Justices of the peace shall have power to appoint special agents to execute orders of arrest, attachments, and other provisional remedies and the summons which accompanies them, whenever an affidavit is filed with the justice by the plaintiff or his agent to the effect that he believes that, owing to the absence or difficulty of procuring a proper officer, the process or other order cannot be executed without injurious delay. In cases where there is no constable in the township, and the appointment provided for in this section shall be made, an endorsement shall be made on the writ or order and signed by the justice.