The germ theory, beriberi, and the deficiency theory of disease.
D000818:Animals; D001602:Beriberi / Q000266:history*; D003141:Communicable Diseases / Q000266:history*; D003677:Deficiency Diseases / Q000266:history*; D049672:History, 19th Century; D049673:History, 20th Century; D006801:Humans