15. Wood v. Weimar, 104 U. S. 786, 26 L. Ed. 779; Clark v. Hy-man, 55 Iowa, 14, 39 Am. Rep. 160, 7 N. W. 386. But see Jewett v. Preston, 27 Me. 400.

16. 4 Wigmore, Evidence, Sec. 2476.

17. Aull v. Lee, 61 Mo. 160; Gilman v. Moody, 43 N. H. 239; Boody v. Davis, 20 N. H. 140, 51 Am. Dec. 210; Jackson v. Bowen, 7 Cow. (N. Y.) 13; Fowler v. Woodward, 26 Minn. 347, 4 N. W. 231; Nazoo v. Ware, 38 Minn. 443, 38 N. W. 359; Riggs v. Armstrong, 23 W. Va. 760.

18. It has been said, in this connection, that the description of the debt must be correct so far as it goes, and full enough to direct attention to the sources of correct information in regard to it, and be such a description of the debt as not to mislead or deceive as to its nature or amount. Bowen v. Ratcliff, 140 Ind. 393, 49 Am. St. Rep. 203, 39 N. E. 860; Goff v. Price, 42 W. Va. 384, 26 S. E. 287; Morris v. Murray, 82 Ky. 36.

19. Clark v. Hyman, 55 Iowa, 14, 39 Am. Rep. 160, 7 N. W. 386.

20. See Booth v. Barnum, 9 Conn. 286, 23 Am. Dec. 339; Merrills v. Swift, 18 Conn. 257, 46 Am. Dec. 315; Hightower v. Wray, 106 Tenn. 336, 61 S. W. 83.

21. See Storms v. Storms, 3 Bush, 77; Hightower v. Wray, 106 Tenn. 336, 61 S. W. 83. The mention of a consideration for the mortgage does not control the clause stating the sum intended to be secured. Keyes v. Bump's Adm'r, 59 Vt. 391, 9 Atl. 598;

Scott v. Thomas, 104 Va. 330, 51 S. E. 829.

22. Campbell v. Perth Amboy Shipbuilding & Engineering Co., 70 N. J. Eq. 40, 62 Atl. 319; Burne v Littlefield, 29 Me. 302.

23. Aull v. Lee, 61 Mo. 160.

24. Boody v. Davis, 20 N. H. 140, 51 Am. Dec. 210.

25. Jackson v. Bowen, 7 Cow. (N. Y.) 19.

26. Stearns v. Porter, 46 Conn. 313. See Doyle v. White, 26 Me. 341, 45 Am. Dec. 110. In Powell v. Huey, 241 111. 132, 89 N. E. 299,

Regarding the bond or note accompanying the mortgage as merely an evidence of personal liability or as collateral security for the debt secured by the mortgage, and not as itself constituting the obligation secured,27 the fact that the mortgage in terms undertakes to secure a note, which note is not executed, would seem to be immaterial if it clearly appears that the mortgage was intended to secure an actually existent debt.28 And so the fact that the mortgage describes the debt as evidenced by a note, while it is actually evidenced by a bond and not by a note, has been regarded as immaterial.29 And this seems a necessary consequence of the well settled rule,30 that a change in the form or evidence of indebtedness does not affect the security, the debt remaining the same.31

In order to aid in the interpretation and application of the language of the mortgage instrument descriptive of the debt secured, so as to determine whether a particular debt is to be regarded as included therein, extrinsic evidence as to the surrounding circumstances and the existing pecuniary relations between the parties is freely admitted,32 while in the absence of such such discrepancy was decided to be no defense to foreclosure.

27. Ante, this section, notes 95, 98

28. It is so decided in Lee v. Fletcher, 46 Minn. 49, 12 L. R. A. 171, 48 N. W. 456; Eacho v. Cosby, 26 Gratt. (Va.) 112; Murphy's Hotel Co. v. Herndon's Adm'r, 120 Va. 505, 91 S. E. 634. But see Og-den v. Ogden, 180 111. 543, 54 N. E. 750; Bramhall v. Flood, 41 Conn. 68; Leader Pub. Co. v. Grant Trust & Savings Co., 174 Ind. 192, 91 N. E. 498.

29. Scott v. Bailey, 23 Mo. 140. See Jackson v. Bowen, 7 Cow. (N. Y.) 13.

30. Post, Sec. 640(h).

31. See Seymour v. Darrow, 31 Vt. 122.

32. Gunn v. Jones, 67 Ga. 398; Babcock v. Lisk, 57 111. 327; Burne v. Littlefield, 29 Me. 302; Williams v. Hilton, 35 Me. 547, 58 Am. Dec. 729; Snow v. Pressey, 85 Me. 408, 27 Atl. 272; Johns v. Church, 12 Pick. (Mass.) 557, 23 Am. Dec. 651; Baxter v. Mcln-tire, 13 Gray (Mass.) 168; Williams v. Moniteau Nat. Bank, 72 Mo. 392; Boody v. Davis, 20 N. K. 140, 51 Am. Dec. 210; Jackson v. Bowen, 7 Cow. (N. Y.) 13; State Bank of Syracuse v. Lighthall, 46 evidence the mortgage can be regarded as security only for such debt as is clearly within the language used.33 And so extrinsic evidence is admitted for the purpose of identifying the obligation secured by the mortgage, even though it conflicts with some of the terms of the description of the obligation as set forth in the mortgage instrument.34 And it may thus be shown that though the mortgage secures a debt in general terms, it is in reality security for future advances.35 Likewise, since a mortgage can be enforced only for the debt actually secured,36 it may be shown that there is no debt as security for which it can be enforced,37 or that the actual debt is less than that expressed.38

Extension to other debts. A mortgage which is in terms security for a certain amount cannot, as against third persons, be extended by agreement between the mortgagor and mortgagee so as to cover a

N. Y. App. Div. 396, 61 N. Y. Supp. 794.

33. New v. Sailors, 114 Ind. 407, 16 N. E. 609; Bowen v. Ratcliff, 140 Ind. 393, 49 Am. St. Rep. 203, 39 N. E. 860.

34. Doe d. Duval's Heirs v. Mc-Loskey, 1 Ala. 708; Babcock v. Lisk, 57 111. 327; Aull v. Lee, 61 Mo. 160; Williams v. Hilton, 35 Me. 547, 58 Am. Dec. 729; Boody v. Davis, 20 N. H. 140, 51 Am. Dec. 210; Baxter v. Mclntire, 13 Gray 168; Hall v. Tefts, 18 Pick. (Mass.) 455.

35. Huckaba v. Abbott, 87 Ala. 409, 6 So. 48; Louisville Banking Co. v. Leonard, 90 Ky. 106, 13 S. W. 521; Farr v. Nichols, 132 N. Y. 327, 30 N. E. 834; Moses v. Hatfield, 27 S. C. 324, 3 S. E. 538. And ante, this section note 12.

36. Ante, Sec. 606, notes 69, 70.

37. Hannan v. Hannan, 123 Mass. 441; Saunders v. Dunn, 175 Mass. 164, 55 N. E. 893; Baird v. Baird, 145 N. Y. 659, 28 L. R. A. 375, 40 N. E. 222; Lucas v. Hen-drix, 92 Ind. 54; Miexsell v. Walton, 49 Kan. 255, 30 Pac. 410.

38. Vogan v. Caminetti, 65 Cal. 438, 4 Pac. 435; Rice v. Rice, 101 Kan. 20, 165 Pac. 799; Ruloff v. Hazen, 124 Mich. 570, 83 N. W. 370; Nazro v. Ware, 38 Minn. 443, 38 N. W. 359; Lee v. Fletcher, 46 Minn. 49, 12 L. R. A. 171, 48 N. W. 456; Burnett v. Wright, 135 N. Y. 543, 32 N. E. 253; Van De-venter v. Stiger, 25 N. J. Eq. 224; Mackey v. Brownfield, 13 Serg. & R. (Pa.) 239; Riggs v. Armstrong, 23 W. Va. 761; Heidtke v. Krause, 97 Wis. 118, 72 N. W. 351. But see Moffitt v. Maness, 102 N. C. 457, 9 S. E. 399.

3 R. P. - 10 greater sum advanced by the latter to the former.39 But, as between the parties to the mortgage, an agreement, made after its execution, that it shall be security for a debt other than that which it was first intended to secure, is effective,40 this constituting in effect an equitable lien on the land for such additional sum.41 Such a subsequent agreement must, by a number of cases, be in writing,42 though in at least two states it has been held that even if it is oral merely, the mortgagor, or a purchaser with notice, cannot redeem without repaying such other debt as well as that originally secured.43 It is obvious that

39. Schiffer v. Feagin, 51 Ala. 335, Fuller v. Griffith, 91 Iowa, 632, 60 N. W. 247; Hughes v. Wor-ley, 1 Bibb (Ky.) 200; Brown v. Hardcastle, 63 Md. 484; Mc-Gready v. McGready, 17 Mo. 597; Large v. Van Doren, 14 N. J. Eq. 208; McCaughrin v. Williams, 15 S. C. 505; Whitney v. Metallic Window Screen Mfg. Co., 187 Mass. 557, 73 N. B. 663 (attaching creditor without notice of agreement); Siter v. McClana-han, 2 Gratt. (Va.) 280; Pettis v. Darling, 57 Vt. 647; Barbour v. Tompkins, 31 W. Va. 410, 7 S. E. 1.

40. Wylly v. Screven, 98 Ga. 213, 25 S. E. 435; State Mut. Building & Loan Ass'n of New Jersey v. New Jersey & Millville Improvement Co., 74 N. J. Eq. 721, 70 Atl. 300, 76 N. J. Eq. 336, 75 Atl. 1101. This appears to be assumed in most of the cases cited in note 42 infra.

When the agreement is indorsed on the original instrument, and duly executed and delivered, it may operate as a new mortgage from the date of such delivery. Choteau v. Thompson, 2 Ohio St.

114. As to an indorsement of such an agreement upon a separate defeasance, see McClure v. Smith, 115 Ga. 709, 42 S. E. 53.

41. Post, Sec. 661.

42. Morris v. Alston, 92 Ala. 502, 9 So. 315; Hughes v. Johnson, 38 Ark. 285; Johnson v. Anderson, 30 Ark. 745; Fleming v. Georgia Railroad Bank, 120 Ga. 1023, 48 S. E. 420; Merrill v. Chase, 3 Allen (Mass.) 339; Jos-lyn v. Wyse, 5 Allen (Mass.) 62; Parkes v. Parkes, 57 Mich. 57, 23 N. W. 458; Stoddard v. Hart, 23 N. Y. 556; Thomas' Appeal, 30 Pa. 378; Lindsay v. Garvin, 31 S. C. 259, 5 L. R. A. 219, 9 S. E. 862; O'Neill v. Bennett, 33 S. C. 243, 11 S. E. 727. But see Ferry v. Meckert, 32 N. J. Eq. 38; Es-terly v. Purdy, 50 How. Pr. (N. Y.) 350, apparently to the effect that a written agreement is unnecessary.

43. Hayhurst v. Morin, 104 Me. 169, 71 Atl. 707; Joslyn v. Wyse. 5 Allen (Mass.) 62; Stone v. Lane, 10 Allen (Mass.) 74; Upton v. National Bank, 120 Mass. 153. See Whitney v. Metallic Window the mortgage creditor cannot, in the absence of any agreement to that effect, assert that the mortgage secures a debt other than that which it was made to secure.44