171 years ago today, March 14, 1854 (February 16, 1854 in the lunar calendar), was the birthday of Paul Ehrlich, a German immunologist and one of the founders of chemotherapy. Paul Ehrlich (1854-1915) translated Ehrlich and Ehrlich. German immunologist and one of the founders of chemotherapy. Born in Strehlen, Silesia, Germany on March 14, 1854 (present-day Schellin, Poland), he graduated from the University of Leipzig in 1878 and received a doctorate in medicine. He served as a teaching assistant, lecturer and associate professor at the Affiliated Hospital of the University of Berlin School of Medicine. In 1890, he served at the Institute of Infectious Diseases led by R. Koch. From 1896 to 1899, he successively served as director of the Steglitz Serum Laboratory and the Institute of Experimental Therapeutics in Frankfurt am Main. In his early years, he was engaged in the research on the affinity between different tissues and cells and dyes in living organisms, and invented the in vivo staining method. Mast cells and plasma cells were identified; eosinophils were found; First, various types of myeloid leukemia were identified; for the first time, a classification of white blood cells according to the staining characteristics of the particles they contained was proposed; and acid-fast staining of tuberculosis bacteria was invented. After 1890, he studied immunity issues, helped E. Behring produce diphtheria antiserum, and designed a method for determining the amount of antitoxin per unit. Created the side chain theory to study the hemolytic reaction of animal serum and proposed the term "complement". In his later years, he specialized in the research of chemical drugs to treat infectious diseases, invented the effective drug 606 (arsenic vannamine) for the treatment of syphilis, and won the 1908 Nobel Prize in Physiology or Medicine with I.I. Mechnikov. It has been awarded 81 honorary titles by various academic groups around the world. He died on August 20, 1915 in Bad Homboldt.