One of the principal classes of quasi contractual obligations in the Roman law was Negotiorum Gestio, a sort of "spontaneous agency" or justifiable intervention in another's affairs in his absence and without his authority. The doctrine was expounded in the Institutes of Justinian as follows:

"Thus, if one man has managed the business of another during the latter's absence, each can sue the other by the action on uncommissioned agency; the direct action being available to him whose business was managed, the contrary action to him who managed it. It is clear that these actions cannot properly be said to originate in a contract, for their peculiarity is that they lie only where one man has come forward and managed the business of another without having received any commission so to do, and that other is thereby laid under legal obligation even though he knows nothing of what has taken place. The reason of this is the general convenience; otherwise people might be summoned away by some sudden event of pressing importance, and without commissioning any one to look after and manage their affairs, the result of which would be that during their absence those affairs would be entirely neglected: and of course no one would be likely to attend to them if he were to have no action for the recovery of any outlay he might have incurred in so doing. Conversely, as the uncommissioned agent, if his management is good, lays his principal under a legal obligation, so too he is himself answerable to the latter for an account of his management; and herein he must show that he has satisfied the highest standard of carefulness, for to have displayed such carefulness as he is wont to exercise in his own affairs is not enough, if only a more diligent person could have managed the business better." 1

Although retained in the modern Continental codes2 and in the law of Louisiana,3 this doctrine has never been adopted in its entirety by the common law. There are various cases, however, often regarded as diverse in principle, in which something like negotiorum gestio is recognized. The following is believed to be a safe generalization: One who, through a dutiful intervention in another's affairs, i.e. an intervention required by a sense of duty, though not by law, confers a benefit for which the recipient ought in justice to pay, is entitled to compensation.

1 Book III, Title XXVII, De Obligationibus Quasi ex Contractu, as translated in Scott, "Cases on Quasi-Contracts," p. 1.

2 See French Civil Code (English translation by Blackwood Wright), arts. 1372-75; Italian Civil Code (French translation by Prudhomme), arts. 1141-44; Spanish Civil Code (Falcon's ed.), arts. 1888-94; 2 Windschied, "Pandektenrecht," Sec. Sec. 430, 431.

3 Martin's Revised Civil Code, arts. 2295-99; Police Jury v. Hampton, 1827, 5 Mart. (N. S.) 389.

The essential elements of the obligation will first be considered upon principle, and then sundry instances in which it arises will be examined.