There shall be a superintendent of public education in each county, who shall be appointed by the board of education by and with the advice and consent of the senate, whose term of office shall be four years, and whose qualifications, compensation and duties, shall be prescribed by law; provided, that the legislature shall have power to make the office of county school superintendent of the several counties elective, or may otherwise provide for the discharge of the duties of county superintendent, or abolish said office.