All county officers shall continue to charge and collect the fees, mileage and emoluments of office for their own use or for the use of the county, as provided by law, and where required by law, such fees, mileage and emoluments shall be paid to the county treasurer as and when required, and if no time of so paying be fixed as to any such fees, mileage or emoluments, then on or before the tenth day of each month.
16 P.S. § 1621