Experiment versus authority.
D002986:Clinical Trials as Topic; D004739:England; D049671:History, 18th Century; D049672:History, 19th Century; D006801:Humans; D009326:Naval Medicine / Q000266:history; D012614:Scurvy / Q000266:history; D013812:Therapeutics / Q000266:history*; D014481:United States; D015004:Yellow Fever / Q000266:history