I. The causes of action stated, are confessedly barred unless revived under section 2539, of the Code, which provides that “causes of action founded on contract are revived by an admission that the debt is unpaid, as well as by a new promise to pay the same. But such an admission or new promise must be ip writing, signed by the party to be charged thereby.” The admission or promise can only be proven by such writing, but when an admission or promise is so evidenced, other proofs are admissible to' show the writing, and that the debt admitted or promised to be paid is the particular debt sued upon. Penley v. Waterhouse, 3 Iowa, 445; Collins v. Bane, 34 Iowa, 385; Wise v. Adair, 50 Iowa, 104; Stout v. Marshall, 75 Iowa, 498. The allegation that Beardsley was at the time indebted to plaintiff in the sum of nine thousand dollars cannot be considered except as shown by the writing, because, as we have seen, the indebtedness can only be established by an admission or promise-in writing. To show a different indebtedness from that sued upon is immaterial. In determining whether the letter shows an admission that the debt is unpaid, or a promise to pay the same, we may consider the allegation that Wilcox was agent for the plaintiff, and that the interest was paid to him as such agent.
From these allegations and the letter, we have this state of facts: That on March 27, 1886, defendant paid to S. S. Wilcox, as agent for plaintiff, interest due and that was not due on nine thousand dollars. While it is possible that interest may be due from one party to another, without there being any indebtedness for the-principal upon which it accrued, such is seldom the *723case. In the absence of proof to tbe contrary tbe payment of interest warrants tbe conclusion that there is an indebtedness for tbe principal. When, as in this case, tbe payment is of interest due and not due, tbe evidence of an existing indebtedness is much more satisfactory. We are of tbe opinion that tbe letter, considered in the light of tbe fact of Wilcox’s agency, shows an admission of an indebtedness from defendant to plaintiff that is unpaid, and that if plaintiff can prove, as alleged, that tbe two notes in suit constitute a part of that indebtedness, tbe cause of action was revived by said letter. '
It follows from these conclusions that tbe judgment of tbe district court should be reversed.