In the civil law, the negotiorum gestor is one who, spontaneously and without authority, undertakes to act for another during his absence, in his affairs.
In cases of this sort, as he acts wholly without authority, there can, strictly speaking, be no contract, but the civil law raises a quasi mandate by implication, for the benefit of the owner in many such cases.
Nor is an implication of this sort wholly unknown to the common law. Where there has been a subsequent ratification of acts of this kind by the owner; and sometimes, when unauthorized acts are done, positive presumptions are made by law for the benefit of particular parties. For example, if a person enters upon a minor's lands and takes the profit's, in many cases the law will oblige him to account to the minor for the profits as his bailiff.
There is a case which has undergone decisions in our law, which approaches very near to that of negotionum gestorum. A master had gratuitously taken charge of, and received on board of his vessel a box, containing doubloons and other valuables, belonging to a passenger who was to have worked his passage but was accidentally left behind. During the voyage, the master opened the box in the presence of the passengers to ascertain its contents, and whether there were contraband goods in it; and he took out the contents and lodged them in a bag in his own chest in his cabin, where his own valuables were kept. After his arrival in port, the bag was missing. The master was held responsible for the loss, on the ground that he had imposed on himself the duty of carefully guarding against all peril to which the property was exposed by means of the alteration in the place of custody, although as a bailee without hire he might not otherwise have been bound to take more than a prudent care of them; and that he had been guilty of negligence in guarding the goods.
This entry contains material from Bouvier's Legal Dictionary, a work published in the 1850's.