title: The development of the virus concept as reflected in corpora of studies on individual pathogens. 1. Beginnings at the turn of the century.
mesh_terms: D005060:Europe; D049672:History, 19th Century; D049673:History, 20th Century; D014773:Virology / Q000266:history*; D014777:Virus Diseases / Q000266:history; D014780:Viruses