from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
TO DISCREDIT, practice, evidence. To deprive one of credit or confidence.
2. In general, a party may discredit a witness called by the opposite
party, who testifies against him, by proving that his character is such as
not to entitle him to credit or confidence, or any other fact which shows he
is not, entitled to belief. It is clearly settled, also, that the party
voluntarily calling a witness, cannot afterwards impeach his character for
truth and veracity. 1 Moo. & Rob. 414; 3 B. & Cress. 746; S. C. 10 Eng. Com.
Law R. 220. But if a party calls a witness, who turns out unfavorable, he
may call another to prove the same point. 2 Campb. R. 556 2 Stark. R. 334;
S. C. 3 E. C. L. R. 371 1 Nev & Man. 34; 4 B. & Adolph. 193; S. C. 24 E. C.
L. R. 47; 1 Phil. Ev. 229; Rosc. Civ. Ev. 96.