Heroes of science

by P. Martin Duncan

But Aristoteles’ work was nearly ended, and the slightly made, delicate, and sensitive man sank during the first year of his exile, in the sixty-third year of his age.

A great writer on moral philosophy, the man whose career has just been noticed will always remain a master in natural history subjects also. He was really a greater student of animal life than of plants; but it appears that his method of study of botany, and much of his knowledge, have descended to us, in consequence of his careful teaching, through his pupil Theophrastus. A great writer remarks that “everywhere Aristoteles observes the facts with attention; he compares them with sagacity, and endeavours to rise to the qualities they have in common.” He found the study of plants in its very infancy and loaded with child-like and wonderful stories, and he rejected the nonsense and studied what was to be observed by any one in nature. In fact, he took the first step which a well-educated boy of the present century does in trying to learn nature unaided. He observed as correctly as possible, took notes of his observations, compared the observations made on one plant with those recorded about another, and tried to explain or discover the things which were common to both. It must not be imagined that the botanical work of Aristoteles exists as part of the systems of botany of the present day; but he clearly gave the method of how to study, by insisting on the superior value of observed facts, over notions and preconceived ideas about things. The childhood of the science passed with him.

The name of Theophrastus has been noticed as that of the pupil of Aristoteles, and it is one which will always be mentioned with respect by students of natural history. He was born at Eresus, on the island of Lesbos; but the date of his birth is uncertain; moreover, nothing is known of his early youth, except that his name was Tyrtamus. His early education must have been good, and he was sent to study at Athens by his father, and to be a pupil of Plato. Becoming a friend of Aristoteles, this great man, charmed with the abilities, and especially with the beautiful pronunciation and oratory of the youth, gave him the name of Theophrastus, or one who speaks divinely. Theophrastus studied with Plato, and on the death of his master, left the academy and mixed with the turbulent politics of the day, but in a truly patriotic spirit. He was absent from Athens for many years, and the historian Plutarch writes that Theophrastus delivered his country twice from the oppression of tyrants. One of the defeated at the battle of Chæronæa, Theophrastus returned to Athens, gave up the military life, and became the favourite pupil of Aristoteles in the Lyceum.

Theophrastus became an earnest student of Aristoteles’ teaching, and his singular grace of expression and knowledge of his mother tongue soon made him a prominent philosopher.

When Aristoteles retired, his pupil became his successor; and as he combined the knowledge of that teacher with the eloquence of Plato, his success was extraordinary. The number of his pupils, on one occasion, is said to have amounted to two thousand who flocked around him from all parts of Greece. He soon began to feel the effects of his well-deserved and useful success upon the envious minds of the men who had caused the retirement of Aristoteles. And this envy and malice were rendered all the more intense because, having been a gallant soldier, and being a great teacher of advanced knowledge, Theophrastus became an authority on all intellectual subjects. A man was put forward by a party in the State, to bring the same charge of impiety against Theophrastus which had succeeded in the instances of Socrates and Aristoteles. But Theophrastus pleaded his own cause before the Areopagus with such convincing eloquence that he was pronounced innocent. On the other hand, his accuser would have fallen a victim to the false charge he had brought, had not his noble-minded antagonist pleaded for his pardon.

After this event the teacher pursued his course of public teaching and private research without any molestation for years. His school increased in reputation, and the most distinguished scholars of the day were members of it. Demetrius Phalereus, ruler of the State, was one of the students in his youth, and he protected Theophrastus and patronized him in every way. Botany was not the strongest subject of this great man, and probably what he knew about it was largely derived from the teaching of Aristoteles; but evidently his work on plants was one of the earliest that was written with anything like scientific precision. Nevertheless, Theophrastus added much original matter, for he had a botanic garden, and he collected plants during his travels in Greece. His military friends kept him supplied with specimens of Asiatic, Egyptian, and Arabian plants, and with descriptions of their natures and peculiarities, some of which were true and others quite imaginary. What was true and what was not true was frequently a puzzle to this philosopher, as it is to modern naturalists. He wrote, “The drug sellers and root cutters tell us some things which may be true, but other things which are merely solemn quackery. Thus they direct us to gather some plants, standing from the wind and with our bodies anointed; some by night, some by day, some before the sun falls on them. So far there may be something in their rules; but others are too fantastical and far-fetched. It is, perhaps, not absurd to use a prayer in plucking a plant; but they go further than this. We are to draw a sword three times round the mandragora, and to cut it looking to the west; again, to dance round it, and to use obscene language, as those who sow cumin should utter blasphemies. Again, we are to draw a line round the black hellebore, standing to the east, and praying; and to avoid an eagle either on the right or on the left; for they say if an eagle be near, the cutter will die in a year.”

This was the nonsense, out of which Theophrastus had to extricate the true wisdom of plants, and he tried to put aside fancies, legends, and the opinions of men, and to puzzle out the meaning of the similarities and differences of plants, by first of all learning and describing their construction, habits, methods of growth, and increase.

Only a fragment of the last of ten books on plants written by Theophrastus has come down to us. The writings made such an impression on the students that their general bearing has been transmitted, and the main points are as follows. Theophrastus classified plants by the manner in which they were reproduced, the localities where they were found, their size, as trees or shrubs or herbs, and according to their uses, as furnishing juices, pot-herbs, and seeds that may be eaten. The first book treated of the parts of the plant—the root, stem, leaves, flower, and seed, and the second of the manner in which plants seed, and the proper times for sowing seeds, and how to sow. In this part he mentions that some plants, evidently of the same kind, have seed and others not, or that there are different sexes in plants, the female bearing the seed. That he was a practical observer is proved by his writings on the method of the reproduction in the great palm trees, which are such striking features in the East. Moreover, he studied the way in which figs grew and the seed became fertile, and he compared the reproduction of the fig with that of the palm tree. The third, fourth, and fifth books are devoted to a consideration of trees, their various kinds, the places they come from, and the economical uses to which they may be applied. The sixth book treats of winter shrubs and spring plants; the seventh of pot-herbs; the eighth of plants yielding seeds used for food; and the ninth of those plants that yield useful juices, gums, resins, and other exudations. The love of the marvellous, however, creeps in here and there, and amongst good facts there are very considerable “tough yarns;” but these come from the old soldiers of Alexander the Great.

There is one thing most interesting in the works of this man, and it is the desire he had to make his knowledge useful to mankind. This is especially noticed in another work on the causes of plants, of which six parts remain to the present day. It is really a work on gardening and farming, with a good deal of pure and applied knowledge on botany. It is not everybody, nowadays, that can combine what is scientific, that is to say, exact knowledge, with useful and applied knowledge. Too frequently the scientific botanist does not teach gardening or farming; and certainly, as a rule, the writers on these last subjects are not scientific botanists, and, indeed, they are often of a very different kind of mind. It has been said of the works of Theophrastus that there is much valuable matter in them that deserves the attention of the botanist, and that a very little knowledge of botany will enable the reader to separate the chaff from the wheat.

So noted was the learning of this great man on other subjects, that his good work on plants remained the text-book of centuries; and, in fact, little or no satisfactory knowledge about plants, beyond that given to us by Aristoteles and Theophrastus, was discovered for many centuries.