While Civil Code, Sec. 1624, requiring agreements employing brokers to buy or sell real estate for hire to be in writing, does not extend to agreements between brokers to co-operate in making sales for a share of the commission, and recovery may be had in such cases on proof of an oral agreement; this pre-supposes that a valid contract for commissions is extant, a division of which could be subject of subsequent oral agreement. Saunders v. Yoakum, 107 P. 1007, 12 Cal. App. 543; Hageman v. O'Brien, 141 P. 33, 24 Cal. App. 270; Hiedak v. Allen, 147 P. 474, 26 Cal. App. 509; Mackroth v. Sinky, 148 P. 978, 27 Cal. App. 112; Giles v. Wilmott, 52 S. 287, 59 Fla. 271; Egeland v. Schiller, 189 I11. App. 426; Blake v. Hunkey, 128 P. 181, 88 Kan. 272; Collins v. Belford & Stump, 130 P. 662, 89 Kan. 92; White v. Robinson, 138 N. Y. Sup. 992, 153 App. Div. 776.