Raymond Pearl (1879-1940), American biologist. Pearl spent most of his career at Johns Hopkins University in Baltimore, where he worked on the statistics of populations and Mendelian genetics. He was also a populariser of science, particularly keen to communicate the quantitative biology he pursued. He was involved in the eugenics movement, which sought to improve human society through selective breeding, although he later rejected many prejudices of the philosophy. This portrait is from the Bain News Service, one of America's oldest news picture agencies, which holds images dating from between the 1890s and 1930s.