Civil Code (Cap. 16), article 743

743. (1) Any alienation of the thing bequeathed whether in whole or in part, made by the testator, even though made by way of sale with the reservation of the power of redemption, or by way of exchange, shall operate as a revocation of the legacy in regard to the subject of the alienation, notwithstanding that such alienation be void, or simulated, or that the thing itself come again to belong to the testator. (2) The same rule shall apply if the testator has converted the thing bequeathed into another in such a manner that it has lost its previous form and designation. Where thing bequeathed perishes.