The Board after holding its first meeting as hereinbefore provided, shall thereafter hold at least two regular meetings each year. Special meetings may be held at such times and places as the bylaws and/or rules of the Board provide; or as may be required in carrying out the provisions hereof. A quorum of the Board shall consist of not less than four members. (1931, c. 52, s. 4; 1989 (Reg. Sess., 1990), c. 842, s. 2.)