Under this principle a right of action may accrue by breach of a subsidiary promise, long before the defendant's main performance is due, and the subsidiary promise may be an implied one. In any case where the plaintiff's performance requires the codperation of the defendant, as in a contract to serve or to make something from the defendant's materials or on his land, the defendant, by necessary implication, promises to give this cooperation12 and if he fails to do so he is immediately liable though his only express promise is to pay money at a future day.13 So in a contract of life insurance a promise on the part of the company to accept the premiums is clearly implied in fact and a refusal to receive premiums is an immediate breach of contract.14 Indeed, it seems that there is generally in a conditional contract an implied promise not to prevent performance of the condition.15 Such prevention would city from the breach, in so far as the future was concerned, would be beset with difficulties. Those difficulties are the same in kind and no greater in degree than are frequently encountered in actions for personal injuries. Pierce v. Tennessee, etc., R. Co., 173 U. S. 1, 16, 19 Sup. Ct. 335, 43 L. Ed. 591; In re Stern, 116 Fed. 604, 607, 54 C. C. A. 60; East Tenn., etc., R. Co. 9. Staub, 7 Lea (Tenn.), 397, 406. Uncertainties that may arise from an inability to forecast correctly what the future has in store for a plaintiff whose rights have been invaded by a breach of contract or a tort do not suffice to convert his right of action into a contingent one or to bar him from recovery as of a matured and accrued claim."

12 See supra, 11293.

13 Lovell v. St. Louis Mut. L. Ins. Co., Ill U. S. 264, 274, 4 Sup. Ct. 390, 28 L. Ed. 423; Edwards v. Slate, 184 Mass. 317, 68 N. E. 342. See also supra, Sec. 1293; infra, J1361; Inchbald v. Western, etc., Co., 17 C. B. (N. S.).

Ford w. Tiley, 6 B. & C. 325, was dearly correctly decided under this principle. The defendant promised to make a lease to the plaintiff as soon as he should become possessed of the property, which was then under lease to a third party. The defendant before the expiration of the prior lease executed another to the same lessee, thereby preventing possession reverting to him at the expiration of the previous lease.

14 O'Neill v. Supreme Council, A. L. of H., 70 N. J. L. 410, 57 Atl. 463; Fischer v. Hope Ins. Co., 69 N. Y. 161. The contrary decisions of Porter v. American Legion, 183 Mass. 326, 67 N. E. 238, and Langan v. Supreme Council, 174 N. Y. 266, 66 N. E. 932, must be deemed erroneous.

15 United States v. Peck, 102 U. S. 64,26 L. Ed. 46; Peck v. United States, ibid.; Lovell v. St. Louis Mut. L. Ins. Co., 111 U. S. 264, 274, 4 Sup. Ct. 390, 28 L. Ed. 423; Knotts v. Clark Const. Co., 249 Fed. 181, 161 C. C. A. 217; Danforth v. Tennessee Ac. R., 93 Ala. 614, 11 So. 60; Gay v. Blanchard, 32 La. Ann. 497; McFarland v. Welch, 48 Mont. 196, 136 Pac. 394; Patterson v. Meyherhofer, 204 N. Y. 96, 97 N. E. 472; Cameron-Hawn Co. v. Albany, then be an immediate breach of contract, and if of sufficiently serious character damages for the loss of the entire contract might be recovered. As countermanding work may have the legal effect of prevention in this country,16 though it does not involve actual physical prevention, it would be a breach of contract on this theory at the time when a stoppage in the performance of the contract had been caused thereby.17 It may be argued that the principle of implied subsidiary promises explains satisfactorily the doctrine of anticipatory breach, and the argument has been stated by courts of the highest authority.18 In spite of the somewhat strained character of such an implication, the explanation would be acceptable, if it did not require such an implication to be made in all contracts - unilateral and absolute as well as bilateral and conditional.19