In an action to recover a commission for a sale of defendant's property, an allegation in the answer that the sale "was not consummated, by reason of which plaintiffs are not entitled to recover of defendants," states no defense, as such failure may have resulted from defendants' fault, they having admitted that plaintiff furnished them a purchaser. Atterbury v. Hopkins, 122 Mo. App. 172, 99 S. W. 11.