This is a simple metal mask with an ether chamber surmounting it. The patient breathes air down through the variable orifice over the surface of ether and in through the variable orifice over the surface of ether and in through the inspiratory valve. Exhalation was by means of the expiratory valve placed in the centre of the mask. All channels are extremely small and would offer considerable resistance to respiration.Metal inhaler with shaped rim edgeEngraved by hand into side of mask: DEWEE'S ETHER / INHALER.. 1901. Stamped into side of mask: J.E. LEECO / PATD. NOV. 12-1901 / 400ether, inhaler, ramsay, dewee, leeco