Where a sale of land negotiated by plaintiff for defendant failed because the record did not show that the "defendant had acquired the alleged outstanding interests of two heirs in the land, plaintiff's right to recover commissions was not affected by the fact that at the time of the purchaser's refusal to accept title there was a will in existence under which defendant acquired full title to the property, and of which will none of the parties had knowledge. Weaver v. Richards, 144 Mich. 395, 108 N. W. 382, 6 L. R, A. n.s. 855. See Sec. 508.