§ 73. Separation for ordinary disability; reinstatement. When an employee has been continuously absent from and unable to perform the duties of his position for one year or more by reason of a disability, other than a disability resulting from occupational injury or disease as defined in the workmen's compensation law, his employment status may be terminated and his position may be filled by a permanent appointment. Such employee may, within one year after the termination of such disability, make application to the civil service department or municipal commission having jurisdiction over the position last held by such employee for a medical examination to be conducted by a medical officer selected for that purpose by such department or commission. If, upon such medical examination, such medical officer shall certify that such person is physically and mentally fit to perform the duties of his former position, he shall be reinstated to his former position, if vacant, or to a vacancy in a similar position or a position in a lower grade in the same occupational field in his former department or agency. If no appropriate vacancy shall exist to which such reinstatement may be made, or if the work load does not warrant the filling of such vacancy, the name of such person shall be placed on a preferred list for his former position in his former department or agency, and he shall be eligible for reinstatement in his former department or agency from such preferred list for a period of four years. In the event that such person is reinstated to a position in a grade lower than that of his former position, his name shall be placed on the preferred eligible list for his former position or any similar position in his former department or agency. This section shall not be deemed to modify or supersede any other provisions of law applicable to the re-employment of persons retired from the public service on account of disability.