from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
INDEBITATUS ASSUMPSIT, remedies, pleadings. That species of action of
assumpsit, in which the plaintiff alleges in his declaration, first a debt,
and then a promise in consideration of the debt, that the defendant, being
indebted, he promised the plaintiff to pay him. The promise so laid is,
generally, an implied one only. Vide 1 Chit. Pl. 334; Steph. Pl. 318; Yelv.
21; 4 Co. 92 b. For the history of this form of action, see 3 Reeves' Hist.
Com. Law; 2 Comyn on Contr. 549 to 556; 1 H. Bl. 550, 551; 3 Black Com. 154;
Yelv. 70. Vide Pactum Constituae Pecuniae.