same genial, tranquil tone which he had always maintained, he drank the cup of hemlock, and expired (May, 399 B.C.). An account of his teaching and of his method of life is given by his loving scholar, _Xenophon_, in the _Memorabilia_. The dialogues of _Plato_, in which Socrates is the principal interlocutor, mingle with the master's doctrine the pupil's own thoughts and speculations. PLATO.--_Plato_ (427-347 B.C.), the foremost of the disciples of Socrates, founded the philosophical school known as the _Academy_ from the place where his pupils were wont to meet him. One of his prominent tenets was the doctrine of _ideas_ which he regarded as spiritual realities, intermediate between God and the world, of which all visible things are the manifestation. They are the shadow, so to speak, of which ideas are the substance. He defined virtue in man to be resemblance to God according to the measure of our ability. In the _Republic_, he sets forth his political views, and sketches the ideal state. More speculative than Socrates, Plato, from the wide range of his discussions, from their poetic spirit as well as their depth of thought, not less than their beauty of style, is one of the most inspiring and instructive of all authors. No other heathen writer presents so many points of affinity with Christian teaching. ARISTOTLE.--Aristotle (384-322 B.C.) studied under Plato, but elaborated a system of his own, which was on some points dissonant from that of his instructor. His investigations extended over the field of material nature, as well as over the field of mind and morals. With less of poetry and of lofty sentiment than Plato, he has never been excelled in intellectual clearness and grasp. He was possessed of a wonderful power to observe facts, and an equally wonderful talent for systemizing them, and reasoning upon them. He is the founder of the science of _Logic_. His treatises on _Rhetoric_ and on _Ethics_ have been hardly less important in their influence. His _Politics_ is a masterly discussion of political science, based on a diligent examination of the various systems of government. In truth, in all departments of research he exhibits the same capacity for scientific observation and discussion. In religion he was a theist; but he is less spiritual in his vein of thought, and more reserved in his utterances on this theme, than Plato. The names of these two philosophers have been very frequently coupled. Their influence, like their fame, is imperishable.