The new States have a heterogeneous population, and will be slower and less unanimous than those in which there is less of the Northern element in the body politic, but interest controls the policy of States, and finally all the planting communities must reach the same conclusion. _My opinion is, therefore, as it has been, in favor of seeking to bring those States into coöperation before asking for a popular decision upon a new policy and relation to the nations of the earth._ If South Carolina should resolve to secede before that coöperation can be obtained, to go out leaving Georgia, and Alabama, and Louisiana in the Union, and without any reason to suppose they will follow her, there appears to me to be no advantage in waiting until the Government has passed into hostile hands, and men have become familiarized to that injurious and offensive perversion of the General Government from the ends for which it was established. I have written with the freedom and carelessness of private correspondence, and regret that I could not give more precise information. Very respectfully, yours, etc., JEFFERSON DAVIS. Mr. Davis remained in the Senate, a friend of peace, and, until the last moment, laboring for adjustment, when he received the summons of Mississippi, forbidding the longer exercise of the trust which she had given to his keeping. Mississippi seceded on the 9th of January, 1861. Mr. Davis, receiving formal announcement of the event, withdrew on the 21st, after pronouncing an impressive valedictory to the Senate. Its dignified, courteous, and statesman-like character has challenged the unqualified eulogy of the enlightened world. SPEECH OF HON. JEFFERSON DAVIS, ON WITHDRAWING FROM THE U. S. SENATE. JAN. 21, 1861. MR. DAVIS. I rise, Mr. President, for the purpose of announcing to the Senate that I have satisfactory evidence that the State of Mississippi, by a solemn ordinance of her people, in convention assembled, has declared her separation from the United States. Under these circumstances, of course, my functions are terminated here. It has seemed to me proper, however, that I should appear in the Senate to announce that fact to my associates, and I will say but very little more. The occasion does not invite me to go into argument; and my physical condition would not permit me to do so, if otherwise; and yet it seems to become me to say something on the part of a State I here represent, on an occasion so solemn as this.