HIPPOCRATES.--Hippocrates created scientific medicine, the medicine of observation, denying prodigies, seeking natural causes for diseases, and already setting up rational therapeutics. There are seventy-two works called "Hippocratical," which belong to his school; some may be by himself. SOPHISTS AND ORATORS.--The language grew flexible in the hands of the learned, subtle, and ingenious sophists (Gorgias, Protagoras) who attacked Socrates by borrowing his weapons, as it were, and making them perfect. A new type of literature was created: the oratorical. Antiphon was the earliest in date alike of the Athenian orators and of the professors of eloquence. In a crowd after him came Isocrates, Andocides, Lysias, Aeschines, Hyperides, and the master of them all, that astonishing logician, that impassioned and terrible orator, Demosthenes. THE PHILOSOPHERS: PLATO.--Contemporaneously the philosophers, quite as much as the sophists, even confining the matter to the literary aspect, cast immortal glory on Attica. Imbued with the spirit of Socrates, even when more or less unfaithful to him, Plato, psychologist, moralist, metaphysician, sociologist, marvellous poet in prose, seductive and fascinating mythologist, really created philosophy in such fashion that even the most modern systems, if not judged by how much they agree or differ from him, at least invariably recall him, whether they seem a distant echo of him or whether they challenge and combat him. ARISTOTLE; XENOPHON; THEOPHRASTUS.--Aristotle, pre-eminently learned, admirably cultivated naturalist, acquainted also with everything known in his day, more prudent metaphysician than Plato but without his depth, a precise and sure logician and the founder of scientific logic, a clear and dexterous moralist, an ingenious and pure literary theorist; Xenophon, who commanded the retreat of the ten thousand, moralist and Intelligent pedagogue displaying much attractiveness in his _Cyropoedia_, the sensible, refined, and delightful master of familiar and practical life in his _Economics_; Theophrastus, botanist, very witty satirical moralist, highly caustic and realistic--these three established Greek wisdom for centuries, and probably for ever, erecting a solid and elegant temple wherein humanity has almost continuously sought salutary truths, and where some at least of our descendants, and those not the least illustrious, will always perform their devotions. The chief works of Plato are the _Socratic Dialogues_, the _Gorgias_, the _Timoeus_, the _Phaedo_ (immortality of the soul), the _Republic_, and the _Laws_. The principal books of Aristotle are his _Natural History_, _Metaphysics_, _Logic_, _Rhetoric_, _Poetica_. The most notable volumes of Xenophon are the _Cyropoedia_, the _Economics_ and the _Memorabilia of Plato_. The only work of Theophrastus we possess is his _Characters_, which was translated and _continued_ by La Bruyère.