38 The usufructuary of a flock, as Julian held, ought to replace any of the animals which die from the young of the rest, and, if his usufruct be of land, to replace dead vines or trees; for it is his duty to cultivate according to law and use them like a careful head of a family.
39 If a man found treasure in his own land, the Emperor Hadrian, following natural equity, adjudged to him the ownership of it, as he also did to a man who found one by accident in soil which was sacred or religious. If he found it in another man's land by accident, and without specially searching for it, he gave half to the finder, half to the owner of the soil; and upon this principle, if a treasure were found in land belonging to the Emperor, he decided that half should belong to the latter, and half to the finder; and consistently with this, if a man finds one in land which belongs to the imperial treasury or the people, half belongs to him, and half to the treasury or the State.
40 Delivery again is a mode in which we acquire things by natural law; for it is most agreeable to natural equity that where a man wishes to transfer his property to another person his wish should be confirmed. Consequently corporeal things, whatever be their nature, admit of delivery, and delivery by their owner makes them the property of the alienee; this, for instance, is the mode of alienating stipendiary and tributary estates, that is to say, estates lying in provincial soil; between which, however, and estates in Italy there now exists, according to our constitution, no difference.
41 And ownership is transferred whether the motive of the delivery be the desire to make a gift, to confer a dowry, or any other motive whatsoever. When, however, a thing is sold and delivered, it does not become the purchaser's property until he has paid the price to the vendor, or satisfied him in some other way, as by getting some one else to accept liability for him, or by pledge. And this rule, though laid down also in the statute of the Twelve Tables, is rightly said to be a dictate of the law of all nations, that is, of natural law. But if the vendor gives the purchaser credit, the goods sold belong to the latter at once.
42 It is immaterial whether the person who makes delivery is the owner himself, or some one else acting with his consent.
43 Consequently, if any one is entrusted by an owner with the management of his business at his own free discretion, and in the execution of his commission sells and delivers any article, he makes the receiver its owner.
44 In some cases even the owner's bare will is sufficient, without delivery, to transfer ownership. For instance, if a man sells or makes you a present of a thing which he has previously lent or let to you or placed in your custody, though it was not from that motive he originally delivered it to you, yet by the very fact that he suffers it to be yours you at once become its owner as fully as if it had been originally delivered for the purpose of passing the property.
45 So too if a man sells goods lying in a warehouse, he transfers the ownership of them to the purchaser immediately he has delivered to the latter the keys of the warehouse.
46 Nay, in some cases the will of the owner, though directly only towards an uncertain person, transfers the ownership of the thing, as for instance when praetors and consuls throw money to a crowd: here they know not which specific coin each person will get, yet they make the unknown recipient immediately owner, because it is their will that each shall have what he gets.
47 Accordingly, it is true that if a man takes possession of property abandoned by its previous owner, he at once becomes its owner himself: and a thing is said to be abandoned which its owner throws away with the deliberate intention that it shall no longer be part of his property, and of which, consequently, he immediately ceases to be the owner.