We have now reached the turning point in the history of Missouri. The State is about to be plunged into the whirlpool of civil war. Undisguised disunionists are in complete possession of the State government, and the population is supposed to be ripe for revolt. Only one spot in it, and that the city of St. Louis, is regarded as having the slightest sympathy with the political sentiments of the Free States of the Union. The State is surely counted for the 'South' in the division that impends, for where is the heart in St. Louis bold enough, or the hand strong enough, to resist the swelling tide of pro-slavery fanaticism that was about to engulf the State? Years ago, when it was but a ripple on the surface, it had overborne Benton, with all his fame of thirty years' growth. What leader of slighter mold and lesser fame could now resist the coming shock? In tracing the origin and growth of rebellion in Missouri, it is interesting to gather up all the threads that link the present with the past. It will preserve the unity of the plot, and give effect to the last acts of the drama. The first visible seam or cleft in the National Democratic party occurred during the administration of President Polk, in the years 1844-48. Calhoun appeared as Polk's Secretary of State. Thomas Ritchie was transferred from Richmond, Va., to Washington, to edit the government organ, in place of Francis P. Blair, Sr. The Jackson _regime_ of unconditional and uncompromising devotion to the 'Federal Union' was displaced, and the dubious doctrine of 'States' Rights' was formally inaugurated as the chart by which in future the national government was to be administered. But the Jackson element was not reconciled to this radical change in the structure and purpose of the National Democratic organization; and, although party lines were so tensely drawn that to go against 'the Administration' was political treason, and secured irrevocable banishment from power, the close of Polk's administration found many old Democrats of the Jackson era ready for the sacrifice. The firm resolve of these men was manifested when, after the nomination of Gen. Cass, in 1848, in the usual form, at Baltimore, by the Democratic National Convention, they assembled at Buffalo and presented a counter ticket, headed by the name of Martin Van Buren, who had been thrust aside four years previously by the Southern oligarchs to make way for James K. Polk. The entire artillery of the Democratic party opened on the Buffalo schismatics. They were stigmatized by such opprobrious nicknames and epithets as 'Barnburners, 'Free Soilers,' 'Abolitionists,' and instantly and forever ex-communicated from the Democratic party. In Missouri alone, of all the Slave States, was any stand made in behalf of the Buffalo ticket. Benton's sympathies had been with Van Buren, his old friend of the Jackson times; and Francis P. Blair, Sr., of the _Globe_, had two sons, Montgomery Blair and Francis P. Blair, Jr., resident in St.