Harry Plotz (1892-1947), American bacteriologist and doctor. Working in New York, Plotz developed a vaccine against typhoid in 1903. Typhoid is a disease caused by the bacterium Salmonella typhi, resulting in fever, weakness, and sometimes death. Later, Plotz studied typhus, a disease which has caused devastating epidemics throughout history, particularly when hygiene is poor. He discovered the bacteria responsible (Rickettsia, sometimes known as Plotz's bacillus), and developed a vaccine in 1914. This portrait is from the Bain News Service, one of America's oldest news picture agencies, which holds images dating from the 1890s to the 1930s.