This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
In an action on a written contract, complete in itself, the validity of which is conceded, the parties are not permitted to show that their prior or contemporaneous oral agreements were not all reduced to' writing, but remain as oral contracts in full force and effect between the parties.1 This rule applies as
8 Bank v. Talbot, 154 Mass. 213; 13 L. R. A. 53; 28 N. E. 163.
8 Pitcairn v. Philip Hiss Co., 125 Fed. 110.
10 Tarver v. Garlington, 27 S. C. 107; 13 Am. St. Rep. 628; 2 S. E. 846. "Upon the face of the paper, unexplained by parol testimony the jury would have been compelled under the cases above to answer (the question of agency) in the negative. But before the judge, with the agency not even disputed, it seems to us error to hold that there was no cause of action."
1 Abrey v. Crux, L. R. 5 C. P. 37; Woollam v. Hearn, 7 Ves. Jr. 211; Omerod v. Hardman, 5 Ves. Jr. 722; Union, etc., Ins. Co. v. Mowry, 96 U. S. 549; Sun, etc., Association v. Edwards. 113 Fed. 445; 51 C. C. A. 279; Hildreth v. Tramway Co., 73 Conn. 631; 48 Atl. 963; Quinn v. Roath, 37 Conn. 16; Rector v. Deposit Co., 190 111. 380; 60 N. E. 528; affirming, 92 111. App. 175; Tichenor v. Newman. 186 111. 264; 57 N. E. 826; Ehrsam v. Brown, 64 well where the intention of the parties is completely embodied in two written contracts instead of one.2 If the parties have voluntarily omitted terms in reducing the contract to writing,3 as where they voluntarily omit from a lease a clause providing for an abatement of rent,4 they cannot enforce such terms thus voluntarily omitted. Accordingly, where A executes a written instrument whereby she relinquishes her claim to certain horses and carriages in B's possession until B's claim for board is paid in full, A cannot show a contemporaneous oral agreement that she might use such horses in the ordinary course of her business.5 So in jurisdictions where there is no priority of payment between notes secured by one mortgage but falling due at different times, extrinsic evidence is inadmissible to show that the assignee should have priority.6 So an indorser of one of several notes secured by mortgage cannot show an oral agreement that the proceeds of the mortgage were to be applied first to the note last maturing.7 So if a mortgage is given to secure four notes, extrinsic evidence is inadmissible to show that such mortgage was to be released when two of such notes were paid.8 So if a contractor has agreed in writing to assume the contracts for materials already made, he cannot show a contemporaneous oral agreement that he should assume only a certain amount of these contracts, the other party to assume the excess over such amount.9 So under a contract for payment of an entire indebtedness, extrinsic evidence is inadmissible to show that a part only of such indebtedness was to be paid.10 So under a contract to pay "all of the outstanding indebtedness" of X, "not to exceed in all one hundred thirty thousand dollars," extrinsic evidence is inadmissible to show an oral contract to pay part only of all X's debts.11 So under a contract to supply X the material which he needed, evidence is inadmissible to show that the contract was for a limited amount only.12 So under a complete written contract for the sale of machines, extrinsic evidence is inadmissible to show that the agent was to set them up.13 Under written permission for the assignment of a lease, it is inadmissible to show that the lessee's liability was to end by such assignment.14 So if a written contract for the sale of land provides for the payment of taxes and assessments, extrinsic evidence is inadmissible to show an agreement by the vendor to pay taxes upon such realty,15 or to show that certain taxes were excepted from a covenant against encumbrances.16 So if the parties have made a contract whereby one of them is to furnish castings and sink a well at a given price, extrinsic evidence is inadmissible to show that he was to furnish the tubing and pump for the same price.17 So under a contract for employing an insurance agent, which by its terms could be ended at will without liability except for commissions warned, the agent cannot show a contemporaneous oral contract giving him commissions on future renewals.18 So one who ships under an ordinary bill of lading, constituting a contract in writing between himself and the railroad company, cannot enforce a prior oral contract to give him as low a rate as was given to any shipper.19
Kan. 466; 67 Pac. 867; Wight v. R. R., 16 B. Mon. (Ky.) 4; 63 Am. Dec. 522; Holmes v. Holmes, 129 Mich. 412; 89 N. W. 47; McCray Refrigerator Co. v. Zent, 99 Mich. 269; 41 Am. St. Rep. 599; 58 N. W. 320; Loth v. Friederick, 95 Mich. 598; 55 N. W. 369; Plumb v. Cooper, 121 Mo. 668; 26 S. W. 678; Largey v. Leggatt, - Mont. - ; 75 Pac. 950; Montana Mining Co. v. Milling Co., 20 Mont. 394; 51 Pac. 824; Crawford v. Improvement Co., 15 Mont. 153; 38 Pac. 713; Russell v. Russell, 63 N. J. Eq. 282; 49 Atl. 1081; affirming, 47 Atl. 37; Thomas v. Scutt, 127 N. Y. 133; 27 N. E. 961; Travelers' Ins. Co. v. Myers, 62 O. S. 529; 57 N. E. 458; Union Central, etc., Co. v. Hook, 62 O. S. 256; 56 N. E. 906; Philadelphia, etc., Ry. v. Conway, 177 Pa. St. 364; 35 Atl.
716; Heist v. Hart, 73 Pa. St. 286; Gilbert v. Stockman, 76 Wis. 62; 20 Am. St. Rep. 23; 44 X. W. 845. Contra, under the California statute. Snyder v. Mfg. Co., 134 Cal. 324; 66 Pac. 311.
2 Harrison v. Tate, 100 Ga. 383; 28 S. E. 227.
3 Eleventh Street Church v. Pennington, 18 Ohio C. C. 408; 10 Ohio C. D. 74.
4 Seitz Brewing Co. v. Ayres, 69 N. J. Eq. 190; 46 Atl. 535.
5 Radigan v. Johnson, 174 Mass. 68; 54 N. E. 358.
6 Jennings v. Moore, 83 Mich. 231; 21 Am. St. Rep. 601; 47 N. W. 127.
7 Schulty v. Bank, 141 111. 116; 33 Am. St. Rep. 290; 30 N. E. 346.
8 First National Bank v. Prior, 10 N. D. 146; 86 N. W. 362.
9 Bandholz v. Judge, 62 N. J. L. 526; 41 Atl. 723.
10 First National Bank v. By. (Term. Ch. App.), 46 S. W. 312.
11 Bell v. Mendenhall, 78 Minn. 57; 80 N. W. 843.
12 Dean v. Mfg. Co., 177 Mass. 137; 58 N. E. 162.
13 Dowagiae Mfg. Co. v. Corbit. 127 Mich. 473, 478; 86 N. W. 954; rehearing denied, 87 N. W. 886. 115
14 Rector v. Deposit Co., 190 111. 380; 60 N. E. 528.
15 Gilbert v. Stockman. 76 Wis. 62; 20 Am. St. Rep. 23; 44 N. W. 845; and see Garwood v. Wheaton, 128 Cal. 399; 60 Pac. 961.
16 Stanisics v. McMurtry, 64 Neb. 761; 90 N. W. 884.
17 Meader v. Allen, 110 Ia. 588; 81 N. W. 799.