Mass. Gen. Laws ch. 218 § 9
In the case of the absence, death or removal of a clerk of a court of the Boston municipal court department, the chief justice of the Boston municipal department may appoint a temporary clerk, to act until the clerk resumes his duties or until the vacancy is filled.
A temporary clerk shall be paid by the commonwealth for each day's service an amount equal to the rate by the day of the compensation of the clerk of such court as established in the salary schedule set forth in section seventy-nine; but compensation so paid to a temporary clerk for service, in excess of the number of days of vacation accumulated by the clerk as provided in section eight in any one year, shall be deducted by the state treasurer from the salary of the clerk; provided, however, that if a clerk is absent, due to his illness or physical disability, for a period not exceeding the number of days of sick leave he has accumulated pursuant to said section eight, no such deduction shall be made. Such thirty days sick leave or any portion thereof not used in any year may be accumulated, but shall, in any event not exceed one hundred and eighty days in any consecutive six-year period. If the person so appointed holds an office or position, the salary or compensation for which is paid out of the treasury of the commonwealth, or of a county, or a municipality, he shall not receive the salary of both office or positions during the period of such temporary service.
Mass. Gen. Laws ch. 218, § 9