The courts allowing a writ of habeas corpus may, in their discretion, require, as a duty to be performed in order to render the service thereof effectual, that the charges of bringing up the prisoner and conveying him back, if remanded, shall be paid by the petitioner; and in such case the court shall, on the allowance of the writ, specify the amount, which shall not exceed ten cents per mile; and the amount so to be paid shall be stated in writing on the writ, signed by the clerk, if in term, or by the officer by whom the writ is awarded.