The same principle of justice which requires.the return of money paid under a mistake, requires that other benefits received under a similar mistake should likewise be restored.82 If the transferee still has possession of all or part of what has been transferred, of of anything received by him in exchange for it, when demand is made upon him or when he discovers the real facts, a mistake of such a character as ever to justify rescission should subject him to a duty to return in specie what he has in his possession; and a failure to perform the duty should involve liability for its value 83 Where what was transferred under a mistake was money, other money is the exact equivalent, so that the mere fact that the money originally received by him is no longer in his possession does not preclude rescission. It may be supposed, however, that goods or serva trust when he paid it. That the plaintiff would undoubtedly have lent the whole sum to the fraudulent person, if the latter previously had paid the prior mortgage from his own funds seems immaterial.

81 In Hathaway v. Delaware County, 185 N. Y. 368,78 N. E. 153,13 L. R. A. (N. 8.) 273, 113 Am. St. 909, the plaintiff had in exchange for a forged note of the defendant county delivered to the forger, a former treasurer of the county, a check payable to A, the existing treasurer. The forger delivered this check to A in payment of a shortage in the forger's accounts, and A so applied it. The plaintiff was allowed to recover. In Continental Caoutchouc Ac. Co. v. Dunlop Ac. Co., 90 L. T. (N. 8.) 474, one who, when under a duty, to pay a particular creditor of another, paid the wrong creditor, was held entitled to recover the payment. See also Kleinwort v. Dunlop Rubber Co., 97 L. T. (N. S.) 263. In Koontz v. Central Nat. Bank, 51 Mo. 275, and Munroe v. Bonanno, 16 N. Y. App. D. 421, 45 N. Y. 8. 61, one who had by mistake paid a debt due from another was allowed to recover the payment.

"In this connection may be considered goods or services rendered under an invalid or unenforceable contract. See supra, Sec. 1479, and topics therein referred to.

83 Johnson v. Saum, 123 Iowa, 145, 98 N. W. 599; Goff v. Gott, 5 Sneed, 562; supra, Sec. 94, ad fin. Cf. Hendricks v. Goodrich, 15 Wis. 679.

ices have been transferred, and that neither they nor traceable products of them are in existence, but that, nevertheless, a pecuniary benefit has been received from their use. It may be argued with great force that on principles of quasi-contract, recovery of the value of this benefit should be permitted; but it may be replied that to allow such recovery is, in effect, to force a bargain upon an innocent defendant for what he may not have desired to buy on such terms.84 In spite of the latter argument it seems the lesser evil, if the plaintiff has been guilty of no negligence, to allow recovery of the value of the benefit received to the extent that the services or property have been of direct pecuniary advantage to the recipient. That is, if he has made or saved money from what he received, e. g.if he would have bought similar property at the market price had he not received that in question, he should pay the value to him of what he has acquired.