The typical form of mistake in expression is found where the parties have agreed orally upon the terms of a contract, have then attempted to express these terms in writing and have, through inadvertence, omitted or misstated terms, or inserted some stipulation which was not agreed upon. Mistake of this sort does not affect the validity of the contract. The question presented to the courts is whether upon these facts the original contract can be enforced or whether the parties are bound by the written stipulations. This question is answered at law by the rule that oral evidence of prior or contemporaneous negotiations cannot contradict the terms of a written contract. This is really a rule of substantive law, though stated as a rule of evidence.1 Hence there can be no reformation at law.2 In equity, subject to proper limitations to be discussed hereafter,3 a contract of the type under discussion may be reformed so as to express the actual agreement of the parties.4

1 See Sec. 1189 et seq.

2 American, etc., Ins. Co. v. Simpson, 43 111. App. 98; Nance v. Met-calf, 19 Mo. App. 183; Winnipi-seogee Paper Co. v. Eaton, 64 N. H. 234; 9 Atl. 221.

3 See Sec. 1241 et seq.

4 Adams v. Henderson, 168 U. S. 573; Equitable Ins. Co. v. Hearne,

20 Wall. (U. S.) 494; Hearne v. Ins. Co., 20 Wall. (U. S.) 488; Bradford v. Bank, 13 How. (U. S.) 57; New York Life Ins. Co. v. Mc-Master, 87 Fed. 63; 30 C. C. A. 532; Western Assurance Co. v. Ward, 75 Fed. 338; State v. Paup, 13 Ark. 129; 56 Am. Dec. 303; West v. Suda, 69 Conn. 60; 36 Atl. 1015; Newell v. Smith, 53 Conn. 72; 3 Atl. 674; Franklin v. Jones, 22 Fla. 526; Jackson v. Magbee,

21 Fla. 622; Snell v. Snell, 123 111. 403; 5 Am. St. Rep. 526; 14 N. E. 684; Lindsay v. Davenport. 18 111. 375; Roszell v. Roszell, 109 Ind.

354; 10 N. E. 114; Zenor v. Johnson, 107 Ind. 69; 7 N. E. 751; Green v. Mfg. Co. (la.), 82 N. W. 483; Huston v. Furnas, 31 la. 154; Stiles v. Willis, 66 Md. 552; 8 Atl. 353; Page v. Higgins, 150 Mass. 27; 5 L. R. A. 152; 22 N. E. 63; Griffith v. Townley, 69 Mo. 13; 33 Am. Rep. 476; Beall v. Martin, 48 Neb. 479; 67 N. W. 433; Searles v. Churchill, 69 N. H. 530; 43 Atl. 184; Minot v. Tilton, 64 N. H. 371; 10 Atl. 682; Green v. Stone, 54 N. J. Eq. 387; 55 Am. St. Rep. 577; 34 Atl. 1099; Whittemore v. Far-rington, 76 N. Y. 452; Moran v. McLarty, 75 N. Y. 25; Jackson v. Andrews, 59 N. Y. 244; Bryce v. Ins. Co., 55 N. Y. 240; 14 Am. Rep. 249; Welles v. Yates, 44 N. Y. 525; Nevins v. Dunlap, 33 N. Y. 676; Rider v. Powell, 28 N. Y. 310; Curtis v. Leavitt, 15 N. Y. 1; Gillespie v. Moon, 2 Johns. Ch. (N. Y.) 585; 7 Am. Dec. 559; Botsford