delivered the opinion of the Court:
1. Appellant’s first assignment of error is founded upon *386-the alleged insufficiency of the plaintiff’s own supporting affidavit, in that it was not made by the plaintiff, Anne W. Frazer, or her agent, as required by the rule.
- The affiant was the assignee of the demand, the beneficial owner, the real party at interest, and to recover his money was compelled to bring an action at law in the name of his assignor to his own use. Hayward, v. Andrews, 106 U. S. 672, 675; Glenn v. Marbury, 145 U. S. 499, 509.
Such actions were common when the rale was adopted, and it is inconceivable that it was intended to exclude the equitable owner—the real plaintiff—from its benefits, unless he could procure the affidavit to be made by his assignor.
In this case, it was specially appropriate that the affidavit should be made by the assignee, Sherman, because the facts •stated were peculiarly within his own knowledge, he having acted as the agent of the assignor in the transactions with the defendant that ended in the account stated.
2. Construed liberally, the affidavit of defense was not sufficient, and the court was right in granting the motion for judgment notwithstanding its recitals.
• It sets out no specific fact that .would constitute a defense to the plaintiff’s action. It relates only to the assignment of the interest in the "Mora claim,” and. the consideration therefor, which was made March 3,1896. That assignment is not a part of the cause of action. It is referred to in the plaintiff’s affidavit by way of introduction merely to the final settlement made November 4, 1897, wherein the account between the parties was stated and the promise made ■to pay the balance then found and agreed to be due.
After more than a year of mutual dealings, the parties met, settled their accounts and struck a balance in favor, of the plaintiff. That settlement the defendant accepted and certified to as correct; the debt so ascertained she promised to pay. The account stated became a new promise and raised up a new cause of action. Tolman v. Sprague, 12 Pet. 300, 333; 1 Am. & Eng. Encyc. of L., (2d Ed.), 456, and *387cases cited. The acceptance and acknowledgment of the balance stated are facts from which the law implies a promise to pay; and in this case the affidavit charges an express promise.
The account when so stated is prima facie correct, and can not be impeached save for fraud, error or mistake. Chappedelaine v. Dechenane, 4 Cranch, 306, 309; Perkins v. Hart, 11 Wheat. 237, 256; Hager v. Thompson, 1 Black, 80, 93; Wiggins v. Burkham, 10 Wall. 129, 132; Oil Co. v. Van Etten, 107 U. S. 325, 334.
The defense to an action upon an account stated must, therefore, relate to it, and hot to matters of anterior liability, except in so far as they constitute a foundation for, or introduction to, the real, substantial defense impeaching the settlement for fraud, or error and mistake.
It was clearly no defense to the new cause of action, notwithstanding it may have grown out of the transaction relating to the assignment of the “Mora claim,” for defendant to say: “ I never promised to give her any other consideration, either orally or in writing, for the assignment she made to me.” Granting the truth of that statement as to the transactions and as of the time referred to, is no impeachment of the fairness and correctness of the voluntary .settlement afterwards made of all matters of claim and counterclaim between the parties.
Nor is there any added strength in the further and concluding words of the affidavit: “ I do not owe her a cent arising out of this transaction or any other.” íhis is merely a conclusion of law from the foregoing statement of fact. It is not enough to say that one has a good defense to the action without exhibiting grounds of the same. Durant v. Murdock, 3 App. D. C. 114, 121.
Notwithstanding the affidavit of defense is not subject to the closeness of scrutiny or the strictness of construction that, for obvious reasons, is given to the affidavit of the plaintiff, yet sométhing more than vague and indefinite *388statements is always required; and especially is this the case where the specific grounds of defense, if any there justly be, must necessarily be within the actual-knowledge of the defendant. Chapman v. Coal Co., 11 App. D. C. 386, 391.
Finding no error in the record, the judgment must be affirmed, with costs; and it is so ordered.