Jan Swammerdam

Scientist

Dutch scientist Jan Swammerdam's microscopic studies of insects repudiated the notion of spontaneous generation and formed the modern basis for the study of bugs, known as entomology. Swammerdam had a medical degree (University of Leiden, 1667), but spent most of his career in research and publishing. The exception was a period after 1675, when he apparently gave up science to follow a religious mystic. During his period of research, Swammerdam examined thousands of insects, devised new ways in which to view them through a microscope, made detailed drawings (turned into etchings), and showed the stages of butterfly metamorphosis for the first time. He's also famous for his research on the human body, especially his discovery of valves in the lymphatic vessels (Swammerdam valves!) and the discovery of oxygen-carrying red blood cells. He published Historia Insectorum Generalis in 1669, but his collective work (Biblia Naturae or The Book of Nature) wasn't translated and published until 1737. He died at the age of 43, a long-time sufferer of what has since been deemed malaria.

Extra credit: He was a contemporary of the other famous Dutch microscopist, Anton van Leeuwenhoek, and of the English inventor Robert Hooke.