§ 100 Relation of the Possessor to the Thing Possessed
The second element in the corpus possessionis is the relation of the possessor to the thing possessed, the first being that which we have just considered, namely, the relation of the possessor to other persons. To constitute possession the animus domini must realise itself in both of those relations. The necessary relation between the possessor and the thing possessed is such as to admit of his making such use of it as accords with the nature of the thing and of his claim to it. There must be no barrier between him and it, inconsistent with the nature of the claim he makes to it. If I desire to catch fish, I have no possession of them till I have them securely in my net or on my line. Till then my animus domini has not been effectively embodied in the facts. So possession once gained may be lost by the loss of my power of using the thing; as when a bird escapes from its cage, or I drop a jewel in the sea. It is not necessary that there should be anything in the nature of physical presence or contact. So far as the physical relation between person and thing is concerned, I may be in possession of a piece of land at the other side of the world. My power of using a thing is not destroyed by my voluntary absence from it, for I can go to it when I will.
Some amount of difficulty or even uncertainty in coming to the enjoyment of a thing is not inconsistent with the present possession of it. My cattle have strayed, but they will probably be found. My dog is away from home, but he will probably return. I have mislaid a book, but it is somewhere within my house and can be found with a little trouble. These things, therefore, I still possess, though I cannot lay my hands on them at will. I have with respect to them a reasonable and confident expectation of enjoyment. But if a wild bird escapes from its cage, or a thing is hopelessly mislaid, whether in my house or out of it, I have lost possession of it. Such a loss of the proper relation to the thing itself is very often at the same time the loss of the proper relation to other persons. Thus if I drop a shilling in the street, I lose possession on both grounds. It is very unlikely that I shall find it myself, and it is very likely that some passer-by will discover and appropriate it.