54 HARVARD LAW REVIEIV.
change for a quid pro quo was, before Slade's case,^ chargeable only in Debt unless he made a second promise to pay the debt
It was only by degrees that the scope of the action was en- larged. The extension was in three directions. In the first place, Indebitatus Assumpsit became concurrent with Debt upon a simple contract in all cases. Secondly, proof of a promise implied in fact, that is, a promise inferred from circumstantial evidence, was at length deemed sufficient to support an action. Finally, Indebi- tatus Assumpsit became the appropriate form of action upon con- structive obligations, or quasi-contracts for the payment of money. These three developments will be considered separately.
Although Indebitatus Assumpsit upon an express promise was valuable so far as it went, it could not be resorted to by plaintiffs in the majority of cases as a protection from wager of law by their debtors. For the promise to be proved must not only be express, but subsequent to the debt. In an anonymous case, in 1572, Manwood objected to the count that the plaintiff ** ought to have said quod postea assumpsit, for if he assumed at the time of the con- tract, then Debt lies, and not Assumpsit ; but if he assumed after the contract, then an action lies upon the assumpsit, otherwise not, quod Whiddon and Southcote, JJ., with the assent of Catlin, C.J., concesse- runtr ^ The consideration in this class of cases was accordingly described as a ** debt precedent" ^ The necessity of a subsequent promise is conspicuously shown by the case of Maylard v, Kester.* The allegations of the count were, that, in consideration that the plaintiff would sell and deliver to the defendant certain goods, the latter promised to pay therefor a certain price ; that the plaintiff did sell and deliver the goods, and that the defendant did not pay according to his promise and undertaking. The plaintiff had a verdict and judgment thereon in the Queen's Bench ; but the judgment was reversed in the Exchequer Chamber ** because Debt lies properly, and not an action on the case ; the matter proving a perfect sale and contract"
What was the peculiar significance of the subsequent promise? Why should the same courts which, for sixty years before Slade's case, sanctioned the action of Assumpsit upon a promise in con- sideration of a precedent debt, refuse, during the same period, to
1 4 Rep. 92 a. 2 Dal. 84, pi.
- Manwood v, Rurston, 2 Leon. 203, 204 ; supra, 16, 17.