6. A banker's general Lien is part of the Law Merchant, and is judicially noticed as such.

A banker has a general Lien over all securities deposited with him by his customer as a banker, for debts due to him by his customer without any specific appropriation.

But he has no Lien over securities placed in his hands for a special purpose. If he receives securities in such a way he undertakes to do what he is requested: and such an undertaking is quite inconsistent with the notion of a Lien.

If a banker takes a security payable at a future day, his Lien is gone. For taking the security payable at a distant day, is payment pro tempore, and an extinction of the debt: and no new debt arises until default is made in payment of the new security.