Morgan, Thomas Hunt, 1866-1945

Thomas Hunt Morgan was a geneticist and embryologist. He was Professor of Experimental Biology at Columbia University (1904-1928) and Professor of Zoology at California Institute of Technology (1928-1945).

Thomas Hunt Morgan received his Ph. D. from the Johns Hopkins University in 1890 where he studied morphology with W.K. Brooks, and physiology with H. Newell Martin. He taught biology at Bryn Mawr College, Columbia University, and the California Institute of Technology.

His research speciality was experimental embryology.

Thomas Hunt Morgan was a geneticist and embryologist. He was Professor of Experimental Biology at Columbia University (1904-1928) and Professor of Zoology at California Institute of Technology (1928-1945).

Morgan received a thorough grounding in animal morphology, especially of marine invertebrates, under W. K. Brooks at Johns Hopkins, and as a postdoctoral fellow for a year at the famed Naples Zoological Station. In his first academic position, at Bryn Mawr College, he collaborated in teaching the basic course in biology with Jacques Loeb, who was later to attain renown as an experimental physiologist. A leave of absence from Bryn Mawr enabled Morgan to spend another year (1894-1895) at the Naples laboratory, working especially with Hans Driesch, who became a lifelong friend. It was then that Morgan declared his independence of the descriptive method of studying animals, so characteristic of W. K. Brooks, and determined to be an experimentalist -- specifically, an experimental embryologist.

Morgan began going to the Woods Hole Marine Biological Laboratory almost from its founding in 1888, while he was still a graduate student. He became a member of its Board of Trustees in 1897, and he remained on the Board as an active member until 1937. Woods Hole was an ideal place for the sort of investigations in embryology Morgan wished to pursue, for it was there that one could study marine animals while they were still alive.

There were other attractions, too. One of Morgan's children is said to have believed that E. B. Wilson dragged a reluctant Morgan from his research one day to meet "his brightest student" at Bryn Mawr College, Lilian Vaughan Sampson. In any case, they met, and in 1891, when Morgan arrived as a new faculty member at the college, Lilian enrolled as a graduate student and Morgan became her adviser. She received an M.A. degree in 1894. Romance came slowly. They did not become engaged until 1903, and were married in 1904, just before Morgan accepted his friend E. B. Wilson's invitation to fill a professorship at Columbia University. Morgan's interests were centered at this time upon problems of heredity and sex determination. He was, however, notoriously skeptical of the validity of Mendelism and the chromosomal theory of heredity advocated by Boveri and by Wilson and his graduate student W. S. Sutton.

While he was at Naples, Morgan had tried to repeat Boveri's experiment on the fertilization of enucleated sea urchin eggs, which Boveri said led to wholly paternal inheritance; and Morgan could not confirm the result. As a consequence, Morgan discounted Boveri's work all too heavily. Yet why he should have disregarded the superb analysis made by Sutton, which tied together the events of meiosis -- the reduction of the chromosome number in the formation of male and female gametes -- with the Mendelian segregation of alternative characters and the random fertilization of egg cells by male germ cells (sperms or pollen), is truly hard to conjecture. In any case, Morgan wrote a number of skeptical papers about Mendelism that he was later to regret -- one, in fact, that he actually deleted in later years from his bibliography. In 1908 he selected the tiny fruitfly Drosophila melanogaster in order to test where those variations important in evolution come from -- from DeVriesian mutations, as he then thought. In 1910, however, he found a recessive sex-linked mutation, white eye color. [In the Davenport Papers there is a highly interesting letter from Morgan to Davenport, dated June 11, 1910, a letter in which Morgan reports his discovery and analysis of its "sex limited inheritance," while saying not a word of the dispelling of his doubts of Mendelian inheritance or his abandonment of the dictum, "Once crossed, always mixed," which he had applied to the results obtained by Cuenot in his breeding of yellow-coated mice. The letter was sent to Davenport almost a month before Morgan submitted the paper to Science for publication. See B. Glass, "An Exciting Find: Thomas Hunt Morgan Letters," Mendel Newsletter 26: 6-7, August 1986.]

So the great Drosophila era of genetics, with its verification of the Chromosome Theory of Heredity, its mapping of genes according to linkage and recombination values, had begun. Already, too, in the "fly room" in Schermerhorn some extraordinary students, both graduate and undergraduate, were at work -- among them Bridges, Sturtevant, and Muller, who collaborated with Morgan in writing the book of the time, The Mechanism of Mendelian Heredity . A number of foreign holders of fellowships also arrived to join the heady atmosphere of novel theories and methods of genetical research. The first of these was probably Otto Lous Mohr, from Norway, who with his wife Tove became especially warm, lifelong friends of the Morgan family. In the late 1920s came Curt Stern and Theodosius Dobzhansky. In 1927 Morgan received an invitation to come to the California Institute of Technology in Pasadena, to establish and head a Biology Division. He accepted, and took Bridges and Sturtevant with him. In planning and administrative work, however, Morgan lost his zest for Drosophila genetics, and when he resumed experimental work, it was to return to his first love, embryology, to seek once again to unite it with genetics and thereby provide a more solid basis for evolutionary theory.

The developmental biologist and ardent vitalist Hans Driesch was born on October 28, 1867, in Bad Kreuznach, Germany. After studying zoology at Freiburg and Munich, he received his doctorate at Jena in 1889 for work under Ernst Haeckel on coelenterates. Through a series of major monographs including Die Biologie als Selbständige Grundwissenschaft (1893), Analytische Theorie der Organischen Entwicklung (1894), Die Seele als Elementare Naturfaktor (1903), and History and Theory of Vitalism (1905), Driesch developed a unqiue "biotheoretical" approach to organismal study, incorporating mathematical analysis of organismal structures in a strongly teleological vitalist framework that he called entelechy. He remained an antimaterialist throughout his career.

Between 1891 and 1900, Driesch worked at the International Zoological Station in Naples, Italy, where he met performed a renowned series of experiments on sea urchin embryos that conclusively demonstrated that the fate of a cell is not determined in the early developmental stages and, in 1896, he became the first to demonstrate embryonic induction. At Naples he also met Thomas Hunt Morgan, the young American embryologist and soon to be geneticist, with whom he maintained a long correspondence. After serving as the Gifford lecturer at Aberdeen in 1907-1908, Driesch was appointed professor of philosophy at Heidelberg (1911-20), and subsequently at Cologne and Leipzig. His pacifism and philosophical beliefs made him anathema to the Nazi regime, however, and he was forced to retire in 1933. He died in Leipzig on April 16, 1941.