The appellant alleges five several errors as grounds for the reversal of the judgment. They are: (1) That the plaintiffs are not the real parties in interest, and for that reason are not the proper parties plaintiff in an action to foreclose this mortgage; (2) that the plaintiffs were not competent parties to declare the option to deem the whole principal sum due; (3) that oral evidence was incompetent to prove the assumption of the mortgage by the appellant; (4) that the finding that the appellant assumed the mortgage is contrary to the evidence of the defendant Eriis, who is the equitable owner of the debt secured by the mortgage, and he is entitled to no benefit to inure from an assumption of the debt by the appellant which he does not claim; and (5) that the. judgment for deficiency provided for will be unfair as against the appellant by reason of the omission therefrom of the defendant Botting, who is jointly liable for the debt, and should be included in the judgment for deficiency. 1. It is well settled that, as a general rule, the pledgee of a chose in action is entitled to bring an action on it in his own name, and to recover its entire amount. Curtis v. Mohr, 18 Wis. 615; Union Nat. Bank v. Roberts, 45 Wis. 373; Potter v. Stranslay, 48 Wis. 235; 18 Am. & Eng. Ency. of Law, 694.
2. The stipulation in the mortgage expressly gives to the assigns of the mortgage the right to exercise the option to deem the whole amount of the principal sum due, on default’ in payment of principal, interest, or taxes. The plaintiffs are such assigns, and within the express terms of the stipulation. ISTo reason is perceived why it should not be given effect according to its terms.
*2783. That parol evidence is incompetent to vary the terms of a written agreement is elementary. It is also elementary that this rule does not inhibit proof by parol of a different or greater consideration than is expressed in a conveyance. Such evidence does not tend to vary or impair the effect of the instrument as a conveyance of the title, which, alone, is its primary purpose. And, so far as it is a receipt for the purchase money, it is not within the rule; for a receipt may always be explained or contradicted by oral evidence. Rut in this case it is not attempted to prove a different or greater consideration than is named in the deed, but to show to whom it was to be paid. The evidence was clearly competent for the purpose within our own decisions. Kirkland v. Menasha Wooden Ware Co. 68 Wis. 34; Beckman v. Beckman, 86 Wis. 655, 660, and case's cited. The promise is not within the statute of frauds, as a promise to pay the debt of another. It is a promise to pay one’s own debt to a third person. Such promises are valid, and the person designated to whom the money is to be paid may maintain an action upon it in his own name. Dyer v. Gibson, 16 Wis. 557; Putney v. Farnham, 27 Wis. 187; Hoile v. Bailey, 58 Wis. 434; Grant v. Diebold S. & L. Co. 77 Wis. 72; Larson v. Cook, 85 Wis. 564; Wilson v. King, 23 N. J. Eq. 150; Remington v. Palmer, 62 N. Y. 31; Jones, Mortgages (5th ed.), § 750.
4. The proper force of the testimony of the defendant Eriis on the question of the assumption of the mortgage by the appellant is not clear. But it certainly shows no ground for denying to the plaintiffs such relief as is properly based upon the finding of such assumption. Whether it should operate to estop the defendant Eriis from claiming a benefit which may, in some contingency, accrue to him from that finding, it is not now necessary to decide.
5. Botting is not liable jointly with the makers of the note, but severally on his contract of indorsement. Kiel v. *279Choate, 92 Wis. 517. He was not a necessary party, even, to the foreclosure action. Jones, Mortgages, § 1394. But the appellant assumed and promised to pay the entire mortgage debt. It is the party which is ultimately liable to pay the whole debt. So judgment should properly go against it for whatever deficiency remains after application of the proceeds of the sale of the mortgaged premises to the payment of the mortgage debt.
No error is found either in the proceedings or in the judgment.
By the Court.— The judgment of the superior court of Milwaukee county is affirmed.