Section 42. A marriage solemnized by a person professing to have the authority to solemnize marriages under section thirty-eight or thirty-nine shall not be void, nor shall the validity thereof be in any way affected by want of authority in such person or society, or by an omission or by informality in the manner of filing the notice of intention, if the marriage is in other respects lawful and is consummated with a full belief of either of the persons so married that they have been lawfully married.