Section 7. Vacancies, etc., not to invalidate acts

7. Vacancies, etc., not to invalidate acts.— No act of the Board shall be invalid merely by reason of— (a) any vacancy in, or defect in the constitution of, the Board, or - (b) any defect in the nomination of a person acting as a member thereof, or (c) any irregularity in its procedure not affecting the merits of the case.