L. R. A. 43; 154 Pa. 396; 44 Wis. 479. In common with other kinds of negotia- ble paper, they must contain an order to pay money, and words of negotiability. This enables a bona fide holder for value to collect the money without regard to the previous history of the paper; 16 Pet. 1; 20 Johns. 637; 42 Ala. 108. They must be properly signed by the per- son or firm keeping the account at the banker's, as it is part of the implied con- tract of the banker that only checks so signed shall be paid. The words "Agt. Glass Buildings" added to the signature of a check used for paying an individual debt of the agent, are enough to put the person receiving it on inquiry as to his authority to use the fund for such pur- pose; 14 L. R. A. 234, and note reviewing cases. Post-dated checks are payable on the day of their date, although negotiated beforehand. See 1 Vroom 284; 10 Wend. 804; 2 Story 502. Where all the parties to a check reside in the same place, the holder has until the day following its date in which to present it; 29 Weekly Notes Cases, Pa. 32. Checks, being payable on demand, are not to be accepted, but presented at once for payment. There is a practice, how- ever, of marking checks "good," by the banker, which fixes his responsibility to pay that particular check when presented, and amounts, in fact, to an acceptance; 10 Wall. 648. Such a marking is called certi- fying; and checks so marked are called certified checks. See 25 N. Y. 143; 73 Pa. 483. The bank thereby becomes the prin- cipal debtor; 52 N. Y. 850; 10 Wall. 648; to the holder, not the drawer; 39 Pa. 92; and the statute of limitation does not run against the check; 89 Pa. 92; and the certi- fying after delivery at payee's instance takes the amount thereof out of the hands of the maker, and any loss by the insolvency of the bank falls on the payee; 37 Ill. App. 475; 156 Mass. 458; but where certified to at maker's request he is not discharged from liability; 156 Mass. 458; 160 Mass. 401. The bank cannot refuse to pay because notified not to pay by the drawer; 12 Hun 537; nor generally can it set up that the check was forged, or that the drawer has no funds; Tiedm. Comm. P. 437; 18 Wall. 621. In New York, it is held that certifying a check warrants only the signature, and not the terms of the check; 67 N. Y. 458. See 40 Ill. App. 640; contra, 28 La. Ann. 189. The certification is in effect merely an accept- ance, and creates no trust in favor of the holder of the check, and gives no lien on any particular portion of the assets of the bank; 77 Hun 159. See CERTIFIED CHECK. Giving a check is not payment unless the check is paid; 1 Hall 56, 78; L. R. 10 Ex. 153; 99 Mass. 277; 4 Hun 639; 66 Ill. 851; 7 S. & R. 116. But a tender was held good when made by a check contained in a letter, requesting a receipt in return, which the plaintiff sent back, demanding a larger sum, without objecting to the nature of the tender; and receiving a check marked "good" is payment; 2 Dan. Neg. Inst. 559. A check cannot be the subject of a do- natio mortis causa, unless it is presented and paid during the life of the donor; because his death revokes the banker's authority to pay; 4 Bro. Ch. 286; 27 La. Ann. 465. But in such a case a check has been considered as of a testamentary char- acter; 3 Curt. Eccl. 650; and see 1 P. Wms. 441. There is a practice of writing across checks "memorandum," or "mem." They are given thus, not as an ordinary check, but as a memorandum of indebtedness; and between the original parties this seems to be their only effect. In the hands of a third party, for value, they have, however, all the force of checks without such word of restriction; 16 Pick. 535; 11 Paige 612; Story, Pr. Notes ยง.499. See INDORSEMENT.