[ REPUBLICAN CAMPAIGN SPEECH ][ ON THE DANGER OF THIRD-PARTIES ][ TO JESSE K. DUBOIS. ][ TO HARRISON MALTBY. ][ TO Dr. R. BOAL. ][ TO HENRY O'CONNER, MUSCATINE, IOWA. ][ AFTER THE DEMOCRATIC VICTORY OF BUCHANAN ][ TO Dr. R. BOAL. ][ 1857 ][ RESPONSE TO A DOUGLAS SPEECH ]