If the defendant knew that the benefit which he received was given under such a mistake as would justify its recovery, he is liable without demand of restitution first being made upon him;85 and it seems that if ignorant of the facts at first, subsequent discovery of them subjects him to immediate liability.86 But if he remains ignorant of the facts, a demand is necessary before an action can be maintained.87 Without regard, however, to the question whether the plaintiff could bring action without a prior demand, it has been generally held that unless the defendant has been guilty of fraudulent concealment, the Statute of limitations begins to run from the time that a payment under mistake was made.88

84 In Concord Coal Co. v. Ferrin, 71 N. H. 33, 51 Atl. 283, 93 Am. St. Rep. 496, the plaintiff delivered coal to the defendant on the assumption that the defendant was to pay the reasonable value thereof in cash. The defendant received the coal on the assumption that its value was to be credited on a debt due the defendant from a third person. So far as appeared, neither party was negligent in its assumption. The court denied recovery of the fair value of the coal.

85 Sharkey v. Mansfield, 90 N. Y. 227, 43 Am. Rep. 161; Martin v. Home

Bank, 30 N. Y. App. Div. 498,52 N. Y.

5. 464, affd., 160 N. Y. 190, 54 N. E. 717; Varnum v. Highgate, 65 Vt. 416, 26 Atl. 628.

86 Sheppard v. Lang, 122 Ga. 607, 50

6. E. 371; Earle v. Bickford, 6 Allen, 549,83 Am. Dec. 651; Bishop v. Brown, 51 Vt. 330.

87 Freeman v. Jeffries, L. R. 4 Exch. 189; Worley v. Moore, 77 Ind. 567, 569; Sibley v. Pine County, 31 Minn. 201, 17 N. W. 337; Gillett v. Brewster, 62 Vt. 312, 20 Atl. 105; Stocks v. Sheboygan, 42 Wis. 315.