THEOPHRASTUS, whose real name was Tyrtamus, was born at Eresa in the island of Lesbos, 371 B.C., fourteen years after Aristotle. He was the originator of the science of plants; he first learned the details of their structure, the uses of their organs, the laws of their reproduction,—in a word, the physiology of the vegetable world. When Aristotle retired to Chalcis, he chose Theophrastus, to whom he gave that name, signifying “a man of divine speech,” as his successor at the Lyceum. This distinguished philosopher devoted himself alike to the exact and speculative sciences. The greater part of his works have perished; what is preserved to us consists of treatises on the history of the vegetable kingdom, of stones, and some fragments of works on physics, medicine, and some moral works. His _History of Plants_ enumerates about five hundred different kinds, many of which are now difficult to identify. He made some attempts at a vague kind of classification, and has chapters on aquatic, kitchen, parasite, succulent, oleaginous, and cereal plants. He carefully explains the principles of the reproduction of vegetables, and the fecundation of the female flowers by the pollen of the male. He recognises hermaphrodite and unisexual flowers, and points out how the fecundation of the latter is effected by the wind, insects, and by the water in the case of aquatic plants. He knew that double flowers were sterile. He devotes a chapter to the diseases of the vegetable kingdom; he almost recognised the characteristics which distinguish the monocotyledonous from the dicotyledonous plants. In a word, he laid the foundations on which our modern botanists have erected their science.[407] THE SCHOOL OF ALEXANDRIA.