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THEOPHRASTUS was born at Eresus in Lesbos. He was sent by his father to Athens to study; and he became the most zealous among the pupils of Aristotle, who bequeathed him his library, and whom he succeeded in the Lyceum. Like several other philosophers, he was accused of impiety, but he made a successful defense against this charge. His school was very numerously attended, and at his death, in advanced age, it is said that nearly the whole population of Athens followed him to the grave.
Theophrastus wrote on many branches of philosophy and natural science. The three chief works that have come down to us are: (1) his Characters, a series of entertaining but rather slight sketches of weak or vicious tendencies; (2) his Natural History of Plants; (3) his Conditions of Plant Life. The last two form the first scientific treatise on Botany. They are written in the true Aristotelean spirit of close observation of Nature, directed with the purpose of seizing the type-form amidst individual variety.
He begins by studying the analogies between vegetable and animal growth. But he is met at once by this difficulty: Have plants organs such as may be detected in animals amidst all their diversities? It is difficult to assert this; for on comparing, e.g., trees, grasses, and fungi, no organs seem common to all. He defines, however, as the best solution available, the root, the stalk, the branch, and the bud. For adequate knowledge of the nutrition of plants men had to wait till the chemical discoveries of the 18th century. Nevertheless Theophrastus noted that the death of a tree followed the removal of a complete ring of bark, which might have led him to an understanding of the cambium. Of the sexual reproduction of plants he knew little more than the vague distinction, due to popular observation, of certain plants into male and female, according as they bore or did not bear seed. Reproduction took place either by seed, or by buds, or by spontaneous generation. In the classification of plants he went no further than the distinction of plants, shrubs, and trees; remarking that under different conditions of the environment these were not seldom convertible.
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| This biography is
reprinted from The New Calendar of Great Men. Ed. Frederic
Harrison. London: Macmillan and Co., 1920. |
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