Massachusetts General Laws Part III. Courts, Judicial Officers and Proceedings in Civil Cases (Ch. 211-262) Ch. 217, § 10

Bonds required to be given to the judge of probate shall be given, in case of vacancy in the office of judge, to the acting judge, and to his successors in office, and all business shall be done in his name or in the name of the probate court or the court of insolvency for the county where the case or matter is pending; but bonds may be approved, and other acts required to be done or certified by the judge may be done or certified, by the acting judge.