Merriam-Webster Dictionary
ETHER: a light volatile flammable liquid C₄H₁₀O used chiefly as a solvent and especially formerly as an anesthetic

January 22, 1847 Saint John's Dr. Martin H. Peters uses Ether as an anaesthetic during surgery for the first time in British North America.

Home of Dr. Martin Hunter Peters, comer of Watson and Gilford Streets. Then Carleton, now Saint John West.

credit: http://vonamsberg.net
(This is not a depiction of Dr. Peters' procedure in 1844. Read this interesting article about the history of Ether and its medical impact dating back to the late 1200s.