Where defendant, having an option on land, put it in the hands of plaintiffs, real estate agents, to trade, and they traded it with one who, as well as defendant, to the knowledge of both, had agreed to pay the commissions, their right to recover a commission of defendant is not affected by the fact that the owners of the record title of defendant's land, with whom plaintiff claimed no contractual relations, did not know of the agreement as to the commission. Cook v. Platt, 126 Mo. App. 553, . 104 S. W. 1131. See also Sec. 454.