1632 PLEADINGS, PRACTICE AND PROCESS AT LAW. [ART. 75

1904, art. 75, sec. 11. 1888, art 75, sec. 11. 1860, art 75, sec. 11.
1785, ch. 80, sec. 3.

11. No plea of "non est factum" shall be received in any action,
unless the party for whom such plea be tendered verify the same by
affidavit, or unless the defendant being heir, executor or administrator
of the person alleged to have made the deed obtain leave from the
court, upon showing just cause, to put in such plea.

The execution of a bond can only be denied by a plea of non est factum,
which must be verified by oath except as provided in this section. State v.
Duvall, 83 Md. 124.

It was unnecessary to determine whether a plea of non est factum was
verified by affidavit, since issue had been Joined on it, and certain other
pleas were demurred to. Milburn v. State, 1 Md. 12.

Ibid. sec. 12. 1888, art. 75, sec. 12. 1860, art. 75, sec. 12. 1785, ch. 46,
sec. 7. 1876, ch. 398.

12. In any suit brought on any judgment or bond or other writing
sealed by the party, if the defendant shall have any demand or claim
against the plaintiff, upon judgment, bond or other instrument under
seal, or upon bill of exchange, check, order for payment of money,
promissory note, agreement, assumpsit or account proved, he shall be
at liberty to file such demand or claim in bar, or plead the same in
discount of the plaintiff's claim, and judgment for the excess of the
one claim over the other, as each is proved, with costs of suit, shall be
given for the plaintiff or the defendant, according as such excess is
found in favor of the one or the other of these parties, if such excess
be sufficient to support a judgment in the court where the cause is
tried according to its established jurisdiction, otherwise the finding of
such excess to be due shall be sufficient prima facie evidence of the fact
of indebtedness for such excess, as upon an award of arbitrators in a
suit in a court having jurisdiction to try and determine the same.

Judgment will be given for the defendant where the plaintiff owes him in
excess of the amount the defendant owes the plaintiff. Although no Judg-
ment can be rendered for the defendant where the set-off arises on account
of what is due by a third party, this does not deprive the defendant of his
right to file the claim in bar of the plaintiff's recovery. The plaintiff's
joint and several liability may be set-off against the defendant's separate
liability. The fact that a defendant has instituted suit on his claim against
the plaintiff which is still pending, does not defeat the former's set-off-
Steele v. Sellman, 79 Md. 6.
See notes to sec. 13.

Ibid. sec. 13. 1888, art. 75. sec. 13, 1860, art. 75. sec. 13. 1785, ch. 46.
sec. 7. 1876. ch. 398.

13. In any suit upon simple contract the defendant may file in bar,
or plead in discount, any claim he may have against the plaintiff,
proved according to law, which may be of equal or superior nature to
the plaintiff's claim, and judgment shall be given for the difference
found, or other consequence follow thereon, as in the preceding section
is provided.

When set-off is applicable.

Joint debts can not be set-off against separate debts, nor separate debts
against joint debts. To support a plea of set-off, the defendant's claim