Historical information

Sir Frederick William Hewitt was a great advocate of nitrous oxide anaesthesia, mainly for short procedures. In 1885, he reviewed the methods of administration and concluded that accurately fitting valves were essential at the commencement of the inhalation, in order to ensure the rapid washout of air from the lungs; and there was a distinct advantage in allowing some rebreathing of nitrous oxide towards the end of inhalation. He thus devised the stopcock. The stopcock consists of a cylinder with two rotating sleeves and two rubber flap valves. The arrangement allows air to be breathed either through the valves or rebreathed to and from the bag; nitrous oxide to be breathed either through the valves from the bag and out to the atmosphere or rebreathed to and from the bag. Soon after the introduction of this stopcock, there was an increased interest in administering oxygen in combination with nitrous oxide.

Physical description

Amber coloured ether inhaler, with leather mask, celluloid shield and inflatable cushion with attached Hewitt's stopcock.