A magistrate is authorized by the Pub. Sts. c. 162, § 28, to take an execution debtor’s recognizance to deliver himself up for examination within thirty days from the day of his arrest, only when the debtor is taken before him upon being arrested as required by § 27. By § 44, if at that time he does not desire to take an oath, he is to be kept in jail until he has recognized “as herein provided.” This he can do by causing *41notice to be given of his desire to take the poor debtor’s oath, under § 31, and then recognizing that he will appear at the time fixed for his examination, &c., as provided in § 36. But when he has been taken before the magistrate and declared that he does not desire to take an oath, and thereupon has been conveyed to jail and kept there, it may be more than thirty days; the recognizance under § 28 ceases to be appropriate; and we do not understand the provisions of § 41, as to the discharge of a debtor imprisoned on execution, to be directed to that point. It follows that, whether the debtor was legally' arrested or not on June 20, the magistrate had no jurisdiction to take the recognizance in this form, when he did so.

If the recital in the recognizance that Harrington was brought before the magistrate “ by John A. Duggan, a constable of said Boston, having been arrested by him,” imports that the custody of the constable had been continuous since the arrest, and that this is a case within § 28, the matter was one not within the personal knowledge of the magistrate, and was open to evidence, even if a jurisdictional fact would not always be. Learnard v. Bailey, 111 Mass. 160. The ruling that the recognizance was void should have been given, and it is unnecessary to consider the questions raised touching the arrest.

Exceptions sustained.