The Schimmelbusch mask is a device for delivering an anesthetic. The device was invented by Curt Schimmelbusch in 1890, and was used until the 1950s (though it is still applied in some developing countries). The device consists of a wire frame which is covered with several beds of gauze and applied to the patient's face over the mouth and nose. Then high-volatility anesthetic (usually diethyl ether or halothane, and historically chloroform) is dripped on it, allowing the patient to inhale a mix of the evaporated anesthetic and air. The device is designed to prevent the anesthetic from coming in contact with the patient's skin, where it can cause irritation.
It is an example of an Open anaesthetic breathing system (the other classifications being semi-open, semi-closed and Closed)