Regnier de Graaf (English spelling), original Dutch spelling Reinier de Graaf, or Latinized Reijnerus de Graeff (30 July 164117 August 1673) was a Dutch physician, physiologist and anatomist who made key discoveries in reproductive biology. He specialized in iatrochemistry and iatrogenesis, and was the first to develop a syringe to inject dye into human reproductive organs so that he could understand their structure and function. Biography De Graaf was born in Schoonhoven as the son of an carpenter/engineer or architect and studied medicine in Leuven (1658), Utrecht and Leiden (1663). There his co-students were Jan Swammerdam, Niels Stensen, Ole Borch and Frederik Ruysch, cooperating with professor Franciscus Sylvius, Johannes van Horne and Lucas Schacht. All of them were interested in the organs of procreation and influenced by Rene Descartes' iatrophysical approach. He submitted his doctoral thesis on the pancreas, and in 1665 he went (together with his brother) to France where he further experimented on dogs, cooperating with Pierre Bourdelot. He obtained his medical degree from the University of Angers with Jean Chapelain as his translator. Back in the Dutch Republic, De Graaf established himself at Oude Delft. He was studying the male genitalia, which led to a publication in 1668. For his research in the anatomical theatre on the ovarian follicle he used female rabbits. (The dissection of corpses was only done in winter, and cadavers were scarce; most were sent to Leiden and available when someone was condemned to death.) In May 1672 he married Maria van Dijk. As a correspondent of the Royal Society in London, De Graaf recommended (at the end of April) Henry Oldenburg that attention should be paid to autodidact Antonie van Leeuwenhoek and his work on the improvement of the microscope. De Graaf died on 17 August and was buried respectfully on 21 August in the nearby Old Church, Delft on a prominent spot, at the choir. It has been speculated that he may have committed suicide, but it is more likely it was malaria, typhoid fever or dysentery as in other Dutch cities; the disease persisted throughout the year, peaking in July and August. Legacy De Graaf's position in the history of reproduction is unique, summarising the work of anatomists before his time, but unable to benefit from the advances about to be made by microscopy, although he reported its use by Antonie van Leeuwenhoek in 1673. His personal contributions include the