The contract of indorsement (except in a few special instances elsewhere discussed) is in reality a double contract. There is first an executed contract operating to transfer to the indorsee such title to the chose in action as the indorser possesses, and secondly, an executory contract by which the indorser undertakes that the bill or note shall be paid at maturity.21 The liability of an indorser under such executory contract will be discussed in the next chapter.