Oral evidence must be direct in all cases. Explain this statement.

Under Section 3(1) of the Indian Evidence Act, 1872 oral evidence means statements which the Court permits or requires to be made before it by witnesses in relation to matters of fact under inquiry. The direct evidence means the evidence of the person who perceived the fact to which he deposes. The two broad rules regarding oral evidence are: all facts except the contents of documents may be proved by oral evidence; oral evidence must in all cases be "direct". According to Section 60 of the Act, Oral Evidence must be direct means that if evidence is about any fact which is heard, seen, perceived by any sense or by making an opinion. Then as per this section it could be valid only if it has been given by the person who heard, saw, perceived or formed an opinion after a particular incident. However, the basis on which such opinions are held may be proved by the production of such treatises. Thus, if any oral evidence needs to be admissible, all the conditions under Section 60 of the Indian Evidence Act must be fulfilled. The section states that oral evidence must, in all cases, whatever, be direct; that is to say: if it refers to a fact which could be seen, it must be the evidence of a witness who says he saw it; if it refers to a fact which could be heard, it must be the evidence of a witness who he says heard it; if it refers to a fact which could be perceived by any other sense or in any other manner, it must be the evidence of a witness who says he perceived it by that sense or in that manner; if it refers to an opinion or to the grounds on which that opinion is held, it must be the evidence of the person who holds that opinion on those grounds: However, the opinions of experts expressed in any treatise commonly offered for sale, and the grounds on which such opinions are held, may be proved by the production of such treatises if the author is dead or cannot be found, or has become incapable of giving evidence, or cannot be called as a witness without an amount of delay or expense which the Court regards as unreasonable. Further, if oral evidence refers to the existence or condition of any material thing other than a document, the Court may, if it thinks fit, require the production of such material thing for its inspection.