PARTICEPS FRAUDIS. fraud. Both parties be in pari delicto is not allowed to allege his own turpitude in such cases, when defendant at law, or prevented from alleging it, when plaintiff in equity, whenever the refusal to execute the contract at law, or the refusal to relieve against it in equity, would give effect to the original purpose, and encourage the parties engaged, in such transactions. 4 Rand. R. 372; 1 Black. R. 363; 2 Freem. 101.