark and [thus] like to the marrow in bones. Some call it the heart (καρδιαν), others the inside (εντεριωνην), yet others call only the innermost part of the metra itself the heart, while others again call this marrow.’[19] He is thus inventing a word to cover all the different kinds of core and importing it from another study. This is the method of modern scientific nomenclature which hardly existed for botanists even as late as the sixteenth century of our era. The real foundations of our modern nomenclature were laid in the later sixteenth and in the seventeenth century by Cesalpino and Joachim Jung.

Theophrastus understood the value of developmental study, a conception derived from his master. ‘A plant’, he says, ‘has power of germination in all its parts, for it has life in them all, wherefore we should regard them not for what they are but for what they are becoming.’[20] The various modes of plant reproduction are correctly distinguished in a way that passes beyond the only surviving earlier treatise that deals in[179] detail with the subject, the Hippocratic work On generation. ‘The manner of generation of trees and plants are these: spontaneous, from a seed, from a root, from a piece torn off, from a branch or twig, from the trunk itself, or from pieces of the wood cut up small.’[21] The marvel of germination must have awakened admiration from a very early date. We have already seen it occupying a more ancient author, and it had also been one of the chief preoccupations of Aristotle. It is thus not remarkable that the process should impress Theophrastus, who has left on record his views on the formation of the plant from the seed.

‘Some germinate, root and leaves, from the same point, some separately from either end of the seed. Thus wheat, barley, spelt, and all such cereals [germinate] from either end, corresponding to the position [of the seed] in the ear, the root from the stout lower part, the shoot from the upper; but the two, root and stem, form a single continuous whole. The bean and other leguminous plants are not so, but in them root and stem are from the same point, namely, their place of attachment to the pod, where, it is plain, they have their origin. In some cases there is a process, as in beans, chick peas, and especially lupines, from which the root grows downward, the leaf and stem upward.... In certain trees the bud first germinates within the seed, and, as it increases in size, the seeds split—all such seeds are, as it were, in two halves; again, all those of leguminous plants have plainly two lobes and are double—and then the root is immediately thrust out. But in cereals, the seeds being in one piece, this does not happen, but the root grows a little before [the shoot].

‘Barley and wheat come up monophyllous, but peas, beans, and chick peas polyphyllous. All leguminous plants have a single woody root, from which grow slender side roots ... but wheat, barley, and the other cereals have numerous slender roots by which they are matted together.... There is a contrast between these two kinds; the leguminous plants have[180] a single root and have many side-growths above from the [single] stem ... while the cereals have many roots and send up many shoots, but these have no side-shoots.’[22]

There can be no doubt that here is a piece of minute observation on the behaviour of germinating seeds. The distinction between dicotyledons and monocotyledons is accurately set forth, though the stress is laid not so much on the cotyledonous character of the seed as on the relation of root and shoot. In the dicotyledons root and shoot are represented as springing from the same point, and in monocotyledons from opposite poles in the seed.

No further effective work was done on the germinating seed until the invention of the microscope, and the appearance of the work of Highmore (1613-85),[23] and the much more searching investigations of Malpighi (1628-94[24] and Grew (1641-1712)[25] after the middle of the seventeenth century. The observations of Theophrastus are, however, so accurate, so lucid, and so complete that they might well be used as legends for the plates of these writers two thousand years after him.

Much has been written as to the knowledge of the sex of plants among the ancients. It may be stated that of the sexual elements of the flower no ancient writer had any clear idea. Nevertheless, sex is often attributed to plants, and the simile of the Loves of Plants enters into works of the poets. Plants are frequently described as male and female in ancient biological writings also, and Pliny goes so far as to say that some students considered that all herbs and trees were sexual.[26] Yet when such passages can be tested it will be found that these so-called males and females are usually different species. In[181] a few cases a sterile variety is described as the male and a fertile as the female. In a small residuum of cases diœcious plants or flowers are regarded as male and female, but with no real comprehension of the sexual nature of the flowers. There remain the palms, in which the knowledge of plant sex had advanced a trifle farther. ‘With dates’, says Theophrastus, ‘the males should be brought to the females; for the males make the fruit persist and ripen, and this some call by analogy to use the wild fig (ολυνθαζειν).[27] The process is thus: when the male is in the flower they at once cut off the spathe with the flower and shake the bloom, with its flower and dust, over the fruit of the female, and, if it is thus treated, it retains the fruit and does not shed it.’[28] The fertilizing character of the spathe of the male date palm was familiar in Babylon from a very early date. It is recorded by Herodotus[29] and is represented by a frequent symbol on the Assyrian monuments.

The comparison of the fertilization of the date palm to the use of the wild fig refers to the practice of Caprification. Theophrastus tells us that there are certain trees, the fig among them, which are apt to shed their fruit prematurely. To remedy this ‘the device adopted is caprification. Gall insects come out of the wild figs which are hanging there, eat the tops of the cultivated figs, and so make them swell’.[30] These gall-insects ‘are engendered from the seeds’.[31] Theophrastus distinguished between the process as applied to the fig and the date, observing that ‘in both [fig and date] the[182] male aids the female—for they call the fruit-bearing [palm] female—but whilst in the one there is a union of the two sexes, in the other things are different’.[32]

Theophrastus was not very successful in distinguishing the nature of the primary elements of plants, though he was able to separate root, stem, leaf, stipule, and flower on morphological as well as to a limited extent on physiological grounds. For the root he adopts the familiar definition, the only one possible before the rise of chemistry, that it ‘is that by which the plant draws up nourishment’,[33] a description that applies to the account given by the pre-Aristotelian author of the work περι γονης, On generation. But Theophrastus shows by many examples that he is capable of following out morphological homologies. Thus he knows that the ivy regularly puts forth roots from the shoots between the leaves, by means of which it gets hold of trees and walls,[34] that the mistletoe will not sprout except on the bark of living trees into which it strikes its roots, and that the very peculiar formation of the mangrove tree is to be explained by the fact that ‘this plant sends out roots from the shoots till it has hold on the ground and roots again: and so there comes to be a continuous circle of roots round the tree, not connected with the main stem, but at a distance from it’.[35] He does not succeed, however, in distinguishing the real nature of such structures as bulbs, rhizomes, and tubers, but regards them all as roots. Nor is he more successful in his discussion of the nature of stems. As to leaves, he is more definite and satisfactory, though wholly in the dark as to their function; he is quite clear that the pinnate leaf of the rowan tree, for instance, is a leaf and not a branch.

Notwithstanding his lack of insight as to the nature of sex in flowers, he attains to an approximately correct idea of the[183] relation of flower and fruit. Some plants, he says, ‘have [the flower] around the fruit itself as vine and olive; [the flowers] of the latter, when they drop, look as though they had a hole through them, and this is taken for a sign that it has blossomed well; for if [the flower] is burnt up or sodden, the fruit falls with it, and so it does not become pierced. Most flowers have the fruit case in the middle, or it may be the flower is on the top of the pericarp as in pomegranate, apple, pear, plum, and myrtle ... for these have their seeds below the flower.... In some cases again the flower is on top of the seeds themselves as in ... all thistle-like plants’.[36] Thus Theophrastus has succeeded in distinguishing between the hypogynous, perigynous, and epigynous types of flower, and has almost come to regard its relation to the fruit as the essential floral element.

Theophrastus has a perfectly clear idea of plant distribution as dependent on soil and climate, and at times seems to be on the point of passing from a statement of climatic distribution into one of real geographical regions. The general question of plant distribution long remained at, if it did not recede from, the position where he left it. The usefulness of the manuscript and early printed herbals in the West was for centuries marred by the retention of plant descriptions prepared for the Greek East and Latin South, and these works were saved from complete ineffectiveness only by an occasional appeal to nature.

With the death of Theophrastus about 287 B. C. pure biological science substantially disappears from the Greek world, and we get the same type of deterioration that is later encountered in other scientific departments. Science ceases to have the motive of the desire to know, and becomes an applied study, subservient to the practical arts. It is an attitude from which in the end applied science itself must suffer also. Yet the centuries that[184] follow were not without biological writers of very great ability. In the medical school of Alexandria anatomy and physiology became placed on a firm basis from about 300 B. C., but always in the position subordinate to medicine that they have since occupied. Two great names of that school, Herophilus and Erasistratus, we must consider elsewhere.[37] Their works have disappeared and we have the merest fragments of them. In the last pre-Christian and the first two post-Christian centuries, however, there were several writers, portions of whose works have survived and are of great biological importance. Among them we include Crateuas, a botanical writer and illustrator, who greatly developed, if he did not actually introduce, the method of representing plants systematically by illustration rather than by description. This method, important still, was even more important when there was no proper system of botanical nomenclature. Crateuas by his paintings of plants, copies of which have not improbably descended to our time, began a tradition which, fixed about the fifth century, remained almost rigid until the re-discovery of nature in the sixteenth. He was physician to Mithridates VI Eupator (120-63 B. C.), but his work was well known and appreciated at Rome, which became the place of resort for Greek talent.[38]

Celsus, who flourished about 20 B. C., wrote an excellent work on medicine, but gives all too little glimpse of anatomy and physiology. Rufus of Ephesus, however, in the next century practised dissection of apes and other animals. He described the decussation of the optic nerves and the capsule of the crystalline lens, and gave the first clear description that has survived of the structure of the eye. He regarded the nerves[185] as originating from the brain, and distinguished between nerves of motion and of sensation. He described the oviduct of the sheep and rightly held that life was possible without the spleen.

The second Christian century brings us two writers who, while scientifically inconsiderable, acted as the main carriers of such tradition of Greek biology as reached the Middle Ages, Pliny and Dioscorides. Pliny (A. D. 23-79), though a Latin, owes almost everything of value in his encyclopaedia to Greek writings. In his Natural History we have a collection of current views on the nature, origin, and uses of plants and animals such as we might expect from an intelligent, industrious, and honest member of the landed class who was devoid of critical or special scientific skill. Scientifically the work is contemptible, but it demands mention in any study of the legacy of Greece, since it was, for centuries, a main conduit of the ancient teaching and observations on natural history. Read throughout the ages, alike in the darkest as in the more enlightened periods, copied and recopied, translated, commented on, extracted and abridged, a large part of Pliny’s work has gradually passed into folk-keeping, so that through its agency the gipsy fortune-teller of to-day is still reciting garbled versions of the formulae of Aristotle and Hippocrates of two and a half millennia ago.

The fate of Dioscorides (flourished A. D. 60) has been not dissimilar. His work On Materia Medica consists of a series of short accounts of plants, arranged almost without reference to the nature of the plants themselves, but quite invaluable for its terse and striking descriptions which often include habits and habitats. Its history has shown it to be one of the most influential botanical treatises ever penned. It provided most of the little botanical knowledge that reached the Middle Ages. It furnished the chief stimulus to botanical research at the time of the Renaissance. It has decided the general form of every modern pharmacopœia. It has practically determined modern plant nomenclature both popular and scientific.

[186] Translated into nearly every language from Anglo-Saxon and Bohemian to Arabic and Hebrew, appearing both abstracted and in full in innumerable beautifully illuminated manuscripts, some of which are still among the fairest treasures of the great national libraries, Dioscorides, the drug-monger, appealed to scholasticized minds for centuries. The frequency with which fragments of him are encountered in papyri shows how popular his work was in Egypt in the third and fourth centuries. One of the earliest datable Greek codices in existence is a glorious volume of Dioscorides written in capitals,[39] thought worthy to form a wedding gift for a lady who was the daughter of one Roman emperor and the betrothed of a second.[40] The illustrations of this fifth-century manuscript are a very valuable monument for the history of art and the chief adornment of what was once the Royal Library at Vienna[41] (figs. 9-10). Illustrated Latin translations of Dioscorides were in use in the time of Cassiodorus (490-585). A work based on it, similarly illustrated, but bearing the name of Apuleius, is among the most frequent of mediaeval botanical documents and the earliest surviving specimen is contemporary with Cassiodorus himself.[42] After the[187] revival of learning Dioscorides continued to attract an immense amount of philological and botanical ability, and scores of editions of his works, many of them nobly illustrated, poured out of the presses of the sixteenth and seventeenth centuries.

But the greatest biologist of the late Greek period, and indeed one of the greatest biologists of all time, was Claudius Galen of Pergamon (A. D. 131-201). Galen devoted himself to medicine from an early age, and in his twenty-first year we hear of him studying anatomy at Smyrna under Pelops. With the object of extending his knowledge of drugs he early made long journeys to Asia Minor. Later he proceeded to Alexandria, where he improved his anatomical equipment, and here, he tells us, he examined a human skeleton. It is indeed probable that his direct practical acquaintance with human anatomy was limited to the skeleton and that dissection of the human body was no longer carried on at Alexandria in his time. Thus his physiology and anatomy had to be derived mainly from animal sources. He is the most voluminous of all ancient scientific writers and one of the most voluminous writers of antiquity in any department. We are not here concerned with the medical material which mainly fills these huge volumes, but only with the physiological views which not only prevailed in medicine until Harvey and after, but also governed for fifteen hundred years alike the scientific and the popular ideas on the nature and workings of the animal body, and have for centuries been embedded in our speech. A knowledge of these physiological views of Galen is necessary for any understanding of the history of biology and illuminates many literary allusions of the Middle Ages and Renaissance.

Between the foundation of the Alexandrian school and the time of Galen, medicine was divided among a great number of sects. Galen was an eclectic and took portions of his teaching from many of these schools, but he was also a naturalist of great ability and industry, and knew well the value of the[188] experimental way. Yet he was a somewhat windy philosopher and, priding himself on his philosophic powers, did not hesitate to draw conclusions from evidence which was by no means always adequate. The physiological system that he thus succeeded in building up we may now briefly consider (fig. 11).

[189]

The basic principle of life, in the Galenic physiology, is a spirit, anima or pneuma, drawn from the general world-soul in the act of respiration. It enters the body through the rough artery (τραχεια αρτηρια, arteria aspera of mediaeval notation), the organ known to our nomenclature as the trachea. From this trachea the pneuma passes to the lung and then, through the vein-like artery (αρτηρια φλεβωδης, arteria venalis of mediaeval writers, the pulmonary vein of our nomenclature), to the left ventricle. Here it will be best to leave it for a moment and trace the vascular system along a different route.

Ingested food, passing down the alimentary tract, was absorbed as chyle from the intestine, collected by the portal vessel, and conveyed by it to the liver. That organ, the site of the innate heat in Galen’s view, had the power of elaborating the chyle into venous blood and of imbuing it with a spirit or pneuma which is innate in all living substance, so long as it remains alive, the natural spirits (πνευμα φυσικον, spiritus naturalis of the mediaevals). Charged with this, and also with the nutritive material derived from the food, the venous blood is distributed by the liver through the veins which arise from it in the same way as the arteries from the heart. These veins carry nourishment and natural spirits to all parts of the body. Iecur fons venarum, the liver as the source of the veins, remained through the centuries the watchword of the Galenic physiology. The blood was held to ebb and flow continuously in the veins during life.

Now from the liver arose one great vessel, the hepatic vein, from division of which the others were held to come off as [190] branches. Of these branches, one, our common vena cava, entered the right side of the heart. For the blood that it conveyed to the heart there were two fates possible. The greater part remained awhile in the ventricle, parting with its impurities and vapours, exhalations of the organs, which were carried off by the artery-like vein (φλεπς αρτηριωδης, the mediaeval vena arterialis, our pulmonary artery) to the lung and then exhaled to the outer air. These impurities and vapours gave its poisonous and suffocating character to the breath. Having parted thus with its impurities, the venous blood ebbed back again from the right ventricle into the venous system. But for a small fraction of the venous blood that entered the right ventricle another fate was reserved. This small fraction of venous blood, charged still with the natural spirits derived from the liver, passed through minute channels in the septum between the ventricles and entered the left chamber. Arrived there, it encountered the external pneuma and became thereby elaborated into a higher form of spirit, the vital spirits (πνευμα ζωτικον, spiritus vitalis), which is distributed together with blood by the arterial system to various parts of the body. In the arterial system it also ebbed and flowed, and might be seen and felt to pulsate there.

But among the great arterial vessels that sent forth arterial blood thus charged with vital spirits were certain vessels which ascended to the brain. Before reaching that organ they divided up into minute channels, the rete mirabile (πλεγμα μεγιστον θαυμα), and passing into the brain became converted by the action of that organ into a yet higher type of spirits, the animal spirits (πνευμα ψυχικον, spiritus animalis), an ethereal substance distributed to the various parts of the body by the structures known to-day as nerves, but believed then to be hollow channels. The three fundamental faculties δυναμεις), the natural, the vital, and the animal, which brought into action the corresponding functions of the body, thus originated as an expression of the primal force or pneuma.

[191] This physiology, we may emphasize, is not derived from an investigation of human anatomy. In the human brain there is no rete mirabile, though such an organ is found in the calf. In the human liver there is no hepatic vein, though such an organ is found in the dog. Dogs, calves, pigs, bears, and, above all, Barbary apes were freely dissected by Galen and were the creatures from which he derived his physiological ideas. Many of Galen’s anatomical and physiological errors are due to his attributing to one creature the structures found in another, a fact that only very gradually dawned on the Renaissance anatomists.

The whole knowledge possessed by the world in the department of physiology from the third to the seventeenth century, nearly all the biological conceptions till the thirteenth, and most of the anatomy and much of the botany until the sixteenth century, all the ideas of the physical structure of living things throughout the Middle Ages, were contained in a small number of these works of Galen. The biological works of Aristotle and Theophrastus lingered precariously in a few rare manuscripts in the monasteries of the East; the total output of hundreds of years of Alexandrian and Pergamenian activities was utterly destroyed; the Ionian biological works, of which a sample has by a miracle survived, were forgotten; but these vast, windy, ill-arranged treatises of Galen lingered on. Translated into Latin, Syriac, Arabic, and Hebrew, they saturated the intellectual world of the Middle Ages. Commented on by later Greek writers, who were themselves in turn translated into the same list of languages, they were yet again served up under the names of such Greek writers as Oribasius, Paul of Aegina, or Alexander of Tralles.

What is the secret of the vitality of these Galenic biological conceptions? The answer can be given in four words. Galen is a teleologist; and a teleologist of a kind whose views happened to fit in with the prevailing theological attitude of the Middle Ages, whether Christian, Moslem, or Jewish. According[192] to him everything which exists and displays activity in the human body originates in and is formed by an intelligent being and on an intelligent plan, so that the organ in structure and function is the result of that plan. ‘It was the Creator’s infinite wisdom which selected the best means to attain his beneficent ends, and it is a proof of His omnipotence that he created every good thing according to His design, and thereby fulfilled His will.’[43]

After Galen there is a thousand years of darkness, and biology ceases to have a history. The mind of the Dark Ages turned towards theology, and such remains of Neoplatonic philosophy as were absorbed into the religious system were little likely to be of aid to the scientific attitude. One department of positive knowledge must of course persist. Men still suffered from the infirmities of the flesh and still sought relief from them. But the books from which that advice was sought had nothing to do with general principles nor with knowledge as such. They were the most wretched of the treatises that still masqueraded under the names of Hippocrates and Galen, mostly mere formularies, antidotaries, or perhaps at best symptom lists. And, when the depression of the western intellect had passed its worst, there was still no biological material on which it could be nourished.

The prevailing interest of the barbarian world, at last beginning to settle into its heritage of antiquity, was with Logic. Of Aristotle there survived in Latin dress only the Categories and the De interpretatione, the merciful legacy of Boethius, the last of the philosophers. Had a translation of Aristotle’s Historia animalium or De generatione animalium survived, had a Latin version of the Hippocratic work On generation or of the treatises of Theophrastus On plants reached the earlier Middle Ages, the whole mental history[193] of Europe might have been different and the rediscovery of nature might have been antedated by centuries. But this was a change of heart for which the world had long to wait; something much less was the earliest biological gift of Greece. The gift, when it came, came in two forms, one of which has not been adequately recognized, but both are equally her legacy. These two forms are, firstly, the well-known work of the early translators and, secondly, the tardily recognized work of certain schools of minor art.

The earliest biological treatises to become accessible in the west were rendered not from Greek but from Arabic.[44] The first of them was perhaps the treatise περι μυων κινησεως, On movement of muscles of Galen, a work which contains more than its title suggests and indeed sets forth much of the Galenic physiological system. It was rendered into Latin from the Arabic of Joannitius (Hunain ibn Ishaq, 809-73), probably about the year 1200, by one Mark of Toledo. It attracted little attention, but very soon after biological works of Aristotle began to become accessible. The first was probably the fragment On plants. The Greek original of this is lost, and besides the Latin, only an Arabic version of a former Arabic translation of a Syriac rendering of a Greek commentary is now known! Such a work appeared from the hand of a translator known as Alfred the Englishman about 1220 or a little later. Neither it nor another work from the same translator, On the motion of the heart, which sought to establish the primacy of that organ on Aristotelian grounds, can be said to contain any of the spirit of the master.[45]

[194] A little better than these is the work of the wizard Michael the Scot (1175?-1234?). Roger Bacon tells us that Michael in 1230 ‘appeared [at Oxford], bringing with him the works of Aristotle in natural history and mathematics, with wise expositors, so that the philosophy of Aristotle was magnified among the Latins’.[46] Scott produced his work De animalibus about this date and he included in it the three great biological works of Aristotle, all rendered from an inferior Arabic version.[47] Albertus Magnus (1206-80) had not as yet a translation direct from the Greek to go upon for his great commentary on the History of animals, but he depended on Scott. The biological works of Aristotle were rendered into Latin direct from the Greek in the year 1260 probably by William of Moerbeke.[48] Such translations, appearing in the full scholastic age when everything was against direct observation, cannot be said to have fallen on a fertile ground. They presented an ordered account of nature and a good method of investigation, but those were gifts to a society that knew little of their real value.[49]

Yet the advent of these texts was coincident with a returning desire to observe nature. Albert, with all his scholasticism, was no contemptible naturalist. He may be said to have begun first-hand plant study in modern times so far as literary records are concerned. His book De vegetabilibus[195] contains excellent observations, and he is worthy of inclusion among the fathers of botany. In his vast treatise De animalibus, hampered as he is by his learning and verbosity, he shows himself a true observer and one who has absorbed something of the spirit of the great naturalist to whose works he had devoted a lifetime of study and on which he professes to be commenting. We see clearly the leaven of the Aristotelian spirit working, though Albert is still a schoolman. We may select for quotation a passage on the generation of fish, a subject on which some of Aristotle’s most remarkable descriptions remained unconfirmed till modern times. These descriptions impressed Albert in the same way as they do the modern naturalist. To those who know nothing of the stimulating power of the Aristotelian biological works, Albert’s description of the embryos of fish and his accurate distinction of their mode of development from that of birds, by the absence of an allantoic membrane in the one and its presence in the other, must surely be startling. Albert depends on Aristotle—a third-hand version of Aristotle—but does not slavishly follow him.

‘Between the mode of development (anathomiam generationis) of birds’ and fishes’ eggs there is this difference: during the development of the fish the second of the two veins which extend from the heart [as described by Aristotle in birds] does not exist. For we do not find the vein which extends to the outer covering in the eggs of birds which some wrongly call the navel because it carries the blood to the exterior parts; but we do find the vein that corresponds to the yolk vein of birds, for this vein imbibes the nourishment by which the limbs increase.... In fishes as in birds, channels extend from the heart first to the head and the eyes, and first in them appear the great upper parts. As the growth of the young fish increases the albumen decreases, being incorporated into the members of the young fish, and it disappears entirely when development and[196] formation are complete. The beating of the heart ... is conveyed to the lower part of the belly, carrying pulse and life to the inferior members.

‘While the young [fish] are small and not yet fully developed they have veins of great length which take the place of the navel-string, but as they grow and develop, these shorten and contract into the body towards the heart, as we have said about birds. The young fish and the eggs are enclosed and in a covering, as are the eggs and young of birds. This covering resembles the dura mater [of the brain], and beneath it is another [corresponding therefore to the pia mater of the brain] which contains the young animal and nothing else.’[50]

In the next century Conrad von Megenberg (1309-98) produced his Book of Nature, a complete work on natural history, the first of the kind in the vernacular, founded on Latin versions, now rendered direct from the Greek, of the Aristotelian and Galenic biological works. It is well ordered and opens with a systematic account of the structure and physiology of man as a type of the animal creation, which is then systematically described and followed by an account of plants. Conrad, though guided by Aristotle, uses his own eyes and ears, and with him and Albert the era of direct observation has begun.[51]

But there was another department in which the legacy of Greece found an even earlier appreciation. For centuries the illustrations to herbals and bestiaries had been copied from hand to hand, continuing a tradition that had its rise with[197] Greek artists of the first century B. C. But their work, copied at each stage without reference to the object, moved constantly farther from resemblance to the original. At last the illustrations became little but formal patterns, a state in which they remained in some late copies prepared as recently as the sixteenth century. But at a certain period a change set in, and the artist, no longer content to rely on tradition, appeals at last to nature. This new stirring in art corresponds with the new stirring in letters, the Arabian revival—itself a legacy of Greece, though sadly deteriorated in transit—that gave rise to scholasticism. In much of the beautiful carved and sculptured work of the French cathedrals the new movement appears in the earlier part of the thirteenth century. At such a place as Chartres we see the attempt to render plants and animals faithfully in stone as early as 1240 or before. In the easier medium of parchment the same tendency appears even earlier. When once it begins the process progresses slowly until the great recovery of the Greek texts in the fifteenth century, when it is again accelerated.

During the sixteenth century the energy of botanists and zoologists was largely absorbed in producing most carefully annotated and illustrated editions of Dioscorides and Theophrastus and accounts of animals, habits, and structure that were intended to illustrate the writings of Aristotle, while the anatomists explored the bodies of man and beast to confirm or refute Galen. The great monographs on birds, fishes, and plants of this period, ostensibly little but commentaries on Pliny, Aristotle, and Dioscorides, represent really the first important efforts of modern times at a natural history. They pass naturally into the encyclopaedias of the later sixteenth century, and these into the physiological works of the seventeenth. Aristotle was never a dead hand in Biology as he was in Physics, and this for the reason that he was a great biologist but was not a great physicist.

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With the advance of the sixteenth century the works of Aristotle, and to a less extent those of Dioscorides and Galen, became the great stimulus to the foundation of a new biological science. Matthioli (1520-77), in his commentary on Dioscorides (first edition 1544), which was one of the first works of its type to appear in the vernacular, made a number of first-hand observations on the habits and structure of plants that is startling even to a modern botanist. About the same time Galenic physiology, expressed also in numerous works in the vulgar tongue and rousing the curiosity of the physicians, became the clear parent of modern physiology and comparative anatomy. But, above all, the Aristotelian biological works were fertilizers of the mind. It is very interesting to watch a fine observer such as Fabricius ab Acquapendente (1537-1619) laying the foundations of modern embryology in a splendid series of first-hand observations, treating his own great researches almost as a commentary on Aristotle. What an impressive contrast to the arid physics of the time based also on Aristotle! ‘My purpose’, says Fabricius, ‘is to treat of the formation of the foetus in every animal, setting out from that which proceeds from the egg: for this ought to take precedence of all other discussion of the subject, both because it is not difficult to make out Aristotle’s view of the matter, and because his treatise on the Formation of the Foetus from the egg is by far the fullest, and the subject is by much the most extensive and difficult.’[52]

The industrious and careful Fabricius, with a wonderful talent for observation lit not by his own lamp but by that of Aristotle, bears a relation to the master much like that held by Aristotle’s pupil in the flesh, Theophrastus. The works of the two men, Fabricius and Theophrastus, bear indeed a resemblance to each other. Both rely on the same group of general ideas, both progress in much the same ordered calm from observation to observation, both have an inspiration which[199] is efficient and stimulating but below the greatest, both are enthusiastic and effective as investigators of fact, but timid and ineffective in drawing conclusions.

But Fabricius was more happy in his pupils than Theophrastus, for we may watch the same Aristotelian ideas fermenting in the mind of Fabricius’s successor, the greatest biologist since Aristotle himself, William Harvey (1578-1657).[53] This writer’s work On generation is a careful commentary on Aristotle’s work on the same topic, but it is a commentary not in the old sense but in the spirit of Aristotle himself. Each statement is weighed and tested in the light of experience, and the younger naturalist, with all his reverence for Aristotle, does not hesitate to criticize his conclusions. He exhibits an independence of thought, an ingenuity in experiment, and a power of deduction that places his treatise as the middle term of the three great works on embryology of which the other members are those of Aristotle and Karl Ernst von Baer (1796-1876).[54]

With the second half of the seventeenth century and during a large part of the eighteenth the biological works of Aristotle attracted less attention. The battle against the Aristotelian physics had been fought and won, but with them the biological works of Aristotle unjustly passed into the shadow that overhung all the idols of the Middle Ages.

The rediscovery of the Aristotelian biology is a modern thing. The collection of the vast wealth of living forms absorbed the energies of the generations of naturalists from Ray (1627-1705) and Willoughby (1635-72) to Réaumur (1683-1757) and Linnaeus (1707-1778) and beyond to the nineteenth century. The magnitude and fascination of the work seems almost to have excluded general ideas. With the end of this period and the advent of a more philosophical type of naturalist,[200] such as Cuvier (1769-1832) and members of the Saint-Hilaire family, Aristotle came again to his own. Since the dawn of the nineteenth century, and since naturalists have been in a position to verify the work of Aristotle, his reputation as a naturalist has continuously risen. Johannes Müller (1801-58), Richard Owen (1804-92), George Henry Lewes (1817-78), William Ogle (1827-1912) are a few of the long line of those who have derived direct inspiration from his biological work. With improved modern methods of investigation the problems of generation have absorbed a large amount of biological attention, and interest has become specially concentrated on Aristotle’s work on that topic which is perhaps, at the moment, more widely read than any biological treatise, ancient or modern, except the works of Darwin. That great naturalist wrote to Ogle in 1882: ‘From quotations I had seen I had a high notion of Aristotle’s merits, but I had not the most remote notion what a wonderful man he was. Linnaeus and Cuvier have been my two gods, though in very different ways, but they were mere schoolboys to old Aristotle.’

Charles Singer.

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