the plea of fraud
when sued for the building by the owner of the land, so here too one who
has in good faith and at his own expense put crops into another man's
soil can shelter himself behind the same plea, if refused compensation
for labour and outlay.

33 Writing again, even though it be in letters of gold, becomes a part
of the paper or parchment, exactly as buildings and sown crops become
part of the soil, and consequently if Titius writes a poem, or a
history, or a speech on your paper and parchment, the whole will be held
to belong to you, and not to Titius. But if you sue Titius to recover
your books or parchments, and refuse to pay the value of the writing,
he will be able to defend himself by the plea of fraud, provided that he
obtained possession of the paper or parchment in good faith.

34 Where, on the other hand, one man paints a picture on another's
board, some think that the board belongs, by accession, to the painter,
others, that the painting, however great its excellence, becomes part of
the board. The former appears to us the better opinion, for it is absurd
that a painting by Apelles or Parrhasius should be an accessory of a
board which, in itself, is thoroughly worthless. Hence, if the owner
of the board has possession of the picture, and is sued for it by the
painter, who nevertheless refuses to pay the cost of the board, he will
be able to repel him by the plea of fraud. If, on the other hand, the
painter has possession, it follows from what has been said that the
former owner of the board, [if he is to be able to sue at all], must
claim it by a modified and not by a direct action; and in this case,
if he refuses to pay the cost of the picture, he can be repelled by the
plea of fraud, provided that the possession of the painter be in good
faith; for it is clear, that if the board was stolen by the painter, or
some one else, from its former owner, the latter can bring the action of
theft.

35 If a man in good faith buys land from another who is not its owner,
though he believed he was, or acquires it in good faith by gift or some
other lawful title, natural reason directs that the fruits which he has
gathered shall be his, in consideration of his care and cultivation:
consequently if the owner subsequently appears and claims the land by
real action, he cannot sue for fruits which the possessor has consumed.
This, however, is not allowed to one who takes possession of land which
to his knowledge