Mass. Gen. Laws ch. 236, § 9: Mortgaged land; appraisal

Section 9. If a right of redeeming mortgaged land is taken and set off on execution, the appraisers shall deduct the value of the encumbrance or the amount of the mortgage debt, when known, from the appraised value of the land, and the amount so deducted shall be stated in the return of the execution.