Streeter, George Linius
STREETER, GEORGE LINIUS
Streeter, the son of George Austin Streeter, a glove manufacturer, and Hannah Green Anthony Streeter, was graduated from Union College in 1895 and from the College of Physicians and Surgeons of Columbia University, where he took his M.D. degree, in 1899. After an internship at Roosevelt Hospital in New York City, he became assistant to Henry Hun, a prominent neurologist, in Albany and also taught anatomy at Albany Medical College. In 1902 he studied at Frankfurt with Ludwig Edinger and at Leipzig with Wilhelm His. Under the latter’s influence Streeter devoted himself thereafter to embryology and particularly to the development of the human nervous system.
Returning to the United States in 1904, Streeter joined the department of anatomy of the Johns Hopkins Medical School in Baltimore, under the leadership of Franklin P. Mall. There he published his first contribution to embryology, on the development of the cranial and spinal nerves of the human embryo. In this work he showed a talent for three-dimensional analysis of complex microscopic structures, accurate observation, and skilled draftsmanship. His only experimental investigation was a study of the early development of the internal ear in frog embryos (tadpoles) by removal and transplantation of the ear vesicles. His interest in the auditory apparatus led to many years’ work on the embryology of the human ear, crowned in 1918 by publication of a distinguished monograph on the development of the labyrinth.
In 1906–1907 Streeter was assistant professor at the Wistar Institute of Anatomy and Biology in Philadelphia and then went to the University of Michigan as professor of anatomy. There he continued his embryological research on the human brain and auditory apparatus with such success that he was recalled to Baltimore to join Mall in the newly organized department of embryology of the Carnegie Institution, located at the Johns Hopkins Medical School. When Mall died in 1917, Streeter succeeded him as director, taking over a well-organized laboratory with the world’s largest collection of human embryological material. Continuing Mall’s program, he not only carried on his own wide-ranging investigations but also, with generous and enthusiastic leadership, promoted the work of a highly competent staff and numerous guest investigators.
Streeter’s paper on the weight and dimensions of human embryos and fetuses at successive stages of development (1920) is the classic account of this subject. His comprehensive chapter on the development of the human brain in Franz Keibel and Mall’s Manual of Human Embryology (1912) has not been superseded. Mall had been deeply interested in the pathological aspects of human prenatal development. Working before the great twentieth-century advance of genetics, he attributed prenatal retardation, malformation, and intrauterine death to defects or disease of the uterine environment. Streeter, on the other hand, tended to attribute these disasters to genetic factors. It is now known that both environmental and genetic causes are operative in prenatal pathology, but Streeter’s skilled exposition of his views was valuable in turning the attention of physicians and biologists to the importance of genetic factors.
Although primarily a morphologist, Streeter always saw the embryo as a living, growing individual, and its organs and tissues as carrying on physiological functions appropriate to its stage of growth. He therefore opposed the kind of embryology represented in its extreme form by Haeckel’s law of recapitulation, which regarded every embryonic structure as no more than a record of phylogeny. He was especially critical of the concept of the mammalian branchial arches as merely rudimentary gills rather than as preliminary stages of the external ears and other definitive parts of the head and neck: and he denied the supposed metamerism of the early vertebrate brain. To combat these older ways of thinking, often supported by oversimplified diagrams, he illustrated his own descriptions as far as possible by photomicrographs or realistic drawings based on actual sections.
Streeter’s joint studies of the early embryology of the pig, with Chester H. Heuser, and of the rhesus monkey, with Heuser and Carl G. Hartman, published in the Contributions to Embryology of the Carnegie Institution between 1927 and 1941, are among the most accurate descriptions of early mammalian development ever published and stand in the front rank of American scientific achievements. With his great descriptive talent, his long experience in the most exacting kind of morphological study, and the skilled assistance of a technical staff that he himself had largely trained, Streeter was well fitted to begin (about 1935) the great advance in early human embryology made by his staff in cooperation with John Rock and Arthur T. Hertig of Boston. Before this time the human embryo was known only after about the eleventh day following conception. New specimens obtained by Hertig and Rock carried the story back to the beginning and made the earliest stages of human development as well known as the earliest stages of other mammals.
Streeter’s last major undertaking, unfinished at his death, was a systematic catalog and analytic description of the human embryo, classified by stages up to the end of the embryonic period–about the forty-eighth day of gestation. The“developmental horizons,”as he called them, were published, as far as completed, in the Carnegie Institution Contributions to Embryology from 1942 to 1951.
Devoting his entire career to intensive research in a difficult field, Streeter had little time or inclination for popularizing his findings or for general scientific affairs. He published no textbooks nor comprehensive reviews; his talents for exposition were demonstrated largely through numerous papers presented at professional meetings. He was elected to the National Academy of Sciences in 1931 and to the American Philosophical Society in 1943, and was president of the American Association of Anatomists in 1926–1928. He married Julia Allen Smith of Ann Arbor, Michigan, in 1910. Their son and one daughter became physicians, and the other daughter took her doctorate in chemistry.
Streeter retired in 1940 from the directorship of the Carnegie department of embryology but continued his work on human embryology until, with his microscope and drawing board at hand and another section of“Horizons of Human Development”in preparation, he died suddenly of coronary occlusion at the age of seventy-five.
A complete bibliography of Streeter’s more than 130 publications follows the obituary by George W. Corner, “George Linius Streeter, 1873–1948,”in Biographical Memoris, National Academy of Sciences, 28 (1954), 261–287, with portrait.
George W. Corner