Mass. Gen. Laws ch. 233, § 3: Witness fees; payment or tender

Section 3. No person shall be required to attend as a witness in a civil case or for the defendant in a criminal case except a person summonsed to attend as a witness for an indigent defendant in a criminal case, unless the legal fees for one day's attendance and for travel to and from the place where he is required to attend are paid or tendered to him.