A Philosophical Path for Paracelsian Medicine: The Ideas, Intellectual Context, and Influence of Petrus Severinus (1540-1602) (review)

It has been customary for historians of medicine and science to downplay the work of Paracelsus and his followers of the sixteenth and seventeenth centuries. This is understandable because the Paracelsians reflect a mystical, Neoplatonic, and Hermetic worldview that often seems far removed from the modern world. Their medicine was mixed with chemistry, alchemy, and religion, subjects that many historians of medicine may not wish to consider. And yet, the intense debates of the period between chemical physicians and Galenists indicate the need to explore the differences between them. In this book Jole Shackelford has given us an essential work that contributes to our understanding of this debate.

The Idea medicinae philosophicae (1571) of Petrus Severinus was one of the first attempts to synthesize the complex and difficult work of Paracelsus. It was also one of the most frequently read books of this genre, having been published in three editions (1571, 1616, and 1660)—indeed, some authors came to refer to a "Severinian School" of chemical physicians. In this work Severinus called for fresh observations in nature that would lead to a true philosophy of the macrocosm and the microcosm. However, like others of the period, he did not disown the work of the ancients; the best of their work was to be accepted, especially that of Hippocrates. Basic to his scheme were the semina: fundamental, immaterial principles out of which material bodies arise and to which they return. The semina were necessary for understanding the human body as well as the universe about us. It was important also to realize that they operated chemically and could be studied in the laboratory. As Shackelford notes, "Severinus' therapy, like that of Paracelsus, is based on the understanding that the world operates on a chemical basis, and that what the chemist may see in the laboratory can reveal the hidden principles of physiology that are valid both in the microcosm and the macrocosm" (p. 195). Although his book is not a chemical text, it is not surprising to find Severinus advocating chemically prepared medicines and suggesting that even poisons such as antimony might be prescribed in limited dosage after having been detoxified by chemical means.

An important part of Shackelford's book is the discussion of the widespread influence of Severinus. On the one hand, we are introduced to relatively unknown figures such as his fellow Paracelsian and professor of medicine at the University of Copenhagen, Johannes Pratensis—but we are also treated to a discussion of his relationship with Tycho Brahe, where we are presented with a reappraisal of his "terrestrial astronomy" and with information on his Paracelsian interests. In Shackelford's survey of sixteenth- and seventeenth-century medical literature he examines a wide spectrum of references to the Idea medicinae philosophicae. Prominent among Severinus's opponents was Thomas Erastus, whose attack on Paracelsus was penned almost immediately after the appearance of the Idea. Among English authors we find references to the Paracelsian apologies of Robert Bostocke and of Thomas Moffett (who dedicated his book to Severinus). Edward Jorden was influenced by Severinus, and even Francis Bacon had words of approval for the Idea. Among French authors Shackelford discusses Joseph Duchesne (Quercetanus) and Guy de la Brosse, and the references to Severinus in the work of Central European authors include books by Gregor Horst and Daniel Sennert. Important for our understanding of the course of the scientific revolution is the section on Ole Worm, who actively sought information on Paracelsus as a young medical student, but who had rejected this school of thought by 1618 for its philosophical as well as its heretical views.

Shackelford gives the reader a detailed account of the commentary on Severinus's work by the relatively unknown Ambrosius Rhodius (1643), and he devotes many pages to the lengthy...