[PAULUS libro primo manualium. ] §17.2.83.prIllud quaerendum est, arbor quae in confinio nata est, item lapis qui per utrumque fundum extenditur an, cum succisa arbor uel lapis exemptus eius sit cuius fundus, pro ea quoque parte singulorum esse debeat, pro qua parte in fundo fuerat? an qua ratione duabus massis duorum dominorum flatis tota massa communis est, ita arbor hoc ipso, quo separatur a solo propriamque substantiam in unum corpus redactam accipit, multo magis pro indiuiso communis fit, quam massa? sed naturali conuenit rationi et postea tantam partem utrumque habere tam in lapide quam in arbore, quantam et in terra habebat.
[PAULUS, Opinions, book 1.] The following question must be asked: whether a tree which has grown on a boundary, and likewise a stone which extends through both properties, when the tree is cut down or the stone is dug out, since it belongs to him whose land it is, ought to belong to each owner in that proportion in which it had been in their land? Or, on the same principle as when two masses of metal belonging to two owners are melted together, the whole mass is common property, so the tree, by the very fact that it is separated from the soil and acquires a distinct substance reduced into one body, becomes common on an undivided basis, much more so than the mass of metal? But it is in accordance with natural reason that even afterwards each of them should have the same share both in the stone and in the tree as they had in the land.