420.) A judgment in favor of a plaintiff upon a failure to answer, is as final and conclusive, and as much upon the merits, as if rendered after the sharpest controversy. 3. The plaintiff did not discontinue his action, nor dismiss his complaint, nor was such discontinuance or dismissal permitted or adjudged. (Cockle a. Underwood, 1 Abbotts’ Pr., 1 ; S. C., at general term, 3 Duer, 676 ; Seaboard & Roanoke R. R. Co. a. Ward, 1 Abbotts’ Pr., 46, recognizing and approving the decision in the last case; Averill a. Patterson, 10 How. Pr., 85 .) Had the action been discontinued, or the • plaintiff hionsuited, both the plaintiff and the" cause would have been out of court. (Hope a. Acker, 7 Abbotts’ Pr., 308.) 4. If the plaintiff in that "action was dissatisfied with the ruling of the judge, he should have appealed. Its correctness cannot now be examined collaterally. 5. “It is true, if a person sues upon several and distinct causes of action, and submits only a part of them to a jury, he is not precluded from suing again for such distinct cause of action as was not passed upon. In that case, he was not bound originally to unite the different'causes of action, and therefore shall not be bound.” (Wheeler a. Van Houten, 12 Johns., 311 ; S. P., Seddon a . Tutop, 6 Term R., 607, where the defendants’ plea could not, of course, be maintained, for the recovery in the former action was not on the' same promises and undertakings.) But .where.there is only a single cause of action, the principle is inapplicable. (See supra ; Markham a. Middleton, 2 Strange, 1259.) 6. That the judgment is a bar, is evident from the nature of a plea of set-off (Eastmure a. Laws, 5 Bingham’s N. C., 444 ; Collins a. Collins, 2 Burr, 825 ; Burgess a. Tucker, 5 Johns., 105 .) It is a plea in bar going to the merits. It confesses and avoids the demand alleged by the plaintiff. It prays that the defendants’ demand be set off or over against the plaintiff’s demand. The recovery is of the balance of such account, and of course is conclusive upon the existence and extent of the ¡plaintiff’s demand.' When a plea of set-off is pleaded, the complaint becomes a defence to the defendant’s plea; and if that defence fail from want of proof or otherwise, and judgment is rendered for the defendant, it is res adjudicata that the pleading by -which such defence is set up is not true, and that the cause of action therein alleged does not exist. ( 9 Johns., 232 ; 12 Ib., 347 ; 14 Ib., 377 ; 13 Ib., 187.) The statute prescribes the judg