A Combined Manometer and Safety Valve for Intratracheal Anæsthesia

capable of accurate adjustment and dosage, at the same time simple in construction, and as far as possible reliable in its action, they started experimenting in March of this year. The first piece of the apparatus to be taken in hand was the safety valve. Those familiar with the intratracheal method of administering anaesthetics well know that an efficient safety valve is a sine qua non. Two types of valve appear to be in use, In the first of these the pressure is regulated by a spring, while in the second the open end of a glass tube is immersed in mercurythe pressure being regulated by the depth to which the tube is immersed.