By the Court,
Savage, Ch. J.
Ordinarily, no doubt, the court- of common pleas are bound to try an appeal cause upon the pleadings and issue joined before the justice; but when new matter exists, which furnishes a defence to the action, arisen since the rendering of the judgment before the justice, and which, unless plead, would be unavailable, the party must be allowed to plead it. Let an alternative mandamus issue.