The subservience on the question of Slavery, which has hitherto characterized both the great parties of the country, has strengthened the hands of the extremists at the South, and has enabled them to get the control of public opinion there by fostering false notions of Southern superiority and Northern want of principle. We have done so much to make them believe in their importance to us, and given them so little occasion even to suspect our importance to them, that we have taught them to regard themselves as the natural rulers of the country, and to look upon the Union as a favor granted to our weakness, whose withdrawal would be our ruin. Accordingly, they have grown more and more exacting, till at length the hack politicians of the Free States have become so imbued with the notion of yielding, and so incapable of believing in any principle of action higher than temporary expedients to carry an election, or any object nobler than the mere possession of office for its own sake, that Mr. Buchanan gravely proposes that the Republican party should pacify South Carolina by surrendering the very creed that called it into existence and holds it together, the only fruit of its victory that made victory worth having. Worse than this, when the Free States by overwhelming majorities have just expressed their conviction, that slavery, as he creature of local law, can claim no legitimate extension beyond the limits of that law, he asks their consent to denationalize freedom and to nationalize slavery by an amendment of the Federal Constitution, that shall make the local law of the Slave States paramount throughout the Union. Mr. Buchanan would stay the yellow fever by abolishing the quarantine hospital and planting a good virulent case or two in every village in the land.