delivered the opinion of the Court::

There is no difficulty in construing this instrument. It is-plainly a present sale of fifty shares of the capital stock of the Big Laramie Land, Cattle and Improvement Company, for the - snm of $5000, upon the condition that the purchaser shall not notify the seller of his intention to return the stock sold, and claim repayment of the money paid therefor, and interest thereon at the rate of ten per cent per annum, less any dividends he may have received upon said stock, at least thirty days before the expiration o'f three years from the date of sale,, and return said stock to the seller at the expiration of three-years from the date of the sale; but if the purchaser shall give such notice, and so return the stock, then the seller shall repay him the $5000 paid for the stock, with interest thereon at the rate of ten per cent per annum, less any dividends he may have received upon the stock. Stated shortly, the sale is absolute if not rescinded as provided by the condition. It may be rescinded, but only by the doing of that which the condition provides, and this is wholly to be done by the purchaser. Until he has thus rescinded the sale, it stands, and he has no right to the purchase money. It is not a case of mutual and concurrent covenants, as is Clark v. Weis, 87 Ill. 438, cited by counsel for appellant. There, the contract was. that the seller should convey and the purchaser should pay, each promise being the consideration of the other, on or before a day named. But here the purchaser does not undertake-that he will rescind the contract by returning the stock, but the undertaking is solely by the seller, that he will repay if the purchaser shall return, etc.,—that is, of course, after he-shall return.

The rule is well settled that “where an act is to be performed" by the plaintiff before the accruing of the defendant’s liability under his contract, the plaintiff must aver in his declaration, and prove, either his performance of such condition precedent, or an offer to perform it, which the defendant rejected; or he may aver his readiness to fulfill the condition until the defendant discharged him from so doing, or prevented the execution of the matter which was to be performed by him.”” Chitty on Contracts, (11th Am. ed.) p. 1083, and cases cited. in note. See, also, Frey v. Johnson, 22 How. Pr. 316; Sanford v. Cloud, 17 Fla. 532; Williams v. Healey, 3 Denio, 363; Bank of Columbia v. Hagner, 1 Pet. 455; Thorpe v. Thorpe, 12 Mad. 465; Savage Manf. Co. v. Armstrong, 19 Me. 147; Brown v. Cannon, 5 Gilm. 174.

The rulings below were clearly right, and the judgment of the Appellate Court is therefore affirmed.

Judgment affirmed.