Evidence must be relevant.
Section 296
SEC. 296. Evidence must be relevant. — Evidence must correspond with the substance of the material allegations and be relevant to the question in dispute. Collateral questions must therefore be avoided. It is, however, within the discretion of the court to permit the inquiry into a collateral fact when such fact is directly connected with the question in dispute and is essential to its proper determination, or when it affects the credibility of a witness.