principle corn is reckoned to become a part of the soil in which
it is sown. But exactly as (according to what we said) a man
who builds on another's land can defend himself by 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 parch-
ment, 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 modi-
fied 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