J.P. Alexander
�189. By the principal debtor becoming the holder in due course.The instrument is discharged if,when it matures, the acceptor or maker is or becomes the holder, since the right to recovery upon the instrument and the liability to pay the instrument are coincident in one and the same person. In order that payment or coincidence of right and liability should operate as a discharge,it is essential that the instrument should have matured."A negotiable instrument is discharged when the principal debtor becomes holder of the instrument at or after maturity in his own right/''*''*An acceptor or maker may acquire it before maturity, as purchaser, and may then further negotiate it.The possession of a bill of exchange by the acceptor after it has been in circulation is prima facie evidence that it has been paid by him.*'-**And the possession of a promissory note by the maker is prima facie evidence that it has been paid by him.'*'*'' But where he admits the execution of the note,the burden of showing payment is on him."*^