Mass. Gen. Laws ch. 233, § 49

The deponent shall be sworn and examined, and his deposition shall be written, read and subscribed in the manner provided in sections thirty to thirty-two, inclusive; and the justices or notaries shall sign and annex thereto a certificate of the name of the person at whose request it was taken, the names of all persons who were notified to attend, of all who attended the taking thereof, of the time and manner of taking it, and that it was taken for the purpose of perpetuating the testimony therein.