sitory of the agreement of the parties on all matters which were the objects of their negotiations, and such contract cannot be altered, varied, contradicted, enlarged, narrowed or added to by parol testimony, but the written contract must speak for itself, except in case of accident, mistake, or fraud when the remedies are other than an action at law for breach of the parol agreement claimed to have been omitted from the written contract. Section 9456, O. S. 1931; Guthrie W. R. Co. v. Rhodes, 19 Okla. 26, 91 P. 1119; Garrison v. Kress, 19 Okla. 433, 91 P. 1130; McNinch v. Northwest Thresher Co., 23 Okla. 386, 100 P. 524; Oland et al. v. Malson et al., 39 Okla. 456, 135 P. 1055; German Stock Food Co. v. Miller, 39 Okla. 634, 136 P. 426; Colonial Jewelry Co. v. Bridges, 43 Okla. 813, 144 P. 577; Reed v. Moore, 54 Okla. 354, 154 P. 348; Reinheimer v. Mays, 75 Okla. 131, 182 P. 230; Ozark States Trust Co. v. Winkler, 84 Okla. 7, 202 P. 12; Posey v. Citizens State Bank, 93 Okla. 266, 220 P. 628 Fuller v. Caraway, 97 Okla. 110, 221 P. 79; Chi Okla. Oil Gas Co. et al. v. Shertzer, 105 Okla. 111, 231 P. 877; Nachtsheim et al. v. Bartle, 131 Okla. 166, 268 P. 195; Wichita Flour Mills Co. v. Guyman Equity Exchange, 150 Okla. 245, 1 P.2d 657; Kansas City Flower Market Co. v. Furrow et al., 165 Okla. 245 25 P.2d 794. Were this not the law, every written contract would ultimately rest in parol and defeat the very purpose of reducing business engagements to writing. In the case of Holcomb Hoke Mfg. Co. v. Jones, 102 Okla. 175, 228 P. 968, this court held that a party who signs a written contract with the agreement that an additional covenant is to be inserted therein cannot treat the omitted covenant as a term of a contract.
"The execution of a contract in writing supersedes all the oral negotiations or stipulations concerning its terms and subject-matter which preceded or accompanied the execution of the instrument, in the absence of accident, fraud, or mistake of fact; and any representation made prior to or contemporaneous with the execution of the written contract is inadmissible to contradict, change, or add to the terms plainly incorporated into and made a part of the written contract." See, also, Western Silo Co. v. Pruitt, 94 Okla. 154, 221 P. 106; Fuller v. Caraway, 97 Okla. 110, 221 P. 79; Stebbins v. Lena Lumber Co., 89 Okla. 244, 214 P. 918; Southard v. Arkansas Valley W. Ry. Co., 24 Okla. 408, 103 P. 750; Fisher v. Gossett, 36 Okla. 261, 128 P. 293; Norris v. Richards, 105 Okla. 269, 232 P. 796. Plaintiffs cite a number of authorities in their brief in support of the well-settled rule that, in the case of doubt as to the meaning of a written contract, prior negotiations between the parties may be considered in construing the contract.
"The execution of a contract in writing supersedes all oral negotiations or stipulations concerning its terms and subject-matter which preceded or accompanied the execution of the instrument, in the absence of accident, fraud, or mistake of facts, and any representations made prior to or contemporaneous with the execution of the written contract are inadmissible to contradict, change, or add to the terms plainly incorporated into and made a part of the written contract." Fuller v. Caraway, 97 Okla. 110, 221 P. 79; Bolon v. Massey, 101 Okla. 8, 222 P. 685; Cromwell v. Lewis, 98 Okla. 53, 223 P. 671. It therefore follows as a necessary corollary that if the evidence to support an allegation in a petition, answer, or cross-petition is inadmissible, such allegation of itself constitutes no cause of action or grounds of defense.
But the vast majority hold that where the lease does not restrict the use of the premises, it may not be shown that there was an oral understanding of restriction. Morgan v. Green, supra; Wetzler v. Patterson, 73 Cal.App. 527, 538, 238 P. 1077; Harrison v. Howe, 109 Mich. 476, 67 N.W. 527; Snead v. Tietjen, 3 Ariz. 195, 24 P. 324; Rickard v. Dana, 74 Vt. 74, 52 A. 113; Van Liew v. Mally, 198 Iowa 347, 197 N.W. 299; Fuller v. Caraway, 97 Okl. 110, 221 P. 79; Barnett v. Clark, 225 Mass. 185, 114 N.E. 317; Rockwell v. Eiler's Music House, 67 Wash. 478, 122 P. 12, 39 L.R.A.,N.S., 894; Colonial Operating Corp. v. Hannan Sales & Service, 265 App.Div. 411, 39 N.Y.S.2d 217. On this appeal we are not prevented from inquiring into the propriety of the admission of parol.