MORGAN, THOMAS HUNT. - American biologist, b. in Lexington on 25 Sept. 1866, d. in Pasadena on 4 Dec. 1945. He graduated in natural sciences in 1890 at Johns Hopkins University. He was professor of biology at Bryn Mawr College (1894) and then of zoology at Columbia University (1904), finally at the Institutes in Pasadena (1928). He received the Nobel Prize for Medicine in 1933.
MORGAN’s work covered the most varied branches of the biological sciences. He began his studies as an experimental embryologist (polarity of the eggs of amphibians and echinoderms, potencies of blastomeres, merogony, etc.), then studied experimental regeneration in various animal groups (protozoa, coelenterates, planarians and annelids), on which he formulated the theory of organic polarity (1902). His major research, however, was devoted to the study of the vinegar fly (Drosophila), where he demonstrated the close connection between heredity and chromosomes, thus founding modern genetics. He had numerous distinguished pupils and collaborators (Bridge, Sturtevant, Müller, Stern, etc.). He published an enormous quantity of works, among which the following should be noted: *The Regeneration* (New York 1901); *Heredity and Sex* (ibid. 1913); *The Physical Basis of Heredity* (Philadelphia 1919); *Evolution and Genetics* (Princeton 1925); *The Theory of the Gene* (New Haven 1926); *Experimental Embryology* (New York 1927); *The Scientific Basis of Evolution* (ibid. 1932); *Embryology and Genetics* (ibid. 1934).