RS40a John Brown & Son 2c Private Die Medicine Stamp, Bronchial Troches Boston

Scott RS40a, a 2c green proprietary revenue stamp issued for John I. Brown & Son of Boston, Massachusetts. The three-part design features wreath-style frames with the inscriptions "BROWN'S BRONCHIAL TROCHES," "UNITED STATES INTERNAL REVENUE," and "JOHN I. BROWN & SON - BOSTON, MASS."