Franciscus Sylvius

Franciscus Sylvius (15 March 1614, Hanau-19 November 1672, Leiden), born Franz de le Boë, was a Dutch physician and scientist (chemist, physiologist and anatomist) who was an early champion of Descartes', Van Helmont's and William Harvey's work and theories. He was one of the earliest defenders of the circulation of the blood in the Netherlands.

Life
Sylvius, a Latinization of "de le Boë" translated as "of the woods", was born in Hanau, Germany to an affluent family originally from Cambrai, but worked and died in Netherlands. He studied medicine at the protestant academy of Sedan, and from 1632 - 1634 in Leiden under Adolph Vorstius and Otto Heurnius. In 1634 he held a disputation Positiones variae medicae under the presidency of Vorstius, in which he defended the proposition that there should be a pulmonary circulation. After that Sylvius made a study tour to Jena and Wittenberg, and on March 16, 1637 he defended a thesis entitled De animali motu ejusque laesionibus at the University of Basel under the presidency of Emmanuel Stupanus. After practicing medicine in his hometown Hanau he returned to Leiden in 1639 to lecture. In this period he became famous for his demonstrations on circulation. From 1641 on he had a lucrative medical practice in Amsterdam. While in Amsterdam he met Glauber, who introduced him to chemistry. In 1658 he was appointed the professor of medicine at the University of Leiden and was paid 1800 guilders which was twice the usual salary. He was the University's Vice-Chancellor in 1669-70.



Work
In 1669 Sylvius founded the first academic chemical laboratory. For this reason, the building in which much of the Leiden University chemistry and natural science faculties are housed has the name Sylvius Laboratory.

He founded the Iatrochemical School of Medicine, according to which all life and disease processes are based on chemical actions. That school of thought attempted to understand medicine in terms of universal rules of physics and chemistry. Sylvius also introduced the concept of chemical affinity as a way to understand the way the human body uses salts and contributed greatly to the understanding of digestion and of bodily fluids. The most important work he published was, "Praxeos medicae idea nova, 1671" (New idea in medical practice).

He researched the structure of the brain and discovered the cleft in the brain now known as Sylvian fissure. The Cerebral aqueduct and the Sylvius' angle are also named after him.

Sylvius is credited with the invention of jenever (gin). He owned a collection of 190 paintings, nine by Frans van Mieris and eleven by Gerard Dou, in the 17th century highly valued and pricely painters.