Dr. John Collins Warren. Daguerreotype. John Collins Warren (1778-1856) was an American surgeon. In 1846 he gave permission to William T.G. Morton to provide ether anesthesia while Warren performed a minor surgical procedure. News of this first public demonstration of surgical anesthesia quickly circulated around the world. He was a founder of the New England Journal of Medicine and was the third president of the American Medical Association. He was the first Dean of Harvard Medical School and a founding member of the Massachusetts General Hospital.