EHRLICH, PAUL

EHRLICH, PAUL (1854–1915), German chemist, pioneer of modern histology, immunology, and chemotherapy; Nobel Prize winner. Ehrlich was born in Strehlen near Breslau. He studied at German universities and began his scientific work in 1878 in Berlin University as an assistant, becoming an associate professor in 1890. In 1896 he became director of the Royal Institute for Serum Research in Steglitz (Berlin) and three years later director of the Institute of Experimental Therapy in Frankfurt on the Main, which was subsequently amalgamated with the Georg Speier Institute for Chemotherapeutic Research. In 1904 Ehrlich was appointed honorary professor at the University of Goettingen and in 1914 became a professor at Frankfurt University. He was awarded the Nobel Prize for Medicine in 1908. Ehrlich began his scientific work in the fields of hematology and histology. From methods of staining dead blood cells he progressed to staining living cells, and discovered methods of staining living nerve fibers. His research work on the staining of microorganisms led to the method of staining TB bacilli and he discovered the diazo reaction in urine for the recognition of aromatic compounds, which serves to diagnose typhoid fever. From 1890 onward Ehrlich concentrated mainly on problems of immunization. He proved the specificity of immunity to toxins, and established the basic concepts of applied immunology: active and passive immunization. He laid the foundation for standardization of therapeutic sera by employing as standard serum a stable antitoxic serum capable of long-term preservation. On the basis of this method he developed, in 1897, the evaluation of the antitoxic sera and its theoretical basis, one of the vital practical achievements in the history of immunology. Recognizing the particular specific affinity of dyes, active organic compounds, and toxins to certain cells, Ehrlich started to search for chemical compounds which would specifically attack the microorganisms causing disease without damaging the body cells. He first treated syphilis with the poisonous organic arsenic compound atoxyl and in 1909, after years of investigation, he discovered, together with his Japanese assistant Hatta, the compound "606," Salvarsan, which can inactivate the treponema causing syphilis, as well as other treponemas causing various tropical diseases. This was the greatest achievement in the fight against syphilis since its appearance in Europe four centuries earlier and marked the beginning of modern systematic chemotherapy. Developments in theoretical and applied medical biology since Ehrlich's day have thrown new light on certain of his concepts and some of his theoretical assumptions have been modified. But his basic concepts and methods remain firm and still serve as fundamentals for research in the fields of hematology, immunology, and chemotherapy. Ehrlich was interested in Jewish affairs all his life. He was an active member of Le-Ma'an Zion, and was also associated with and supported the Nordau Institute, one of the nuclei of the Hebrew University of Jerusalem. -BIBLIOGRAPHY: A. Lazarus, Meister der Heilkunde, Paul Ehrlich (1922); M. Marquard, Paul Ehrlich als Mensch und Arbeiter (1924); W. Bulloch, The History of Bacteriology (1938); F. Himmelweit (ed.), The Collected Papers of Paul Ehrlich (1956–57); S. Munther, Paul Ehrlich, Founder of Chemotherapy (1966); C.E. Dolman (ed.),   Paul Ehrlich and William Bulloch: A Correspondence and Friendship (1896–1914); Clio Medica, 3 (1968), 65–84. (Aryeh Leo Olitzki)