PAROL CONTRACTS PRIOR TO ASSUMPSIT. 261 of the jury being treated as equivalent to a determination of the parties at the time of bargain. The ancient conception of a creditor's claim in Debt as analo- gous to a real right manifested itself in the rule that a plaintiff must prove at the trial the precise amount to be due which he demanded in his prcecipe quod reddat. If he demanded a debt of £20 and proved a debt of £<^y he failed as effectually as if he had declared in Detinue for the recovery of a horse and could prove only the de- tention of a cow.^ For the same reasons Debt would not lie fot money payable by instalments, until the time of payment of the last instalment had elapsed, the whole amount to be paid being regarded as an entire sum, or single thing.^ The quid pro quo which the debtor must receive to create his duty might consist of anything that the law could regard as a substantial benefit to him. Debts were usually founded upon a loan of money, a sale, a lease of property to the debtor, or upon work and labor performed for him. The quid pro quo in all these cases is obvious.^ The execution of a release by an obligee to an obligor was also a sufficient quid pro quo to create a new debt be- tween the same parties.* Forbearance to sue on a claim has been regarded in the same light : " for the forbearing of a suit is as bene- ficial in saving, as some other things would have been in gaining." ^ But Debt will not lie upon mutual promises. In Smith v. Airey^ Holt, C. J., said that "winning money at play did not raise a debt, nor was debt ever brought for money won at play, and an 1 Y. B. 3 Hen. VI. 4-4; Y. B. u Hen. VI. 5-9 ; Y. B. 21 Ed. IV. 22-2 ; Smith V. Vow, Moore, 298 ; Bagnall v. Sacheverell, Cro. El. 292 ; Bladwell v. Stiglin, Dy. 219; Baylis v. Hughes, Cro. Car. 137 ; Calthrop v. Allen, Hetl. 119; Ramsden's Case, Clayt. 87; Hooper v. Shepard, 2 Stra. 1089; Hulme v. Sanders, 2 Lev. 4. In Vaux V. Mainwaring, Fort. 197, i Show. 215 s. c, the distinction was taken that in In- debitatus Assumpsit the plaintiff might recover the amount proved, but in Debt the amount stated in the writ or nothing. But afterwards the plaintiflf was not held to a proof of the amount stated in the writ even in Debt. Aylett v. Lowe, 2 W. Bl. 1221 ; Walker v. Witter, Doug. 6 ; M'Quillin v. Cox, i H. Bl. 249; Lord v. Houston, 11 East, 62. See also Parker v. Bristol Co., 6 Ex. 706, per Pollock, C. B., and i Chitty, P. (7th Ed.) 127-128. 2 Rudder v. Price, i H. Bl. 547.
- If a bargain was for the sale of unascertained chattels, the transaction gave rise to
mutual debts, the reciprocal grants of the right to a sum certain of money and a fixed amount of chattels forming the quid pro quo for the corresponding debts. Y. B. 21 Hen. VI. 55-12 ; Anon. Dy. 30, pi. 301 ; Slade's Case, 4 Rep. 94 b. See supra, p. 259.
- Y. B. 12 Hen. IV. 17-13.
6 Bid well V Catton, Hob. 216.
- 2 Ld. Ray. 1034, 6 Mod. 128, Holt, 329 s. C.
