Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 41, § 61A

If the office of city auditor, city treasurer, city collector of taxes or other officer having charge of a city department is vacant, or if any such officer, because of disability or absence, is unable to perform his duties, the mayor, without confirmation by the city council, any provision of a city charter to the contrary notwithstanding, shall appoint a temporary officer to hold such office and exercise the powers and perform the duties thereof until another is duly elected or appointed and has qualified according to law, or the officer who was disabled or incapacitated resumes his duties; but no such temporary officer shall be appointed under this section for a period longer than sixty days. Any such temporary officer shall be sworn and give bond for the faithful performance of his duties in accordance with the provisions of law applying to the officer whose place he fills, and if he fails so to do within ten days after his appointment the mayor shall rescind the appointment and appoint another.