Academy still educate the world and prepare a _nidus_ for the ethics of Christianity; and Alexandria, where physical science is cultivated under the Ptolemies, where mystical theology flourishes in the schools of the Neoplatonists, where libraries are formed and the labor of literary criticism is conducted on a gigantic scale, but where nothing new is produced except the single, most beautiful flower of idyllic poetry and some few epigrams. In this fifth period, Rome and Byzantium, where the Greek spirit, still vital, overlives its natural decay upon a foreign soil, close the scene. In these five periods--periods of superb adolescence, early manhood, magnificent maturity, robust old age, and senility--we can trace the genius of the Greeks putting forth its vigor in successive works of art and literature, concentrating its energy at first upon its own self-culture, then extending its influence in every direction, and controlling the education of humanity, finally contenting itself with pondering and poring on its past, with mystical metaphysics and pedantic criticism. Yet even in its extreme decadence the Hellenic spirit is still potent. It still assimilates, transmutes, and alchemizes what it works upon. Coming into contact with the new and mightier genius of Christianity, it forces even that first-born of the Deity to take form from itself. One dying effort of the Greek intellect, if we may so speak, is to formulate the dogma of the Trinity and to impress the doctrine of the Logos upon the author of the Gospel of St. John. The analogy between the history of a race so undisturbed in its development as the Greek, and the life of a man, is not altogether fanciful. A man like Goethe, beautiful in soul and body, exceedingly strong and swift and active and inquisitive in all the movements of his spirit, first lives the life of the senses and of physical enjoyment. His soul, "immersed in rich foreshadowings of the world," has scarcely begun to think consciously in the first period. But he feels the glory of existence, the strivings of inexhaustible energy, the desire of infinite expansion. The second period is one of _Sturm und Drang_. New things are learned: much of the beautiful physical activity is sacrificed; he discovers that life involves care and responsibility as well as pleasure; he concentrates his mental faculty on hard and baffling study, in which at first he halts and falters. Then he goes forth to the world and wins great fame, and does the deeds and thinks the thoughts by which he shall be known to all posterity. His physical and mental faculties are now in perfect harmony; together they offer him the noblest and most enduring pleasures. But after a while his productiveness begins to dwindle. He has put forth his force, has fully expressed himself, has matured his principles, has formed his theory of the world. Our fourth period corresponds to the early old age of such a man's life. He now applies