Printed abridgments and printed indexes, both of persons and of places, applicable to each county in Scotland, in the form heretofore in use in the General Register House, or in such other form as may from time to time be prescribed by the Lord Clerk Register, shall, from and after the discontinuance of all the particular registers of sasines directed to be discontinued as aforesaid, be prepared under the superintendence of the keeper of the general register of sasines, and as nearly as possible contemporaneously with the minute books and volumes of the register; and such indexes shall be consolidated from time to time for such periods as may be deemed expedient: Provided always, that it shall be lawful at any time for the Lord Clerk Register, if he shall think fit, to direct that abridgments shall cease to be prepared separately from the minutes, and in that case, and in lieu of the preparation and printing of said abridgments, the minutes shall be printed under the superintendence of the keeper of the general register of sasines, in lieu of printing such abridgments.