of mental diseases and that curative treatment of them which is one of the countless services of science to suffering mankind. To Luther, the descent of Christ into hell, which modern research has shown to be a variant of an Orphic legend of the underworld, was a real event, Jesus going thither that he might conquer Satan in a hand-to-hand struggle. Therefore, freedom of thought, as we define it, had the bitterest foe in Luther, although, in his condemnation of "works," and his fanatical dogma of man's "justification by faith alone," which made him reject the Epistle of James as one "of straw," and as unworthy of a place in the Canon, he unwittingly drove in the thin end of the rationalist wedge. The Reformers had hedged the canonical books with theories of verbal inspiration which extended even to the punctuation of the sentences. They thus rendered intelligent study of the Bible impossible, and did grievous injury to a collection of writings of vast historical value, and of abiding interest as records of man's primitive speculations and spiritual development. But Luther's application of the right of private judgment to the omission or addition of this or that book into a canon which had been closed by a Council of the Church, surrendered the whole position, since there was no telling where the thing might stop. Copernicus waited full thirty years before he ventured to make his theory public. The Ptolemaic system, which assumed a fixed earth with sun, moon, and stars revolving above it, had held the field for about fourteen hundred years. It accorded with Scripture; it was adopted by the Church; and, moreover, it was confirmed by the senses, the correction of which still remains, and will long remain, a condition of intellectual advance. Little wonder is it, then, that Copernicus hesitated to broach a theory thus supported, or that, when published, it was put forth in tentative form as a possible explanation more in accord with the phenomena. A preface, presumably by a friendly hand, commended the Revolutions of the Heavenly Bodies to Pope Paul III. It urged that "as in previous times others had been allowed the privilege of feigning what circles they chose in order to explain the phenomena," Copernicus "had conceived that he might take the liberty of trying whether, on the supposition of the earth's motion, it was possible to find better explanations than the ancient ones of the revolutions of the celestial orbs." A copy of the book was placed in the hands of its author only a few hours before his death on 23d of May, 1543.