satisfied mortgage

It is undoubtedly well settled as a general principle, that a court of law will not permit an outstanding satisfied mortgage to be set up against the mortgagor... Yet the legal title is not technically released by receiving the money. This rule must then be founded on an equitable control exercised by courts of law over parties in ejectment. It would be contrary to the plainest principles of equity and justice, to permit a stranger, who had no interest in the mortgage, to set it up when it had been satisfied by the mortgagor himself, to defeat his title.