Infection. Explanatory approaches by early modern scholars of the University of Helmstedt

Diseases are recurring challenges in history. Scholars of the early modern era also sought to understand what diseases are and how to explain their spread. In a Helmstedt disputation from 1681, the smallest corpuscles ("effluvia") flowing through the air were identified as carriers.


The power of hardly visible particles

Nature holds phenomena in store that elude our immediate visibility. The societies of the early modern era, experienced with epidemics, knew only too well that deathly diseases often creep in unnoticed and are only recognised too late. The various corpuscular, effluvial, and miasma theories, which had been formulated in the course of the 17th century by scholars such as Robert Boyle (1627-1691) and numerous others in response to Aristotelian philosophy, were to lead to virulent discourses on the question of what contagions were and, above all, how diseases actually spread through them.

The title page of the disputation


Effluvia: Everything flows through the air

These questions were also raised by the professors of physics and medicine at the Academia Julia in Helmstedt (1576-1810), the then state university of the Duchy of Brunswick-Lüneburg. There, in March 1681, the plague outbreaks of Vienna (1679), Leipzig (1680) and Wolfenbüttel (1681) provoked a disputation dedicated to the imminent threat. The professor of physics Justus Cellarius (1649-1689) and the student and later well-known epidemiologist and personal physician to Duke Anton Ulrich (1633-1714) Conrad Barthold Behrens (1660-1736) published it in the same year under the following title: Disputatio physica de penetrabili efficacia effluviorum in afficiendis corporibus animalium. The core term, "effluvia" (literally "emanations"), already shows how the Helmstedt scholars explained the phenomenon of infection: Smallest corpuscles, flowing through the air, are the triggers of the diseases. The famous English natural scientist and experimental chemist Robert Boyle had previously described these particles in his treatise De mira subtilitate effluviorum. According to Cellarius and Behrens, the effluvia are also compatible with Aristotle, who had already mentioned that earth and water produced such exhalations. Even more precisely, Robert Boyle, Kenelm Digby (1603-1665) and others used magnets and odours to show that bodies emit effluvia into the air and give these properties of themselves. How else could animals on the hunt or during the rut, such as Giovanni Alfonso Borelli (1608-1679) and again Boyle had plausibly argued, smell each other with the help of the wind across such long distances, if not through these emitted effluvia?


Subtle and all-pervading miasms

If some odours seemed to be nutritious and pestilences even odorable, harmful effluvia (also “miasmata”, from the Greek μιαίνω = "stain, defile"), as Cellarius and Behrens conclude, of course had to hold a tremendous danger: infection with deadly diseases. Since smells caused nausea and animals could transmit rabies without direct contact, doctors from Helmstedt such as Heinrich Meibom (1638-1700) and Valentin Heinrich Vogler (1622-1677) assumed that the plague was also transmitted by effluvia and entered the human body via the pores. Cellarius and Behrens impressively warned that these effluvia lasted for an extraordinarily long time, even on inanimate material. Epees, wallpaper, household utensils of all kinds, even cobwebs and money: all these things could, as famous plague doctors such as Isbrand van Diemerbroeck (1609-1674) have shown, be contaminated with the virus (which is by no means identical with our modern concept of the term!) for months. Cellarius and Behrens doubted, however that this could also be a tiny kind of worm (vermiculi), as the Jesuit Athanasius Kircher (1602-1680) had suspected in his Scrutinium physico-medicum contagiosae luis, quae pestis dicitur, since these were more a product than a cause of the infection. As the famous physician Hermann Conring (1606-1681) from Helmstedt had already criticised in his Disputatio inauguralis medica de peste, it had not yet been proven under the microscope that such animated plague corpuscles (animata ista pestis seminaria) really moved through the air like inanimate, poisonous effluvia (venenata effluvia), like Kircher believed.


Contagious theories

It goes without saying that in the 17th century there were no clear-cut terms that could have distinguished between viral or bacterial infections and it would be more than misleading to assume precursors of modern conceptions here. However, when Justus Cellarius died of severe dysentery in 1689 at the age of 40, he most likely realised on his deathbed that he had fallen victim to an infection in one way or another, as he had previously described it. What makes this disputation of 1681 so special is not so much what it might have predicted in an extremely vague way, but rather what it actually began to break away from. The various contemporary corpuscular theories, especially the ones on effluvia and miasms that Robert Boyle had developed from atomistic, Cartesian and Aristotelian philosophical themes, caused the University of Helmstedt, at the end of the seventeenth century, not to leave the unlimited throne in natural philosophy to Aristotle, whom it praised so highly.





About the author

Benjamin Wallura is a (neo-) Latin philologist and research associate at the Herzog August Bibliothek Wolfenbüttel and the Freie Universität Berlin. His research focuses on early modern scholarly- and debate cultures as well as the Central and Northern European university history of the 17th and 18th century.