We’ve never really understood why anaesthesia works, only that it does, and that surgery was horrifying before its advent. But perhaps brain imaging will soon reveal the mystery of anesthesia’s potency. An excerpt from New Scientist about the history of surgery with gas:

“It was a Japanese surgeon who performed the first known surgery under anaesthetic, in 1804, using a mixture of potent herbs. In the west, the first operation under general anaesthetic took place at Massachusetts General Hospital in 1846. A flask of sulphuric ether was held close to the patient’s face until he fell unconscious.

Since then a slew of chemicals have been co-opted to serve as anaesthetics, some inhaled, like ether, and some injected. The people who gained expertise in administering these agents developed into their own medical specialty. Although long overshadowed by the surgeons who patch you up, the humble ‘gas man’ does just as important a job, holding you in the twilight between life and death.” (Thanks Browser.)