[CELSUS libro uicensimo tertio digestorum. ] §8.6.12.prQui fundum alienum bona fide emit, itinere quod ei fundo debetur usus est: retinetur id ius itineris: atque etiam si precario aut ui deiecto domino possidet: fundus enim qualiter se habens ita, cum in suo habitu possessus est, ius non deperit, neque refert, iuste nec ne possideat, qui talem eum possidet.
[CELSUS, from the twenty-third book of the Digests.] A person who has bought another's estate in good faith has used a right of way that is owed to that estate; that right of way is retained. This is also the case even if he possesses by precarious tenure, or after having dispossessed the owner by force. For when an estate is possessed in its own condition, just as it is, the right does not perish; nor does it matter whether he who possesses it in such a state possesses it lawfully or not.
quare fortius et si aqua per riuum sua sponte perfluxit, ius aquae ducendae retinetur, quod et Sabino recte placet, ut apud Neratium libro quarto membranarum scriptum est.
Therefore, all the more so, even if water has flowed through a channel of its own accord, the right to draw water is retained, which also rightly pleases Sabinus, as is written in the fourth book of Neratius's Parchments.