Section 19.22.
Upon the application of a member, or his department head, a member who has become or becomes totally and permanently incapacitated for duty in the service of the City in his own department by reason of a personal injury or disease, which the Board finds to have occurred as the natural and proximate result of causes arising out of and in the course of his employment by the City, shall be retired by the Board: Provided that after a medical examination of the said member, made by or under the direction of the medical director, the medical director certifies to the Board (1) that the said member is mentally or physically totally incapacitated for duty in the service of the City, and (2) that such incapacity will probably be permanent, and provided further, that the report of the medical director is concurred in by the Board.