ESHS/HSS Annual Meeting

Picturing the “Round Globules”: Visualizing Microscopic Observations of Ferns in Early Modern Europe

• In Event: How to Visualize the Previously Unknown – A Multidisciplinary Approach

English Abstract

Following the previous two papers, this paper presents a specific example of how early modern images of microscopic observations are pictorially represented through images of fern sorus, sporangium, and spore. In a letter published in the Philosophical Transactions of the Royal Society of London in 1705, Antoni van Leeuwenhoek described in detail his observations through the lenses of the small “round globules” on Polypodium fern leaves, referring to the sporangia that contain spores. Accompanying the description is an engraving that shows the back of a close-to-life-size Polypodium leaf with many sori, as well as greatly enlarged visualizations of the sporangium in multiple stages of opening and several spores. While there are stylistic differences, images by or for other contemporary natural philosophers—including Federico Cesi, Marcello Malpighi, and Johannes Swammerdam—visualize their microscopic observations of ferns in similar ways. Despite being subtle at times, there is an effort to pictorially represent the observations as three-dimensional as possible on two-dimensional surfaces, comparable to how Van Leeuwenhoek’s word choice of the “round globules” emphasizes that the sporangia are not just flat circles, but balls. Turning to this emphasis on three-dimensionality, this paper shifts the perspective to focus on how these images developed a shared vision of microscopic observations, instead of the microscopists’ personal experiences and individual contributions to the field, using the fern as an example. Through re-enacting microscopic observations, this paper further incorporates historical reconstruction and reverse engineering to better understand how the shared vision provides clarity and makes sense of what was observed under the microscopes.

Author

• Jessie Wei-Hsuan Chen, Huygens Institute/Royal Netherlands Academy of Arts and Sciences