SACHS, JULIUS

SACHS, JULIUS (1832–1897), German botanist. Born in Breslau of a poor family, he was encouraged in his studies by the Czech physiologist Johannes Evangelista Purkinje (1787–1869), then at the University of Breslau. When Sachs was 18, Purkinje moved to Prague, and he invited Sachs to come to his institute as an assistant. After obtaining his degree at the University of Prague, Sachs went to Tharandt, where first he taught botany at the forestry school; in 1861 he was appointed professor at the agricultural school at Poppelsdorf, near Bonn. In 1867 Sachs became professor of botany at Wuerzburg, remaining for nearly 30 years. Sachs held an important place in the history of biology, both as a teacher and as a researcher. His textbooks, Handbuch der Experimentalphysiologie der Pflanzen (1865) and the Lehrbuch der Botanik (1868; Textbook of Botany, 1875), widely influenced the teaching of botany. Sachs's personal influence as a teacher was equally great. Under his genial and enthusiastic leadership, Wuerzburg became an international center for plant physiology, where some of Europe's most eminent botanists were trained. Sachs has been called the creator of experimental botany. Among Sachs's noteworthy contributions were his demonstration that starch is the first perceptible product of photosynthesis and that it is translocated from the leaf in the form of sugar. Sachs was the first to demonstrate that the chloroplasts are the site of photosynthesis, and it was he who showed that light is necessary for the synthesis of chlorophyll. Sachs also pioneered in studies of the nutritional requirements of plants; he published the first formula for a standard culture solution, a necessary basis for identifying the mineral elements essential for growth. Sachs introduced the auxanometer, an instrument for quantitatively studying plant growth, and the clinostat, a rotating apparatus by means of which he investigated the plant's response to gravity. -BIBLIOGRAPHY: E.G. Pringsheim, Julius Sachs (Ger., 1932). (Mordecai L. Gabriel) SACHS, JULIUS SACHS, JULIUS (1849–1934), U.S. educator. Sachs, who was born in Baltimore, Maryland, was founder and headmaster of the Sachs Collegiate Institute School of Boys in New York City (1871–1904), a school considerably attended by the German-Jewish upper class of that city; and professor of secondary education at Columbia Teachers College (1902–17). Sachs gained national recognition for leadership in raising the standards of secondary school education and improving teacher training. He served as president of the Schoolmasters' Association of New York (1889) and the Headmasters' Association of the United States (1899). In addition to activities and publications concerned with education, Sachs produced several studies in the field of philology and archaeology. He was president of the American Philological Association in 1891. He belonged to the sachs family of educators. (Frederick M. Binder) SACHS, LEO SACHS, LEO (1924– ), Israeli geneticist. Sachs was born in Leipzig, Germany, and in 1933 immigrated to England with his parents following Hitler's accession to power. He received his doctorate from Cambridge in 1951 and in 1952 came to Israel as a research scientist at the Weizmann Institute of Science, Rehovot. He initiated research on various aspects of biomedical sciences and established the Department of Genetics and Virology. He was appointed associate professor in 1960 and full professor in 1962. His research pioneered new approaches to basic and medically applied aspects of stem cell biology, development, hematology, and oncology, and led to new therapies. His honors include the Israel Prize for natural sciences (1972), the Rothschild Prize in biological sciences (1977), the Wolf Prize in medicine (1980), and the EMET Prize for life sciences, medicine, and genetics (2002). He is a member of the Israel Academy of Sciences and Humanities, a foreign associate of the U.S. National Academy of Sciences, and a fellow of the Royal Society, London, since 1997. (Bracha Rager (2nd ed.)