Ether was most famously used in Boston on 16 October 1846 by dentist William Morton. He succeeded in his public demonstration of using a substance he called lethion to eliminate pain, previously a necessary part of dentistry or surgery. Anaesthesia was used here at the Old Operating Theatre from 1847, after news of the invention had reached England.
But this is not where the story of ether begins. From Valerius Cordus first description of producing Sweet Oil of Vitriol in 1540 it took 300 years to explore its full potential for medicine: Anaesthesia.