The same principle that prohibits recovery of money paid after the defendant has changed his position, makes it clear that whatever (equity there may be in favor of one who has made a unilateral mistake in the formation of a bilateral contract, the effect of it is confined to cases where the transaction is still wholly executory. Therefore if the parties proceed with a contract under a bid or offer erroneously calculated, there can be no relief;5 and in other cases also unilateral mistake will not justify rescission of a wholly or partly executed contract.6
2 See Sec. 1598.
3 An equitable defence "which sets forth some equitable consideration for the sole purpose of resisting the plaintiff's claim without asking any affirmative action of the court whatever, will not affect the mode of trial." Gill v. Pelkey, 54 Ohio St. 348, 360, 43 N. E. 991; Raymond v. Toledo, etc., R. Co., 57 Ohio St. 271, 48 N. E. 1093.
4 Sec. 1573.
5 Hubbert v. Fagan, 99 Ark. 480, 138
S. W. 1001; Tatum v. Coast Lumber Co., 16 Idaho, 471, 101 Pac. 957, 23 L. R. A. (N. S.) 1109; Gtriffin v. O'Neil, 48 Kan. 117, 29 Pac. 143; Boeckler Lumber Co. v. Cherokee Realty Co., 135 Mo. App. 708, 116 S. W. 452; Chaplaine Realty, etc., Co. v. Philip Gruner, etc., Co., 137 Mo. App. 451, 118 S. W. 665. See also Young v. Springer, 113 Minn. 382, 129 N. W. 773; Harter v. Bomberger, 47 Pa. 492.