Answer: Carl Zimmer writes in Discover
The first public demonstration of public anesthesia during surgery took place in 1846 in Boston. A man named Gilbert Abbott took some deep drafts of ether, and surgeons began cutting a tumor off his jaw. The audience was shocked that Abbott did not scream and squirm. One London newspaper expressed the amazement that many must have felt: "Oh, what delight for every feeling heart to find the new year ushered in with the announcement of this noble discovery of the power to still the sense of pain and veil the eye and memory from all the horrors of an operation."