Ewing, Judge,
delivered the opinion of the court.
This was an action on a due bill executed by the plaintiff in error to Jabez Smith, deceased, for three hundred dollars, borrowed money. The answer sets up a verbal agreement between the defendant and Smith at the time the due bill was given, by which it is alleged that but half of the sum called for by it was to be paid by the defendant in a certain event.
The only point in this case that need be noticed is whether the verbal agreement relied on by the defendant was admissible as a defence to the action, and we are of opinion it was not. The instrument is in form a due bill, but in legal *310effect a promissory note, because it is an acknowledgment of indebtedness* which it is well settled implies a promise of payment. It being then a promissory note absolute on its face and complete in itself, was.parol evidence admissible to make it conditional or payable upon a contingency ? The defence is not that there is a want or failure of consideration, or that a fraud was practiced upon the defendant in respect to the transaction by Smith; but the question is whether effect shall be given to a contemporaneous oral agreement, by which the liability of the defendant is to pay one hundred and fifty instead of three hundred dollars; whether, in other words, he may by proof of a verbal understanding show that a contingency or condition not incorporated into the writing has happened, and in consequence thereof the debt is only half of what it purports to be by the due bill. I am unable to see any thing in the transaction that takes the case out of the operation of the general rule against admitting parol evidence to add to, vary or contradict a written instrument. This contract is sought to be controlled by an oral agreement, made concurrently with it, engrafting upon it a stipulation by which the absolute promise shall be a conditional one; and, instead of an agreement to pay the amount called for by the writing, the defendant proposes to show that, upon the failure of Todd to pay him that sum, he in that event only owes the plaintiff half the face of the note. If the rule adverted to does not apply in this and like cases, it is not easy to imagine a case to which it would apply. Whatever difficulty there may be sometimes in the application of the general principle to given cases, it does not exist in the class of cases to which the one under consideration belongs. For the cases are numerous of the application of the rule in actions on notes absolute on their face, where it has been attempted to control their effect by proof of a contemporaneous oral agreement, showing that payment was to be made on a condition. (Ransom v. Walker, 1 Stark. 361; Mosely v. Hariford, 10 B. & C. 729; Foster v. Jolly, 1 C. M. & R. 703; Adams v. Wordly, 1 M. & W. 378; Hunt *311v. Adams, 7 Mass. 518; Cotes v. Wakefield, 15 Pick. 437; 9 Metc. 41.) Hence a note payable on “ demand” or a specified day can not be varied in its operation by parol evidence of a verbal agreement that the principal should not be called for as long as the interest was punctually paid; (5 Pick. 506;) or tl>at it should be paid at another time or in any other mode than is imported on its face. (1 Chitty, 661; 3 Pair. 466; 4 Mass. 414.) A sum in which a note is made payable can not, consistently with the rule, be varied by parol except upon the principle of showing want, failure or fraud in the consideration. The same rule forbids evidence of a contemporaneous or anterior parol stipulation between the parties varying the legal effect of a note where no time of payment is specified. (8 John. 189; see also Jones v. Jeffries, 17 Mo. 578.) The general rule on this subject is too familiar to require a reference to authorities, and the cases cited are referred to as instances of the application of the rule to promissory notes alone, and to cases analogous to that under consideration.
The judgment is affirmed ;
the other judges concurring.