From and after the commencement of this Act it shall be competent to any owner of lands to settle the succession to the same in the event of his death, not only by conveyances de praesenti, according to the existing law and practice, but likewise by testamentary or mortis causa deeds or writings, and no testamentary or mortis causa deed or writing purporting to convey or bequeath lands which shall have been granted by any person alive at the commencement of this Act, or which shall be granted by any person after the commencement of this Act, shall be held to be invalid as a settlement of the lands to which such deed or writing applies on the ground that the grantor has not used with reference to such lands the word “dispone,” or other word or words importing a conveyance de praesenti; and where such deed or writing shall not be expressed in the terms required by the existing law or practice for the conveyance of lands, but shall contain with reference to such lands any word or words which would, if used in a will or testament with reference to moveables, be sufficient to confer upon the executor of the grantor, or upon the grantee or legatee of such moveables, a right to claim and receive the same, such deed or writing, if duly executed in the manner required or permitted in the case of any testamentary writing by the law of Scotland, shall be deemed and taken to be F1valid as a settlement on a grantee or legatee of the lands to which it applies; and the executor of the grantor may complete title to such lands by expeding and recording a notarial instrument as aforesaid: Provided always, that nothing herein contained shall be held to confer any right to such lands on the successors of any such grantee or legatee who shall predecease the grantor, unless the deed or writing shall be so expressed as to give them such right in the event of the predecease of such grantee or legatee.