Our present difficulties, which, as you well know, have arrested the gaze of the nation, and almost suspended the legislative functions of Congress, pertain to the destiny of freedom or of slavery, to which our new territories are to be devoted. After the acquisition of Louisiana, and Florida, and Texas, for the aggrandizement and security of the Slave-power; after the aboriginal occupants of the soil of the Southern States have been slaughtered, or driven from their homes, at an expense of not less than a hundred millions of dollars, and at the infinite expense of our national reputation for justice and humanity; and after the area of the slave states has been made almost double that of the free states, while the population of the free is about double that of the slave; the reasons seem so strong that they can hardly be made stronger, why the career of our government, as a slavery-extending power, should be arrested. On the other hand, the oligarchy who rule the south, seeing that, notwithstanding their rich and almost illimitable domain, they are rapidly falling behind the north in all the distinctive elements of civilization and well being,--industry, temperance, education, wealth,--not only defend the Upas that blasts their soil, as though it were the tree of life, but seek to transplant it to other lands. With but about three slaves to a square mile,--three millions of slaves to nearly a million of square miles,--they say they are too crowded; that they feel a sense of suffocation, and must have more room, when all their weakness and pain proceed, not from the limited quantity, but from the malignant quality of the atmosphere they breathe. Hence the war with Mexico, commenced and prosecuted to add slave territory and slave states to the southern section. Hence the refusal to accept propositions of peace, unless territory _south_ of latitude 36° 30´, (the Missouri compromise line, so called,) should be ceded to us. Hence, when the Mexican negotiators proposed to insert a prohibition of slavery in the treaty of cession, and declared that the inquisition would not be more odious to the American people than the reinstitution of slavery to them, our minister, Mr. Trist, told them he would not consent to such a prohibition though they would cover the soil a foot deep with gold. And hence, also, the determination of a portion of the southern members of Congress to stop the whole machinery of the government, to sacrifice all the great interests of the country, and assail even the Union itself, unless slavery shall be permitted to cross the Rio Grande and enter the vast regions of the west, as it heretofore, in its aggressive march, crossed the Mississippi and the Sabine.