In an action for a broker's commissions, an instruction that if the broker caused a change to be made in the contract, believing the defendant would see the change when the contract was delivered to him, then the defense of fraud on the part of the broker in so changing the contract was not sufficiently established to defeat plaintiff's claim for commissions, was not prejudicial to plaintiff. Robertson v. Vasey, 125 Iowa, 526, 101 N. W. 271.