Magistrates in counties in which a county court has been established under the provisions of Chapter 9 of Title 14 shall, in binding over witnesses to appear and testify on behalf of the State before the county court in cases wherein the punishment exceeds a fine of one hundred dollars or imprisonment for thirty days, insert a provision in the recognizance requiring such witnesses to appear and testify in such case before the grand jury at the next ensuing term of the circuit court when the next ensuing term of the circuit court is appointed by law to be held before a term of the county court.