purpose they were one with the paterfamilias. Justinian's Institutes tell us that the right of a slave to receive a binding promise is derived ex persona domini.[1] And with regard to free agents, the commentators said that in such instances two persons were feigned to be one.[2]
Such a formula, of course, is only derivative. The fiction is merely a convenient way of expressing rules which were arrived at on other grounds. The Roman prætor did not make innkeepers answerable for their servants because "the act of the servant was the act of the master," any more than because they had been negligent in choosing them. He did so on substantive grounds of policy—because of the special confidence necessarily reposed in innkeepers. So when it was held that a slave's possession was his owner's possession, the practical fact of the master's power was at the bottom of the decision.[3]
But when such a formula is adopted, it soon acquires an independent standing of its own. Instead of remaining only a short way of saying that when from policy the law makes a master responsible for his servant, or because of his power gives him the benefit of his slave's possession or contract, it treats him to that extent as the tort-feasor, possessor, or contractee, the formula becomes a reason in itself for making the master answerable and for giving him rights. If "the act of the servant is the act of the master," or master and servant are "considered as one person," then the master must pay for the act if it is wrongful, and has the advantage of it if it is right. And the mere habit of using these phrases, where the master is bound or benefited by his servant's act, makes it likely that other cases will be brought within the penumbra of the same thought on no more substantial ground than the way of thinking which the words have brought about.
I shall examine successively the English authorities with regard to agency in tort, contract, ratification, and possession. But some of those authorities are of equal importance to every branch of the proposed examination, and will prove in advance that the foregoing remarks are not merely hypothetical. I therefore begin with citations sufficient to establish that family headship was recognized as a factor in regal rights and duties; that this
