22. It shall be the duty of the prosecuting officer to submit to the Registrar of the Court a form and counterfoil as approved by the Accountant-General setting forth the required particulars in regard to every witness whose costs are to be paid out of the public treasury. The Registrar shall, as far as possible, check the particulars and (in cases other than those coming within rule 21) direct payment of such amount as in his view is properly payable.