The often quoted rule that debts which were once enforceable through the medium of an implied promise, and which have thereafter been barred by some positive rule of law, may be revived by a new promise, was suggested by the reporter in the note to Wennall v. Adney.10 Such a rule had not previously been stated by the courts, but it has often been repeated subsequently as expressing the correct rule. The statement, however, is not wholly satisfactory. It is not perfectly clear what defences are included under the designation of a positive rule of law. Moreover, in at least one class of cases where it is well settled that recovery is allowed because of the new promise, the liability was never previously enforceable through the medium of an implied promise or otherwise. This is the case of a surety's promise to pay though a condition precedent to any liability on his part has never been performed.11 The rule itself professes no explanation why such cases should be excepted from the general principle requiring contemporaneous consideration to support a promise. It is an empirical classification, and doubtless in the main is accurate, but as has been indicated not entirely so.