No penitentiary convict shall ever be leased or hired to any person or persons, or corporation, private or public or quasi public, or board, after December the 31st, A. D. 1894, save as authorized in the next section, nor shall any previous lease or hiring of convicts extend beyond that date; and the legislature shall abandon the system of such leasing or hiring as much sooner than the date mentioned as may be consistent with the economic safety of the State.