For the sake of greater clarity we shall divide this chapter into four main sections — geography; zoology and biology; botany; geology and mineralogy; medicine — in spite of the fact that this entails a few repetitions, chiefly in the case of Aristotle, who will naturally reappear in every section. This is another way of appreciating the comprehensiveness of his mind, the universality of his genius. One cannot deal with any science, or with any branch of science, without having to drag him in.



The most fundamental set of queries on natural history would naturally deal with the Earth itself, its shape, size, and surface. The shape and size have already been discussed in the astronomic section, and we have seen that Aristotle’s estimate of the size was too large, but not shockingly so.¹³⁹⁶ His knowledge of the size of the whole Earth was based upon calculations, which could be gradually improved without going out of a relatively small region, but his knowledge of the part of the Earth that was inhabited (the oicumen ) was derived from the reports of explorers and travelers. At the very best it was guesswork, for however well one might know certain regions this did not enlighten one at all with regard to the others. By the middle of the century many explorations had already been conducted (we have briefly described them in previous chapters), but if these were outlined on a sphere, one would realize at once that they covered only a very small portion of it. Alexander’s expeditions improved considerably the knowledge of the Middle East and of the region west of the Indus and Jaxartes,¹³⁹⁷ but their results were not completely available to Aristotle. The latter could avail himself, however, of the information collected by Scylax of Caryanda, whose Periplus was published c. 360–347 (p. 299). It is highly problematic how much Aristotle knew of descriptive geography,¹³⁹⁸ yet he was bold enough to postulate the extension of the inhabited world in the temperate zone “round the whole circle.”¹³⁹⁹ If that habitable region did not extend beyond the Pillars of Hercules in the west and India in the east, this was caused by the presence of the Ocean, not by climatic difficulties. On the other hand, he assumed a priori that the inhabited world was limited in breadth, because the cold would be too severe for human life in higher latitudes. If he had heard of Pytheas’ voyages, he would have been more prudent.

The idea of zones goes back to Parmenides. He it was who conceived the spherical earth as divided into five parallel zones: a broad equatorial one, torrid; two polar ones, frigid; and in between two zones of moderate climate. The Greek oicumen was included in the north temperate zone. This was made a little more precise by Aristotle (or rather by the author of the Meteorology¹⁴⁰⁰) but he was still unable to determine the limits of each zone. More precision would be introduced a century later by Eratosthenes of Cyrene (III–2 B.C.), and it is he, not Aristotle, who deserves to be called the founder of mathematical geography.¹⁴⁰¹


If one means by “Italian” a man who was born and lived in the territory at present governed by the Italian Republic, then we have already come across many “Italians.” Indeed, Magna Graecia¹⁴⁰² (h megal Hellas) was one of the cradles of Greek science. If Zenon of Elea was an “Italian,” then Pytheas was a “Frenchman.” It is better, however, not to mix old history with modern geography. Pytheas was born at Massilia (modern Marseille), in Gaul, and was thus the earliest representative of Western Europe in the history of science. He was probably one of Aristotle’s younger contemporaries, for the latter did not know of his achievements, but they were quoted by Dicaiarchos.

Pytheas was one of the greatest navigators of antiquity. It is possible that his voyages were undertaken by order and at the expense of the Massilian colony, which was competing bitterly with its Carthaginian rivals and was anxious to outdo them in foreign trade, especially the rich trade in amber and tin.¹⁴⁰³ It is equally possible that he was driven by his own eagerness and scientific curiosity. In the history of geographic discoveries, both motives, the personal and the social, are generally combined. Great deeds can be done only by great men, but however great, these men need help in order to accomplish their bold designs.

Pytheas was a scientific navigator; he was able to determine exactly the latitude of Massilia by means of a gnomon, and was one of the first Greeks to establish a relation between the Moon and the tides. This was due, of course, not so much to special intelligence as to the fact that he navigated outside of the Mediterranean where the tides were too small to attract attention. On the Atlantic shores the tides were high and as ancient people (not only the educated ones but also farmers and shepherds) observed the Moon carefully, they could not have failed to notice any relation that might exist between the lunar cycle and the tidal one.

Our knowledge of Pytheas’ navigations is second hand¹⁴⁰⁴ and he reported so many “marvels” that some of the ancient historians, like Polybios ( II–1 B.C.) and Strabon (I–2 B.C.) distrusted him. His fate was comparable to that of Marco Polo in later times; some of the things that they told were so extraordinary, so contrary to common experience, that wise and prudent men could not believe them and concluded that they were fables. In both cases the stories that had been disbelieved were vindicated by later observations.

While certainty is out of the question, historians of ancient geography are now agreed that the achievements ascribed to Pytheas are real and occurred in Aristotle’s time or very soon afterward (say in the period 330–300). There are, of course, unavoidable divergencies concerning localities and other details, but the general account as summarized below may be accepted as truthful.¹⁴⁰⁵

Pytheas and his companions sailed from Massilia, passed the Pillars of Hercules, visited Gades just west of them, then followed the Spanish and French coast northward. They were aware of the immense depth of the Bay of Biscay and of the enormous size of the Armorican peninsula (Brittany). Reaching the British Isles, they visited tin mines and the island Ictis,¹⁴⁰⁶ connected to the shore at low tide, which was their commercial center. Pytheas gave a rough description of Britain as seen by a circumnavigator; yet he had made excursions inland, he noticed the native use of mead, the use of barns for threshing in bad weather, and the decrease of cultivation as one goes farther north. The general shape of Great Britain is a triangle of which the three vertexes are Orcas in the north (Orcades insulae, the Orkney and Shetland Islands), Belerion in the southwest (Land’s End), and Cantion (Kent) in the southeast.

According to Polybios,¹⁴⁰⁷ Pytheas followed the European coast all the way from Gades to Tanais. What is Tanais? ¹⁴⁰⁸ Two very different conjectures have been made; the Tanais would be a Baltic river, either the Vistula, which enters the Baltic at Danzig, or the Dvina, which enters it further east in Courland. The Tanais is more generally identified, however, with the Don, flowing into the Sea of Azov (Maeotis Palus). Pytheas visited places where amber was found, and the most famous of such places were along the southern shore of the Baltic. It may be that he sailed in the Baltic as far east as the longitude of the Maeotis Palus (strictly speaking that would be impossible, but the determination of longitudes was very vague).

We are on safer ground concerning the North Sea. He navigated it very far to the north, witnessed (or heard about) the extraordinary inrush of the sea at Pentland Firth, and may have sailed as far as the island Thule, to which he gave that name. Was Thule Iceland or northern Norway? ¹⁴⁰⁹ It was six days’ voyage north of Britain and close to the frozen ocean. Did he go there or hear of it? Every traveler is tempted to extend his voyages beyond the limits that he has actually reached, by referring to countries beyond that are known to him by hearsay. It is clear that wherever one goes, one is likely to meet natives who have been farther.

At any rate, among Pytheas’ incredible stories were the first reports of arctic conditions. He spoke of regions where the nights were exceedingly short, and of the “sleeping place of the sun,” meaning perhaps the Arctic Circle, where during one day in the year the sun does not appear above the horizon. He described the inextricable mixture of air, sea, and land obtaining in these regions, and the frozen sea which can neither be traversed on foot nor by boat. Arctic travelers of our own time vindicate Pytheas, saying that his descriptions contain many details that could not have been invented. Says Fridtjof Nansen:

What Pytheas himself saw may have been the ice sludge in the sea which is formed over a great extent along the edge of the drift ice, when this has been ground to a pulp by the action of waves. The expression ’can neither be traversed on foot nor by boat’ is exactly applicable to this ice sludge. If we add to this the thick fog, which is often found near drift ice, then the description that the air is also involved in the mixture, and that land and sea and everything is merged in it, will appear very graphic.¹⁴¹⁰

It is certain that arctic travelers are more competent to appreciate the verisimilitude of the statements ascribed to Pytheas than are armchair philologists, and their verdict is in his favor. This ought to satisfy us.

We owe to Pytheas not only the first account of northwest Europe and particularly of Great Britain, but also our first vision of the arctic world. This was an enormous increase of the knowledge available to Greek geographers.


After this entirely unexpected trip to the arctic world, let us return to more familiar regions, the Mediterranean Sea and the Near East. When we gave a brief description of Alexander’s conquests, we remarked that they increased considerably the geographic knowledge available to the Greeks. Much of our knowledge of the world originated in that very way: the terrae incognitae were not gently unveiled by lovers of science; they were brutally raped by conquistadors and their followers, men of prey, whose only interest was power and wealth, yet who could not help increase geographic knowledge. Even if there had been no geographers attached to Alexander’s army or detached by him for exploration, if there had been no scholars around him but historians without special interest in geographic facts, even then they could not have described intelligibly their master’s razzias without explaining as clearly as possible where these took place. Historical events happen in a definite geographic background, and the geography that is inseparable from historiography, the geography of history, includes valuable fragments of the history of geography.

As a matter of fact, Alexander, who was a scientific organizer as well as a conqueror, had in his train not only secretaries, men of letters, historians, but also explorers, pathfinders,¹⁴¹¹ surveyors, some of whom are known by name: one Heracleides, Archias, Androsthenes, Hieron of Soloi, Diognetos, Baiton; by far the most important was Nearchos, whose account has been preserved for us in the Indica of Arrian.¹⁴¹²

A fleet having been rigged in 327 to convey Alexander’s army from the Hydaspes (one of the tributaries of the Indus) to Persia, Nearchos was put in charge as admiral, while Onesicritos was the helmsman of Alexander’s own ship.¹⁴¹³ Nearchos was a Cretan, but he flourished in Amphipolis;¹⁴¹⁴ he had been employed by Philip, then disgraced, but Alexander had realized his merit and taken him back in the Macedonian service. Nearchos acquitted himself very well in a highly difficult and dangerous undertaking. He sailed his fleet down the Hydaspes and the Indus, then to the Persian Gulf, the Shatt al–‘Arab, the Tigris, the Pasitigris, and the Choaspes to Susa. His voyage occupied five months. He observed tidal phenomena ( unknown to the Mediterranean sailors); he could not help observing them, of course, even as Pytheas could not help observing them along the Atlantic shores at about the same time. The fact that the tides existed in the Atlantic and in the Arabian Sea encouraged Eratosthenes ( III–2 B.C.) to conclude that the whole of the outer ocean was a single mass of water.¹⁴¹⁵

Nearchos made other observations; he was aware of the immense size of India (as compared with the Mediterranean scale of countries) and the fabulous length of her rivers. After passing Karachi they sailed along the country of the ichthyophagi (flsh–eating people). They encountered a shoal of whales, and Nearchos (or Arrian) gives a vivid account of that astonishing and frightening spectacle. In the Persian Gulf he observed the pearl fisheries, which have continued to be operated there until our own day.¹⁴¹⁶

As far as can be judged from many comparisons and verifications, Arrian’s account is faithful and reliable.


The men of whom we have spoken thus far were explorers, travelers, and though their activities extended geographic knowledge considerably they were not professional geographers. Dicaiarchos, who now engages our attention, was a historian and geographer. His abundant writings dealt with history, politics, literature, philosophy, and geography proper, but only fragments of them remain.¹⁴¹⁷ He was born in Messina, Sicily, but flourished on the Greek continent, especially in the Peloponnesos and in Athens. He was a disciple of Aristotle, a friend of Theophrastos and Aristoxenos; thus we may place his acme (his flowering age) in the last quarter of the century.

His main work seems to have been a kind of cultural history of Greece, significantly called The life of Hellas (Bios Hellados) of which nineteen fragments have come to us. We are more directly interested, however, in his geographic books, one of which was a description of the world, possibly accompanied with maps (Periodos g s), and the other a treatise on the measurement of mountains; the fragment of it that has come to us deals with mountains in the Peloponnesos.

The reason why we suggest that his description of the world was illustrated with maps, or that he used maps, is a statement made by Agathemeros:

Dicaiarchos divides the earth... by a completely straight line from the Pillars through Sardinia, Sicily, Peloponnese, Caria, Lycia, Pamphylia, Cilicia, Tauros, and on to Imaos. Of the regions thus formed he names one part the northern, the other the southern.¹⁴¹⁸

Another novelty to the credit of Dicaiarchos is his attempt to measure the heights of mountains.¹⁴¹⁹ His estimates were generally too high, and yet he concluded that these mountains were as nothing compared with the size of the Earth. This was a bold conclusion; it required imagination and courage to declare that the gigantic mountains, the ascension of which may tax our strength to the limit, are but wrinkles of the Earth’s surface. He influenced Eratosthenes and later geographers, like Strabon ( I–2 B.C.), who admired him, but also philosophically minded writers like Cicero. The latter, who knew Dicaiarchos better than we can know him today, took his life as a model of the practical life, while Theophrastos’ was a model of the theoretical life. This opinion was perhaps based upon Dicaiarchos’ interest in measurements.¹⁴²⁰ Aristotle’s estimate of the size of the Earth was probably derived from that of his disciple. Dicaiarchos realized that the tides were influenced not only by the Moon but also by the Sun.

Thanks to the Alexandrian epic and to the commercial rivalries between the Greek and the Phoenican colonies, knowledge of geography, climatology, and anthropology had grown so much that the scholars who flourished during the last quarter of the century had a vision of the inhabited world that was at the same time broader and more detailed. We may assume that the efforts made by Dicaiarchos were not unrelated to that new vision. As one’s knowledge increases and becomes more precise, it invites new surveys. Dicaiarchos prepared such a survey and began a new series of measurements which would make possible eventually the creation of scientific geography by Eratosthenes.

Fig. 94. Title page of the Liber de animalibus, as Latinized by Theodoros Gaza (c. 1400–1475) of Thessalonica; first edition, folio, 30 cm ( Venice: John of Cologne and John Manthen de Gherretzen, 1476; Klebs, 85.1). Theodoros was one of the collaborators of Vittorino da Feltre in Mantua; he translated many books from Greek into Latin, and also from Latin into Greek. [From the copy in the Harvard College Library.]



The main texts for the study of Aristotelian biology (Figs. 94, 95, 96) are De anima, Historia animalium, De partibus animalium, De motu animalium, De incessu animalium, De generatione animalium. These books touch some of the fundamental problems of biology and contain an almost incredible wealth of information on innumerable subjects. Much of that information has naturally lost its validity, but the surprising thing is that so much of it is still valid today, with relatively few qualifications. The abundance of facts mentioned in the zoölogic treatises is such that it would have been impossible for a single man to collect them. We must assume that Aristotle was helped by many colleagues and disciples. This assumption entails a relatively late date of composition¹⁴²¹even if Aristotle’s own investigations began very early. His interest in natural history may have originated in his boyhood when his father took him with him on his medical rounds; it continued in Athens and was probably stimulated during the years spent at the seashore in Assos and Lesbos. Among Aristotle’s helpers was Alexander the Great, who provided information and obtained specimens in distant countries. No matter how many men collaborated with him, the zoölogic books were very probably written by himself; the style is uniform in its scientific austerity, and the teleologic point of view permeating the whole is typical of Aristotelian thought.¹⁴²²

Fig. 95. Colophon of the Liber de animalibus. [From the copy in the Harvard College Library.]

Fig. 96. Page 232 verso of volume 1 of the second edition of the Greek Aristotle, prepared by Erasmus of Rotterdam with emendations by Simon Grynaeus ( folio; Basel: Bebel, 1531). This page shows the end of the De generatione animalium and the beginning of the De partibus. [From the copy in the Harvard College Library.]

The Greek princeps of Aristotelian zoology was in vol. 3 (1497) of the Aristotle–Theophrastos princeps (5 vols.; Venice: Manutius, 1495–1498), represented in Fig. 102.

English readers may easily consult these texts in the Oxford English Aristotle and in the Loeb Classical Library. The Loeb volumes are especially convenient, because they contain the Greek original on opposite pages to the translation.

Among recent studies of Aristotelian biology we may mention Thomas East Lones, Artstotle’s researches in natural science (302 pp., ill.; London, 1912) [Isis 1, 505–509 (1913)], and above all the many publications of my good friends, the late D’Arcy W. Thompson¹⁴²³ and Charles Singer. Of Sir D’Arcy’s, it will suffice to recall his Glossary of Greek birds ( London: Oxford University Press, 1895, 1936) [Isis 29, 135–138 (1938)], his translation of Historia animalium (Oxford, 1910), his Arfstotle as a biologist (London, 1913),¹⁴²⁴ and his Glossary of Greek fishes ( London: Oxford University Press, 1947 ) [Isis 38, 254 (1947–48)]; of Singer’s, his Greek biology (Studies in the history and method of science, vol. 2, pp. 1–101; (Oxford: Clarendon Press, 1921) and his Short history of biology (London: Harper, 1931; often reprinted).

The strange vicissitudes of Aristotle’s fame in antiquity have been related in the previous chapter. To Cicero and the latter’s contemporaries he was known as a Platonist; later, his early Platonic writings vanished, and he became known by the works of his maturity. Not by all of these, however; for centuries, attention was centered upon the Organon; then his other works were gradually appreciated, those dealing with astronomy, physics, ethics, government. The books on natural history were read also, but modern biologists gradually lost their respect for them, as their own ideas became more “scientific.” It was only in the second half of the nineteenth century that the best parts of Aristotelian biology were properly appreciated, and from that time on, Aristotle the zoologist, Aristotle the biologist was the subject of increasing praise and wonder. Some enthusiasts went so far as to say that Aristotle’s genuine fame rested on his biology alone, the rest of Aristotelian writings might be abandoned,¹⁴²⁵ but those dealing with natural history were truly astounding.

It is my hope that the four chapters devoted to Aristotle in this book will make a better–balanced judgment of him possible. He was certainly one of the very greatest men in the whole of our past, but greatness is never absolute. Aristotle’s encyclopedic knowledge was astounding indeed; yet it was very imperfect; it could not be otherwise.

Modern biologists reading the Aristotelian books concerning their own studies are astonished by the wealth of detail and even more so by the broadness and complexity of his outlook. He opened up the main fields of inquiry — comparative anatomy and physiology, embryology, customs of animals (ethology), geographic distribution, ecology — and in each field he assembled the relevant facts, described and discussed them, and drew philosophic conclusions. The facts have been gradually corrected because of the availability of better observational and experimental methods, yet many of the conclusions have reappeared periodically in sundry dresses; they are still acceptable in our own day to a number of well–informed biologists.

The writings enumerated above may be classified as follows.

The Historia animalium contains all the zoölogic observations collected under Aristotle’s guidance.

In spite of its title, De partibus animalium is physiologic rather than anatomic. That title ( who is responsible for it?) is very misleading;¹⁴²⁶ the book concerns functions of the body; it does not deal with parts (limbs and organs), but with what we would call tissues. At the beginning of it, three kinds of composition are recognized, the first being the purely physical kind, the second, homogeneous parts or tissues, the third, heterogeneous parts or organs. Six kinds of “tissues” are referred to: blood, fat, marrow, brain, flesh, bone. The De partibus animalium is the earliest treatise on animal physiology in any language. De incessu animalium also deals with physiology in the same way; it explains how the bodies of animals are made to serve their purposes. We must remember that every living being is made up of matter and form (soul). The two books just named deal with the matter; De anima, on the other hand, deals with the form; it is a treatise on psychology.

The two other treatises, De motu animalium and De generatione animalium, plus the smaller treatises grouped under the general title Parva naturalia, discuss functions common to matter and form (body and soul) and various peculiarities of behavior. If we realize that physics (as we understand it) hardly existed in Aristotle’s time, and chemistry not at all, we can hardly expect his physiology to be other than rudimentary. Indeed, in all fairness, we must consider it as a kind of protophysiology. Yet it is surprising how much of the truth Aristotle had already managed to catch a glimpse of. He had no understanding of respiration, but he had some general idea of nutrition. He conceived it as the transformation of the ingested food into nutriment which was carried by the blood to the parts of the body. Not bad at all. How could he have imagined, without any chemical knowledge, the infinitely complex chemical reactions that are involved? He realized the existence of excretory organs and the meaning of excreta such as bile, urine, and sweat. His account of the gall bladder was remarkably correct (with due regard to the limitations unavoidable in his time), but he thought ¹⁴²⁷ that some viviparous quadrupeds lacked it; in this he was wrong, for all the mammals have it.

We must return for a moment to teleology, which we have already described as an essential part of Aristotelian thought. In order to understand its application to life, or rather to living beings, it will be helpful to reconsider the Aristotelian notions of cause and of soul. Though both words have a general meaning, there are various kinds of causes and various kinds of souls.

As to causes, we must distinguish ( 1 ) the final cause or rational purpose, something that pulls from ahead, (2) the motive or efficient cause, (3) the formal cause, (4) the material cause. More simply, one might group the first three as formal causes, as against the material cause. Both (1) and (3) are occasionally represented by the same word, logos. Yet we must often draw the line between the final cause and the formal cause stricto sensu as we do between future and present.

The most general definition of the soul is given in De anima: “The soul is the first grade of actuality of a natural body having life potentially in it. The body so described is a body which is organized.”¹⁴²⁸ All living beings have a nutritive soul (a soul that guides their nutrition and their material life); in addition, all animals have a sentient soul, which enables them to feel; in addition, some higher animals have an appetitive and locomotive soul; in addition, men have a rational soul.¹⁴²⁹ All these souls are parts (or faculties) of the soul. To put it otherwise, we might say that the soul of a living being becomes more and more complex as we go up the scale of relative perfection, the acme being reached in the highest being, man. In any case, the soul belongs to the body and cannot be detached from it (as the Pythagoreans thought ) ; it is not separate from it, but is the form or realization (entelecheia, actuality) of it. Every living body is animated (empsychos as opposed to apsychos); that is, every living body is made up of matter and form.¹⁴³⁰

Aristotle’s teleology was of the limited kind called by Bergson the “doctrine of internal finality”; in the case of each individual all the parts are united for the greatest good of its wholeness and are intelligently organized in view of that end, but without regard for other individuals. That doctrine was generally accepted until Darwin elaborated his theory of natural selection (1859). Teleology could then be extended (“doctrine of external finality”) from the individual or from the species, to all the individuals or to all the species, which constitute a greater whole, the whole of life.¹⁴³¹

Aristotelian teleology is expressed by the formula “Nature never makes anything that is superfluous”;¹⁴³² hence, it did not consider vestigial or rudimentary organs which could be interpreted only in terms of “evolution,” that is, in terms not of any single individual but of a long series of them. Nature does nothing without a purpose. But what is the purpose of each individual? His purpose is revealed to us by his activities, and chiefly by their best and ultimate fruits.

These views have been developed by many biologists and are accepted to this day with technical qualifications by many of them, who are called vitalists.¹⁴³³

Aristotle’s classification of souls of increasing complexity as one goes up the scale of nature implies a belief in the existence of such a scale, and that belief was very clearly expressed by him in the Historia animalium.

Nature proceeds little by little from things lifeless to animal life in such a way that it is impossible to determine the exact line of demarcation, nor on which side thereof an intermediate form should lie. Thus, next after lifeless things in the upward scale comes the plant, and of plants one will differ from another as to its amount of apparent vitality; and, in a word, the whole genus of plants, whilst it is devoid of life as compared with an animal, is endowed with life as compared with other corporeal entities. Indeed, as we just remarked, there is observed in plants a continuous scale of ascent towards the animal. So, in the sea, there are certain objects concerning which one would be at a loss to determine whether they be animal or vegetable. For instance, certain of these objects are fairly rooted, and in several cases perish if detached; thus the pinna is rooted to a particular spot, and the solen ( or razor–shell ) cannot survive withdrawal from its burrow. Indeed, broadly speaking, the entire genus of testaceans have a resemblance to vegetables, if they be contrasted with such animals as are capable of progression.

In regard to sensibility, some animals give no indication whatsoever of it, whilst others indicate it but indistinctly. Further, the substance of some of these intermediate creatures is fleshlike, as is the case with the so–called tethya ( or ascidians ) and the acalephae ( or sea–anemones ) ; but the sponge is in every respect like a vegetable. And so throughout the entire animal scale there is a graduated differentiation in amount of vitality and in capacity for motion.

A similar statement holds good with regard to habits of life. Thus of plants that spring from seed the one function seems to be the reproduction of their own particular species, and the sphere of action with certain animals is similarly limited. The faculty of reproduction, then, is common to all alike. If sensibility be superadded, then their lives will differ from one another in respect to sexual intercourse through the varying amount of pleasure derived therefrom, and also in regard to modes of parturition and ways of rearing their young. Some animals, like plants, simply procreate their own species at definite seasons; other animals busy themselves also in procuring food for their young and after they are reared quit them and have no further dealings with them; other animals are more intelligent and endowed with memory, and they live with their offspring for a longer period and on a more social footing.

The life of animals, then, may be divided into two acts — procreation and feeding; for on these two acts all their interests and life concentrate. Their food depends chiefly on the substance of which they are severally constituted; for the source of their growth in all cases will be this substance. And whatsoever is in conformity with nature is pleasant, and all animals pursue pleasure in keeping with their nature.¹⁴³⁴

Note that the Aristotelian scala naturae does not necessarily imply evolution, for that scala might be conceived as static and the idea of the fixity of species is not incompatible with it.¹⁴³⁵ The scala appealed to medieval imagination, especially in the Muslim world. Arabic men of science often spoke of it, and those who were mystically minded liked to think of a continual scale or chain of being leading from the minerals to plants, from plants to animals, from animals to men, and from men to God.¹⁴³⁶ The scala naturae was a means of illustrating the fundamental unity and order of nature. It implied a classification, but Aristotle did not stop there. He had recognized some 540 species of animals, a number that may seem ridiculously small to modern taxonomists but was immense in his age. Many of these animals have such obvious relations that they group themselves, as it were; yet a complete classification involves great difficulties. Aristotle faced those difficulties and solved many of them; for example, the fishlike Cetacea did not fool him, and he recognized their mammalian nature. In spite of the availability of his zoölogical books to the Latin West from the thirteenth century on, medieval scholars overlooked his just conception of the cetaceans, which was forgotten until Pierre Belon rediscovered it and published ( in 1551) a description of the cetacean placenta. It is clear that Aristotle had devoted considerable thought to problems of classification; he showed that one had to be very careful and not mistake apparent resemblances, such as are due to homology (bone and fish spine, scales and feather, nail and hoof), with real ones, due to the “more or less” (excess or defect) of this or that part. He had certainly a table of classification in mind, and it is highly probable that he put it down either in words or in synoptic form; such a table has not come down to us, but it is not difficult to reconstruct it.

Aristotle objected to excessive dichotomy, but his classification began with a fundamental one, the division of the animal kingdom into two very different parts, which he called the bloody animals and the bloodless (this fundamental division is preserved under the names vertebrates and invertebrates). We cannot discuss the details of his classification; it will suffice to publish its reconstruction. Thanks to the kindness of Charles Singer, we reproduce here two forms of it (Figs. 97 and 98).¹⁴³⁷

That scheme included many errors and imperfections, but if one bears in mind the number of facts available to Aristotle, most of which had been collected under his direction, and the poverty of his observational means, one cannot help admire the results he obtained.

Comparative anatomy and physiology. Most of the anatomic notes are to be found in the Historia animalium, but they are mixed with physiologic remarks. The other books are more physiologic. The distinction between anatomy and physiology was not as clear–cut as it is today. Aristotle’s main purpose was to describe the animals, and it was hardly possible to speak of the organs without speaking of their functions; from the Aristotelian point of view the function created the organ rather than the opposite. To give a full account of Aristotle’s anatomy and physiology would be endless. It will suffice to give a few examples of good and bad.

Because Aristotle was a zoologist, his anatomy naturally took the form of comparative anatomy, and his classification was based, as it ought to be, on anatomic evidence. For example, he studied the stomach of the ruminants and gave a correct account of the four chambers.

Fig. 97. The Aristotelian classification of animals as reconstructed from the Historia animalium. [Reproduced from Studies in the history and method of science ( Oxford, 1921), viol. 2, p. 16, with kind permission of Dr. Charles Singer and of the Clarendon Press.]

Fig. 98. Diagram reproducing the Aristotelian idea of scala naturae implicit in the Historia animalium. [Reproduced from Studies in the history and method of science, vol. 2, p. 21, with kind permission of the author and publisher.]

In spite of his prudence he was sometimes led into dangerous comparisons. Here is a good example of bad Aristotle, which I need not discuss. It combines a whole series of unrelated topics.

Of all animals human beings are the ones which go bald most noticeably, but still baldness is a general and widespread condition. Thus, although some plants are evergreen, others shed their leaves, and birds which hibernate shed their feathers. Baldness, in those human beings whom it affects, is a comparable condition to these. Of course, a partial and gradual shedding of leaves takes place in all plants, and of feathers and hair in those animals that have them; but it is when the shedding affects the whole of the hair, feathers, etc., at once that the condition is described by the terms already mentioned ( baldness, moulting, etc.). The cause of this condition is a deficiency of hot fluid, the chief hot fluid being greasy fluid, and that is why greasy plants tend more to be evergreen than others. However, we shall have to deal with the cause of this condition so far as plants are concerned in another treatise, since in their case there are other contributory causes of it. Now in plants this condition occurs in winter: this seasonal change overrides in importance the change in the time of life. The same is true of the hibernating animals; they too are in their nature less fluid and less hot than human beings. For human beings, however, it is the seasons of life which play the part of summer and winter; and that is why no one goes bald before the time of sexual intercourse, and also why that is the time when those who are naturally prone to intercourse go bald. The reason is that the effect of sexual intercourse is to cool, as it is the excretion of some of the pure, natural heat, and the brain is by its nature the coldest part of the body; thus, as we should expect, it is the first part to feel the effect: anything that is weak and poorly needs only a slight cause, a slight momentum, to make it react ... And it is owing to the same cause that it is on the front part of the head only that human beings go bald, and that they are the only animals which do so at all; i.e., they go bald in front because the brain is there, and they alone do so, because they have by far the largest brain of all and the most fluid. Women do not go bald because their nature is similar to that of children: both are incapable of producing seminal secretion. Eunuchs, too, do not go bald, because of their transition into the female state, and the hair that comes at a later stage they fail to grow at all, or if they already have it, they lose it, except for the pubic hair: similarly, women do not have the later hair, though they do grow the pubic hair. This deformity constitutes a change from the male state to the female.¹⁴³⁸

These statements are foolish, but they are not contemptible. They are not uncritical folklore, but premature generalizations based upon too small a number of facts, facts that had not been observed with sufficient care and had been brought together too hastily. Some of the topics dealt with in such a casual way are extremely difficult.¹⁴³⁹

What is much worse, Aristotle had very wrong ideas concerning the brain and the heart, in spite of the fact that the main function of the brain had been recognized almost two centuries before by Alcmaion of Croton. Aristotle considered the heart the seat of intelligence, the function of the brain being then simply to cool the heart by the secretion of phlegm and to prevent its overheating. How could this experienced and wise man reach such preposterous conclusions? The insensitivity of the exposed brain to handling and wounding is striking, and even more so the sensitiveness of the heart to emotions; the brain seems comparatively bloodless; and so on.¹⁴⁴⁰ At any rate, Aristotle’s position was clear: the brain may serve the mind indirectly (by its action upon the heart), but it is not the seat of reason. It is very curious that Aristotle, son of a physician, was less interested in medicine than in science and philosophy, and was apparently unacquainted with the Hippocratic writings.¹⁴⁴¹ One cannot help being shocked, however, by his wrongness on one of the most fundamental points of human life.

Habits of animals. The Historia animalium is full of observations concerning the curious habits of animals. Much of that had been known to observant farmers or fishermen long before Aristotle’s time, but it required scientific curiosity and persistence such as the master possessed to criticize those stories and put them together in scientific language. His criticism varies greatly from one case to another; sometimes we are astonished by its depth and sureness; sometimes we shake our head and wonder how he could be so careless. The answer to that is, of course, that genius even at its best is never continuous. Aliquando bonus dormitat . . . Aristoteles! This remark must be made, because the good examples that I am going to offer should not give one a false idea of the Historia antmalium. The critics have devoted their attention mainly to the good pieces. It would be interesting to make a statistical analysis of the whole work and determine how often the master is right, how often wrong, and to evaluate his degree of correctness in every case.

His description of the shock produced by the torpedo fish¹⁴⁴² is perhaps not surprising, for many fishermen must have experienced that phenomenon; yet Aristotle’s description is significant, because it is sober and objective––the description of a man who could not yet know the electric nature of that shock, who had no knowledge of electricity whatsoever, yet was not swept off his feet and did not speak of marvels, but described simply what he had observed.

Now read his account of the breeding habits of the catfish:

The catfish deposits its eggs in shallow water, generally close to roots or close to reeds. The eggs are sticky and adhere to the roots. “The female catfish, having laid her eggs, goes away. The male stays on and watches over the eggs, keeping off all other little fishes that might steal the eggs or fry. He thus continues for forty or fifty days, till the young are sufficiently grown to escape from the other fishes for themselves. Fishermen can tell where he is on guard, for, in warding off the little fishes, he sometimes makes a rush in the water and gives utterance to a kind of muttering noise. Knowing his earnestness in parental duty the fishermen drag into a shallow place the roots of water plants to which the eggs are attached, and there the male fish, still keeping by the young, is caught by the hook when snapping at the little fish that come by. Even if he perceive the hook, he will still keep by his charge, and will even bite the hook in pieces with his teeth.”¹⁴⁴³

Aristotle’s story of the catfish was disbelieved, because the catfish of Western Europe do not look after their young in such a fashion, but Louis Agassiz discovered that the American catfish confirmed the story. Some of the catfish of the Achelous river (running into the Gulf of Corinth) were sent in 1856 to Agassiz, who could verify Aristotle’s account and calls them Parasilurus Aristotelis. It was only in 1906, however, that those facts became generally known to men of science.

Aristotle also remarked¹⁴⁴⁴ that the catfish and some other fishes produce sounds by rubbing their gills (more exactly the gill covers); it is not true then to say that all fishes are silent.¹⁴⁴⁵

The Greeks were familiar with bees, to which they owed honey — a substance incredibly precious when no other sugar was available — and it is natural enough to find many references to them in the Historia animalium. The account that Aristotle gave of them is admirable, except that he did not realize unambiguously that the ruler of the hive is a female, a queen, not a king.

Aristotle’s descriptions are the more startling when we recall the extreme paucity of his means; not only did he lack the instruments (magnifying glasses, etc.) and drugs with which our naturalists are always armed, but he had no reference books and dictionaries which enable us to check and recheck our own conclusions in a moment. There was probably a library at the Lyceum, but it was rudimentary, especially with regard to scientific subjects. The language, without which ideas cannot be communicated, did not even exist. The marvelous tool created by the poets and historians lacked the technical terms without which a brief and clear description is impossible. Aristotle had to create many of the necessary terms as he needed them. But even the most highly developed technical language is insufficient in biologic description without drawings. It is certain that Aristotle (or his collaborators) added drawings, though we have no means of estimating their number and their value. For example, speaking of the womb, he says, “As to the appearance of this organ I must refer the reader to diagrams in my Anatomy.¹⁴⁴⁶ As to the bladder and penis, he remarks a little further in the same book, “All these descriptive particulars may be seen in the accompanying diagram,” ¹⁴⁴⁷ and he refers to various parts of it by means of letters, just as was done in the geometric figures. In another book, he remarks, “All this should be studied with the help of the illustrative diagrams given in the Dissections and Researches.” ¹⁴⁴⁸

Fig. 99. Lewes’s book of 1864 was a brilliant, if imperfect, synthesis of Aristotle’s scientific thought. It was the first elaborate study of Aristotelian science and the first instalment of his projected history of science. He was one of the pioneer historians of science, and is now unfairly decried, especially by people, men of letters or men of science, who have but little knowledge of the subject. Wrote Lewes in his Preface, “I have been for many years preparing myself to attempt a sketch of the Embryology of Science, so to speak, — an exposition of the great momenta in scientific development; and the present volume is the first portion of such an exposition...” [From the copy in the Harvard College Library.]

Embryology. One of the earliest elaborate studies in Aristotle’s scientific thought was written by George Henry Lewes in 1864 (Fig. ¹⁴⁴⁹ Lewes was not by any means an uncritical admirer of Aristotle, but when he came to the biologic writings which, being himself a naturalist, he could fully appreciate, he could no longer restrain his admiration. Here is the way he spoke of De generatione animalium:

It is an extraordinary production. No ancient, and few modern works, equal it in comprehensiveness of detail and profound speculative insight. We there find some of the obscurest problems of Biology treated with a mastery which, when we consider the condition of science at that day, is truly astounding. That there are many errors, many deficiencies, and not a little carelessness in the admission of facts, may be readily imagined; nevertheless, at times the work is frequently on a level with, and occasionally even rises above, the speculations of many advanced embryologists. At least so it appears to me; and the reader knows how little I am disposed to discover in ancient texts the fuller meanings of modern science, and how anxiously I strive to represent what Aristotle actually thought. It is difficult to disengage ancient texts from the suggestions of modern thought; but I should not be candid were I to conceal the impression which the study of this work left on my mind, that the labors of the last two centuries from Harvey to Kölliker have furnished the anatomical data to confirm many of the views of this prescient genius. Indeed, I know no better eulogy to pass on Aristotle than to compare his work with the “Exercitations concerning Generation” of our immortal Harvey. The founder of modern physiology was a man of keen insight, of patient research, of eminently scientific mind. His work is superior to that of Aristotle in some few anatomical details; but it is so inferior to it in philosophy, that at the present day it is much more antiquated, much less accordant with our views.¹⁴⁵⁰

The English critic did not hesitate to place the De generatione animalium of Aristotle above that of his illustrious countryman, published in 1651, some two thousands years later!

As this is a subject remote from my own investigations, it will be better to withdraw for a moment and allow one of my friends, who is a very distinguished embryologist, to judge his forerunner:

His outstanding contributions to embryology may be put in the following way:

1. He carried to their logical conclusion the principles of the observation of facts suggested by the unknown Hippocratic embryologist, and added to them a discipline of classification and correlation of facts which gave embryology a quite new coherence.

2. He introduced the comparative method into embryology, and by studying a multitude of living forms was able to lay the foundation for future science of the various ways in which embryonic growth can take place. Thus he knew of oviparity, ovoviviparity, and viviparity. and one of his distinctions is substantially the same as that known to modern embryology between holoblastic and meroblastic yolks.

3. He distinguished between primary and secondary sexual characteristics.

4. He pushed back the origin of sex determination to the very beginning of embryonic development.

5. He associated the phenomena of regeneration with the embryonic state.

6. He realized that the previous speculations on the formation of the embryo could be absorbed into the definite antithesis of preformation and epigenesis, and he decided that the latter alternative was the true one.

7. He put forward a conception of the unfertilized egg as a complicated machine, the wheels of which would move and perform their appointed function in due course when once the master lever had been released.

8. He foreshadowed the theory of recapitulation in his speculations on the order in which the souls came to inhabit the embryo during its growth, and in his observation that universal characteristics precede particular characteristics in embryogeny.

9. He foreshadowed the theory of axial gradients by his observations on the greater and more rapid development of the cephalic end in the embryo.

10. He allotted the correct functions to the placenta and the umbilical cord.

11. He gave a description of embryonic development involving comparison with the action of rennet and yeast, foreshadowing thus our knowledge of organic catalysts in embryogeny.

But there was another side to the pic ture. Aristotle made three big mistakes, and here I do not refer to any matters of detail, in which it would not have been humanly possible to be more than very often right, but rather to general notions, such as the eleven correct ones.

They were as follows:

1. He was incorrect in his view that the male supplies nothing tangible to the female in the process of fertilization. To say that the semen gave the “form” to the inchoate “matter” of the menstrual blood was equivalent to saying that the seminal fluid carried nothing in it but simply an immaterial breath along with it. Aristotle did not, of course, envisage the existence of spermatozoa.

2. He was entirely wrong in his teaching about the scolex. The caterpillar is not, as he supposed, an egg laid too soon, but has already passed through the embryonic state.

3. He was misled by some observations on castrated animals and so did not ascribe to the testis its true function.¹⁴⁵¹

Let us now give four concrete illustrations of Aristotle’s genius as an embryologist; they deal with the chick, the placental shark, the cephalopods, and the belone.¹⁴⁵²

The case of the chick is the simplest, for it was easy enough (provided one had the idea of doing it) to break and examine eggs of known age (freshly laid, 1, 2, 3, ... days old). Aristotle observed the first indication of an embryo just after 3 days (a little earlier, he noted, in smaller birds, a little later in larger ones). He saw the heart beating, a speck of blood which later writers called punctum saliens (the heart primordium). It may be that this observation, the appearance of the heart ahead of all the other organs, confirmed his opinion that the heart was the seat of the soul or of the mind. Observing older eggs, he described the growth of the embryo, the absorption of the yolk, the shriveling of the membranes, and so forth. It was a magnificent beginning of scientific embryology, which remained unsurpassed until Harvey’s time or even until later (if we accept Lewes’s judgment quoted above).

Aristotle knew that most fishes bring out their young in the potential form of eggs, but that a group of these, which he called selache, brought them out fully shaped and actively alive. In one of the group, the resemblance to mammals goes even further.

The so–called smooth shark has its eggs in betwixt the wombs like the dog–fish; these eggs shift into each of the two horns of the womb and descend, and the young develop with the navel–string attached to the womb, so that, as the egg–substance gets used up, the embryo is sustained to all appearance just as in the case of quadrupeds. The navel–string is long and adheres to the under part of the womb (each navel–string being attached as it were by a sucker), and also to the center of the embryo in the place where the liver is situated. If the embryo be cut open, even though it has the egg–substance no longer, the food inside is egg–like in appearance. Each embryo, as in the case of quadrupeds, is provided with a chorion and separate membranes.¹⁴⁵³

This was so extraordinary a phenomenon that it was almost disregarded until modern times. Pierre Belon (1553) and Guillaume Rondelet (1554) were aware of the connection between the embryo and the maternal oviduct or uterus, and Niels Stensen (Steno) realized a century later (1673) that this was for the nourishment of the embryo, and was in short a true functional placenta. Yet for all that Aristotle’s early discovery was overlooked until Johannes Muller reëxplained it (1839—1842).¹⁴⁵⁴ One must admit that there is something almost uncanny in the anticipation by Aristotle, unequipped with tools and books, of a discovery remade a century ago by one of the leading physiologists of the nineteenth century.

The. sexual congress of cephalopods such as the octopus, the sepia, and the calamary was imperfectly described by Aristotle¹⁴⁵⁵ and involved him in self–contradiction, yet he adumbrated the discovery of the process known as hectocotylization, which was not correctly described until the nineteenth century. It is not expedient to quote Aristotle’s own words because that would entail too many qualifications, nor the modern descriptions, for the best anatomists of the last century did not find the truth except after many detours. Suffice it to say that hectocotylus is the name given to one arm of the male of most cephalopods, which is specially modified to accomplish the fertilization of the eggs. In the Argonauta (such as the paper nautilus),¹⁴⁵⁶ the hectocotylus after receiving the spermatophores is detached from the male and attaches itself to the female. When the detached hectocotylus was first discovered, it was mistaken (even by such a man as Cuvier) for a kind of worm parasitic on the female. The mystery was first solved by Albrecht von Kölliker in 1842 (1847), but many more investigations were required to elucidate it and some details remain unexplained to this day.¹⁴⁵⁷

Aristotle’s description of the belone is ambiguous; part of it applies to one kind of fish, another part to another kind. The part that applies to the pipefish or needlefish (Syngnathus acus) describes with remarkable precision the singular mode of reproduction of that very small and needlelike fish. According to his statements in various places:

Fishes then in general produce their young by copulation, and lay their eggs; but the pipefish, as some call it, when the time of parturition arrives, bursts in two, and the eggs escape out. For the fish has a diaphysis or cloven growth under the belly and abdomen ( like the blind snakes), and, after it has spawned by the splitting of this diaphysis, the sides of the split grow together again.¹⁴⁵⁸

There are some fishes, such as the one known as belone, which burst asunder owing to the size of the eggs, the fetations of this fish being large instead of numerous; here Nature has taken away from their number and added to their size.¹⁴⁵⁹

The so–called needlefish ( or pipefish ) is late in spawning, and the greater portion of them are burst asunder by the eggs before spawning; and the eggs are not so many in number as large in size. The young fish cluster around the parent like so many young spiders, for the fish spawns onto herself; and, if any one touch the young, they swim away.¹⁴⁶⁰

So far so good, but Aristotle did not see that the pouch is developed under the belly of the male fish, that the eggs are deposited into it by the female, and that it is the male that continues to nurse and look after the young. Aristotle’s discovery was completed only in 1784 by John Walcott of Teignmouth, and published half a century later by William Yarrell.¹⁴⁶¹ Later investigations (in our own century) established that the marsupium of the male of such fishes with its epithelial lining and its capillaries and lymph vessels is a functional uterus placenta.¹⁴⁶² One could not expect Aristotle to discover all that; it was materially impossible for him to do so; but is it not astounding that he came so close to the edge of the mystery, and — we must always insist on this — spoke of it in a sensible and quiet way, even as any zoologist of our own times?

Geographic distribution of living beings. The Greeks were a roving kind of people, restless amphibians ¹⁴⁶³ sailing across the Mediterranean or caravaning across foreign lands in search of business or of knowledge. They were intelligent and alert, good observers, and Aristotle must have enjoyed many opportunities of interviewing travelers. His own journeys were not extensive; yet they included a good diversity of landscapes and climates and the travelers whom he met in Macedonia, in the Troad, or in Athens were able to give him some idea of the other climates. Above all, Alexander could bring many novelties to his knowledge; we may imagine that the mot d’ordre had been given to his scientific entourage, that whatever Aristotle asked for should be granted and that every novelty should be communicated to him. Hence the richness of Aristotle’s biologic point of view, and his keen realization of the geographic distribution of plants and animals. Plants were fixed to the land of their birth, but animals could move and did move when the climate became unsuitable to them or unpleasant. Listen to this, the earliest text concerning one of the most mysterious of all biologic subjects, the migration of animals:

The habits of animals are all connected with either breeding and the rearing of young or with the procuring a due supply of food; and these habits are modified so as to suit cold and heat and the variations of the seasons. For all animals have an instinctive perception of the changes of temperature, and, just as men seek shelter in houses in winter, or as men of great possessions spend their summer in cool places and their winter in sunny ones, so also all animals that can do so shift their habitat at various seasons. Some creatures can make provision against change without stirring from their ordinary haunts; others migrate, quitting Pontos and the cold countries after the autumnal equinox to avoid the approaching winter, and after the spring equinox migrating from warm lands to cool lands to avoid the coming heat. In some cases they migrate from places near at hand, in others they may be said to come from the ends of the world, as in the case of the crane; for these birds migrate from the steppes of Scythia to the marshlands south of Egypt where the Nile has its source. And it is here, by the way, that they are said to fight with the pygmies; and the story is not fabulous, but there is in reality a race of dwarfish men, and the horses are little in proportion, and the men live in caves underground. Pelicans also migrate, and fly from the Strymon to the Ister, and breed on the banks of this river. They depart in flocks, and the birds in front wait for those in the rear, owing to the fact that when the flock is passing over the intervening mountain range, the birds in the rear lose sight of their companions in the van. Fishes also in a similar manner shift their habitat now out of the Euxine and now into it. In winter they move from the outer sea in towards land in quest of heat; in summer they shift from shallow waters to the deep sea to escape the heat. Weakly birds in winter and in frosty weather come down to the plains for warmth, and in summer migrate to the hills for coolness. The more weakly an animal is the greater hurry will it be in to migrate on account of extremes of temperature, either hot or cold; thus the mackerel migrates in advance of the tunnies, and the quail in advance of the cranes. The former migrates in the month of Bo dromi n [22 August–22 September], and the latter in the month of Maimac–t ri n [22 October–22 November]. All creatures are fatter in migrating from cold to heat than in migrating from heat to cold; thus the quail is fatter when he emigrates in autumn than when he arrives in spring. The migration from cold countries is contemporaneous with the close of the hot season. Animals are in better trim for breeding purposes in spring–time, when they change from hot to cool tands. . . .¹⁴⁶⁴

Not only was Aristotle acquainted with what we would call today geographic biology or biological geography; he had some definite knowledge of ecology, the relation not only between living beings and their physical environment, but also between living beings and their biologic environment. How is each animal affected by other animals or by the plants living near it? Some of the other animals prey on it, or it preys on them. Some animals are rivals, others are collaborators. But this subject brings us so close to sociology that it is better to save our examples of Aristotelian ecology until the next chapter.

Our enumeration of his biologic knowledge could be extended considerably; yet enough has been said to illustrate the magnitude of his biologic genius. He was not only the first great one in his field, somewhat like Hippocrates in medicine, but he remained the greatest for two thousand years.

After a period of anti–Aristotelian reaction and oblivion, Aristotle the biologist was fully rehabilitated and vindicated by the end of last century. This could be proved in many ways, but I shall restrict myself to a single document, the letter that Charles Darwin wrote to Dr. William Ogle to acknowledge receipt of the latter’s translation of the Parts of animals.¹⁴⁶⁵ A part of that letter has often been quoted, but I reproduce it completely, because it is typical of Darwin’s kindness and honesty.

DOWN, February 22, 1882 MY DEAR DR. OCLE:

You must let me thank you for the pleasure which the introduction to the Aristotle book has given me. I have rarely read anything which has interested me more, though I have not read as yet more than a quarter of the book proper.

From quotations which 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. How very curious, also, his ignorance on some points, as on muscles as the means of movement. I am glad that you have explained in so probable a manner some of the grossest mistakes attributed to him. I never realized, before reading your book, to what an enormous summation of labour we owe even our common knowledge. I wish old Aristotle could know what a grand Defender of the Faith he had found in you. Believe me, my dear Dr. Ogle,

Yours very sincerely,


What greater testimony could one obtain than the one freely given by the master of general biology in the second half of the last century? If Hippocrates deserves to some extent to be called the father of medicine, Aristotle deserves more fully to be called the father of biology.



When we tried to explain the Greek background of Hippocratic medicine, we spoke of the herb gatherers, thanks to whom an enormous amount of plant lore had been patiently accumulated. How long the accumulation lasted we cannot say; one might speak of millennia as well as of centuries. People learned to know gradually, very slowly, by a process of trial and error that had to be endlessly repeated, for its results were never properly recorded, that certain plants were useful and others dangerous; some were foods, palatable and nutritious, others were refreshing; some were sweet and others bitter; and so on. The main discoveries concerned the pharmacologic qualities of herbs and roots, which might be laxative, emetic, sedative, diuretic, emmenagogic, analgesic, antipyretic, etc.; it was observed that the best results were obtained with a definite dose and that if the dose were excessive death might ensue. In other words, the people of Greece, like the people of other countries, discovered foods, drugs, and poisons. In the course of ages, there developed among them a special profession of herb gatherers or herbalists; as the virtues of plants were often concentrated in the roots, the familiar Greek name for them was rhizotomists. These men were indispensable and rendered great services; it is probable that the folklore transmitted by them concerned not only drugs but also poisons and magic potions. Judging from allusions to them in Greek literature, the rhizotomists did not enjoy a good reputation; they were accused of being magicians, witches, poisoners; they certainly knew dark secrets and were ready to use them, and even to abuse them. There was no ethical code to restrain their activities, but their manners and customs were permeated with superstitious rites.¹⁴⁶⁷


That immense botanic folklore was available to the men of science as well as to the common people and it was up to the former to investigate it, to verify the claims that were made for each plant, and to incorporate some items into their scientific publications. Thus, we find some 300 plants mentioned in the Hippocratic corpus;¹⁴⁶⁸ the mention, being restricted to medical use, takes for granted that the plant is known to the reader and makes it impossible for him to identify it if he is not already familiar with it.

It is certain that botanic topics were discussed in the Academy and the Lyceum. Aristotle and his pupils were not interested only in the practical value of plants, they were anxious to define them and to discuss their form and growth.¹⁴⁶⁹ Unfortunately, we can give no precision to that idea, because Aristotle’s botanic writings, if any, have disappeared. The De plantis included in the Opuscula is certainly apocryphal; it is generally ascribed to Herod’s friend, Nicholas of Damascus ( I–2 B.C.), and its tradition is so crooked that we may digress a moment in order to summarize it. It is a good example of the precariousness and capriciousness of literary tradition.

The original Greek text of the De plantis was translated at least once into Arabic, by Is q ibn Hunain (IX–2). The Arabic text was translated into Latin by the Englishman Alfred of Sareshel (XIII–1), and into Hebrew by the Provençal Qalonymos ben Qalonymos (XIV–1). The Greek and Arabic texts are lost. The Greek text in the Bekker edition¹⁴⁷⁰ is a retranslation of the Latin into Greek! In this case, it is thus better to refer to the Latin, one step closer to the lost original than to the Greek, which is thrice removed from it.¹⁴⁷¹ Though the De plantis is certainly not Aristotelian, it contains many passages that are parallel to various writings of Aristotle and Theoprastos.¹⁴⁷² Its general structure is typical of Peripatetic thought.

Book 1 is divided into seven chapters: 1. The nature of plant life. 2. Sex in plants. 3. The parts of plants. 4. Structure variations in plants. Book 11 is divided into ten chapters: 1. Origins of plant life; “concoction.” 2. Digression on “concoction” in the earth and sea. 3. The material of plants; effects of outward conditions and climate. 4. Water plants. 5. Rock plants. 6. Other effects of locality on plants; parasitism. 7. Production of fruit and leaves. 8, 9. Colors and shapes of plants. 10. Fruits and their flavor.¹⁴⁷³

We need not worry too much about the botanic knowledge of Aristotle; he was probably like many other naturalists of all ages who know botany, and may even have a fair knowledge of it, yet who are more interested in animals. Moreover, Aristotle had an immense amount of work to do, for he had cut out for himself the encyclopedic survey of all knowledge. When a master is thus overburdened by a gigantic labor and finds an intelligent pupil who is ready to do a part of it, he may be willing enough to abandon that part to him. This is exactly what happened; his best disciple, Theophrastos, took a special interest in botany and Aristotle abandoned botany to him. Who was Theophrastos and how did he meet Aristotle and become his best collaborator and his successor?


We have already taken our readers to Lesbos (main city, Mytilene), the largest island along the Asiatic coast in the Aegean Sea, the native region of the Aeolian school of lyric poetry. During the seventh century it gave birth to four illustrious poets: Terpandros, Arion, Alcaios, and, greatest of all, sweet Sappho.¹⁴⁷⁴ The word Lesbian has stupidly acquired a bad connotation; to me it suggests lyric poetry and beauty. During the same century Lesbos gave to Greece one of her Seven Wise Men, Pittacos; in the fifth century, one of the earliest historians, Hellanicos; and finally, in the fourth century it gave her two philosophers and to Aristotle two disciples, Phanias and Theophrastos.

Theophrastos, son of Melantas, a fuller, was born at Eresos c. 372, and he died in very old age, c. 288. He came to Athens to sit at Plato’s feet, and during that period must have become acquainted with Aristotle. Their acquaintance was renewed and their friendship established when Aristotle lived in Assos, Aterneus, and Lesbos. It was probably during that period that both men engaged in the study of natural history, in the island, along its shores, or sailing on the blue sea. They belonged to the same generation, for Theophrastos was only a dozen years younger than Aristotle. They flourished together at the Lyceum and when Aristotle was obliged to leave Athens in 323/22, he appointed him his successor ¹⁴⁷⁵ and bequeathed to him his library and the manuscripts of his own works. Theophrastos continued the master’s tradition in great style and may be called the second founder of the Lyceum; he was head of the school for thirty–five years (thrice as long as Aristotle); ¹⁴⁷⁶ he reorganized the school and enlarged it. His rich pupil, Demetrios of Phaleron, enabled him to buy an adjoining estate and to increase the garden of the Lyceum. His fame as a lecturer was so great that he gathered around him some two thousand disciples; ¹⁴⁷⁷ this is a very large number, but it refers presumably to the whole of Theophrastos’ career; it would mean a yearly average of fewer than sixty pupils — still a large number in the Athens of those days, but acceptable. He was at least eighty–five years old when he died, and, like every great man who had the privilege of remaining intelligent and lucid until the end, he complained that life is so short that a man must go just when he is beginning to understand its mysteries.

He continued Aristotle’s encyclopedic purpose and his activity was prodigious. Diogenes Laërtios ascribes 227 treatises to him, dealing with religion, politics, ethics, education, rhetoric, mathematics, astronomy, logic, meteorology, natural history, etc. The main works that have come down to us are the two on plants and the one on stones that will be discussed below. Fragments exist of his treatises De sensu et sensibilibus, De igne, De odoribus, De ventis, De signis tempestatum (pluviarum, ventorum, tempestatis et serenitatis), De lassitudine, De vertigine, De sudore, De animi defectione (lipopsychia), De nervorum resolutione (paralysis), Metaphysica, etc.

The most convenient edition of the opera omnia is the Greco–Latin by Friedrich Wimmer (Paris, 1866), with indices nominum, graecitatis et rerum, plantarum. The text covers 462 pp., of which 319 are botanical; it does not include the Characters.

On stones, Greek and English edition by Sir John Hill¹⁴⁷⁸ (234 pp.; London, 1746; 2nd ed., London, 1774).

On winds and On weather signs, translation by James George Wood (97 pp.; London, 1894).

Enquiry into plants, On odours and On weathersigns, Greek–English by Sir Arthur Hort (2 vols.; Loeb Classical Library, 1916) [Isis 3, 92 (1920–21)].

On the senses, Greek–English by George Malcolm Stratton (London, 1917).

We have not yet mentioned the most popular of all of Theophrastos’ writings, the Characters ( thicoi charact res), a series of thirty sketches of typical weaknesses, such as arrogance, backbiting, boorishness, buffoonery, written in 319. Their genuineness has been questioned, but they have never been ascribed to another author. They were not discovered together but gradually and thus the date of the editio princeps varies according to the number of characters included.

The first edition, by Willibald Pirckheimer (Nuremberg, 1527), included only Characters 1 to xv; Characters XVI to XXIII were first published by Giambattista Camozzi ( Venice, 1552), Characters XXIV to XXVIII by Isaac Casaubon ( in his second edition of the Characters, Leyden, 1599; the first edition had appeared in 1592), Characters XXIX to xxx by Giovanni Cristoforo Amaduzzi (Parma, 1786). The first edition of the thirty Characters was published, singularly enough, by the English dilettante, John Wilkes (London, 1790) (Fig. 100). There is a very convenient Greek–English edition by John Maxwell Edmonds in Loeb Classical Library (1929).

We reproduce the full text of Character XVI, Superstitiousness,¹⁴⁷⁹ for two reasons:

Fig. 100. First page of the first edition of the Thirty characters, by John Wilkes (1727–1797), politician, lord mayor of London in 1774; edition de luxe, 103 copies printed (84 pp.; 21 cm; London, 1790). The autiaor’s dilettantism is illustrated by the fact that the text is printed without breathings and without accents! [From the copy in the Harvard College Library.]

Superstitiousness, I need hardly say, would seem to be a sort of cowardice with respect to the divine; and your Superstitious man such as will not sally forth for the day till he have washed his hands and sprinkled himself at the Nine Springs, and put a bit of bayleaf from a temple in his mouth. And if a cat cross his path he will not proceed on his way till someone else be gone by, or he have cast three stones across the street. Should he espy a snake in his house, if it be one of the red sort he will call upon Sabazios, if of the sacred, build a shrine then and there. When he passes one of the smooth stones set up at crossroads he anoints it with oil from his flask, and will not go his ways till he have knelt down and worshiped it. If a mouse gnaw a bag of his meal, he will off to the wizard’s and ask what he must do, and if the answer be “send it to the cobbler’s to be patched,” he neglects the advice and frees himself of the ill by rites of aversion. He is forever purifying his house on the plea that Hecate has been drawn thither. Should owls hoot when he is abroad, he is much put about, and will not on his way till he have cried “Athena forfend!” Set foot on a tomb he will not, nor come nigh a dead body nor a woman in childbed; he must keep himself unpolluted. On the fourth and seventh days of every month he has wine mulled for his household, and goes out to buy myrtle boughs, frankincense, and a holy picture, and then returning spends the livelong day doing sacrifice to the Hermaphrodites and putting garlands about them. He never has a dream but he flies to a diviner, or a soothsayer, or an interpreter of visions, to ask what God or Goddess he should appease; and when he is about to be initiated into the holy orders of Orpheus, he visits the priests every month and his wife with him, or if she have not the time, the nurse and children. He would seem to be one of those who are forever going to the seaside to besprinkle themselves; and if ever he see one of the figures of Hecate at the crossroads wreathed with garlic, he is off home to wash his head and summon priestesses whom he bids purify him with the carrying around him of a squill or a puppy dog. If he catch sight of a madman or an epilept, he shudders and spits in his bosom.

We reprint this text in the first place, because it is a good description of the darker side of Greek thought in its golden age. There were superstitious people in Athens close to the Academy and even to the Lyceum, even as there are superstitious people today in the shadow of our own academies and colleges. Our second reason is that this sketch renders Theophrastos’ authorship very plausible. Indeed, we would expect a man of science to deride superstitions in that very manner. Assuming his authorship, Theophrastos was in his early fifties when he composed them; they show that he was not a pedant (scholasticos, micrologos); he was a philosopher and had a good sense of humor.

Such characteristic portraits were not invented by him; we find some in Herodotos, Plato, Aristotle, not to mention Aristophanes and Menandros; but Theophrastos was the first to publish a gallery of them, and by so doing he created a new literary genre. La Bruyère’s French translation, to which he added a series of sketches characterizing the manners and customs of his own century, was published in Paris in 1688 ¹⁴⁸⁰ and became one of the classics of French literature (Fig. 101). More than two millennia (2008 years) separate the two books, composed respectively in the golden age of Athens and the grand siècle of France, but they are very close, except that Theophrastos was primarily a man of science, and La Bruyère, a man of letters.

My last statement should not be misunderstood. Theophrastos at his best wrote simply but well; he wrote like a man of science who appreciates literary values yet must subordinate them to scientific purposes. Truth first, beauty next. He realized the danger of superfluous words from the scientific point of view, but also from the artistic one. “It is better not to say everything at great length but to leave some things for the reader to guess at and to find for himself. The reader who has guessed what was left unsaid becomes a collaborator and a friend. Should you try to say everything to him as one would to a fool, he would sense your distrust of his intelligence.”¹⁴⁸¹

The characters of Theophrastos are more concrete than the sketches that Aristotle introduced in his Rhetoric to illustrate various passions, but they are less individual than those of La Bruyère.

To return for a moment to Theophrastos’ nonbotanic writings, the following remarks will suffice.

One of his most important small writings is the De signis tempestatum (On weather signs ) which was used by Aratos of Soli (III–1 B.C.); as Aratos’ poem was commented upon by Hipparchos ( II–2 B.C.), Theophrastos helped to initiate a great astronomic tradition.

His treatise on odors, good and bad, perfumes and disagreeable smells, is very curious. It illustrates the Peripatetics’ eagerness to explain everything and their insatiable curiosity. Theophrastos discusses the various smells of plants and animals, for example, the smells of the latter during the breeding season. We cannot expect him to throw much light on a subject that is still very obscure today, yet we cannot help admiring the boldness of his initiative.

He apparently ¹⁴⁸² replaced the seat of intelligence in the brain, instead of putting it in the heart as Aristotle did. He knew that some animals living in northern regions have a white coat of fur in the winter.

Fig. 101. Title page of the first edition of the Caractères of La Bruyère (Paris, 1688), a small volume (15.5 cm) containing La Bruyère’s discourse on Theophrastos, then his French translation of Theophrastos’ Characters (97 pp.), and his own Characters (210 pp.). [From the copy in the Harvard College Library.]

Among his lost works was the Physicon doxai, the opinions of the physicists, which is one of our best indirect sources for the history of Greek philosophy and science.¹⁴⁸³


We may now approach the botanic works of Theophrastos, which have survived in their integrity and are the earliest books of this kind in world literature. Our readers already know that he was not by any means the first botanist, for they will assume that the most intelligent of the rhizotomists did not simply gather roots and herbs but thought about them; yet his books are the earliest and, at their best, they are excellent. He fully deserves to be called the father of botany.¹⁴⁸⁴

Theophrastos wrote two large botanic works entitled respectively Historia de plantis (History of plants, or Enquiry into plants) and De causis plantarum (The causes of plants) (Figs. 102 and 103). The first is very largely descriptive; Theophrastos tries to distinguish the different parts of plants, and the differences obtaining between plants (tõn phytõn tas diaphoras). As its title suggests, the second is more philosophic, or more physiologic. Given those differences between plants or between their organs, how shall we account for them, in Aristotelian (teleologic) terms? What are the intentions of Nature, which does nothing in vain? How do the plants live, grow, and multiply? In spite of its being less descriptive than the first work, it is full of facts. Theophrastos’ accumulation of botanic knowledge is as wonderful as Aristotle’s accumulation of zoölogic knowledge; both are almost unbelievable. We must admit the same partial explanation in both cases: Theoprastos (as well as Aristotle) wrote the synthesis and did most of the work, but his facts were gathered not only by himself but by many other men. Among his two thousand disciples, he must have obtained the collaboration of many; though Alexander died before Theophrastos’ accession to the mastership, we may be sure that his staff sent botanic specimens as well as zoölogic ones to the Lyceum, and Theophrastos’ knowledge of foreign plants (for example, those of India) was partly due to Alexander’s generous patronage.

Fig. 102. First page of the princeps edition of Theophrastos’ Historia plantarum, forming vol. 4 of the Greek princeps of Aristotle (5 vols., folio, 30.5 cm; Venice: Aldus Manutius, 1495–1498; Klebs, 83). Volume 4, printed in June 1497, contains the Greek text of the Historia plantarum and also of De causis plantarum. [From the copy in the Harvard College Library.]

Fig. 103. Colophon of Theophrastos’ De causis plantarum; first Latin edition (Treviso: Confalonerius, 1483; Klebs, 958). This folio volume (30.5 cm) contains the Latin text of both De historia and De causis plantarum, as translated by Theodoros Gaza (c. 1400–1475), who added a long preface. [From the copy in the Harvard College Library.]

Let us first see how these two treatises are built. The History of plants is divided into nine books, dealing roughly with the following topics: 1. Parts of plants and their nature, classification. 2. Propagation, especially of trees. 3. Wild trees. 4. Trees and plants special to particular districts and situations (geographic botany). 5. Timber of various trees and its uses. 6. Undershrubs. 7. Herbaceous plants, other than coronary; potherbs and similar wild herbs. 8. Herbaceous plants: cereals, pulses, and “summer crops.” 9. Juices of plants and the medicinal properties of herbs.

The Causes of plants is divided into fewer books but is almost as long as the former work:¹⁴⁸⁵ 1. Generation and propagation of plants, fructification and maturity of fruits. 2. Things which help most the increase of plants; horticulture and sylviculture. 3. Plantation of shrubs and preparation of the soil; viticulture. 4. Goodness of seeds and their degeneration; culture of legumes. 5. Diseases and other causes of failure. 6. Savors and odors of plants.

Theophrastos deals with about 500–550 species and varieties of plants, most of them cultivated; the wild plants, he adds, are very largely unknown and unnamed, yet he often refers to such. He assumed that certain wild plants could not be domesticated; this implies that attempts at acclimatization had already been made, and we are not surprised that some had failed.

What is most striking in both works is their methodic nature, in the best Aristotelian tradition. Some curious and idle facts are mentioned here and there, because the author found them too interesting to be thrown out, but in general there is a clear purpose of explanation, of differentiation and classification. Theophrastos (like Aristotle before him) was handicapped by insufficient terminology, but he introduced a few technical terms, the most needful, such as carpos for fruit, pericarpion for seed vessel, metra or matrix for the central core of stems.

He distinguished various modes of reproduction of plants — spontaneous,¹⁴⁸⁶ from a seed, from a root, or from other parts. What is more remarkable, he had observed the behavior of germinating seeds and had seen the fundamental difference that we express by the words monocotyledon and dicotyledon.¹⁴⁸⁷ His explanation was insufficient, yet it held the ground until it was corrected and completed in the second half of the seventeenth century by Marcello Malpighi (1628–1694).

The urge for botanic knowledge was at the beginning nothing but the urge for food and drugs. Theophrastos had long passed that stage and was interested in botany for its own sake, the understanding of plant life in all its forms, yet he did not lose interest in the many applications of botany to human purposes. The ninth book of the History of plants is largely medical. We find in it a good account of the superstitious rites of the rhizotomists in the gathering of roots and herb.¹⁴⁸⁸ Another illustration of his scientific spirit is given in the same work when he describes the “spontaneous changes in the character of trees and certain marvels” and remarks that “soothsayers call such changes portents.” ¹⁴⁸⁹ He is not able to indicate the cause of each, but assumes that there is a cause; the changes are not miraculous but natural.

Book ix will appeal to students of economics and sociology, as well as to students of botany and pharmacy, for its chapters describe the methods of collecting resin and pitch, of making pitch in Macedonia and Syria, of collecting frankincense and myrrh in Arabia, and so on. The products and methods are described with some detail, though they often refer to countries that Theophrastos had not visited, and this proves again that much of his information was obtained from other people.

There are even references to Indian plants.¹⁴⁹⁰ The first is a fig (Ficus bengalensis, banyan) and he noticed the ability of its branches to reach to the ground and become roots, the second a reed, the third a plant having a powerful aphrodisiac virtue.¹⁴⁹¹Theophrastos must have received such information either from Hindu merchants who came to Athens, from members of Alexander’s expedition, or perhaps from old students of his who had traveled to India.

The De causis plantarum is less known than the other work, but my examination of it suggests that it would deserve to be investigated more deeply and to be translated into English. Let us sample it. There is an account of mistletoe and its habit of refusing to sprout except upon the bark of living oaks.¹⁴⁹²

We have discussed above Herodotos’ confused account of fructification of palms and of the caprification of fig trees; Theophrastos’ account is much better, and that is what we would expect, for not only did he come a century later but he was a professional botanist while Herodotos was an amateur. Theophrastos’ account of caprification is still very imperfect (there is a confusion in his mind between caprification and the formation of galls by insects), but let me quote his way of explaining the fecundation of palm trees:

With dates it is helpful to bring the male to the female; for it is the male which causes the fruit to persist and ripen, and this process some call, by analogy, “the use of the wild fruit.” The process is thus performed: when the male palm is in flower, they at once cut off the spathe on which the flower is, just as it is, and shake the bloom with the flower and the dust over the fruit of the female, and, if this is done to it, it retains the fruit and does not shed it. In the case both of the fig and of the date it appears that the “male” renders aid to the “female,” — for the fruit–bearing tree is called “female” — but while in the latter case there is a union of the two sexes, in the former the result is brought about somewhat differently.¹⁴⁹³

Is this clear–cut introduction of plant sexuality not amazing, especially if one considers that it was almost completely forgotten until its reintroduction more than two millennia later?

The amount of detailed information included in the two works (and both must be considered if we wish to judge fairly the extent of Theophrastos’ botanic knowledge) is so vast that he must have had fairly continual access to a number of plants. The garden of the Lyceum was to some extent a botanic garden; it may be that the estate added to the original property thanks to the munificence of Demetrios of Phaleron was partly devoted to that purpose. In his will (preserved by Diogenes Laërtios), Theophrastos requests that he be buried in the garden and hopes that Pamphylos “who dwells in it shall keep it and everything else in the same condition as it has been in hitherto.” This does not prove, of course, that the garden was a botanic garden, but when does a garden become botanic? Or, to put it otherwise, does not every garden become botanic when a botanist uses it for his own scientific needs? The garden of the Lyceum was probably a botanic garden of that simple kind. It could not be botanic in the sense of a later age when taxonomy was given supreme importance and gardens were arranged for the main purpose of teaching it.¹⁴⁹⁴

There is also a fair amount of phytopathology in both works,¹⁴⁹⁵ and why not? Phytopathology is a learned word which the Greeks never knew, but every Greek husbandsman could not help being aware of the degeneration and untimely destruction of some of his crops. These were terrible facts which hurt him and might even ruin him, and there was no means of forgetting them. Greek farmers would discuss such events in their respective families or with other farmers. Writers on horticultural subjects like Theophrastos did not need to invent anything new when they spoke of various pests; they simply dealt with the obvious.

As for pests, — radish is attacked by fleas, cabbage by caterpillars and grubs, while in lettuce, leek, and many other herbs occur “leek–cutters.” These are destroyed by collecting green fodder, or when they have been caught somewhere in a mass of dung, the pest being fond of dung emerges, and having entered the heap, remains dormant there; wherefore it is then easy to catch, which otherwise it is not. To protect radishes against fleas it is of use to sow vetch among the crop; to prevent the fleas from being engendered they say that there is no specific.¹⁴⁹⁶

Other passages of the same kind occur in the History of plants.¹⁴⁹⁷ The insects referred to can sometimes be identified by modern entomologists.

The fleas on radish were flea–beetles; the caterpillars on cabbage were cabbage butterflies; the “horned–worm,” a cerambycid beetle; the grubs engendered in seeds, pea–weevils; the cobweb of olive, red spider; the worm of fruits, codling–moth; the teredo of timber in sea–water, the ship worm.¹⁴⁹⁸

Theophrastos’ phytopathology was restricted to the damage caused by insects and worms; he could not yet know of those caused by vegetable parasites. Yet his was a good beginning.

The best summary of Theophrastos’ botanic achievements has been given by Greene, and we reproduce it. That summary is a little deceptive in that it includes, for the sake of clearness and brevity, some technical terms (for example, petal, corolla, androecium) that were unknown to Theophrastos, and thus his knowledge seems sharper than it really was.

1. [Theophrastos] distinguished the external organs of plants, naming and discussing them in regular sequence from root to fruit; the naturalness of which sequence was afterwards pointedly denied; but in modern botany it stands everywhere approved.

2. He classified such organs as (a) permanent, and (b) transient; a division of them which may yet be shown more scientific than the modern distinguishing of them as (a) vegetative, and (b) reproductive.

3. The existence of aërial roots, as being of the nature of roots, and thus different from tendrils and other prehensile organs, was discovered by him and has never since been disputed.

4. He remarked upon the inconsistency of retaining in the category of roots certain enlarged, solidified, jointed, and otherwise peculiar underground parts; a suggestion which lay unheeded during two thousand years of botanical history, and has only recently led to the open recognition of the category of subterranean stems.

5. He recognized, by differences of size, solidity, and other particulars of structure, three classes of stems: the trunk, stalk, and culm.

6. By never speaking of calyx and corolla as peculiar and separate organs, but always referring to their parts as leaves merely, it is evident he regarded the flower but as a metamorphosed leafy branch; to which forgotten Theophrastan philosophy of the flower neither Goethe nor Linnaeus had but returned, when each supposed himself the discoverer of a new anthogeny.

7. He divided the plant world into the two subkingdoms of the flowering and flowerless.

8. The subkingdom of the flowering he again saw to be made up of plants leafy–flowered and capillary–flowered; really the distinction between the petaliferous and the apetalous; one the deep import of which was first realized and taken advantage of by the systematists of some two centuries ago.

9. He indicated the still more important differences of the hypogynous, perigynous, and epigynous insertion of corolla and androecium.

10. He distinguished between the centripetal and centrifugal in inflorescences.

11. He was first to use the term fruit in the technical sense, as applying to every form and phase of seed encasement, seed included; and gave to carpology the term pericarp.

12. He classified all seed plants as (a) angiospermous and (b) gymnospermous.

13. Respecting the texture and duration of their parts he classified all plants as tree, shrub, half–shrub, and herb; also noted that herbs were of perennial, biennial, or annual duration.

14. He indicated with clearness several of those differences in the structure of stems, leaves, and seeds by which the botany of later times separates plants monocotyledonous and dicotyledonous.

15. He described the differences between the excrescent and deliquescent in tree development.

16. He knew how the annual rings in the stems or trunks of certain woody growths were formed.

17. Theophrastos, with natural vision unaided by so much as the simplest lens, and without having seen a vegetable cell, yet distinguished clearly between parenchymatous and prosenchymatous tissues; even correctly relating the distribution of each to the fabrics of pith, bark, wood, leaves, flowers, and fruits.¹⁴⁹⁹

It is very strange that so much botanic knowledge should have been accumulated by the end of the fourth century, and that so little, if anything, was added to it in ancient times. Theophrastos is not only the first botanic writer but also the greatest until the Renaissance of the sixteenth century in Germany. His Greek followers, Nicandros of Colophon (111–1 B.C.), Cratevas (1–1 B.C.) and the latter’s royal employer, Mithridates Eupator (1–1 B.C.), Dioscorides of Anazarbos (1—2), enriched the Greek herbal and Cratevas illustrated it, but I am not aware of any material contribution of theirs to botanic science. As to the Romans, Cato the Censor (11–1 B.C.), Varro (1–2 B.C.), Columella of Gades (1–2), their main contributions were agricultural. Pliny (1–2) put together all the knowledge available in his time but added nothing. The botany of Theophrastos and the zoology of Aristotle represent the climax of natural history in antiquity.



Much knowledge of geology and mineralogy had been collected for centuries because of mining undertakings in Egypt, Greece, and elsewhere. The quest for metallic ores and for gems began very early. Many curious geologic phenomena could be witnessed in the Near East, such as earthquakes, volcanic explosions, hot and mineral springs, caverns and underground waters, strange mountain shapes, narrow canyons. People who were attentive enough and reflective, as many Greeks were, could not help cogitating on those mysteries. Why did they happen? And how? The first explanations were mythologic and could not satisfy very long those gifted men, wise in their generation. The Pythagoreans postulated the existence of a central fire within the earth, an idea that could not be disproved and has continued to be entertained almost to our own day, coalescing with the conception of an underground hell.¹⁵⁰⁰ In our note on Xenophanes of Colophon above, he was called with justice the earliest geologist as well as the earliest paleontologist. Herodotos explained the formation of Lower Egypt by alluvia. The extraordinary behavior of the Nile had exercised the curiosity of Greek travelers from early days, and they speculated on the causes of the annual flood. Even the most intelligent admitted the possibility of interchanges between earth and water; it was possible, they thought, for earth to appear where water was, and vice versa. Xenophanes’ ideas concerning fossils were accepted by Xanthos of Sardis,¹⁵⁰¹ by Herodotos, Eudoxos of Cnidos, Aristotle, Theophrastos; and such ideas would have remained in circulation had they not been driven down and out by the Jewish–Christian dogma of creation.

Precious stones were collected from the earliest times for the adornment of women or for ceremonial purposes.¹⁵⁰² There was an immemorial knowledge of them, comparable to the immemorial knowledge of animals and plants. The three kingdoms of nature were equally familiar to prehistoric men. The novelty in the age of Aristotle was not so much in the knowledge as in the scientific form given to it, in its partial disentanglement from folklore and superstition.

Various geologic topics are discussed in the Meteorologica ascribed to Aristotle.¹⁵⁰³ It is significant that in ancient and medieval times the two fields, meteorology and geology, were closely interlocked. For Aristotle and for all the men of science of classical antiquity, earthquakes and volcanic explosions were interrelated. They continued to accept the idea of a central fire, and Aristotle tried to explain it by his assumption of underground winds which would be heated up by friction and shock; that might lead to explosions, even submarine explosions, such as occurred in one of the Lipari Islands. The idea of underground winds was itself very ancient; ¹⁵⁰⁴ it was symbolized by the myth of Aiolos; Aiolos was supposed to dwell in or under the Aiolian Islands (that is, the Lipari Islands, where volcanic explosions were not unfrequent). It was thus natural enough to pass from the consideration of winds above ground (meteorology) to winds underground (seismology, geology). The genesis of stones, metals, and minerals was expressed in terms of winds or exhalations, some of them giving birth to minerals and insoluble stones, others to metals which are fusible or ductile.

Aristotle’s explanation of earthquakes is interesting in itself, and in addition it includes an account of the earlier views of Anaximenes, Anaxagoras, and Democritos. That subject had forced itself upon the attention of Greek philosophers; it is not even necessary to be a philosopher in order to be aware of a volcanic.explosion or of an earthquake, and, according to one’s temperament and education, such a sharp warning will start one dreading and praying, or wondering, imagining, and cogitating. Some Greeks invented appropriate myths and incantations; others, the natural philosophers, tried to find explanations and started a new branch of science, seismology.


It so happens that the earliest scientific book on stones (minerals and gems) was written by Theophrastos. It is as if Aristotle and he had shared the three kingdoms of nature between them: the first two were dealt with by Theophrastos, the third by Aristotle himself.¹⁵⁰⁵

The De lapidibus is counted as a fragment, but it is fairly long (some ten closely printed pages in the Didot edition), and it would be better to call it a treatise, even if the whole of it has not come down to us. It deals with stones in the broadest sense; one might call it a treatise on petrography, the very first, of course. It describes the characteristics of various rocks and minerals and indicates their provenience and their uses. Theophrastos’ ideas on fossils were not explained in this book, however, but in another one on fossil fishes,¹⁵⁰⁶ wherein he refers to the remains of fishes found in the rocks of the region south of the Black Sea.

He thought that these fossils were developed from fish spawn left in the earth, or that fishes had wandered from neighboring waters and had finally been turned into stone. He also expressed the idea that a plastic force is inherent in the earth whereby bones and other organic bodies are imitated.¹⁵⁰⁷

To return to the rocks, Theophrastos described their several kinds and tried to classify them, according to the action of fire upon them. Part of that is naturally chemical, for a mineralogic analysis, however crude, leads to the consideration of chemical reactions or chemical applications. For example, Theophrastos describes the preparation of white lead:

A piece of lead the size of a brick is placed over vinegar in an earthenware vessel. When the lead has acquired a [rust–like] layer, which usually happens in ten days, they open the vessel and scrape off the decayed part. The process is then repeated again and again until the lead is entirely consumed. They take what has been scraped off and keep pulverizing it in a mortar and filtering it. What finally settles to the bottom is white lead.¹⁵⁰⁸

Theophrastos, continuing Aristotle’s meditations, tried to account for the genesis in inorganic nature of two kinds of things that were extremely different, stones and metals. The stones, he suggested, were of earthy origin (stones disintegrate into earth), the metals of watery origin. Among the stones he attached special importance to those wonders of the lifeless world, the precious stones, the gems. A good part (one quarter) of his treatise deals with gems and it was that part which interested posterity most. In his description of gems he recognized many physical peculiarities, such as weight, color, transparency, luster, fracture, fusibility, hardness. He indicated the locality where some gems could be found, and the high prices that they fetched. His descriptions are sufficient to identify a number of stones: alabaster, amber, amethyst, emerald, garnet, lapis lazuli, jasper, agate, onyx, carnelian, rock crystal, prase, chrysocolla, malachite, magnetite, and hematite. About many others we cannot be sure or we are entirely in the dark. For example, adamas, which is not injured by fire. What is that? Diamond? It is impossible to say. His information came from almost every quarter of the world known to the Greeks, from the three continents centered upon the Mediterranean. Much of it was very ancient, Babylonian or Egyptian perhaps, immemorial, prehistoric folklore. Hence, we must not be surprised when we come across some irrational sayings; yet the book as a whole is remarkably rational, or call it scientific. Some of his conclusions were correct. He knew that pearls were secreted by oysters (of course, pearls were always found in oysters and nowhere else), that corals grow in the sea; he was aware of the existence of fossil ivory. Theophrastos’ De lapidibus was the main source of Book XXXVII of Pliny’s Natural history¹⁵⁰⁹ and through Pliny it influenced all the more scientific lapidaries until modern times. A comparison between Theophrastos and Pliny is entirely to the advantage of the former. In spite of his coming no less than four centuries later, Pliny is far less scientific than Theophrastos; he knew incomparably more, but his knowledge was definitely of a poorer quality. This illustrates the abyss that was formed between Hellenic science and Roman science, the latter being at best a very imperfect offspring of the former.



In our account of Aristotle’s life, we remarked that he perhaps owed his scientific proclivities to his father, who was a physician. Yet Aristotle did not become a physician, and there are very few medical references in his writings. The few references in Topica and Politica are insignificant; it is true that a whole book of Problemata, the first one, discusses “problems connected with medicine,” but we cannot draw anything from that as the Problemata is certainly apocryphal and probably very late; some critics would place it as late as the fifth or sixth century.¹⁵¹⁰ The Peripatetic character of that book is admitted, but it can tell us nothing concerning Aristotle’s own ideas.

It is curious, on the other hand, that his anatomic and physiologic observations were so often right in the case of animals, yet wrong in the case of men. He drew a distinction between the sutures of the skull in men and women, he stated that there are eight ribs, and only three chambers in the heart (he overlooked the interauricular septum). It is clear that he did not make human dissections but was satisfied to accept statements on human anatomy without attempting to verify them. The case of Aristotle is not as abnormal as it seems to be at first sight. Many sons of physicians have inherited from their fathers a love of science and a strong dislike of medicine; the two feelings are not by any means incompatible.

Aristotle was not interested in medicine, but some physicians took a deep interest in his philosophy and in his scientific methods, and therefore he exerted a definite influence upon the progress of medicine, as is proved by the emergence of the Dogmatic school.


The history of the Dogmatic school has been badly outlined by historians of medicine because of a fundamental error. The founder of the school, Diocles of Carystos, was supposed to have preceded Aristotle and influenced him. It has been proved by Jaeger ¹⁵¹¹that Diocles was, on the contrary, a younger contemporary of Aristotle, and that his medical theories were formed under the influence of the Lyceum.

What happened to medicine in the second half of the fourth century does not surprise the historian, for similar phenomena have happened many times. Athenian and Greek education was dominated by two illustrious schools, the Academy and the Lyceum, which gave to ambitious young men a new style of research, discussion, and exposition. A group led by Diocles realized the need of reshaping medical doctrines in accordance with academic usage and of reëxplaining them in philologic language.¹⁵¹² There have always been physicians who loved learning, who were learned themselves, or who liked to be taken for learned men, and used the most high–brow jargon of their age. Diocles did that very well and by so doing founded a new school of medicine, the Dogmatic school; he was called by the Athenians “another Hippocrates.”

It is very significant that he was the first physician to write in the Attic dialect instead of the Ionian, and that linguistic change is, perhaps, the best symbol of the intellectual revolution that occurred under his direction. Up to that time, Hippocrates’ dialect had been accepted as the medical dialect par excellence; it was now superseded by the language that had been stabilized by Plato and Aristotle. This marks a new epoch in medical thought. Diocles was also the first to refer to a Hippocratic collection, and this shows that for him Hippocrates was still the main guide; he did not necessarily object to Hippocratic knowledge but he believed — rightly — that scientific knowledge should be expressed in the best logical order and in the most elegant language. He was well acquainted also with the physiologic theories of the Sicilian school, as set forth by Philistion of Locroi, and combined them with the traditional views of the school of Cos.

Though Diocles is called the founder of the Dogmatic school, the foundation had been gradually prepared by other men. This was a natural development of the old Hippocratic teaching. The teaching of a man of genius is generally informal, but it cannot be preserved and continued except in a more systematic manner; this was realized unconsciously by Hippocrates’ followers, to begin with, his son Thessalos, his son–in–law Polybos, his grandsons, as well as his immediate disciples, Apollonios of Cos and Dexippos of Cos, and finally Diocles. The name given to them later (by Galen and others) was logicoi, logicians. The translation of that term that I have just given and the traditional one, Dogmatists, are equally imperfect; the word logicos means many things, such as “intellectual,” “dialectical,” “argumentative”; it is clear that Galen used it to distinguish logical and philosophic methods of exposition from simpler ones. To put it as briefly as possible, the Dogmatists gave to the medicine of Aristotle’s time its speculative coloring.

As far as can be judged from fragments (for none of his many writings has been preserved in its integrity) and from the early commentators, Diocles was not simply an able writer who put the medical knowledge of his day in logical order; he increased that knowledge by his own observations. He made embryologic, gynecologic, and obstetric studies and carried on animal dissections (for example, he dissected the womb of a mule). He described the cotyledonous placenta of ruminants and early human embryos. He held that both man and woman contribute “seed” toward the creation of their children. It is said that he wrote the first textbooks on anatomy and on medical botany.¹⁵¹³

Diocles’ successor as leader of the Dogmatists was Praxagoras of Cos, who was the first to make a clear distinction between veins and arteries, holding that the former carry blood while the others are filled with air.¹⁵¹⁴ His study of the blood vessels led him to that of the pulse, strangely neglected in the Hippocratic corpus. Three of Praxagoras’ pupils are known — Philotimos, who paid special attention to gymnastics and diet, Mnesitheos of Athens, who made anatomic investigations (on the bodies of animals) and tried to classify diseases, and the illustrious Herophilos. If we accept (as we do) Jaeger’s new dating of Diocles, he ended his life in the first quarter of the third century and was thus already a witness of the Hellenistic period; a fortiori, Praxagoras and Mnesitheos, fin de siècle children of Hellenism, belong to the new period; they are contemporaries of Herophilos of Chalcedon (III—1 B.C.), and we would have been justified in leaving them out of this volume.

We know the ideas of the Dogmatists only in a fragmentary way, but their evolution from Polybos to Mnesitheos suggests that their dogmatism was tempered with genuine observations and sound criticism. The Dogmatic school was the necessary transition from Hippocratism to the new anatomy and physiology; it constructed one of the bridges leading from Cos to Alexandria.


It is with some diffidence that we bring this chapter to a close with a brief account of the mysterious Menon. According to Galen, if one wishes to know the ideas of the ancient physicians, one should read the historical outline ascribed to Aristotle but written by his disciple, Menon, and therefore called Menoneia.¹⁵¹⁵ If Menon was Aristotle’s disciple, then, of course, his place is here, but Galen’s assumption is vague; Menon might be a distant disciple, instead of an immediate one.

The tradition of Menon’s outline is curious. The British Museum acquired in 1891 a medical papyrus of considerable size,¹⁵¹⁶ the importance of which was soon appreciated and advertised by Sir Frederick Kenyon.¹⁵¹⁷ The text was written at the beginning of the Christian era, before Galen’s time, perhaps just before that time, in the first half of the second century. The first half of it is a historical outline derived from Menon’s. The outline ends with the second half of the fourth century B.C., and this would confirm the hypothesis that Menon flourished in that period or very soon afterward.

The fact that a disciple of Aristotle thought it necessary to write a history of ancient medicine is significant. It will not surprise the readers who have followed in this volume our own very brief outline of it. By the end of the fourth century, medicine was not only an art and a profession of immemorial antiquity; it was also a science with many centuries of experience, and it was, or tried to be, a philosophy. The learned physician who was flourishing at the turn of the fourth century in Athens was a very sophisticated man. If he was wise enough, he recognized his ignorance of many things and the urgent need of deeper investigation, especially in the basic fields of anatomy and physiology. Hellenic medicine was ending in a dignified philosophic atmosphere, with a magnificent record of achievements to its credit; it had gone as far as was possible with its own methods. More investigations were needed to justify new theories. The last Hellenic physicians were preparing the way for the Hellenistic anatomists.

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