In the event that the testator is unable to speak, but is able to write, he may make a mystical will, on the express condition that the will shall be signed by him and written by him or by another, that he shall present it to the notary and to the witnesses, and that at the top of the act of suscription he shall write, in their presence, that the paper he is presenting is his will and shall sign. It shall be mentioned in the act of suscription that the testator has written and signed these words in the presence of the notary and the witnesses and, in addition, all that is prescribed by Article 976 and is not contrary to this article.
In all the cases provided for in this article or in the preceding articles, a sealed will in which the legal formalities have not been observed, and which is null as such, shall nevertheless be valid as a holographic will if all the conditions required for its validity as a holographic will are fulfilled, even if it has been qualified as a sealed will.