The device illustrated is a portable nitrous oxid-oxygen apparatus, embodying some of the points emphasized by Dr. Flagg (The Journal, Jan. 3, 1914, p. 35). The oxygen is admitted close to the face-piece, a feature which has been found of great practical value. The flow of oxygen is estimated by watching the bubbles of gas pass through water in a Woulfe bottle. It can be entirely shut off if desired by turning a cock on the face-piece; in this case the small bag placed between the cylinder and the bottle receives the gas till the cylinder can be closed. A more rapid flow of gas from the cylinder, with or without a shutting off of the nitrous oxid, suffices to give the patient all the oxygen ever required.
The holder for the cylinders consists of a board 15 inches long fitted with four loops of webbing for their reception. A