A contract arises upon an executed consideration when one of the parties has either in the act which amounts to a proposal or to an acceptance, as the case may be, done all that he is bound to do under the contract, leaving an outstanding liability on the other side only. The two forms of consideration thus suggested have been described as (1) acceptance of an executed consideration, and (2) consideration executed upon request.62 They arise when the proposal is an offer of an act for a promise, and the act is accepted; or where it is an offer of a promise for an act, and the act is done.

In the first case a man offers his labor or goods under such circumstances that he obviously expects to be paid for them, and the contract arises when the labor or goods are accepted, the acceptor becoming bound to pay a reasonable price for them.63 The consideration executed upon request, or the contract which arises on the acceptance by act of the offer of a promise, is best illustrated by the case of an advertisement of a reward for services, which makes a binding promise to give the reward when the service is rendered. Under these circumstances, it is not the offeror, but the acceptor, who has done his part in becoming a party to the contract.64 This form of consideration will support an implied as well as an express promise where a man is asked to perform certain services which will entail certain liabilities and expenses. Thus, where a person is employed to deal with property for a certain purpose, and, in the course of the employment, he is compelled to pay duties to the government, he may recover the amount from his employer on an implied promise to repay.05

61 The first two exceptions are doubtful, post, pp. 171-173.

62 Leake, Cont 23.

63 Ante, p. 19; Hoadley v. McLaine, 10 Bing. 482; Hart v. Mills, 15 Mees, & W. 87. See "Contracts," Dec. Dig. (Key-No,) §§ 78, 79; Cent. Dig. §§ 354 381.