Ineffective dispositions.

The legacies shall not take effect:- (a) if the testator alienates the bequeathed thing; or (b) when the bequeathed thing is res extracommercium; or (c) when the testator transforms the bequeathed thing in such a way that it does not have either its original form or its denomination; or (d) where the testator has been dispossessed of the bequeathed thing by a person having a lawful title thereto or it has been wholly destroyed during the lifetime of the testator and the heir is not responsible therefore.