Before Parris's lawsuit against Railroad had settled, he left town and closed out his account with Bank. Railroad then issued a check to him which somehow came to be in Eddy's possession. Eddy indorsed the check "Railroad Eddy" and deposited it in his own account at Bank. Parris sued Bank, alleging that it was liable to him for having paid the check over an unauthorized indorsement. Is Bank liable to Parris? On what theory?