fields Leidy was also a renowned parasitologist, and determined as early as 1846 that trichinosis was caused by a parasite in undercooked meat. He was also a pioneering protozoologist, publishing Fresh-water Rhizopods of North America in 1879 – a work that is still referenced today. Leidy collected gems as well as fossils, and donated his important collection of the former to the Smithsonian before he died. At Swarthmore, he also taught a class on mineralogy and geology. Leidy served as a surgeon to Satterlee Military Hospital in Philadelphia during the American Civil War. Forensic innovator In 1846, Leidy became the first person ever to use a microscope to solve a murder mystery. A man accused of killing a Philadelphia farmer had blood on his clothes and hatchet. The suspect claimed the blood was from chickens he had been slaughtering. Using his microscope, Leidy found no nuclei in these erythrocytes (human erythrocytes are anucleate). Moreover, he found that if he let chick erythrocytes remain outside the body for hours, they did not lose their nuclei. Thus, he concluded that the blood stains could not have been chicken blood. The suspect subsequently confessed. Bibliography His bibliography includes 553 works. Citations References External links 1823 births 1891 deaths American forensic scientists American paleontologists American parasitologists American people of German descent Lyell Medal winners Perelman School of Medicine at the University of Pennsylvania alumni Scientific illustrators Scientists from Philadelphia Swarthmore College faculty University of Pennsylvania faculty University of Pennsylvania Department of Biology faculty