From Today in Science History:
Jan Swammerdam. Born 12 Feb 1637; died 15 Feb 1680.
Dutch naturalist, known for his skilled biological microscopical observations and accurate illustrations, who was the first to describe the red blood cells (1658). He studied and illustrated the life histories and anatomy of many species of insects, which he classified on the basis of development. He demonstrated the presence of butterfly wings in caterpillars about to undergo pupation. To facilitate the study of human anatomy, he developed better methods for injecting wax and dyes into cadavers. He was one of the first to dissect under water and to remove fat by organic solvents. He demonstrated experimentally that whereas muscles alter in shape during contraction, their volume is not thereby increased, which contradicted beliefs of the time.