of the things promised on the other side, and yet that a failure of the latter should not warrant a rescission of the contract.  Wherever one party has already received a substantial benefit under a contract of a kind which cannot be restored, it is too late to rescind, however important a breach may be committed later by the other side.  Yet he may be [334] excused from going farther.  Suppose a contract is made for a month’s labor, ten dollars to be paid down, not to be recovered except in case of rescission for the laborer’s fault, and thirty dollars at the end of the month.  If the laborer should wrongfully stop work at the end of a fortnight, I do not suppose that the contract could be rescinded, and that the ten dollars could be recovered as money had and received; 1 but, on the other hand, the employer would not be bound to pay the thirty dollars, and of course he could sue for damages on the contract. 2

But, for the most part, a breach of promise which discharges the promisee from further performance on his side will also warrant rescission, so that no great harm is done by the popular confusion of the two questions.  Where the promise to perform on one side is limited to the case of performance on the other, the contract is generally conditioned on it also.  In what follows, I shall take up the cases which I wish to notice without stopping to consider whether the contract was in a strict sense conditioned on performance of the promise on one side, or whether the true construction was merely that the promise on the other side was limited to that event.

Now, how do we settle whether such a condition exists?  It is easy to err by seeking too eagerly for simplicity, and by striving too hard to reduce all cases to artificial presumptions, which are less obvious than the decisions which they are supposed to explain.  The foundation of the whole matter is, after all, good sense, as the courts have often said.  The law means to carry out the intention of the parties, and, so far as they have not provided [335] for the event which has happened, it has to say what they naturally would have intended if their minds had been turned to the point.  It will be found that decisions based on the direct implications of the language used, and others based upon a remoter inference of what the parties must have meant, or would have said if they had spoken, shade into each other by imperceptible degrees.

Mr. Langdell has called attention to a very important principle, and one which, no doubt, throws light on many decisions. 1 This is, that, where you have a bilateral contract, while the consideration of each promise is the counter promise, yet prima facie the payment for performance of one is performance of the other.  The performance of the other party is what each means to have in return for his own.  If A promises a barrel of flour to B, and B promises him ten dollars for it, A means to have the ten dollars for his flour, and B means to have the flour for his ten dollars.  If no time is set for either act, neither can call on the other to perform without being ready at the same time himself.