Popper wrote his doctoral thesis in Vienna in 1903 and then became a military surgeon with the artillery. From 1904 to 1905 he worked as a candidate and assistant physician at the Wiedner Hospital in Vienna, then moved to the Wilhelminenspital. In 1911 he became a resident doctor at the Allgemeine Poliklinik (outpatients clinic). As of 1918 he worked as a paediatrician in Vienna and director of the pediatric ambulance of the Vienna Krankenkasse (statutory medical insurance company). In 1938 he emigrated to England and held jobs as Medical Officer in children’s homes until 1942, subsequently he worked as a Resident Medical Officer in Cheshire until 1945.
- Paul Speiser: Karl Landsteiner, Entdecker der Blutgruppen und Pionier der Immunologie ; Biographie eines Nobelpreisträgers aus der Wiener Medizinischen Schule, 3rd edition, Berlin, Blackwell Ueberreuter-Wiss. 1990 ISBN 3-89412-084-3, page 150
- Title of German publication: Landsteiner, K. und Popper, E.: Übertragung der Poliomyelitis acuta auf Affen in Zeitschrift für Immunitätsforschung und experimentelle Therapie, Vol 2 (1909), pp. 377-390