Johann Christian Polycarp Erxleben (22 June 1744 – 19 August 1777) was a German naturalist from Quedlinburg.
Erxleben was Professor of physics and veterinary medicine at the University of Göttingen. He wrote Anfangsgründe der Naturlehre and Systema regni animalis (1777). He was founder of the first and oldest academic Veterinary School in Germany, the Institute of Veterinary Medicine, in 1771.
He was Dorothea Christiane Erxleben’s son, who was the first woman in Germany to be promoted to a medical doctor.
Christian Ehrenfried Weigel (24 May 1748 – 8 August 1831) was a German scientist and, beginning in 1774, a professor of Chemistry, Pharmacy, Botany, and Mineralogy at the University of Greifswald.
Born in Stralsund, in 1771 he received his degree, having studied under Johann Christian Erxleben in Göttingen. In 1806, Weigel was ennobled and carried from then on a “von” in his name. He became the personal physician of the Swedish royal house two years later. Among other things, Weigel developed a cooling heat exchanger (German Gegenstromkühler) (1771), which was later improved upon by Justus von Liebig and then became to be known as the Liebig condenser (Liebigkühler). Furthermore, the Genus Weigela is named after him.
