The Department of Agriculture shall be an executive department, under the supervision and control of a Secretary of Agriculture, who shall be appointed by the President, by and with the advice and consent of the Senate. The provisions of title 4 of the Revised Statutes, including all amendments thereto, shall be applicable to said department; and all laws and parts of laws relating to the Department of Agriculture in existence February 9, 1889, as far as the same are applicable and not in conflict with this section, and only so far, are continued in full force and effect.