2. Every party has a right to cross-examine a witness produced by his antagonist, in order to test whether the witness has the knowledge of the things he testifies and if, upon examination, it is found that the witness had the means and ability to ascertain the facts about which he testifies, then his memory, his motives, everything may be scrutinized by the cross- examination.
3. In cross-examinations a great latitude is allowed in the mode of putting questions, and the counsel may put leading questions. (q. v.) Vide further on this subject, and for some rules which limit the abuse of this right, 1 Stark. Ev,. 96; 1 Phil. Ev. 210; 6 Watts & Serg. 75.
4. The object of a cross-examination is to sift the evidence, and try the credibility of a witness who has been called and given evidence in chief. It is one of the principal tests which the law has devised for the ascertainment of truth, and it is certainly one of the most efficacious. By this means the situation of the witness, with respect to the parties and the subject of litigation, his interest, his motives, his inclinations and his prejudices, his means of obtaining a correct and certain knowledge of the facts to which he testifies the manner in which he has used those means, his powers of discerning the facts in the first instance, and of his capacity in retaining and describing them, are fully investigated and ascertained. The witness, however artful he may be, will seldom be able to elude the keen perception of an intelligent court or jury, unless indeed his story be founded on truth. When false, he will be liable to detection at every step. 1 Stark. Ev. 96; 1 Phil. Ev. 227; Fortese. Rep. Pref. 2 to 4; Vaugh. R. 143.
5. In order to entitle a party to a cross-examination, the witness must have been sworn and examined; for, even if the witness be asked a question in chief, yet if he mahe no answer, the opponent has no right to cross-examine. 1 Cr. M. & Ros. 95; 1 16 S. & R. 77; Rosc. Cr. Ev. 128; 3 Car. & P. 16; S. C. 14 E. C. L. Rep. 189; 3 Bouv. Inst. n. 3217. Formerly, however, the rule seems to have been different. 1 Phil. Ev. 211.
6. A cross-examination of a witness is not always necessary or advisable. A witness tells the truth wholly or partially, or he tells a falsebood. If he tells the whole truth, a cross-examination may have the effect of rendering his testimony more circumstantial, and impressing the jury with a stronger opinion of its truth. If he tells only a part of the truth, and the part omitted is favorable to the client of the counsel cross-exaimining, he should direct the attention of the witness to the matters omitted. If the testimony of the witness be false, the whole force of the cross-examination should be directed to his credibility. This is done by questioning him as to his means of knowledge, his disinterestedness, and other matters calculated to show a want of integrity or veracity, if there is reason to believe the witness prejudiced, partial, or wilfully dishonest. Arch. Crim. Pl. 111. See Credible Witness.