Any instrument (whether executed before or after the commencement of this Act) expressed to be supplemental to a previous instrument, shall, as far as may be, be read and have effect as if the supplemental instrument contained a full recital of the previous instrument, but this section does not operate to give any right to an abstract or production of any such previous instrument, and a purchaser may accept the same evidence that the previous instrument does not affect the title as if it had merely been mentioned in the supplemental instrument.