In an action for commissions for procuring a purchaser for land where the land was purchased by one claiming to buy on his own initiative, evidence that the land had been listed two months before the transaction in issue, and the purchaser informed of the land being for sale from that source, was admissible as tending to explain how the purchaser ascertained that the land was for sale and came to negotiate with defendant for its purchase. Ryan v. Page, 134 Iowa 60, I11 N. W. 405.