The gas nitrous oxide was first identified by Joseph Priestley in 1772. Years later, in the late 1790s, the British chemist Humphry Davy began experimenting with the effects of inhaling nitrous oxide. He noted its exhilarating effects, and the way it made him want to laugh--which gave the gas its popular name of "laughing gas." Davy published his findings in 1800, remarking that "As nitrous oxide... appears capable of destroying pain, it may probably be used with advantage during surgical operations."

Little attention was paid to Davy's observations, or to those of Henry Hill Hickman (1800-1830), a general practitioner from Shropshire, England, who in 1824 explored methods of painless surgery on animals using both carbon dioxide and nitrous oxide gas. Nevertheless, nitrous oxide became widely known in the first half of the nineteenth century. Davy repeatedly demonstrated the gas's exhilarating effects to gatherings of his friends, and inhalation parties...