§ 103 The Acquisition of Possession
Possession is acquired whenever the two elements of corpus and animus come into coexistence, and it is lost so soon as either of them disappears. The modes of acquisition are two in number, namely Taking and Delivery. Taking is the acquisition of possession without the consent of the previous possessor. The thing taken may or may not have been already in the possession of some one else, and in either case the taking of it may be either rightful or wrongful. Delivery, on the other hand, is the acquisition of possession with the consent and co-operation of the previous possessor. It is of two kinds, distinguished by English lawyers as actual and constructive.243 Actual delivery is the transfer of immediate possession; it is such a physical dealing with the thing as transfers it from the hands of one person to those of another. It is of two kinds, according as the mediate possession is or is not retained by the transferor. The delivery of a chattel by way of sale is an example of delivery without any reservation of mediate possession; the delivery of a chattel by way of loan or deposit is an instance of the reservation of mediate possession on the transfer of immediate.
Constructive delivery, on the other hand, is all which is not actual, and it is of three kinds. The first is that which the Roman lawyers termed traditio brevi manu, but which has no recognised name in the language of English law. It consists in the surrender of the mediate possession of a thing to him who is already in immediate possession of it. If, for example, I lend a book to some one, and afterwards, while he still retains it, I agree with him to sell it to him, or to make him a present of it, I can effectually deliver it to him in fulfilment of this sale or gift, by telling him that he may keep it. It is not necessary for him to go through the form of handing it back to me and receiving it a second time from my hands. For he has already the immediate possession of it, and all that is needed for delivery under the sale or gift is the destruction of the animus through which mediate possession is still retained by me.244
The second form of constructive delivery is that which the commentators on the civil law have termed constitutum possessorium (that is to say, an agreement touching possession). This is the converse of traditio brevi manu. It is the transfer of mediate possession, while the immediate possession remains in the transferor. Any thing may be effectually delivered by means of an agreement that the possessor of it shall for the future hold it no longer on his own account but on account of some one else. No physical dealing with the thing is requisite, because by the mere agreement mediate possession is acquired by the transferee, through the immediate possession retained by the transferor and held on the other’s behalf. Therefore, if I buy goods from a warehouseman, they are delivered to me so soon as he has agreed with me that he will hold them as warehouseman on my account. The position is then exactly the same as if I had first taken actual delivery of them, and then brought them back to the warehouse, and deposited them there for safe custody.245
The third form of constructive delivery is that which is known to English lawyers as attornment.246 This is the transfer of mediate possession, while the immediate possession remains outstanding in some third person. The mediate possessor of a thing may deliver it by procuring the immediate possessor to agree with the transferee to hold it for the future on his account, instead of on account of the transferor. Thus if I have goods in the warehouse of A., and sell them to B., I have effectually delivered them to B., so soon as A. has agreed with B. to hold them for him, and no longer for me. Neither in this nor in any other case of constructive delivery is any physical dealing with the thing required, the change in the animus of the persons concerned being adequate in itself.247