323. Procedure when, after commencement of inquiry or trial, Magistrate finds case should be committed.- If, in any inquiry into an offence or a trial before a Magistrate, it appears to hi m at any stage of the proceedings before signing judgment that the case is one which ought to be tried by the Court of Session, he shall commit it to that Court under the provisions hereinbefore contained and thereupon the provision of Chapter XVIII shall apply to the commitment so made.