The validity of the note upon which the present action is brought is not denied; but the defendant relies upon the facts offered by him in evidence, as available in defence of the suit, either by way of set-off, or as proof of an agreement that the account of the defendant and his partners should be taken in payment of the note, as far as it would apply; or as a substitution of one contract for the other; or as an accord and satisfaction.
The case has been argued with much ability by the learned counsel for the defendant; but, after a careful examination, we are of opinion that the evidence does not support the prop*344ositions advanced by him. The defence rests either on the right of set-off, or on proof of an agreement between the parties. The defendant, therefore, must bring his case within the statute, or must establish an agreement to discharge one lebt by the other.
The right of set-off, while it admits the plaintiff’s cause of action, permits the defendant to introduce a claim against the plaintiff to meet the demand sued, in whole or in part. This species of defence, which is equitable in its character, is limited, by the statute, to mutual debts or demands between the plaintiff and defendant, and consequently does not embrace a case like the present. The account offered by way of set-off is not that of the defendant solely, but it is the account of himself and two others; and, reversing the situation of the parties, if a suit had been brought upon it against the plaintiff’s intestate, the note now in suit could not have been filed in set-off. And the reason is obvious. The contracting parties are different, whichever is plaintiff, and there is, therefore, that want of mutuality which the statute requires; and it is obvious that, if such set-off were allowed, a firm might be made to pay all the private debts of one of the partners. This right of set-off not being matter of agreement, a defence grounded upon it must fail, if not embraced within the provisions of the statute. Fuller v. Wright, 18 Pick. 403.
The counsel for the defendant, in answer to this objection, has argued, that the case may be brought under the Rev. Sts. c. 96, § 5, on the ground that the partners of the defendant assigned to him the account against the intestate. But such an assignment cannot be inferred from the assent of Stetson that the note might be applied to the account. The assignment must be proved to have been made by the other partners, and there is no evidence to establish it, or from which it can be legally inferred. The authorities cited for the defendant go far to show that an agreement to pay a joint debt, by a separate demand of the debtor against one of the joint creditors, may be sustained, as founded upon mutual promises. Kinnerley v. Hossack, 2 Taunt. 173, and Wallace v. Kelsall, 7 Mees. & *345Welsb. 264. 2 Stark. Ev. (2d Lond. ed.) 727. But the evidence in the present case establishes no such agreement. The proof stops short of the point which the defendant must reach, in order to enforce his argument with effect. The evidence is that of a mere intention expressed by Parker, the intestate, of turning his note in for the balance of the account; which was assented to by Coleman, one of the partners, if the fact were so, as all right, and to which, as he testifies, Stetson afterwards agreed; but there is no evidence that the fact was communicated to Boyden, the third partner, or that Parker was told that the note would be received in payment, and that, in consequence thereof, he then concluded a bargain. The proposal was, indeed, satisfactory, but through carelessness or inadvertency, it never ripened into an agreement; it remained to be executed, and it is now too late to enforce it. Allen v. Kimball, 23 Pick. 473.
The same remarks apply to the positions advanced, that here was the substitution of one contract for the other, or an accord and satisfaction. No such substitution, in fact, took place. There was no satisfaction, no delivery of the note, and no credit given in account. The proposed mode of settlement never was carried into effect, and the parties remained without any change as to their respective rights. We do not see that this case is different in principle from that of Cary v. Bancroft, 14 Pick. 315, where a similar agreement or proposal was held to be executory, and therefore was not an extinguishment of the smaller demand.
It is urged that there is great equity in the defence by reason of the hardship suffered by the defendant. But even if it were so, (though we do not view it in that light,) the rights of the parties are not thereby altered ; and the law must be enforced. Otherwise, cases would be determined without regard to well established principles, and rules of law would yield in all cases of supposed expediency.
It was also contended that the learned judge should have submitted the question to the jury, whether an agreement to pay one demand by the other was made by the parties. But, as *346there were no facts in dispute, it was the appropriate duty of the judge to instruct the jury whether the facts which were proved constituted an agreement, valid in law, between the parties ; and his instructions, we think, were correct.
Exceptions overruled.