The consideration for a promise may be an act or a forbearance, or a promise to do or forbear. When a promise is given for a promise, the contract is said to be made upon an executory consideration. The obligations created by it rest equally upon both parties, each being bound to a future act. An example is in case of mutual promises to marry, in which the consideration for the promise of each is the promise of the other. When the consideration for a promise is, an act or forbearance, the contract is said to be made upon a consideration executed. This arises when either the offer or acceptance is signified by one of the parties doing all that he is bound to do under the contract so created.54

A contract consisting of mutual promises, so that both parties are bound to some future act or forbearance, is said to be bilateral. A contract in which the offer or acceptance is signified by one of the parties doing all he is required to do under the agreement, leaving outstanding obligations on the other party only, is said to be unilateralr

Same - Mutual Promises - Mutuality

68. A promise is a sufficient consideration for a promise.

69. The promises must be concurrent.

70. The promise may be contingent or conditional, except that - MUTUALITY - Mutuality of engagement is necessary, and, if the condition or contingency produces want of mutuality, the consideration is insufficient. Both parties must be bound or neither is bound.

It is well settled that a promise is a sufficient consideration for a promise.55 And this is true although the performance of the act promised will result in greater benefit to the promisor than to the promisee.66 In the case of mutual promises to marry, the promise of each party is a sufficient consideration for the promise of the other;57 and so it is in any other case of mutual promises, provided, of course, the promises are to do something of value in the eye of the law. In other words, as a rule, a promise to do a thing is just as valuable a consideration as the actual doing of it would be. After a person had sold and conveyed land, the parties, differing as to the quantity of land embraced in the tract, made an agreement by which the land was to be surveyed, and the grantor should pay for any deficiency, while the grantee should pay for any excess over the acreage mentioned in the deed. It turned out that there was an excess, but the grantee, when sued on his promise to pay therefor, claimed that, as all the land was conveyed by the deed, his promise was without consideration. It was held, however, that the promise of the grantor to pay for any deficiency was a sufficient consideration.58

54 Thomas v. South Haven & E. R. Co., 138 Mich. 50, 100 N. W. 1009. See "Contracts," Dec. Dig. (Key-No.) § 78; Cent. Dig. §§ S5J,-S56.

55Higgina v. Hill, 56 Law T. R. ON. S.) 426; Strangborough and Warner's Case, 4 Leon, 3; Gower v. Capper, Cro. Eliz. 543; Nichols v. Raynbred, Hob.

Clark Cont.(3d Ed.) - 10

The promises, to constitute a consideration for each other, must be concurrent, or become obligatory at the same time; otherwise each will be without consideration at the time it is made, and both will therefore be nuda pacta.59 As explained in treating of offer and acceptance, some time must necessarily elapse between an offer and its acceptance, and in some cases a considerable time may elapse. The offer, however, is considered as continuing during the time allowed for acceptance; and when it is accepted by the giving of a promise both promises become obligatory at the same time, or are concurrent.

88; Missisquoi Bank v. Sabin, 48 Vt 239; Buckingham v. Ludlum, 40 N. J. Eq. 422, 2 Atl. 265; Phillips v. Preston, 5 How. 278, 12 L. Ed. 152; Funk v. Hough, 29 111. 145; Coleman v. Eyre, 45 N. Y. 38; Briggs v. Tillotson, 8 Johns. (N. Y.) 304; Baker v. Railroad Co., 91 Mo. 152, 3 S. W. 486; Porter v. Rose, 12 Johns. (N. Y.) 209, 7 Am. Dec. 306; Cramer v. Redman, 10 Wyo. 328, 68 Pac 1003. Promise to attend a person's funeral in return for promise by the latter to pay money. Earle v; Augell, 157 Mass. 294, 32 N. E. 164. See "Contracts," Dec. Dig. (Key-No.) § 56; Cent. Dig. §§ 344-353.

56 Dendy v. Russell, 74 Pac. 248, 67 Kan. 721. See "Contracts," Dec. Dig. (Key-No.) § 57; Cent. Dig. §§ 344, 345.

57 Harrison v. Cage, 5 Mod. 411; Holt v. Ward Clemencieux, 2 Strange. 937. See "Breath of Marriage Promise," Dec. Dig. (Key-No.) § 5; Cent. Dig. § 2.

58 Seward v. Mitchell, 1 Cold. (Tenn.) 87; Howe v. O'Mally, 5 N. C. 287, 3 Am. Dec. 693. It would be otherwise if there were no promise by the grantor. Smith v. Ware, 13 Johns. (N. Y.) 259. See "Contracts," Dec. Dig. (Key-No.) §§ 56-58; Cent. Dig. §§ 344-353.

59 Nichols v. Raynbred, Hob. 88; Keep v. Goodrich. 12 Johns. (N. Y.) 397: Tucker v. Woods, 12 Johns. (N. Y.) 190, 7 Am. Dec. 305; Buckingham v. Lud-

A promise which is merely voidable, as in case of an infant, may be a sufficient consideration.60 And, as we have seen, an oral promise which is unenforceable within the statute of frauds is generally held to be a good consideration for the promise of the other if he has signed the writing.61