By the Court,

Dixon, C. J.

It was competent for the cashier, as agent for the board of directors, to execute the promissory notes in question, and bind the bank by such execution. Rockwsll v. Elkhorn Bank, 13 Wis., 653. Whether then the cashier has prima facie authority by virtue of his office, or. whether absolute, or whether still, the party seeking to charge the bank through his act, must give evidence that he was expressly authorized by the board of directors, we need not now inquire. A subsequent ratification is equivalent to a previous expresss authority. Such ratification may be by mere silence *134and acquiescence, after knowledge of the transaction comes to the board. Bridge Company v. Phoenix Bank, 5 Cowen, 156; Hoyt v. Thompson, 19 New York, 207. Supposing an express authority necessary, and that it was not given, the fact of ratification is so fully admitted in the answer of the defendant bank, as to preclude all possibility of defense upon that ground. The board of directors received and appropriated the proceeds of the notes to the use of the bank; at least, they acquiesced, in such appropriation. They suffered the note to be several times renewed, and numerous payments of interest to be made. If it bad been their wish to repudiate, because the cashier bad exceeded bis authority, they should have done so at the outset by restoring the consideration for which the notes were'given, or, if that could not be done, by affording the plaintiff the earliest opportunity of redress. No man can avail himself of an unauthorized act to bis advantage, and then reject it to the injury of the other party. The benefit arising from ratification has its corresponding burden, and the parties thenceforth become reciprocally bound.

The articles of association, though offered for that purpose, did not prove that the cashier acted without authority. They are entirely consistent with the supposition that be was expressly authorized. Section one of article three declares, that the board of directors “ shall appoint such officers and agents as may be necessary for the transaction of the business of the association.” Under this provision, with the facts before us, the presumption, when necessary to be resorted to, would seem to be rather that there was, than that there was not, a previous express authority.

The objection to the notes on the ground of variance was of the most technical nature; and the court was right in permit-ing an instantaneous amendment. There was no proof, or plausible pretence even, that the defendants were actually misled to their prejudice ; and surprise at the decision of the court in such case, is no ground for refusing the amendment *135or postponing the hearing. Gillett vs. Robbins, 12, Wis., 239; Fisk vs. Tank, id., 301; Bonner vs. Insurance Co., 13 Wis., 683.

Beside not showing due diligence, the affidavit for a continance was defective in not showing a valid defense, Rule 22, Old Rules. Furthermore, the facts to which the absent witness was to be called, namely, that he, as cashier, had no express or implied authority to execute the notes, were, as we have already seen, inconsistent with the answer.

The application of the defendant, bank, for leave to amend its answer, was properly denied. It was not in furtherance of justice. Hot founded in mistake, and substantially changing the defense, it would have been a gross perversion of the discretionary powers of the court to have granted it. R. S., ch. 125, sec. 37. It would have been allowing the defendant at the trial, and without cause, to withdraw admissions deliberately made, and thus to compel the plaintiff to ask for delay.

The circulation of foreign currency is not prohibited in this state, and we have no statute indicating a policy adverse to it. Individuals may receive and disburse it as much as they please, and no reason is perceived why the banks may not. If they may receive and pay it out, they certainly may borrow and give their notes for it.

The act of New York, laws of 1850, chap. 172, that “ no corporation shall hereafter interpose the defense of usury,” repeals the usury law of that state as to corporations. Such is the opinion of the court of that state, and we do not differ with them. Per Comstock, Brown, Paige and Selden, J. J., in Curtis v. Leavitt, 15 New York, 85, 151, 228 and 255; and Insurance Co. v. Packer, 17 New York, 51. It is immaterial, therefore, to consider whether the notes are New York contracts or Wisconsin contracts.

It seems to us upon general principles applicable alike to all cases, that extrinsic or parol evidence is admissible to show the agreement extending the time of payment, notwithstanding it was not inserted in the receipt given for the collaterals. *136It is a clear mistake to suppose that the receipt is the contract upon which the collaterals were deposited. It does not purport to he, but was evidently given to show the nature of the transfer, that it was security, and not absolute. The contract upon which the transfer was made, or rather the consideration for it, is entirely omitted. It might, it is true, if the parties had chosen, have been inserted; but there is no rule of law compelling them to do so. When only part of an entire agreement is reduced to writing, the residue may be proved by extrinsic evidence. Jeffery v. Walton, 1 Starkie, 267 (2 E. C. L., 385); Coates v. Sangeton, 5 Md., 121; Knight v. Knotts, 8 Rich., Law, 35; 2 Parsons on Con., 66. If we look upon the receipt we cannot say what was the consideration for the deposit. It may have been one thing, or it may have been another; hence, to prove that the securities were given in consideration of further time upon the principal debt, does not vary or contradict the terms of the receipt It is no alteration of, or addition to a written contract.

The instructions to the jury upon this latter point were erroneous, and for that reason the judgment below must be reversed as to the defendants Hoover and Medbury, and a new trial awarded. As to the defendant, The Marine Bank of Milwaukee, the judgment is affirmed.