Oswald Croll

Oswald Croll, also called Crollius (c. 1563 to 1609), was an alchemist and professor of medicine at the University of Marburg in Hesse, Germany. A strong proponent of alchemy and of using chemistry in medicine, he wrote books that influenced thinkers of his day to treat chemistry and alchemy as two separate fields. He received his doctorate in medicine at Marburg in 1582, continued his studies at Heidelberg, Strasburg and Geneva, and after working as a tutor arrived in Prague in 1597, where through Rudolf II he met other alchemical writers such as Edward Kelley. His major work, Basilica Chymica, first published in 1608, summarised his methods of preparation and his studies of chemical medicine, or iatrochemistry, and pressed for recognition of the chemical compounds and herbal remedies first put forward by Paracelsus. In 1609 he published a treatise on signatures, which suggested using the doctrine of signatures to determine the medical properties of plants. He died suddenly in 1609.