By common consent and the usage of the commercial world, the certification of a check, or the acceptance of it by the bank at the instance of the payee, discharges the drawer of the check and substitutes the bank as a debtor.1 In other words, a novation takes place. The depositor owes his creditor, and the bank owes the depositor. The three agree that the bank may owe the creditor, and the depositor is discharged. The result is that so much of the depositor's account as corresponds to the accepted or certified check at once becomes the property of the bank;2 that is to say, the check is paid. But the same result as to the bank becoming entitled to so much of the depositor's account follows upon a certification granted to the drawer of the check; but in this latter case the transaction is a different one, because there is in fact no novation, there being no third party to the transaction. Hence such a certified check delivered to the payee is not payment of a debt between the drawer of the check and the payee.3 Upon both such descriptions of certified checks the bank becomes responsible to the payee, but with this difference: a certification granted to the drawer of the check, not being payment of any claim as between the drawer and the payee, and not being, therefore, a novation, may be revoked by the bank for a mistake as to the drawer's credit with the bank, except when the check has passed to a bona fide indorsee, or when the payee of the check has parted with value or suffered a detriment on the faith of the certification.4 The reasons for this rule are that the certification has been granted by a mistake of the bank. The drawer has no right to complain, because he knew that the official of the bank had no right to grant him a certification of his check when he had no sufficient credit with the bank. The payee of the check who has suffered no detriment, or his indorsee who did not pay value for the check, has no right to complain, because he has lost nothing by the certification.5 But where a certification has been granted to the payee or the indorsee of the check, the situation is wholly differ-ent. The debt owing by the drawer to the payee, for which the check was given, has been paid by the payee choosing to go to the bank and accepting its certification in lieu of the drawer's debt to him. A complete novation has taken place, and on the strength of the certification the payee has parted with full value, to wit: the debt or claim owing to him by the drawer of the check, which has been paid. To this transaction there were three parties; to the former transaction there were but two. Therefore,' a certification granted to a payee or a bona fide indorsee of a check is final and cannot be revoked.6 But here again courts have refused to see a plain distinction, and they are found holding, in spite of well-settled principles, that the bank may revoke its certification granted to the payee, where he has not altered his position and will lose nothing, as they say;7 a statement a check, forged as to the name of the drawer, only binds the bank as to the payee's loss upon it, is proper, because the bank cannot charge the check against the drawer. Herein lies the distinction between this case and that of certification to the payee, owing to a mistake as to the state of the account, spoken of in section 150, write. The bank is, of course, held as to a bona fide indorsee, for he relied upon the bank's certificate when he paid value. Even if a certified check has been stolen, a bona fide holder of negotiable paper is protected as against the bank.3 If the person obtaining the check to be certified had notice of the forgery, his conduct, it is plain, would be a fraud and he could claim nothing from the certification. If the holder of the check, however, believes it to be good and alters his position on the strength of the certification, he becomes a bona fide holder for value.4 But in the case of a holder who has lost nothing by the certification, the rule ordinarily would be, both thinking the check genuine, that the certification could be revoked on the ground of mutual mistake.5 The bank, it is true, is bound to know its drawer's signature, as it is bound to know the state of the drawer's account; yet the holder of the check has parted with nothing of value on the strength of the certificate.6 But there are cases where the bank can charge a check forged as to the maker's name against the maker.7 In such a case the bank, under any circumstances, ought not to be permitted to revoke its certification or to recover its payment, because it would otherwise charge the check against the drawer; yet the drawer would have paid nothing by the check.8 Therefore, in a suit between the bank and the holder to whom it had certified a check forged as to the drawer's name, there would necessarily be litigated the right of the matter as between the bank and the drawer of the check. So that the common sense of the matter is that certification of a check forged as to the maker's name, where the bank can charge the check against the- drawer, ought to bind the bank to the person to whom the certification was given or into whose hands the certified check came, if he were in good faith. The same rule would apply to a check paid, whatever the circumstances, where the forgery was of the drawer's signature.9 Such payment is final. But leaving out of view this exceptional case of a certified check, if the person to whom the check was paid was at fault,10 or did not perform his whole duty in the matter,11 the bank will not be estopped by its payment. These rules suffer some modification owing to the rules of clearing-houses and transactions between banks, as will appear in the next section. As regards the depositor, the bank cannot charge against him paper which he never signed.12 But the depositor may have been at fault in misleading the bank by his conduct prior to the time the bank paid the forged paper. In such a case, if his conduct amounts to an estoppel upon him, the bank may charge such checks against him.13 The depositor may also have been guilty of wrong conduct after the bank has paid the check. The majority of courts, basing their holding upon the proposition that the subsequent negligence of the depositor misleads the bank, recognize that a depositor owes to his banker the duty of examining the returned vouchers and at once notifying him of the forgery.14 The failure in this duty is said to be an implied admission of the genuineness of the signature,15 or a ratification of the payment.16 Even if the depositor commits this duty to an agent who happens to be the forger, the depositor is bound by the agent's act, either in not communicating his own