The members of the board shall receive no compensation, but each member shall receive from the commonwealth the expenses necessarily incurred by him in connection with his official duties; provided, that such compensation and expenses shall not in any year be in excess of the annual receipts for examinations and registration and from other sources paid to the commonwealth by the board for the purposes of sections eighty-one D to eighty-one T, inclusive, of chapter one hundred and twelve.
Mass. Gen. Laws ch. 13, § 47