Face mask and regulator from Clover's "Portable Regulating Ether Inhaler", made by Mayer and Meltzer of London, 1880-1920

Joseph Thomas Clover (1825-1882) was during his lifetime one of the leading anaesthetists in England. Originally training as a surgeon, Clover turned to general practice and eventually anaesthesia. In 1871, he wrote that he had given anaesthetics 13,000 times without a single death.

During his career he developed different devices for giving anaesthetics to his patients including this on in 1877. It was the first to incorporate a method of regulating the amount of ether inhaled as well as preventing air getting inside the inhaler. This became known as the closed method for ether. It is thought that Clover did not use his own invention much, but several people made modifications to it. This example has a tap which allows a gas bag filled with nitrous oxide to be attached. Clover introduced using nitrous oxide to produce unconsciousness, then with ether. This type of inhaler was still being described in anaesthetic textbooks in the 1940s and was supplied to the Royal Air Force at the outbreak of the Second World War.