It was not error to strike from the record on this appeal the charge of the presiding judge at the former trial. A mistrial having been ordered, the rulings of the judge presiding at that trial as to the admissibility of evidence offered before him are in no way determinative of the admissibility of like evidence upon a subsequent trial or of the defendant’s right to amend or need to amend his answer. There is no reason to suppose that the defendant would have been any less surprised by the rulings of Latham, S.J., concerning such evidence had there never been any former trial of the action.
The motion to amend, originally oral, was reduced to writing after the trial and inserted into the record. The oral ruling denying the motion was not so reduced to formal writing. There being no indication to the contrary, we assume that the written motion, so filed and now appearing in the record, is in the same terms as the oral motion. It states that the defendant “moves the court that it, in its discretion,” allow the defendant to amend his answer. (Emphasis added.) The record shows that, on objection by the plaintiff, this motion was denied, but the record does not show the reason, if any, given by the court for its ruling. The defendant now contends that, since the court did not state that the motion was denied in its discretion, we must deem it to have been denied on the ground that, as a matter of law, the defendant could not so amend his answer and, therefore, the ruling is reviewable by us.
This Court has repeatedly held that after the time allowed for answering a pleading has expired, as in this instance, such pleading may not be amended as a matter of right, but only in the discretion of the court. Hardy v. Mayo, 224 N.C. 558, 31 S.E. 2d 748; Cody v. Hovey, 219 N.C. 369, 14 S.E. 2d 30; Osborne v. Canton, 219 N.C. 139, 13 S.E. 2d 265; Biggs v. Moffitt, 218 N.C. 601, 11 S.E. 2d 870. Since the motion to amend was, by its very terms, directed to the discretion of the court and, as a matter of law, was necessarily so directed, we find no merit in the defendant’s contention. See Osborne v. Canton, supra. Since the motion to amend was denied in the dis*581cretion of the trial judge, his ruling is not reviewable in the absence of a clear showing of abuse of discretion, which does not appear on this record. See in addition to the authorities above cited: Service Co. v. Sales Co., 264 N.C. 79, 140 S.E. 2d 763; Crump v. Eckerd’s, Inc., 241 N.C. 489, 85 S.E. 2d 607.
There was no error in sustaining the objections to the proposed cross examination of the plaintiff’s witness relative to the plaintiff’s foregoing of an opportunity to receive “promotion money” in connection with the Charlotte Speedway, or in withdrawing from the consideration of the jury testimony of the defendant with reference thereto. The unamended answer asserts that credits should have been allowed upon the note because of “promotion money” received by the plaintiff in connection with its operations at the Danville and Concord Speedways, no claim being made in the answer to any credit as a result of the operations at the Charlotte Speedway. The proposed evidence, relating to operations at Charlotte, is a substantial variance from the defense so pleaded. It is elementary that proof without allegation is as unavailing as allegation without proof. Eason v. Grimsley, 255 N.C. 494, 121 S.E. 2d 885; Lucas v. White, 248 N.C. 38, 102 S.E. 2d 387; Poultry Co. v. Equipment Co., 247 N.C. 570, 101 S.E. 2d 458; Bank v. Caudle, 239 N.C. 270, 79 S.E. 2d 723; Wilkins v. Finance Co., 237 N.C. 396, 75 S.E. 2d 118, rehear, den., 238 N.C. 745, 76 S.E. 2d 164; McIntosh, North Carolina Practice and Procedure, 2d Ed., § 981. This principle applies to evidence offered to establish an affirmative defense not pleaded in the answer as truly as it does to evidence offered to show a cause of action not alleged in the complaint. Payment, or the right to a credit, upon a note is an affirmative defense. White v. McCarter, 261 N.C. 362, 134 S.E. 2d 612.
Furthermore, the testimony in question did not purport to show the receipt by the plaintiff of any “promotion money” in connection with its operation at the Charlotte Speedway. It purported to show that the Coca-Cola Company made certain payments direct to the Speedway Company in return for advertising rights granted by it to the Coca-Cola Company, and that the plaintiff, for this reason, gave up its opportunity to receive “promotion money” from the Coca-Cola Company. Even had the proposed amendment to the answer been allowed, it would have alleged only that the plaintiff agreed to credit the note with “promotion money” which it received. There is neither allegation nor proof that the plaintiff promised to exact from its suppliers all possible “promotion money” and that it would not, in the exercise of its own best business judgment, forego an opportunity to require such payments to it. The food and drink concessions at the Charlotte Speedway would be of little value if *582the speedway, itself, ceased to operate. The proposed testimony did not purport to show any interest of the plaintiff in the Charlotte Speedway, or in any payment to it, other than a desire to keep its concession rights alive and valuable.
The defendant also assigns as error the sustaining of the plaintiff’s objection to the offer in evidence of transcripts of adverse examinations of the president and auditor of the plaintiff. Since no part of these transcripts is included in the record before us, it cannot be determined from the record that the defendant was prejudiced by this ruling, even if it be assumed that the transcripts were competent. Therefore, this assignment cannot be sustained. Cooperative Exchange v. Scott, 260 N.C. 81, 89, 132 S.E. 2d 161; Service Co. v. Sales Co., 259 N.C. 400, 411, 131 S.E. 2d 9.
The defendant next contends that the court below erred in including in the instructions to the jury abstract principles of law not germane to the issues; namely, references to certain provisions of the Negotiable Instruments Law, G.S. 25-7, 25-20, 25-29 and 25-34. The defendant testified that he received no part of the loan for which the original note was given, that the amount of the renewal note, upon which this suit was brought, was blank at the time he signed it and that such blank was filled in thereafter by the plaintiff. In view of this evidence it was not error for the court to include these instructions in the charge to the jury. The defendant makes no contention that there was any error in the content of these instructions.
There is no merit in the assignment of error asserting that the court failed to state correctly the contentions of the defendant and failed to declare and explain the law arising on the evidence in accordance with G.S. 1-180. Specifically, the defendant complains that the court did not instruct the jury as to the contention that the plaintiff gave up its opportunity to receive “promotion money” at Charlotte and as to the contention that there was a collateral agreement between the parties that the defendant would not have to pay the note since it would be paid entirely by receipts of “promotion money.” Since the testimony concerning the plaintiff’s supposed relinquishment of its opportunity to receive “promotion money” at Charlotte was properly withdrawn from the consideration of the jury, no further instruction with reference thereto was required. The promise set forth in the note could not be contradicted or destroyed by parol testimony that the makers thereof would not be called upon to pay in accordance with the terms of the note. Bank v. Slaughter, 250 N.C. 355, 108 S.E. 2d 594; Manufacturing Co. v. McCormick, 175 N.C. 277, 95 S.E. 555; Cherokee County v. Meroney, 173 N.C. 653, 92 S.E. 616.
*583Other assignments of error have been waived by failure to present argument or cite authorities in support thereof in the defendant’s brief. We have nevertheless considered them and find no merit therein.
Moore, J., not sitting.