Section 301. Conveyance and record as evidence

1. The certificate of the
  acknowledgment or of the proof of a conveyance, or the  record,  or  the
  transcript  of  the record, of such a conveyance, is not conclusive, and
  it may be rebutted, and the effect thereof may be contested, by a  party
  affected thereby.
    2.  If  it appears that the acknowledgment or proof was taken upon the
  oath of an interested or incompetent witness,  the  conveyance,  or  the
  record  or  transcript  of  the record thereof, shall not be received in
  evidence until its execution is established by  other  competent  proof,
  except  in  a  case  where the title to the land conveyed or affected by
  such conveyance or instrument has passed to a subsequent purchaser for a
  valuable consideration.