The copy of "Nature" from which I take these lines, his own, of course, like so many others which he prefixed to his different Essays, was printed in the year 1849, ten years before the publication of Darwin's "Origin of Species," twenty years and more before the publication of "The Descent of Man." But the "Vestiges of Creation," published in 1844, had already popularized the resuscitated theories of Lamarck. It seems as if Emerson had a warning from the poetic instinct which, when it does not precede the movement of the scientific intellect, is the first to catch the hint of its discoveries. There is nothing more audacious in the poet's conception of the worm looking up towards humanity, than the naturalist's theory that the progenitor of the human race was an acephalous mollusk. "I will not be sworn," says Benedick, "but love may transform me to an oyster." For "love" read science. Unity in variety, "_il piu nell uno_" symbolism of Nature and its teachings, generation of phenomena,--appearances,--from spirit, to which they correspond and which they obey; evolution of the best and elimination of the worst as the law of being; all this and much more may be found in the poetic utterances of this slender Essay. It fell like an aerolite, unasked for, unaccounted for, unexpected, almost unwelcome,--a stumbling-block to be got out of the well-trodden highway of New England scholastic intelligence. But here and there it found a reader to whom it was, to borrow, with slight changes, its own quotation,-- "The golden key Which opes the palace of eternity," inasmuch as it carried upon its face the highest certificate of truth, because it animated them to create a new world for themselves through the purification of their own souls. Next to "Nature" in the series of his collected publications comes "The American Scholar. An Oration delivered before the Phi Beta Kappa Society at Cambridge, August 31, 1837." The Society known by these three letters, long a mystery to the uninitiated, but which, filled out and interpreted, signify that philosophy is the guide of life, is one of long standing, the annual meetings of which have called forth the best efforts of many distinguished scholars and thinkers. Rarely has any one of the annual addresses been listened to with such profound attention and interest. Mr. Lowell says of it, that its delivery "was an event without any former parallel in our literary annals, a scene to be always treasured in the memory for its picturesqueness and its inspiration. What crowded and breathless aisles, what windows clustering with eager heads, what enthusiasm of approval, what grim silence of foregone dissent!"