Oswald Croll

Who was Oswald Croll?

Oswald Croll or Crollius was an alchemist, and professor of medicine at the University of Marburg in Hesse, Germany. A strong proponent of alchemy and using chemistry in medicine, he was heavily involved in writing books and influencing thinkers of his day towards viewing chemistry and alchemy as two separate fields.

Croll received his doctorate in medicine in 1582 at Marburg, then continued studies at Heidelberg, Strasburg, and Geneva. After working as a tutor, he arrived in Prague in 1597. He remained there for two years, and again from 1602 until his death. There, through Rudolf II, he came into contact with other alchemical writers such as Edward Kelley.

In 1608, Croll's opus magnum "Basilica Chymica" was first published, self-described as containing a philosophick description, confirmed by the experience of [Croll's] own labours, and application of the choicest chymical remedies drawn from the light of Nature and of Grace. It is a hefty summary of his researches, methods of preparation, and studies into chemical medicine or iatrochemistry. In 1609 his treatise "De signatura rerum" was published. Some of his work pushed for the understanding and recognition of chemical compounds and medicinal value of herbs and other processes first put forth by Paracelsus. It also discussed matters such as compound remedies, chemical organization and acted as an introduction to chemistry in later years. The second book covered alchemy's and chemistry's relation to other fields of science, especially botany, suggesting the use of the doctrine of signatures to determine the medical property of plants.