The ether/chloroform mask was designed with cross-shaped bars, which supported gauze, and a thumbpiece. The mask was held by the thumbpiece over the patient's nose and mouth, and ether or chloroform was dripped into the gauze as an anaesthetic. Chloroform was generally favoured over ether because the latter acted quicker, smelled nicer, lasted longer and was not flammable.
The anaesthesia mask permitted the patient to directly inhale a gas, perhaps a mixture of ether, chloroform and oxygen, allowing the anaesthetic to work more quickly and effectively.
Both masks date from around the mid-nineteenth century.