The questions raised by the exceptions relate either to matters of evidence, or to the refusal to instruct the jury as the plaintiff requested. It was the plaintiff’s contention, upon which in opening he rested his right to recover, that the deposit standing in the name of the intestate had been paid over in his lifetime on a check to which the signature had been forged, and consequently that the defendant must repay the amount. McIntosh v. Eliot National Bank, 123 Mass. 393. In support of the contention that the forgery had been accom*312plished, the check presented and payment procured through a conspiracy in which the intestate’s wife, who received the proceeds participated, she was called as a witness by the plaintiff. If later in the trial it appeared from the evidence of the defenddant’s witnesses, that she received the money directly from her husband, who previously had cashed the check, it was entirely competent for the plaintiff to show, if he could, that she actually had obtained it by unlawful means. It appeared from her testimony, that after having been received the money had been deposited in another trust company, and then withdrawn some two months later, and used for the payment of rent and household expenses. The further question then put was, as to where she had kept the money while it was being spent. No doubt it is well settled in the law of evidence, as the plaintiff contends, that presumptions or inferences of fact may be drawn from the proof of other facts. But, if the charge was a conspiracy in which the witness was said to have participated, yet, upon the plaintiff’s theory, the illegal purpose having been accomplished when the defendant paid over the money, it is manifest that the conduct of the witness as to its custody some two months after became immaterial, and the question even under the offer of proof was excluded rightly. Commonwealth v. Meserve, 154 Mass. 64, 70.
The refusal to permit the examination of the defendant’s actuary, by putting material leading questions, if placed upon the common law ground of hostility of the witness, was discretionary. If based upon R. L. c. 175, § 22, which confers upon either party to a suit the right to call and cross-examine his adversary, the answer is, that the witness was not a party, although an officer of the defendant company. Emerson v. Wark, 185 Mass. 427, 429. By R. L. c. 173, § 61, where a corporation is the adverse party ample provision is made for the examination by written interrogatories of its officers as if they were principals, and until further legislation this method must be treated as exclusive. The plaintiff, moreover, not only previously had interrogated the witness under the statute, but later, upon his being called by the defendant, the plaintiff then was afforded an opportunity for extended cross-examination.
Upon the question of the mental capacity of the decedent and *313the genuineness of his signature, the evidence was conflicting. Both parties introduced certain checks the signatures to which were admitted to be genuine, and these were used as standards of comparison by the respective handwriting experts. The order on the savings bank having been admitted as a standard, subsequently an expert called by the defendant, but who never had seen the decedent write, was permitted, subject to the exception of the plaintiff, to give his opinion based upon a comparison with the standards furnished by the checks, that the signature to the order was genuine. The argument, however, that this evidence was incompetent because an attempt to establish a standard by a witness without testimonial knowledge derived from seeing the decedent write, is inapplicable. If the decedent signed the order the day before he signed the check, this fact furnished some evidence of his ability to transact business, and that the check was issued by him. This testimony, therefore, was admissible, not as proof of a standard which could be used with the others by the jury upon the principal question,- but as the opinion of a qualified expert that the signature to the order was written by the same person who had signed the checks.
Ho error appearing either in the exclusion or admission of evidence, there remain the exceptions to a refusal to give the rulings requested. The check would have been complete if a payee had been named. But at common law, by which the rights of the parties must be ascertained, unless issued by the maker no authority was given either to the person presenting the check, or to the defendant to complete the instrument by writing in the name of the bearer as payee, and its unauthorized payment would constitute no defense against a subsequent claim for .the amount by the depositor. Crutchly v. Mann, 5 Taunt. 529. Ives v. Farmers' Bank, 2 Allen, 236, 240. See Boston Steel & Iron Co. v. Steuer, 183 Mass. 140, 145. But while the first and third requests which embodied this distinction were denied, the plaintiff suffered no prejudice. In the instructions given, the jury were told in various forms of expression, that the liability of the defendant had not been discharged unless the money was paid out by the authority of the decedent, which was explained as meaning, that being of suffi*314cient intelligence he made and delivered the check to some one who lawfully took it to the trust company, and received the money. Graham v. Middleby, 185 Mass. 349.
The refusal to grant the second request, although presenting a question of more difficulty, was right. It is urgently argued, that if the intestate presented the check when insane, the plaintiff as his administrator can avoid the transaction, and recover the amount in the present action, even if the defendant cannot he restored to its original status. Seaver v. Phelps, 11 Pick. 304. Gibson v. Soper, 6 Gray, 279. Chandler v. Simmons, 97 Mass. 508. Brigham v. Fayerweather, 144 Mass. 48, 51. Atwell v. Jenkins, 163 Mass. 362, 363. But while great mental weakness of the individual may exist without being accompanied by an entire loss of reason, and mental incapacity in one case is not necessarily so in another, in such an inquiry the true test is, was the party whose contract it is sought to avoid in such a state of insanity at the time as to render him incapable of transacting the business. When this fact is established the contract is voidable by the lunatic or his representatives, and it is no defense under our decisions that the other party acted fairly and without knowledge of his unsoundness or of any circumstances which ought to have put him upon inquiry. Sever v. Phelps, ubi supra. Brigham v. Fayerweather, ubi supra. Compare Molton v. Camroux, 4 Exch. 17. Matthews v. Baxter, L. R. 8 Ex. 132, and Lawson on Contracts, (2d ed.) § 161, n. 2, for a collection of the American cases.
But the present case does not fall within this general rule. Upon becoming a depositor the relation between the defendant and the decedent was that of banker and customer, or of debtor and creditor, and the company agreed on demand to repay to him, or to his order, the amount of the deposit. Heath v. New Bedford Safe Deposit & Trust Co. 184 Mass. 481. The contract had been made previously at a time when his sanity was unquestioned, and when the check was cashed he simply received his own in full measure according to its terms. By this transaction the parties did not enter into a new contract, because the act of payment of itself did not constitute an agreement, but was only the performance of the promise whereby the defendant discharged its indebtedness. In the absence of information as to *315his incapacity, no duty devolved upon the defendant to anticipate the use, or guard against any misuse, to which the intestate might put the money lawfully due and paid to him, and, if in the ordinary course of business, without any knowledge of his lunacy, the company honestly dealt with him, there is no sound legal or moral reason why the plaintiff should be permitted to disaffirm the payment.
Exceptions overruled.