Except in the Cases herein specifically provided for, if either Party plead several Pleas, Replications, Avowries, Cognizances, or other Pleadings, without Leave of the Court or a Judge, the opposite Party shall be at liberty to sign Judgment; provided that such Judgment may be set aside by the Court or a Judge, upon an Affidavit of Merits, and such Terms as to Costs and otherwise as they or he may think fit.