The Secretary of the Interior is authorized, in his discretion, to enter into a contract or contracts with any State or Territory, or political subdivision thereof, or with any State university, college, or school, or with any appropriate State or private corporation, agency, or institution, for the education, medical attention, agricultural assistance, and social welfare, including relief of distress, of Indians in such State or Territory, through the agencies of the State or Territory or of the corporations and organizations hereinbefore named, and to expend under such contract or contracts, moneys appropriated by Congress for the education, medical attention, agricultural assistance, and social welfare, including relief of distress, of Indians in such State or Territory