Zinsser, Hans (zĭnsˈər) [key], 1878–1940, American bacteriologist, b. New York City, grad. Columbia (B.A., 1899; M.D., 1903). He was professor of bacteriology at Stanford (1911–13), Columbia (1913–23), and Harvard medical school (from 1923). A noted epidemiologist, he was a leader in combating typhus and served with the American Red Cross sanitary commission during the 1915 typhus epidemic in Serbia and with the League of Nations sanitary commission (1923) in the USSR. Zinsser isolated the germ of the European type of typhus, and with his colleagues at Harvard, he developed (1940) a method for mass production of the vaccine. He wrote a popular work on typhus, Rats, Lice, and History (1935); several textbooks, including Infection and Resistance (1914; 4th ed. rev., Resistance to Infectious Disease, 1931; 5th ed. rev., Immunity, 1939); and the autobiographical As I Remember Him (1940).