The effect of a material modification of a contract agreed upon between the two adversary principals thereto without the consent of the sureties of one of such principals, is in some respects analogous to alteration, and requires a brief notice here. It is not usually a case of technical alteration, because the change is rarely made upon the face of the instrument; but in some respects the effect of such modification is the same as that of alteration. If one of two or more joint-parties to a contract is a surety, a modification of the contract made between his principal and the adversary party without the consent of the surety discharges the latter. The common form of modification exists where the principal obtains an extension of time by a valid contract.1 So extension of time discharges a guarantor.2 However, under a bond exacted by the government from a contractor under a public contract for the benefit of sub-contractors and material men, conditioned on the contractor's paying them " promptly," it has been held that the act of the material men in taking notes for thirty and sixty days does not discharge the surety.3 If A guarantees performance of a contract before it is made, he is released by a change in its terms from those guaranteed.4 In jurisdictions where A becomes a surety when X assumes A's debt to B, an extension of time given by B to X without A's consent discharges A.5 This principle does not, of course, apply where A does not under such circumstances become a surety, but remains primarily liable.6 If extension of time is relied upon as the alteration, there must be a binding contract for an extension. An implied contract for an extension of time will operate as a discharge as well as an express contract.7 An unenforceable promise to grant an extension does not, however, discharge the surety.8 Still less does mere delay, without any agreement therefor, discharge the surety in the absence of statute.9 In order that extension of time may operate as a discharge, the holder of the note must know when he contracts for the extension that one of the parties is a surety.10 If, however, he does not know of the fact of suretyship when he takes the note, but he does know of it when he grants the extension of time, he releases the surety.11 If the surety assents to the extension of time, he is not discharged thereby.12 Extension of time granted by a contract between the creditor and one co-surety does not discharge a non-consenting surety.13 If the creditor grants an extension of time and expressly reserves his right of action against the surety, the surety is held not to be discharged by such contract.14 To operate as a discharge, the contract to which the surety is a party must be modified. Thus a collateral contract for paying two per cent interest additional to that stipulated in the main contract does not release a surety on the main contract.15 A release of the principal debtor operates as a discharge of the surety,16 unless the creditor expressly reserves his right to hold the sureties.17

9 Cornell v. Nebeker, 58 Ind. 425; Zimmerman v. Rote, 75 Pa. St. 188.

10 Woollen v. Ulrich, 64 Ind. 120; Brown v. Reed, 79 Pa. St. 370; 21 Am. Rep. 75.

11 Harvey v. Smith, 55 111. 224.

12 Stephens v. Davis, 85 Tenn. 271; 2 S. W. 382.

13 Wait v. Pomeroy, 20 Mich. 425; 4 Am. Rep. 395.

1 Union, etc., Ins. Co. v. Hanford. 143 U. S. 187; Landon v. English, 75 111. App. 483; Bugh v. Crum, 26

Ind. App. 465; 84 Am. St. Rep. 307; 59 N. E. 1076; Schieber v. Traudt, 19 Ind. App. 349; 49 N. E. 605; Roberson v. Blevins, 57 Kan. 50; 45 Pac. 63; Murray v. Marshall, 94 N. Y. 611: Calvo v. Davies, 73 N. Y. 211; 29 Am. Rep. 130; Jenkins v. Daniel, 125 N. C. 161; 74 Am. St. Rep. 632; 34 S. E. 239; Watauga Bank v. Matson, 99 Tenn. 390; 41 S. W. 1062; Schroeder v. Kinney, 15 Utah 462; 49 Pac. S94: Gillett v. Taylor, 14 Utah 190; 60 Am. St.

Rep. 890; 46 Pac. 1099; Bank v. Jeffs, 15 Wash. 230; 46 Pac. 247; Parsons v. Harrold, 46 W. Va. 122;

32 S. E. 1002.

2 National Eagle Bank v. Hunt, 16 R. I. 148; 13 Atl. 115.

3 (United States Fidelity &) Guaranty Co. v. Brick Co., 191 U. S. 416. This holding was based upon the peculiar character of the covenant, the surety having no idea when he entered into the contract when the respective payments would fall due.

4 Page v. Krekey, 137 N. Y. 307;

33 Am. St. Rep. 731; 21 L. R. A. 409; 33 N. E. 311.

5 Herd v. Tuohy, 133 Cal. 55; 65 Pac. 139; Tuohy v. Woods, 122 Cal. 665; 55 Pac. 683; Schroeder v. Kinney, 15 Utah 462; 49 Pac. 894.

6 Denison University v. Manning, 65 O. S. 138; 61 N. E. 607.

7 Roberson v. Blevins, 57 Kan, 50; 45 Pac. 63.

8 Tatum v. Morgan, 108 Ga. 336, 33 S. E. 940; Bunn v. Bank, 98 Ga 647; 26 S. E. 63; Heenan v. How ard, 81 111. App. 629; Olson v Chism, 21 Ind. App. 40; 51 N. E. 373; Voris v. Shotts, 20 Ind. App. 220; 50 N. E. 484; Krupp v. Ritter Verein (Ky.), 53 S. W. 648; Har. burg v. Kumpf, 151 Mo. 16; 52 S. W. 19; Sully v. Childress, 106 Tenn. 109; 82 Am. St. Rep. 875; 60 S. W. 499.

9 Bull v. Coe, 77 Cal. 54; 11 Am. St. Rep. 235; 18 Pac. 808; Hall v. Pratt, 103 Ga. 255; 29 S. E. 764; Villars v. Palmer, 67 111. 204; Hall v. Bank, 5 Kan. App. 493; 47 Pac. 566; Forstall v. Fussell, 50 La. Ann. 249, 256; 23 So. 273, 1012; Gray v. Bank. 81 Md. 631; 32 Atl. 518; Colby Wringer Co. v. Coon, 116 Mich.

208; 74 N. W. 519; Hefferlin v. Krieger, 19 Mont. 123; 47 Pac. 638 Bank v. McAllister, 56 Neb. 188 76 N. W. 552; Eickhoff v. Eiken bary, 52 Neb. 332; 72 N. W. 308 Grier v. Flitcraft, 57 N. J. Eq. 556 41 Atl. 425; Bailey Loan Co. v Seward, 9 S. D. 326; 69 N. W. 58 Bank v. Matson, 99 Tenn. 390; 41 S. W. 1062; Weaver v. Rubra (Tenn. Ch. App.), 47 S. W. 171; Wallace v. .Richards, 16 Utah 52; 50 Pac. 804; First National Bank v. Parsons, 45 W. Va. 688; 32 S. E. 271.

10 Union, etc., Ins. Co. v. Han-ford, 143 U. S. 187; Gillett v. Taylor, 14 Utah 190; 60 Am. St. Rep. 890; 46 Pac. 1099; Parsons v. Har-rold, 46 W. Va. 122; 32 S. E. 1002.

11 Zapalac v. Zapp, 22 Tex. Civ. App. 375; 54 S. W. 938; Gillett v. Taylor. 14 Utah 190; 60 Am. St. Rep. 890; 46 Pac. 1099. 148

12 Williams v. Gooch, 73 111. App. 557; Barrett v. Davis, 104 Mo. 549; 16 S. W. 377; Kuhlman v. Leavens, 5 Okla. 562; 50 Pac. 171.

13 Merchants' Bank v. Bussell, 16 Wash. 546; 48 Pac. 242.

14 Hodges v. Land Co., 109 Ala. 617; 20 So. 23; Dean v. Rice, 63 Kan. 691; 66 Pac. 992; Bie Rapids National Bank v. Peters. 120 Mich. 518; 79 N. W. 891; Kaufman v. Rowan, 189 Pa. St. 121; 42 Atl. 25; Boston National Bank v. Jose, 10 Wash. 185; 38 Pac. 1026.

15 Stuts v. Strayer, 60 O. S. 384; 71 Am. St. Rep. 723; 54 N. E. 368.

l6 Union National Bank v. Grant. 48 La. Ann. 18; 18 So. 705; Commercial Bank v. Cunningham. 24 Pick. (Mass.) 270; 35 Am. Dec. 322.

17 Faneuil Hall National Bank v. Meloon. 183 Mass. 66; 97 Am- St. Rep. 416; 66 N. E. 410.