The credit of a witness may be impeached in the following ways by the adverse party, or, with the consent of the Court, by the party who calls him :- (1) by the evidence of persons who testify that they, from their knowledge of the witness, believe him to be unworthy of credit ; (2) by proof that the witness has been bribed, or has [accepted] [Substituted by Act 18 of 1872, Section 11, for "had".] the offer of a bribe, or has received any other corrupt inducement to give his evidence ; (3) by proof of former statements inconsistent with any part of his evidence which is liable to be contradicted ;[* * *] [Sub-Clauses (4) omitted by Act 4 of 2003, Section 3 (w.e.f. 1.1.2003) . Prior to its omission, sub-Clause (4) read as under:- [ (4) when a man is prosecuted for rape or an attempt to ravish, it may be shown that the prosecutrix was of generally immoral character].]Explanation. - A witness declaring another witness to be unworthy of credit may not, upon his examination-in-chief, give reasons for his belief, but he may be asked his reasons in cross-examination, and the answers which he gives cannot be contradicted, though, if they are false, he may afterwards be charged with giving false evidence.Illustrations (a) A sues B for the price of goods sold and delivered to B. C says that he delivered the goods to B.Evidence is offered to show that, on a previous occasion, he said that he had not delivered the goods to B.The evidence is admissible. (b) A is indicted for the murder of B.C says that B, when dying, declared that A had given B the wound of which he died.Evidence is offered to show that, on a previous occasion, C said that the wound was not given by A or in his presence.The evidence is admissible.