Civil Code (Cap. 16), article 699

699. Where the thing forming the subject of a legacy is an indeterminate movable thing included in a genus or species, suc h legacy is valid, even though no thing pertaining to such genus or species existed in the estate of the testator at the time of th e will or is found to exist at the time of the death of the testator. Where thing bequeathed is not found to exist in estate of testator.