Notice of suit against Board.

No suit shall be instituted against the Board, or any member or any officer or other employee of the Board, or any person acting under the direction of the Board, or of the Chairman or of any officer or other employee of the Board, in respect of any act done or intended to be done under this Act or any rule or regulation made thereunder until the expiration of sixty days next after written notice has been delivered or left at the office of the