Though no other contract can be enforced except that which is represented by the written memorandum, subsequent oral agreement varying the terms of the contract may not be without effect. Admitting, as a court must admit, that the writing proves the only contract which can be enforced, any defence in pais to that contract can be shown which is not based on the enforcement of a parol agreement as such. It would be a defence to an action by A against B for breach of a contract evidenced by a memorandum that A refused to accept performance; and in a cross suit by B against A, even though by the terms of the-memorandum, A's obligation to perform on his part was expressly conditional on the receipt by him of B's performance which he had refused, A would not be allowed to insist on B's failure to perform the condition. If instead of refusing to receive performance, A had requested B to delay performance or had simply said he did not care for it at once, and had thereby caused B to fail to perform a condition, A for the same reason as before, would not be permitted to insist on B's failure to perform the condition. One who has caused a certain situation cannot rely upon it as an excuse for his failure to perform his own obligations27a It seems immaterial whether A had caused the situation by a positive oral agreement that B need not perform as the written memorandum specified, or had only requested or even permitted the changed performance without attempting to contract.28 If an oral agreement were made it

26Goss v. Lord Nugent, 5 B. 4 Ad. 67; Harvey v. Grabham, 6 A. & E. 74; Marshal v. Lynn, 6 M. ft W. 116. But see Morris v. Baron, [1918) A. C. 1, 25.

27 Per Parke, B., Marshall v. Lynn, M.&W. 116, 117. 27a See infra, Sec.Sec. 676 et seq. 28 The English decisions have in some would not be enforceable as a contract, but might nevertheless operate as a continuing cause for non-performance of the written agreement. It seems essential, however, that B could, and presumably would have performed the condition or obligation on his part, had it not been for A's action. Otherwise A has not caused B's failure to perform. Whether it be supposed

(1) That the plaintiff is seeking to enforce the contract and the defendant sets up as a defence that the plaintiff has not performed according to the terms of the original written memorandum; or, as less commonly happens,

(2) That the plaintiff is seeking to enforce the contract and the defendant to excuse himself from liability sets up an oral agreement or statement by which the performance for which the plaintiff sues was prevented, the principle is the same: form the contract according to its original tonus. Perhaps this should be qualified if the change of mind was so near the time for performance as to make performance extremely difficult for the other party. See Tyers v. Rosedale Co., L. R. 8 Ex. 305, L. R. 10 Ex. 195. So in Scheenichmidt v. Smith, 74 Minn. 224, 228, 77 N. W. 34, the court said: "This oral extension of the time of payment became no part of the contract so as to bind the parties. Because it was not in writing, as well as because there was no consideration for it, defendant might have repudiated it and demanded payment at any time. But in such case he could not declare the contract forfeited for nonpayment until the plaintiff had a reasonable time thereafter in which to make payment, because the failure to pay on due day was caused by the defendant's own conduct." See also White Oak Fuel Co. v. Carter, 257 Fed.; 54 Hirach Rolling Mill Co. v. Milwaukee etc. R. Co., 165 Wis. 220, 161 N. W. 741. In Thomson v. Poor, 147 N. Y. 402, 42 N. E. 13, the court said: "We know of no principle of law which will permit a party to a contract, who is entitled to demand the performance by the other party of some act within a specified time, and who has consented to the postponement of the performance to a time subsequent to that fixed by the contract, and where the other party has acted upon such consent, and in reliance thereon has permitted the contract time to pass without performance, to subsequently recall such consent and treat the nonperformance within the original time as a breach of the contract." In Marsh v. Bellow, 45 Wis. 36, 52; it is there said: "We are of the opinion that the waiver of payment at the time fixed m a contract for the sale of real estate, or the extension of the time for such payment, is not such a variation of the terms of the written contract as to exclude it from being received in evidence in a court of equity; and that in all cases where such waiver or extension of time has been given, either by parol or otherwise, and the purchaser has acted upon the faith of such extension or waiver, the courts have held the vendor bound by his contract." In Neppach v. Oregon & Cal. R. R. Co., 46 Or. 374, 395, 80 Pan. 482, the court said: "Conceding the law to be as contended for by the defendant, and that the oral extension agreement or contract was invalid as an executory contract, and did not change or modify the terms of the written agreement, it was, nevertheless, acted upon by the plaintiff and Himpel, and the defendant, cannot now assert its invalidity to their injury," and in the same case (46 Oreg. 374, 397) "A party to a contract for the sale of land who knowingly consents or agrees to a postponement of the performance by the other at the time specified of some stipulation for his benefit, cannot, after the other has acted upon such consent, avail himself of the default, and treat the contract as forfeited, although the performance of the stipulation at the time specified may have been made of the essence of the contract," citing: Smiley v. Barker, 83 Fed. 684, 28 C. C. A. 9; Longfellow p. Moore, 102 111. 289; Missouri, K. ft T. R. Co. v. Pratt, 64 Kan. 118, 67 Pac. 464; Stearns v. Hall, 9 Cush. 31; Scheerschmidt v. Smith, 74 Minn. 224, 77 N. W. 34; Sheridan v. Nation, 160 Mo. 27, 59 S. W. 972; Long v. Hart-well, 34 N. J. L. 116; Dodge v. Well-man, 1 Abb. Dec. 512: Fleming v. Gilbert, 3 Johns. 528; Wilber v. Paine,

To the extent that a failure to perform has been caused by either party he cannot take advantage of the non-performance. He may have caused merely temporary failure to perform, or he may have caused a permanent failure. Generally it will be only a temporary delay in performance which will be caused. One who requested or prevented performance when due may withdraw his request or cease his prevention, and on so doing, or in a reasonable time thereafter, the other party must give the performance promised by him unless the delay has operated to make performance impossible, or materially more burdensome.29 cases relied on a supposed distinction. In Ogle v. Vane, L. R. 2 Q. B. 275, L. R. 3 Q. B. 272, Blackburn, J., said: "The difference is between writing and binding one's self to wait." See also the following note.

29 In Hickman v. Haynee, L. R. 10 C. P. 598, the plaintiff had agreed to sell and the defendant to buy iron in the future. The defendant had requested, before the time for performance, an enlargement of the time for taking delivery. This was granted, but the defendant ultimately refused altogether to take the iron. In an action on the contract the defendant set up that the plaintiff was not himself ready and willing to perform the coo-tract at the time when performance was due according to the written memorandum. Reliance was placed to some extent on the fact that there was no agreement to forbear, but merely a voluntary forbearance, but it is hard to see that a mutual agreement, which was unenforceable, would have altered the decision. The court held that having induced the plaintiff to withhold delivery when it was due, the defendant could not insist afterwards that prompt delivery was a condition precedent, though before that time either party could have changed his mind and required the other to per-