In one of the South-western States a vast subterranean cave has been discovered, deep down in whose chambers there is a pool of water, on which no beam of sunlight ever shines. A sightless fish is said to inhabit this rayless pool. In this animal, indeed, the rudiments of a visual organ are supposed to be dimly discernible; but of an orb to refract the rays of light, or of a retina to receive them, there is no trace. Naturalists suppose that the progenitors of these animals, in ages long gone by, possessed the power of vision; but that, being buried in these depths by some convulsion of nature, long disuse at first impaired, at length extinguished, and has at last obliterated the visual organ itself. The animal has sunk in the scale of being, until its senses are accommodated to the blackness of darkness in which it dwells. Were this account wholly fabulous, it has the strongest verisimilitude, and doubtless describes what would actually occur under the circumstances supposed. Thus will it be with faculties above the surface of the earth, as well as below it. Thus will it be with human beings, as well as with the lower orders of creation. Thus will it be with our own brethren or children, should we shut up from them the book of knowledge, or seal their senses so that they could not read it. Thus will it be with all our God-given faculties, just so far as they are debarred from legitimate exercise upon their appropriate objects. The love of knowledge will die out, when it ceases to be stimulated by the means of knowledge. Self-respect will die out, under the ever-present sense of inferiority. The sentiments of truth and duty will die out, when cunning and falsehood can obtain more gratifications than frankness and honesty. The noblest impulses of the human soul, the most sacred affections of the human heart, will die out, when every sphere is closed against their exercise. When such a dreadful work is doing, or threatens to be done, can any one stand listlessly by, see it perpetrated, and then expect to excuse himself, under the false, impious pretext of Cain, “Am I my brother’s keeper?” Fully, then, do I agree with you and the delegates of the convention you represent, in saying that the successor of Mr. Adams should be one “whose voice and vote shall, on all occasions, be exercised in extending and securing liberty to the human race.” Of course I do not understand you to imply any violation of the constitution of the United States, which every representative swears to support.