several proteins (Crick and Watson, 1953; and Perutz & 

 Kendrew, 1960); the synthesis of polymers (long mole- 

 cules). In biology: the detailed study of the genetics of 

 several species (Morgan, 1904 onwards); the discovery of 

 viruses (Ivanovski, 1892); the elucidation of the function 

 of viruses (1930 onwards); the use of the electron micro- 

 scope (1932 onwards). In psychology: the Theory of Psy- 

 chology of Freud (c. 1910); the experiments by Pavlov on 

 conditioned reflexes (1900 onwards); the studies of visual 

 perception by Kohler (1929). In medicine: the elucidation 

 of the function of the pancreas (Banting and Best, 1921); 

 the treatment of certain cancers with radium (c. 1900 on- 

 wards); the establishment of the cause of malaria by Ross 

 (1898); the use of antibiotics (from c. 1930); the success 

 in performing heart operations (Rehn, 1896; the success- 

 ful prevention of poliomyelitis (Salk, 1954); the discovery 

 of electrical waves in the brain (Berger, 1929). In geology: 

 the radioactive determination of rock ages (c. 1920 — ); 

 the discovery of remains of fossil men (Breuil, 1901 — ; von 

 Koenigswald, 1937; Black, 1926); the mapping of the 

 ocean floors (Heezen & Tharp, 1961), leading to the dis- 

 covery of the mid-oceanic ridges; the confirmation of 

 Wegener's continental drift hypothesis by studies of rock 

 magnetism (Blackett, 1960); the first descents by bathy- 

 scaphe into the ocean depths (Piccard, 1953); the dis- 

 covery of the ionosphere (Appleton, 1925); concentrated 

 studies of the Antarctic (1959). In astronomy: the theore- 

 tical understanding of stellar energy generation (Eddington, 

 1926), and of the dynamics of star systems (Jeans, 1919); 

 the detailed investigation of the Sun's surface (Hale, c. 

 1890 — , and others); the study of magnetic fields in stars 

 (Babcock, c. 1950); the photographic determination of 

 star distances (Schlesinger, c. 1900 — , and others); the 



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