257. Sub-mortgage of securities.

257.     Sub-mortgage of securities.

By implication of law, a mortgagee of securities has the right to sub-mortgage the securities to the extent of his own interest in them without an express agreement to that effect1. Any attempt to sub-mortgage beyond that extent is, however, inoperative, except where negotiable securities are taken in good faith and for value2 or where the sub-mortgagee has otherwise acquired a good legal title, and the original mortgagor can recover the securities from the sub-mortgagee upon payment of the amount due from him upon them3.