T. W. Evans--before and after.
D000766:Anesthesia, Dental / Q000266:history*; D000769:Anesthesia, Inhalation / Q000266:history*; D004739:England; D005602:France; D006665:History of Dentistry; D006666:History of Medicine; D049672:History, 19th Century; D006801:Humans; D009609:Nitrous Oxide / Q000266:history*
D009609:Nitrous Oxide