Conclusiones ex tit. D. de rei vindicatione

51. For either a new species arises from them, or one has been added to another by the right of accession, or the things have been reduced into a mass.
52. In the first case, he who made the species—for example, mulsum honeyed wine from his own wine and another's honey—is the owner of the species, even if, as it seems, he did so in bad faith, so that a claim for his own material is denied to the other party.
53. However, an action on the facts will be given to him, or an action for theft, or a condictio furtiva a personal action for the recovery of stolen goods, so that one may not be enriched at another's loss.
54. In the second case, the rule obtains that the thing to which something has been added draws to itself that which was added.
55. Whence it follows that the owner of the principal thing acquires the accessory thing of another by the right of accession, so that the other party cannot claim it.
56. Which rule, however, is to be tempered by this distinction: one must see whether things joined by accession can be separated or whether they cannot.
57. If they can be separated—as if someone has patched his clothes with my purple cloth—because the prior materials remain and can easily be separated without damage, an action for exhibition is given to me, so that I may then claim my separated thing.
58. But if they cannot be separated—as if he has woven my purple cloth into his own garments—an action for exhibition will not be given, nor consequently a claim for the thing, but an action on the facts.
59. The same obtains in the third case, where things have been reduced into a mass.
60. For if separation is easy, as if lead has been joined to silver, an action for exhibition will be given so that one may be separated from the other, and afterwards a claim may be made.