The discharge of a contract by the parol agreement of the parties would seem on principle to require the same elements of mutual consent and consideration that are necessary for the formation of simple contracts; and certainly this is the general rule.

If the parties to a bilateral contract agree to rescind it there is no difficulty in regard to consideration, whether the agreement to rescind is made before or after the breach of the original contract, so long as neither party has completely performed or been discharged from his obligation. The promise of one party to forego his rights under the contract is sufficient consideration for the promise of the other party to forego his rights.25

The agreement to rescind need not be express. Mutual assent to abandon a contract, like mutual assent to form one, may be inferred from circumstances.26 Therefore, "If either

24 Re Perkins, [1808] 2 Ch. 182, 190. To the same effect are Payler v. Homer-sham, 4 M. & S. 423; Lindo v. Lindo, 1 Beav. 496; London Ac. Ey. Co. v. Blackmore, L. R. 4 H. L. 610; Turner 0. Turner, 14 Ch. D. 829; Texas & Pac. R. v. Dashiell, 198 U. S. 521, 49 L. Ed. 1150, 25 Sup. Ct. 737; Gold Hunter Min. Ac. Co. v. Bowden, 252 Fed. 388, 164 C. C. A. 312; Tryon 0. Hart, 2 Conn. 120; Seymour v. Butler, 8 la. 304; Rich 0. Lord, 18 Pick. 322; Wiggin i7. Tudor, 23 Pick. 434; Hoes v. Van Hoesen, 1 Barb. Ch. 379; Mat-lack's Appeal, 7 Watts & S. 79; Heiser 0. Reynolds (Pa.), 106 Atl. 888. See also Danby v. Coutts, 29 Ch. D. 500, and supra, Sec.1551. Cf. especially with Turner v. Turner, supra, Dorman v. Dorman, 185 Mass. 153, 69 N. E. 1043.

25 King v. Gillett, 7 M. & W. 55; Farrar v. Toliver, 88 111. 406; Rollins v. Marsh, 128 Mass. 116; Brigham v. Herrick, 173 Mass. 460, 467, 53 N. E. 906; Blagborne 0. Hunger, 101 Mich. 375, 59 N. W. 657; Bandman 0. Finn, 185 N. Y. 508, 78 N. E. 175, 12 L. R. A. (N. S.) 1134; Spier v. Hyde, 78 N. Y. App. Div. 151,158, 79 N. Y. S. 699; Enderlien v. Kulaas, 25 N. Dak. 385, 141 N. W. 511; Dreifus 0. Columbian Salvage Co., 194 Pa. 475, 486, 45 Atl. 370; Blood v. Enos, 12 Vt. 625; Tacoma etc. Lumber Co. v. Field, 100 Wash. 79, 170 Pac. 360, 362; Montgomery v. American Central Ins. Co., 108 Wis. 146, 159, 84 N. W. 175.

26 Green 0. Wells, 2 Cal. 584; Mark v. Stuart-Howland Co., 226 Mass. 35, 41, 42, 115 N. E. 42; Heinlin 0. Fish, 8 Minn. 70; Fine v. Rogers, 15 Mo. 315; party without right claims to rescind the contract, the other party need not object, and if he permit it to be rescinded, it will be done by mutual consent." ** Sometimes circumstances of a negative character, such as the failure to take any steps looking towards the enforcement or performance of the contract, justify the inference of mutual assent to rescind.28 Also "a subsequent contract completely covering the same subject-matter, and made by the same parties, as an earlier agreement, but containing terms inconsistent with the former contract, so that the two cannot stand together, rescinds, substitutes, and is substituted for the earlier contract and becomes the only agreement of the parties on the subject." *• But the subsequent agreement must have sufficient consideration. Therefore if the undertaking by one party is simply to perform the whole or part of what he promised in the original contract, it Chouteau v. Jupiter Iron Works, 94 Mo. 388, 7 S. W. 467; Wheeden v. Fiflke, 60 N. H. 125; Schwartzreich v. Bauman-Basch, Inc., 172 N. Y. S. 683. See also cases cited in the following two notes.

» Woodard v. Willamette Valley Ac. Land Co., 89 Oreg. 10, 173 Pac. 262, 264, quoting 2 Parsons Cont. *678, and citing Moline Jewelry Co. v. Crew, 171 Ala. 415, 55 So. 144; McKenna v. McKenna, 118 111. App. 240; Ralya v. Atkins, 157 Ind. 331, 61 N. E. 726; Kingman Colony v. Payne, 78 Oreg. 238, 152 Pac. 891. It should be observed that this is not an acceptance of the common but misleading expression that any material breach or a repudiation by a party to a contract is an offer to rescind. It is a pure question of fact whether such an inference can be drawn. See supra, Sec. 1302.

"Hobbs v. Columbia Falls Brick Co., 157 Mass. 109, 31 N. E. 756; Mowry v. Kirk, 19 Ohio St. 375.

" Housekeeper Pub. Co. v. Swift, 97 Fed. 290, 38 C. C. A. 187. See in accord, Patmore v. Colburn, 1 C. M. & R. 65, 71; McCabe Const. Co. v. Utah Const. Co., 199 Fed. 976; Mobile will not support a promise by the other party to perform what he had previously agreed and something more.90 Nor (what is substantially the same thing) can an existing contract be altered by mutual assent by an agreement merely to give one party a right or privilege, or subject the other party to a burden which he did not have previously.81

Electric Co. v. Mobile (Ala.), 79 So. 39; Stow v. Russell, 36 111. 18, 30; Harrison v. Polar Star Lodge, 116 111. 279, 287, 5 N. E. 543; Hayes ». Carey, 287 111. 274, 122 N. E. 524; Holbrook v. Elec-c trie Appliance Co., 90 HI. App. 86; Western Ry. Equipment Co. v. Missouri Iron Co., 91 111. App. 28, 37; Thompson v. Elliott, 28 Ind. 55; Paul v. Meservey, 58 Me. 419; Howard v. Wilmington Ac. R. Co., 1 Gill, 311, 340; Smith v. Kelly, 115 Mich. 411, 73 N. W. 385; Chrisman v. Hodges, 75 Mo. 413, 415; Tuggles v. Callison, 143 Mo. 527, 536, 45 S. W. 291; McClurg v. Whitney, 82 Mo. App. 625; McDowell t>. Hemming Mfg. Co., 91 N. J. L. 209, 102 Atl. 680; Renard v. Sampson, 12 N. Y. 561, 568; Bandman v. Finn, 185 N. Y. 508,78 N. E. 175, 12 L. R. A. (N. S.) 1134; McKeogh v. Browning, 125 N. Y. S. 368; Gaylord v. McCoy, 161 N. C. 685, 77 S. E. 959; Robert Grace Contracting Co. v. Norfolk Ac. Ry. Co., 259 Pa. 241, 102 Atl. 956; Runnion v. Morrison, 71 W. Va. 254, 76 S. E. 457. C/. Rhoades v. Chesapeake Ac. R. Co., 49 W. Va. 494, 39 S. E. 209, 55 L. R. A. 170, 87 Am. St. Rep. 826.

A contract not infrequently reserves to one of the parties a right to rescind it under certain circumstances or by certain action. For one party to exercise such a right without the assent of the other, it is essential that the provisions of the original reservation be strictly followed.82 But such a provision like any other term in a contract may itself be rescinded by mutual assent, and, therefore, no limitation is imposed by it on the power of the parties to rescind by mutual agreement.88