from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
NEW MATTER, pleading. All facts alleged in pleading, which go in avoidance
of what is before, pleaded, on the opposite side, are called new matter. In
other words, every allegation made in the pleadings, subsequent to the
declaration, and which does not go in denial of what is before alleged on
the other side, is an allegation of new matter; generally, all new matter
must be followed by a verification. (q.v.) Gould, Pl. c. 3, Sec. 195; 1
Saund. 103, n. 1; Steph. PI. 251; Com. Dig. Pleader, E 32; 2 Lev. 5; Vent.
121; 1 Chit. PI. 538; 3 Bouv. Inst. n. 2983. In proceedings in equity, when
new matter has been discovered by either plaintiff or defendant, before a
decree has been pronounced, a cross bill has been permitted to bring such
matter before, the court to answer the purposes of justice. After the answer
has been filed, it cannot be introduced by amendment; the only way to
introduce it, is by filing a supplemental bill. 4 Bouv. Inst. n. 4385-87;
1 Paige 200; Harring. Ch. 438.