Without prejudice to the present law and practice, any deed, instrument, or writing, whether relating to land or not, may, after having been read over to the granter, be validly executed on behalf of such granter, who, from any cause, whether permanent or temporary, is unable to write, by one notary public or justice of the peace subscribing the same for him in his presence and by his authority, without the ceremony of touching the pen, all before two witnesses, and the docquet thereto shall set forth that the granter of the deed authorised the execution thereof, and that the same had been read over to him in presence of the witnesses. Such docquet may be in the form set forth in Schedule I. hereto annexed, or in any words to the like effect.