Neither the council nor any of its committees or members shall dictate or attempt to dictate the appointment of any person to, or his removal from, office or employment by the city manager or any of his subordinates, or in any manner interfere in the appointment of officers and employees in the departments of administrative service vested in the manager by this Charter. Except for the purpose of inquiry, the council and its members shall deal with that part of the administrative service for which the city manager is responsible solely through such manager, and neither the council nor any member thereof shall give orders to any of the subordinates of the city manager in said departments, either publicly or privately.