There must be a principal debtor liable, otherwise the promise becomes an original contract; and, the promise being collateral, the surety must be bound to no greater extent than the principal. Surety- ship is one of the contracts included in the statute of frauds; 29 Car. II. c. 3. The contract must be supported by & consideration, like every other promise. Without that, it is void, apart from the statute of frauds, and whether in writing or not; 4 Taunt. 117: 17 Pa. 469; 43 III. App. 584: 36 Kans. 205. Kent, C. J., divides sccondary undertak- ings into three classes: 1. Cases in which the guaranty or promise is collateral to the principal contract, but is made at the same time and becomes an essential ground of the credit given to the principal or direct debtor. Here there is not, and need not be, any other consideration than that moving between the creditor and original debtor. 2. Cases in which the collateral undertaking is subsequent to the creation of the debt, and was not the inducement to it, though the subsisting liability is the ground of the promise without any distinct and unconnected inducement. Here there must be some further consideration shown, having an immediate respect to such liabil- ity; for the consideration for the original debt will not attach to this subsequent promise. 3. When the promise to pay the debt of another arises out of some new and original consideration of benefit or harm moving between the newly con- tracting parties. The two first classes of cases are within the statute of frauds; the last is not: 8 Johns. 29. This classifi- cation has been reviewed and affirmed in numerous cases; 21 N. Y. 415; 15 Pick. 159. The rule that the statute does not apply to class third has, however, been doubted; and it appears to be admitted that the principle is there inaccurately stated. The true test is the nature of the promise, not of the consideration; 50 Pa. 39; 94 E. С. L. R. 835. But see infra. A simpler division is into two classes. Where the principal obligation exists before the collateral undertaking is made. Where there is no principal obligation prior in time to the collateral undertaking. In the last class the principal obligation may be contemporaneous with or after the collateral undertaking. The first class includes Kent's second and third, the second includes Kent's first, to which must be added cases where the guaranty re- ferring to a present or future principal obligation does not share the consideration thereof, but proceeds on a distinct consider- ation. Moreover, there are other original un- dertakings out of the statute of frauds and valid though by parol, besides his third class. These are where the credit is given exclusively to the promisor though the goods or consideration pass to another. Under this division, undertakings of the first class are original: 1. When the prin- cipal obligation is thereby abrogated. 2. When without such abrogation the prom- isor for nis own advantage apparent on the bargain undertakes for some new con- sideration moving to him from the prom- 3. Where the promise is in con- sideration of some loss or disadvantage to the promisee. 4. Where the promise is made to the principal debtor on a consider- ation moving from the debtor to the prom- isor; Theob. Sur. 37. 49. The cases under these heads will be considered separately. зее. First, where the principal obligation is pre-existent, there must be a new consider- ation to support the promise; and where this consideration is the discharge of the principal debtor, the promise is original and not collateral, as the first requisite of a collateral promise is the existence of a principal obligation. This has been held in numerous cases. The discharge may be by agreement, by novation or substitution, by discharge on final process, or by for- bearance under certain circumstances; 4 B. & P. 124; 21 N. Y. 412; 8 Gray 281 But the converse of this proposition, that where the principal obligation re- mains, the promise is collateral, cannot be sustained, though there have been repeated dicta to that effect; Browne, Stat. Fr. S 193; 12 Johns. 291; denied in 21 N. Y. 415; 7 Ala. N. S. 54; 33 Vt. 132. The main question arising in cases under this head is whether the debtor is dis- charged; and this is to a great extent a question for the jury. But if in fact the principal debt is discharged by agreement and the new promise is made upon this consideration, then the promise is original, and not collateral; 1 Allen 405. But where there is an existing debt, for which a third party is liable to the prom- isee, and the promisor undertakes to be responsible for it, still the contract need not be in writing if its terms are such that it effects an extinguishment of the original liability; 160 Mass. 225. A discharge of the debtor from custody, or surrender of property taken on an exe- cution, is a good discharge of the debt: 11 M. & W. 857; 9 Vt. 137; 4 Dev. 261; 21 Ν. Υ. 415; 34 Barb. 97. Where the transactio