had flowered luxuriantly in æsthetic fancies, while the spiritual life of Judaism languished amid strict obedience to forms and precepts. The far-reaching thoughts of Greek philosophers and the lofty ethics of Hebrew preachers were divorced from the primitive ghost-world, even as the mental processes of the modern scholar are separated by a great gulf from those of the woman who comes to scrub the floor. The advent of Christianity fused together the various elements. The doctrine of a future life was endowed with all the moral significance that Jewish thought could give to it, and with all the mystic glory that Hellenic speculation could contribute, so that the effect upon men was that of a fresh revelation of life and immortality through the gospel. Grotesque and hideous features also were brought in from the ghost-worlds of the classic ages, as well as from that of the Teutonic barbarians, and the result is seen in mediæval Christianity. At no other time, perhaps, has the Unseen World played such a leading part in men's minds as in the twelfth and thirteenth centuries of our Christian era, in the age that witnessed the culmination of sublimity in church architecture, in the society whose thought found comprehensive expression in the "Summa" of St. Thomas, as the thought of our times is expressed in Spencer's "First Principles," in an intellectual atmosphere, which just as it was about passing away was depicted for all coming time in the poem of Dante. It was a time of spiritual awakening such as mankind had never before witnessed, but it was also an age of new problems, an age wherein the seeds of revolt were thickly germinating. The nature and constitution of the Unseen World had been too rashly and too elaborately set forth in theorems born of the slender knowledge of primitive times, and the growing tendency to interrogate Nature soon led to conclusions which broke down the old edifice of thought. In the sixteenth century came Copernicus and administered such a shock to the mind as even Luther's defiance of the papacy scarcely equalled. In recent days, when Bishop Wilberforce reckoned without his host in trying to twit Huxley with his monkey ancestry, our minds were getting inured to all sorts of audacious innovations, so that they did not greatly disturb us. For its unsettling effects upon time-honoured beliefs and mental habits the Darwinian theory is no more to be compared to the Copernican than the invention of the steamboat is to be compared to the voyages of Columbus. We are in no danger of overrating the bewilderment that was wrought by the discovery that our earth is not the physical centre of things, and that the sun apparently does not exist for the sole purpose of giving light and warmth to man's terrestrial habitat. We need not wonder that in conservative Spain scarcely a century ago the University of Salamanca prohibited the teaching of the Newtonian astronomy. We need not wonder