Zeno lived to the extreme old age of ninety-eight, although his constitution was not strong. He retained his powers by great abstemiousness, living chiefly on figs, honey, and bread. He was a modest and retiring man, seldom mingling with a crowd, or admitting the society of more than two or three friends at a time. He was as plain in his dress as he was frugal in his habits,--a man of great decorum and propriety of manners, resembling noticeably in his life and doctrines the Chinese sage Confucius. And yet this good man, a pattern to the loftiest characters of his age, strangled himself. Suicide was not deemed a crime by his followers, among whom were some of the most faultless men of antiquity, especially among the Romans. The doctrines of Zeno were never popular, and were confined to a small though influential party. With the Stoics ended among the Greeks all inquiry of a philosophical nature worthy of especial mention, until centuries later, when philosophy was revived in the Christian schools of Alexandria, where the Hebrew element of faith was united with the Greek ideal of reason. The struggles of so many great thinkers, from Thales to Aristotle, all ended in doubt and in despair. It was discovered that all of them were wrong, or rather partial; and their error was without a remedy, until "the fulness of time" should reveal more clearly the plan of the great temple of Truth, in which they were laying foundation stones. The bright and glorious period of Greek philosophy was from Socrates to Aristotle. Philosophical inquiries began about the origin of things, and ended with an elaborate systematization of the forms of thought, which was the most magnificent triumph that the unaided intellect of man ever achieved. Socrates does not found a school, nor elaborate a system. He reveals most precious truths, and stimulates the youth who listen to his instructions by the doctrine that it is the duty of man to pursue a knowledge of himself, which is to be sought in that divine reason which dwells within him, and which also rules the world. He believes in science; he loves truth for its own sake; he loves virtue, which consists in the knowledge of the good. Plato seizes the weapons of his great master, and is imbued with his spirit. He is full of hope for science and humanity. With soaring boldness he directs his inquiries to futurity, dissatisfied with the present, and cherishing a fond hope of a better existence. He speculates on God and the soul. He is not much interested in physical phenomena; he does not, like Thales, strive to find out the beginning of all things, but the highest good, by which his immortal soul may be refreshed and prepared for the future life, in which he firmly believes. The sensible is an impenetrable empire; but ideas are certitudes, and upon these he dwells with rapt and mystical enthusiasm,--a great poetical rhapsodist, severe dialectician as he is, believing in truth and beauty and goodness.