Gujarat High Court Civil Manual (subordinate court practice), 1960
(i) If appears that in some original suits the parties still abstain from coming forward as witnesses on their own behalf to substantiate by their own evidence on solemn affirmation the statements of fact on which they respectively ask the Court to give judgment in their favour. The non-appearance in the witness-box of a party in support of his own allegation of facts within his own knowledge, would ordinarily be regarded, in the absence of some satisfactory explanation, as throwing grave doubt on the bona fides of his case. (ii) The practice of calling the opponent in the case as one's own witness has been condemned by the Privy Council.