In all cases the clerk shall render his account against the county for fees in State cases under oath, to be taken and subscribed before the judge, magistrate or other office authorized to administer an oath. In such statement the nature of the services shall be fully set forth and, if in the sessions, the name of the party, offense and termination thereof. He shall not be entitled to receive any fees from the county in any case in which the defendant is convicted unless he makes oath that the costs in such case have not been recovered out of the defendant and that the defendant is unable to pay costs. And he must, in all cases, further make oath that all fines and penalties theretofore collected by him have been faithfully and fully paid over to the county treasurer.