Mr. Justice Holdom delivered the opinion of the court.
2. Civil service, § 25*—when presumed that park civil service board authorized one of its members to act as trial board. Where a park civil service board had the power to change the personnel of its trial board at any time, in the absence of any averment to the contrary, in mandamus by a discharged park patrolman for reinstatement, it will be assumed that it authorized a single member of such trial board to proceed as sole trial officer. 3. Civil service—when any illegality in appointment of persons on trial board corrected by action of board. If there is room for any doubt as to the legality of the appointment of the persons constituting a park trial board, the ratification of the action of the board by the park civil service commission in approving and adopting its report and findings is a sufficient corrective. 4. Civil service, § 25*—when patrolman petitioning for reinstatement may not raise jurisdictional question of trial board on appeal. A discharged park patrolman, petitioning for mandamus to reinstate himself as such patrolman, who appeared at the trial before a trial board in person and was heard in his own defense, and made no protest or objection to the jurisdiction of the trial board either before that board or to the park civil service commission, cannot raise the jurisdictional question for the first time on appeal.