BARNES, J.
There is no ambiguity about the order except that it fails to state the name of the party from whom the goods were ordered. The order was filled by the National Medical Company and an invoice of the goods corresponding therewith was mailed to defendant and he accepted the goods and placed them on his shelves for sale, so that the ambiguity referred to was removed by the parties themselves.
The order in question, coupled with the acceptance thereof, constituted a written contract. Schultz v. Coon, 51 Wis. 416, 8 N. W. 285; Wiener v. Whipple, 53 Wis. 298, 10 N. W. 433; McQuaid v. Ross, 77 Wis. 470, 46 N. W. 892. By such contract the defendant agreed to pay the purchase price of the goods listed therein within ninety days from August 1, 1906. The defendant seeks to relieve himself from liability by showing a parol agreement with the agent who took the order, to the effect that defendant should be called upon to pay for only so much of the goods as he sold, and that he might return the unsold portion thereof at any time. The *22agreement was made, if at all, prior to tbe signing of the order. Stated in another way, the attempt is made to establish bv parol a commission contract in lien of the one of absolute sale found in the writing. It is important to the business world that written contracts should have stability. If,, in a case such as we have before us, without any attempt at reformation, a party may avoid the effect of the writing by showing that the making of the payment called for by the writing was contingent upon the sale of the goods, it is difficult to imagine a case where a written agreement would furnish any protection against evidence of contemporaneous parol agreements materially modifying the same. It is elementary law in this state.that, in the absence of fraud or mutual mistake, proof of antecedent or contemporaneous verbal agreements between the contracting parties cannot be received to alter or control their written agreement. A large-number of the cases so holding are cited in Jackowski v. Ill. S. Co. 103 Wis. 448, 454, 79 N. W. 757. The defendant does not claim that he did not read the order before signing or that he did not understand its contents or its legal effect, lie simply asserts that he relied on the agreement of the agent that the provision as to- payment would not be enforced unless he succeeded in selling the goods ordered. Defendant’s counsel stated to the court, in support of his right to- offer the evidence, that it was not offered to- vary the terms of the written contract, hut to prove other conditions to the contract not contained in the writing. The evidence, under the circumstances of this case, was just as improper for the purpose of adding to the contract as it was for the purpose of modifying it, but as a matter of fact it did modify the writing by substituting for the provision as to payment contained therein an entirely different provision. There are certain well-recognized exceptions to the general rule above stated, but we fail to see wherein the defendant has brought himself within any of those exceptions.
*23It is further urged that plaintiff pleaded a second cause of action in bis complaint, which was based on alleged parol agreements between the defendant and the agent who took the order, and that inasmuch as the plaintiff showed by his pleading that the entire contract was not contained in the writing he should not now be heard to assert the contrary. At the opening of the trial the plaintiff announced in open court that he abandoned his second cause of action and would make no claim thereunder. It does not appear that the defendant was misled to his detriment by such action or that the essential elements necessary to constitute an estoppel exist. It is •true that there is a rule of law which prevents a party from taking inconsistent positions in court. But where no wrong would be done to the court or to other parties by permitting a change of position, such change should on principle be allowed. Green Bay & M. C. Co. v. Hewitt, 62 Wis. 316, 327, 21 N. W. 216, 22 N. W. 588; Bigelow, Estoppel, 722, 723. If the plaintiff became satisfied that he could prove a cause of action set out in his complaint, by the introduction of incompetent evidence only, and therefore abandoned it, such conduct would not confer on the defendant the right to establish a defense to another cause of action by the introduction of- improper evidence.
The respondent further contends that no -recovery can be had because the plaintiff’s assignor, the National Medical Company, was a foreign corporation and bad not complied with the provisions of sec. 1770&, Stats. (1898), when the contract was made. The order was procured by an agent representing the corporation and was forwarded to it and filled, and the goods called for by the order were shipped from the vendor in Iowa to the vendee in Wisconsin. Transactions involving a physical transfer of merchandise from the possession and title of an owner in one state to the possession and ownership of a purchaser in another are interstate. The soliciting of the order for such goods is but an inherent *24part of tbe transaction, and tbe transaction in its entirety constitutes interstate commerce, to which sec. 1710b, Stats. (1898), basno application. Loverin, & B. Co. v. Travis, 135 Wis. 322, 115 N. W. 829; Elwell v. Adder M. Co. 136 Wis. 82, 116 N. W. 882.
Tbe notice of entry of judgment in this case was served on November 1, 1907. The notice of appeal, together with an undertaking thereon, was served on October 29, 1909. The undertaking was' executed by tbe United States Fidelity & Guaranty Company,-a foreign corporation, and was not accompanied with any certificate from tbe commissioner of insurance showing that it was authorized to transact tbe business of suretyship in Wisconsin at tbe time the undertaking was signed. On January 24, 1910, tbe respondent served on tbe attorneys for tbe appellant a notice of motion to dismiss tbe appeal because no sufficient undertaking was given or filed on said appeal. Such motion was beard at the time tbe case was orally argued, and upon such argument tbe appellant was permitted to file a certified copy of a certificate of authority issued to tbe surety and authorizing it to transact a surety business in tbe state of Wisconsin from March 4, 1909, to March 1, 1910.
See. 3052, Stats. (1898), requires the execution of an undertaking for costs by two sureties in order to render an appeal effectual for any purpose. Sec. 3065, Stats. (1898), provides that such undertaking shall be of no effect unless tbe sureties justify in a manner provided therein. See. 1966 — 33, Stats. (1898), empowers surety companies authorized to do business in Wisconsin to execute undertakings like tbe one in question. Sec. 1966 — 34, Stats. (1898), provides, among other things, that tbe certificate of the insurance commissioner, or a certified copy thereof, as to tbe authority of tbe surety company to transact business, shall be equivalent to tbe justification required of sureties by law. In Johnston v. Northwestern L. S. Ins. Co. 107 Wis. 337, 83 N. W. 641, *25mis court held that an undertaking by a surety company, wbicb was not accompanied by a certificate of authority to transact business in this state, or a duly certified copy thereof, was defective. It has been held under the statutes referred to that a service of a notice of appeal within the time limited by law that is not accompanied by any undertaking is not effective for any purpose, and that an undertaking could not be supplied after the time had expired within which the appeal might be taken. Munk v. Anderson, 94 Wis. 27, 68 N. W. 407; Haessly v. Secor, 135 Wis. 548, 116 N. W. 175. On the contrary, it has been held that undertakings' upon appeal which are defective because of imperfect justification of the sureties may be perfected in this court. Helden v. Helden, 9 Wis. 557; Smith v. C. & N. W. R. Co. 19 Wis. 89; Ulrich v. Farrington Mfg. Co. 69 Wis. 213, 214, 34 N. W. 89: Johnston v. Northwestern L. S. Ins. Co., supra; Oconto L. Co. v. Mosling, 122 Wis. 440, 100 N. W. 824; Haessly v. Secor, supra: The certificate which was here lacking furnished evidence of the authority of the surety company to sign the undertaking, and was by the statute made equivalent to the justification of sureties as required by law. Sec. 1966—34, Stats. (1898).
We conclude that under the decisions cited the appellant might properly be allowed to supply the certificate in question even after the time had expired within which to take the appeal.
By the Court. — The motion to dismiss the appeal is denied with $10 costs in favor of the respondent, the same to be offset against the costs taxed in favor of the appellant. The judgment appealed from is reversed, and the cause is remanded with directions to enter judgment oni the verdict in favor of the plaintiff and against the defendant for the amount due upon the first cause of action stated in the complaint.