A broker is not entitled to a commission, where he procures a contract between the parties subject to approval, and that approval has been withheld. Halprine v. Schachne, 54 N. Y. S. 1103, 25 Misc. 797; Hammond v. Crawford, 66 Fed. 425, 14 C. C. A. 109; Hamlin v. Schulte, 31 Minn. 486; Gough v. Coffin (Tex. Civ. App. '09), 120 S. W. 210; Oliver v. Battler, 233 I11.

536, 84 N. E. 652; Oban v. Ducharme, 106 A. 727, - Vt. Sup. - . See references under Sec. 307.