(1)Where a bill or acceptance is materially altered without the assent of all parties liable on the bill, the bill is avoided except as against a party who has himself made, authorised, or assented to the alteration, and subsequent indorsers.Provided that,Where a bill has been materially altered, but the alteration is not apparent, and the bill is in the hands of a holder in due course, such holder may avail himself of the bill as if it had not been altered, and may enforce payment of it according to its original tenor.
