Where, in a suit for a commission for finding a purchaser for land, plaintiff alleged that the owner listed it with brokers, who listed it with plaintiff's firm, with the owner's consent, the owner could show that shortly before the alleged listing with such broker, he gave them an option to purchase a tract, including the land on account of which the commission was claimed, as tending to corroborate the owner's claim that the option contract was the only agreement between him and the broker. Sterling v. De Laune (Tex. Civ. App. '07), 105 S. W. 1169.