Eye to Eye with a 350-Year Old Cow: Leeuwenhoek’s Specimens and Original Microscope Reunited

Unknown artist for Antoni van Leeuwenhoek, section of an optical nerve of a cow, 4 December 1674. Graphite and ink on paper. 303 x 215 mm. London, Royal Society archives, EL/L1/9. Photo credit ©The Royal Society. This is the drawing of a section of an optical nerve of a cow that Antoni van Leeuwenhoek had made by an anonymous artist in Delft. This is the image he sent to the Royal Society in the same letter in which he sent the specimens. The drawing together with his written description was supposed to guide the observations made by the Fellows of the Royal Society when they would observe his specimens in London. We can easily recognise the larger and smaller holes and the sieve-like form which he described. Comparing the photograph with the drawing, it is easy to distinguish the thicker outer layer of the nerve and the uneven holes in the middle of the nerve section.
Unknown artist for Antoni van Leeuwenhoek, section of an optical nerve of a cow, 4 December 1674. Graphite and ink on paper. 303 x 215 mm. London, Royal Society archives, EL/L1/9. Photo credit ©The Royal Society.
This is the drawing of a section of an optical nerve of a cow that Antoni van Leeuwenhoek had made by an anonymous artist in Delft. This is the image he sent to the Royal Society in the same letter in which he sent the specimens. The drawing together with his written description was supposed to guide the observations made by the Fellows of the Royal Society when they would observe his specimens in London. We can easily recognise the larger and smaller holes and the sieve-like form which he described. Comparing the photograph with the drawing, it is easy to distinguish the thicker outer layer of the nerve and the uneven holes in the middle of the nerve section.
Original Leeuwenhoek microscope with specimen envelopes sent by Antoni van Leeuwenhoek to the Royal Society in London between 1674 and 1687. The microscope is kept at Rijksmuseum Boerhaave in Leiden, the specimens are from the Royal Society in London. Photo credit ©Wim van Egmond
Original Leeuwenhoek microscope with specimen envelopes sent by Antoni van Leeuwenhoek to the Royal Society in London between 1674 and 1687. The microscope is kept at Rijksmuseum Boerhaave in Leiden, the specimens are from the Royal Society in London.
Photo credit ©Wim van Egmond

What may be the earliest surviving objects seen by microscope – specimens prepared and viewed by the early Dutch naturalist Antoni van Leeuwenhoek – have been reunited with one of his original microscopes for a state of the art photoshoot. This event allowed science historians to recapture the ‘look’ of seventeenth-century science, recording the moment digitally on film and with stunning high-resolution colour photographs for the first time.

Delft-based naturalist Antoni van Leeuwenhoek was one of the first generation of serious microscope users, famous for his high-powered single-lens instruments that enabled him to see the natural world down to the scale of large bacteria. As evidence for his 1670s and 1680s observations, narrated in letters to the London’s Royal Society, he sent a variety of specimens: cows’ optic nerves, sections of cork and elder, and ‘dried phlegm from a barrel’. In September 2019, these materials, in their original packages, flew back across the North Sea to Leiden and the Rijksmuseum Boerhaave—the Dutch national museum of the history of science and medicine—where they were reunited with an original Leeuwenhoek microscope. The museum provided the opportunity for taking photographs through the original microscope, as well as the shooting of moving images. 

Section of optic nerve of a cow
Section of an optical nerve of a cow. This compound image is created with focus stacking photography. Photo credit ©Wim van Egmond.
Leeuwenhoek made this specimen himself. He dried the optical nerve before cutting it in slices, and described how he saw “many openings, very similar to a leather sieve with large and small holes, with the only difference that the holes in the nerve are not round and they are not of the same size.” (Leeuwenhoek to the Royal Society on 4 December 1674).

Science and art historian Dr Sietske Fransen, former ‘Making Visible: The visual and graphic practices of the early Royal Society‘ postdoc at CRASSH and now Leader of the Max Planck Research Group ‘Visualizing Science in Media Revolutions’ at the Bibliotheca Hertziana – Max Planck Institute for Art History orchestrated the event. She conducted readings of Leeuwenhoek’s letters, while photographer Wim van Egmond and Rijksmuseum Boerhaave curator Tiemen Cocquyt were entrusted with the exceedingly delicate operation of filming through the priceless original silver microscope. In combining words and images, the team hope to arrive at a better understanding of Leeuwenhoek’s groundbreaking observations and his use of artists to capture microscope views.  

Cork specimen, photographed through the original Leeuwenhoek microscope with lighting from below, closely resembling imagery that Leeuwenhoek might have observed himself. The center of the image is more in focus than the outside due to field curvature of the original Leeuwenhoek lens. Photo credit ©Wim van Egmond. ​In his letter from 1 June 1674 to the Royal Society, Leeuwenhoek explains how he cut very small particles off a cork with a sharp shaving knife, which he enclosed with the letter.
Cork specimen, photographed through the original Leeuwenhoek microscope with lighting from below, closely resembling imagery that Leeuwenhoek might have observed himself. The center of the image is more in focus than the outside due to field curvature of the original Leeuwenhoek lens. Photo credit ©Wim van Egmond.
​In his letter from 1 June 1674 to the Royal Society, Leeuwenhoek explains how he cut very small particles off a cork with a sharp shaving knife, which he enclosed with the letter.

Professor Sachiko Kusukawa is the Principle Investigator of ‘Making Visible: The visual and graphic practices of the early Royal Society’, a four-year project based at the University of Cambridge dedicated to understanding the illustrative practices of the early Royal Society. She said of the photoshoot: “This event is a result of a network of scholars brought together by the ‘Making Visible’ project, an interdisciplinary research project supported by the Arts and Humanities Research Council of the United Kingdom. It shows what can be achieved through true European collaboration, thanks to the Royal Society, Rijksmuseum Boerhaave, the University of Cambridge (CRASSH) and the Bibliotheca Hertziana – Max Planck Institute for Art History.”

Antoni van Leeuwenhoek was learning how and what to see through a microscope by comparing his own observations with the images printed in Robert Hooke's Micrographia: or some physiological descriptions of minute bodies made by magnifying glasses with observations and inquiries thereupon. This richly illustrated book on microscopy was published by the Royal Society in 1665. Photo credit ©The Royal Society.
Antoni van Leeuwenhoek was learning how and what to see through a microscope by comparing his own observations with the images printed in Robert Hooke’s Micrographia: or some physiological descriptions of minute bodies made by magnifying glasses with observations and inquiries thereupon. This richly illustrated book on microscopy was published by the Royal Society in 1665. Photo credit ©The Royal Society.

Amito Haarhuis, Director of the Rijksmuseum Boerhaave, commented: “With his microscopes, Van Leeuwenhoek opened a whole new world, the microcosmos. He made it possible to see things that no human being had seen before. Thanks to this wonderful project and thanks to the latest technology, we are finally able to see in full detail what Van Leeuwenhoek might have seen 350 years ago. We couldn’t be more excited!”

Keith Moore, the Royal Society’s Librarian said: Our first colour views of the sections cut by Leeuwenhoek’s razor, with the lens made by the same hand, was a heart-stopping moment. The Royal Society will look forward to sharing the excitement with audiences in the run-up to the anniversary of this great Dutch scientist in 2023.

Jan Verkolje, Portrait of Antoni van Leeuwenhoek, 1686. Mezzotint. 296 x 227 mm. London, Royal Society archives. Photo credit ©The Royal Society.
Jan Verkolje, Portrait of Antoni van Leeuwenhoek, 1686. Mezzotint. 296 x 227 mm. London, Royal Society archives. Photo credit ©The Royal Society.

Some Background

Although Leeuwenhoek’s specimens have been imaged before, this is the first time that the latest digital techniques have been applied to the surviving specimens. Each item was recorded with still images before being filmed with a modern camera, through an original Leeuwenhoek microscope. These moving images allow researchers to replicate the changing light conditions and specimen orientation that were possible while using one of Leeuwenhoek’s hand-held devices. It is the closest recreation to date of Leeuwenhoek’s working conditions.

Antoni van Leeuwenhoek (1632 – 1723) was born in Delft, Netherlands, where he lived and worked. His interest in lens-making may have been spurred by his connection with the textile trade. He became adept at hand-crafting single-lens microscopes. In these small instruments, the lens was held within silver or brass plates. Specimens were manipulated using an ingenious pin and screw arrangement: brought close to the eye they proved to be a powerful research tool. Very few Leeuwenhoek microscopes survive and today, they are among the treasures of Early Modern science in European museums.

Leeuwenhoek sent his many observations to the Royal Society in London, for publication in the journal Philosophical Transactions. Although the written descriptions were Leeuwenhoek’s own, he collaborated with artists to capture what he was seeing in original drawings, which were engraved for wider dissemination. In a fifty-year period from the 1670s to the 1720s, Leeuwenhoek became the first, or one of the first, to see many aspects of life: he described ‘animalcules’ (micro-organisms such as rotifers), human and animal spermatozoa and investigated the structure of plants. Leeuwenhoek became a Fellow of the Royal Society in 1680.

The specimens under the lens were:

• Cork sections and elder pith, 1 June 1674
• Optic nerves of cows, 4 December 1674
• Cotton seeds, dissected by Leeuwenhoek, 2 April 1686
• ‘Heavenly paper’ [algae mats], 17 October 1687

Rijksmuseum Boerhaave is the national museum of the history of science and medicine in the Netherlands and one of the most important scientific and medical history collections in the world, home to four of the 11 remaining original Leeuwenhoek microscopes.

Footnote

Although Leeuwenhoek’s specimens have been imaged before [1], this is the first time that the latest digital techniques have been applied to the surviving specimens.
[1] Brian J. Ford, ‘The Van Leeuwenhoek Specimens’, Notes and Records of the Royal Society,36 (1981), 37-59; see also further work by him at http://www.brianjford.com/wavbiblio.htm

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Rijksmuseum Boerhaave www.rijksmuseumboerhaave.nl is the Netherlands’ national museum of the history of science and medicine. With a world-famous collection spanning five centuries of research and innovation and based on close collaboration with prominent modern scientists, Rijksmuseum Boerhaave offers visitors of all ages a fascinating insight into the world of science. The museum is winner of the European Museum of the Year Award 2019.

Bibliotheca Hertziana – Max Planck Institute for Art History in Rome promotes scientific research in the field of Italian and global history of art and architecture. Established in 1913 as a private foundation by Henriette Hertz (1846–1913), today the Bibliotheca Hertziana is part of the German Max Planck Society and one of the world’s most renowned research institutions for art history. Its impressive specialized library and vast photographic collection are an outstanding scientific resource for art historians from all over the world. 

The Royal Society is a self-governing Fellowship of many of the world’s most distinguished scientists drawn from all areas of science, engineering, and medicine. The Society’s fundamental purpose, as it has been since its foundation in 1660, is to recognise, promote, and support excellence in science and to encourage the development and use of science for the benefit of humanity. 

An Image Interview with Louisiane Ferlier

Plate from first volume of the Philosophical Transactions, 1665

Can you tell us briefly about yourself and your background?

Dr Louisiane Ferlier, Digitisation Project Manager at the Royal Society, in charge of the Royal Society Journal Collections: Science in the making. I have come to the project as an historian of ideas, my research investigates the role of religious institutions in the circulation of knowledge in the 17th century.

Which picture have you chosen, and what does it show? 

I have chosen the engraved plate inserted with issue 5 of the first volume of the Philosophical Transactions. It is composed of four figures corresponding to three articles from the issue published by Henry Oldenburg on July 3rd 1665.

Figure 1 relates to an article by Robert Moray entitled ‘An Account, how Adits & Mines are wrought at Liege without Air-shafts’. It shows a brick chimney and details how air, ash and minerals circulate within it.

Figure 2 and 3 are connected to the previous article as they show the promising invention by a Monsieur Du Son of a tool to ‘break easily and speedily the hardest Rocks’ which was communicated to Oldenburg by Moray. Resembling a stake, the tool was to be used as a chisel to drill through hard rocks when constructing mineshafts.

Figure 4 is the best known of the group and illustrates a two-part article communicating Robert Boyle’s description of a monstrous calf. The calf was born with a monstrous head described in the article as having ‘no sign of any Nose (…) the two Eyes were united into one Double Eye […] Lastly, that just above the Eyes, as it were in the midst of the Forehead, was a very deep depression, and out of that grew a kind of double Purse or Bagg.’ Alerted by the farmer of the monstrous birth, Boyle ordered for the head to be cut and preserved in alcohol.

Why have you chosen this image? 

This image frames powerfully the variety of topics discussed during the early meetings of the Royal Society and the wide range of scientific illustrations that can be found within the Philosophical Transactions. The juxtaposition of figures representing engineering tools next to the sketch of a zoological wonder captures the origins of the two strands of science which were separated into the A and B sides of the Philosophical Transactions in 1887 (A = mathematical, physical and engineering sciences and B = biological sciences).

I find that this juxtaposition creates a particularly interesting tableau reflecting the complexity of disciplinary boundaries in the early modern period. Considered as a single plate within a single publication, the plate unites scientific illustrations vastly different in their aims, executions as well as subjects. And, taken separately, each of the figures would lead us to discover a different network of correspondents, witnesses and collaborators, all supporting science in the making in a different way.

How does this image resonate with you in the context of your work or research?

The aim of the project I manage at the Royal Society is to create a new digital archive of its original journal collections. Illustrations such as this one are what motivated me to join the project in the first place. The archive will contain this image, its related articles and several thousands of others in high definition. It will allow researchers, curious visitors and future scholars to wonder about this strange creature, and wander from its representation to its fascinating description by Boyle. Or, to discover that mines are discussed throughout the history of the Royal Society and that a fascinating history of mining could be retraced from this illustration to the twentieth century through the pages of the Philosophical Transactions.

In many ways this image symbolizes the richness of the Philosophical Transactions as an archive of science.

Do you know anything about the making-process of the image? Does knowing how the image was created affect your understanding of the image?

I also picked this image precisely because I know very little about the original draughtsman of each figure as they could have been drawn by various people. The digging tool for instance could have been drawn by Monsieur du Son, its inventor, or equally, by Moray who communicated it to Oldenburg. The calf’s head, although it is described by Boyle, could have been drawn by another observer after it was preserved in alcohol (which would explain why the observer did not include the rest of the body, which Boyle did see before he had the head removed). The many hands through which each sketch must have travelled before that of the engraver are unknown, and even the engraver did not sign this specific plate.

This is an ideal example of a puzzle to offer to the ‘Making visible project’ where each piece is, in itself, another puzzle. Knowing about the specific of the making-process would reveal much about the circulation of knowledge in the early modern period.

What significance does the image have for the historical understanding of the relationship between knowledge-making and image-making?

The composite nature of the plate displays side by side two technical drawings and a natural history drawing. Much of the scholarship which discusses early image-making focuses on natural history but technical drawings used fascinating techniques to ‘truly’ and ‘faithfully’ represent science in the making. The engraving also encapsulates the complexity of scientific illustrations: without a scale or measures dedicated to each figure, the tool is of the same proportions to the shaft and the calf’s head with its dark lines attracts any viewer’s eye away from the technical drawings. The composition of the plate therefore transforms the experience of each figure. Moreover, each figure depends very heavily on its description included in the related articles to make any sense, yet, there is no explicit reference on the plate to the article.

Do you have any additional thoughts or comments on the image you would like to share?

I always thought that representing the calf’s head in profile was a strange choice: if the calf has no nose and a single eye, a front-facing view would be an easier perspective to depict the monstrosity. Accentuating the twisted tongue and the protuberance on the forehead, I find that the profile view makes him look nearly mischievous: as if he was pulling its tongue and winking at the reader.

An Image Interview with Alice Marples

Studies of a Crocodile or the Leviathan in Musaeum Regalis Societatis, 1686.
Studies of a Crocodile or the Leviathan from Nehemiah Grew, Musaeum Regalis Societatis, 1681

Tell us briefly about yourself and your background?

Alice Marples, historian of science and medicine in the 17th and 18th centuries, broadly interested in the social and cultural history of knowledge collection and exchange. My recently completed thesis explored diverse collecting and correspondence practices within medical and natural historical communities in Britain in the early eighteenth century, and examined how the physician and naturalist Hans Sloane influenced the institutionalisation and popularisation of science in Britain. Currently a postdoctoral research associate at the John Rylands Research Institute at the University of Manchester, working on medical education in Manchester between 1750-1850.

Which picture have you chosen, and what does it show?

This is an illustration entitled ‘Studies of a Crocodile or the Leviathan.’ It is a table from the 1686 edition of Musaeum Regalis Societatis, which was the catalogue of the contents of the Royal Society Repository (or Museum) written by its Keeper, Nehemiah Grew, and first published in 1681. It is a three foot, fold-out picture of one of the prize objects of the collection, a fifteen-foot crocodile.

Why have you chosen this image?

Crocodiles might be said to be symbolic of the Renaissance practice of natural history collecting. They were the jewel in most virtuoso’s collections and regularly feature in the visual representations of Cabinets of Curiosity or Kunstkammer, such as in Ferrante Imperato’s Dell’Historia Naturale (1599), which showed the crocodile suspended from the ceiling in his collection displayed at the Palazzo Gravina in Naples. Their ferocious appearance and exotic qualities helped to inspire wonder in the glory of God, his natural world, and those who were able to possess extraordinary pieces of it.

How does this image resonate with you in the context of your work or research?

For me, this image represents the ways in which the Society argued for a new, modern kind of science through the tropes and traditions of earlier forms of inquiry. Grew’s inclusion of the crocodile directly invokes the spectacle of the early modern scholarly Cabinet while simultaneously situating the Society’s Repository as its rational successor, bringing the crocodile down from the ceiling, dissecting, measuring and displaying its interior skeleton for all to see. Grew’s catalogue was a lavishly illustrated folio, one of the first scientific works produced entirely by subscription. It was a luxury commodity designed to popularise the work of the Society within polite circles, and invoke wonder not only in God but in the instruments and methods of ‘the New Science’ in bringing it under control and revealing its inner mysteries. I think that it is particularly pertinent that Grew explicitly includes a reference to the creature as the Leviathan in the Book of Job – a monstrous creature which no man can harness… Except, perhaps, in a company of natural philosophers.

Do you know anything about the making-process of the image? Does knowing how the image was created affect your understanding of the image?

Though it is not clear who made the drawing, the text accompanying it states that the specimen itself was ‘Given to Sir Robert Southwell; to whom it was sent from the East-Indies.’ Objects, drawings and scraps of knowledge were being sent from all over the world to private collectors and scientific societies via extensive and overlapping scholarly and commercial correspondence networks, all of which depended on multiple forms of authority. In the Catalogue, this picture is accompanied by an extensive description, the longest in the work, which includes information from many different accounts of the crocodile from ancient times to the present. It therefore places the Catalogue, and the Royal Society, fully in contemporary context of information exchange and, particularly, the increasing number of natural historical works attempting to compile, compare and systematise this in-flood of information about the world. Representing the skeleton of the crocodile according to scale alongside this text linked these efforts, the material with the historical, and implied that the Royal Society was an integral part of this process of knowledge production. Further, that it represented the sole means of epistemological arbitration.

What significance does the image have for the historical understanding of the relationship between knowledge-making and image-making?

Also on this page are drawings of ‘An Elephant’s Tusk’, ‘A Rattle Snak’s tail’ and ‘The Wessan’ (the windpipe of the crocodile) – all chosen, perhaps, for their similar aesthetic qualities. This helps to remind us that the comparative acts of looking in the physical space of the collection were also mirrored on paper and engineered through texts, and that the material boundaries between objects were liminal. Catalogues reflected, disseminated and imagined physical stocks of knowledge, interacting with published tracts, tacit knowledge and correspondence networks, allowing individuals to work with collections from a distance. The arrangement of similar but diverse objects together was designed, in part, to draw links between them: Grew’s Catalogue extended this comparative reach out from the Repository, to readers in the comfort of their own homes, with their own libraries, collections, reports and borrowed objects.

Do you have any additional thoughts or comments on the image you would like to share?

Grew’s catalogue was so successful at creating an image of power and intellectual authority for the Royal Society – an image which was retained through the Philosophical Transactions and the personal correspondence networks of Fellows – that visitors in the eighteenth century were often appalled by the relatively humble nature of the institution when they went to visit. Zacharias Conrad von Uffenbach, for example, wrote in 1710 of his shock that ‘the finest instruments and other articles (which Grew describes), [lie] not only in no sort of order or tidiness but covered with dust, filth and coal-smoke, and many of them broken and utterly ruined.’ I think this should serve to remind us that the physical possession of objects or knowledge was not necessarily as important as historians have sometimes deemed it, and that there was always a distance between the image and reality of the Royal Society.

Johannes Swammerdam’s Scientific Images (I)

By Eric Jorink

Fig. 1: Drawing by Johannes Swammerdam, Royal Society Archives LBO/6/58 © Royal Society

On 4 March 1673, Johannes Swammerdam sent a letter to Henry Oldenburg, including these images (fig. 1). Only an abstract of the letter appeared in the Philosophical Transactions (19 May 1673, page 6041), without including what was basically the point of the message: a visual report of observations of the pulmonary arteries of a frog, and of the genital system of the horn-noosed beetle. As a biographer of Swammerdam, I find these images fascinating, both for their intrinsic quality, as for the fact that they are a nice point of departure for some thoughts on the role of the visual in early modern scientific culture.

Like Robert Hooke, Swammerdam was a skilled draftsman. During his years as a student in Leiden (1661-1667) he did pioneering research on insects, toads and other forms of low life. Swammerdam maintained that all creatures, great and small, obeyed the same laws of nature. He rejected the theory of spontaneous generation, according to which insects were devoid of an internal anatomy and had their origin in decaying flesh or plants.

Fig 2: The water gnat, as depicted by Robert Hooke in Micrographia (1665). © Royal Society
Fig 2: The water-gnat, as depicted by Robert Hooke in Micrographia (1665). © Royal Society
Fig. 3: the water gnat, as depicted by Robert Hooke in Micrographia (1665) and Johannes Swammerdam, Historia generalis insectorum (1669). Swammerdam depicts the creature in its context, both life sized and enlarged (ca. 15 times).
Fig. 3: the water-gnat, as depicted Johannes Swammerdam, Historia generalis insectorum (1669). Swammerdam depicts the creature in its context, both life sized and enlarged (ca. 15 times). © University Library Leiden

Swammerdam considered it his duty to point to the marvels of God’s creation. Swammerdam was very much aware of his talent as an anatomist and draftsman. He applauded the publication of Hooke’s Micrographia (1665), Redi’s Esperienze intorno alla generazione degl’insetti (1668) and Malpighi’s De Bombyce (published by the Royal Society in 1669) and considered them as allies in his campaign against spontaneous generation.

In his Historia insectorum generalis (1669) Swammerdam demonstrated that all insects come from eggs, and all go through a stage-like development. Occasionally, he also went into a visual dialogue with Hooke (figs 2 and 3). Whereas the latter famously had represented the alien micro-world with no visual clues of the absolute size and context of the objects portrayed, Swammerdam employed a technique in which each creature was represented both life-size, and magnified. The microscope was only used occasionally. Graphically, he showed the uniformity of nature, pointing at similarities between the development of an insect, frog and carnation (figs 4 and 5).

Figs 4 and 5; the stage-like development of the louse; and the frog and carnation as depicted in Johannes Swammerdam, Historia generalis insectorum (1669). Visually, the uniformity of nature is demonstrated. Each creature is depicted life sized, and enlarged in various stages of development.
Figs 4 and 5: The stage-like development of the louse; and the frog and carnation as depicted in Johannes Swammerdam, Historia generalis insectorum (1669). Visually, the uniformity of nature is demonstrated. Each creature is depicted life sized, and enlarged in various stages of development. © University Library Leiden
Fig. 5. © University Library Leiden

In Historia insectorum Swammerdam concentrated on the outward appearance of insects. Inspired by the work of Malpighi from 1670 he now focused on anatomizing and using the microscope more intensively. Studying and representing the inner parts of these tiny creatures required new visual techniques. Since Swammerdam observed what no one before him had seen, he had to train his eye with regard to the observations, and invent ways to represent them. Without external aid, showing the strange and previously unseen forms of isolated organs of a creature would make no sense.

The images Swammerdam sent to Oldenburg could be seen as experiments in form. Compared to the visual strategy he previously used, Swammerdam was now both zooming in and zooming out. To make an easy start: the creature depicted in figure V in the right lower corner marked A (see fig. 1 above) is easily recognizable as a nose-horned beetle (depicted at life size). The drawing is deceptively simple, but shows Swammerdam’s talent to represent the creature with just a few well-chosen lines and brushes of ink. Swammerdam deeply admired the work of artist Joris Hoefnagel (1542-1600), who at the end of the sixteenth century had made pioneering watercolors of all kinds of insects. We could read Swammerdam’s sketch as a self-aware introduction to the beholder – see how easily I can draw things familiar to you; you can also trust me when I show you places and things unknown to you. Later drawings by Swammerdam of the nose-horned beetle (fig. 5) are much more elaborated, and can be seen as explicit references not only to Hoefnagel but also to the works of art by Jacques de Gheyn (1565-1629) and even Albrecht Dürer.

Fig. 6: Some beetles; the male genitals system of the nose-horned beetle (fig. viii). Swammerdam drew this in 1678 for his Biblia Naturae; the manuscript, now kept in Leiden university Library, was only published in 1737. Leiden, UB, BPL 126B, fol. 31r. © University Library Leiden

By now, we should refer to the letter. By focusing on the creature’s inner parts, Swammerdam uses the strategy of both mapmakers and earlier anatomists: the legend. He writes: ‘Figure V expresses to the life (‘ad vivum exprimit’) the genitalia of the horn-nosed beetle. A the beetle, B the horny part of the penis, C the place from which the penis protrudes when erect….’ Etcetera. What we see are interior details: strangely shaped organs, curled lines, flower-shaped structures. Using a legend is a successful strategy here, and perhaps the only workable way in representing the previously unknown. Moreover, as Swammerdam occasionally stressed to his readers, the slightly stylized drawings also helped the observer who for the first time would enter this unknown territory to discern and identify the organs in there. Swammerdam also employs this strategy in the Figures I-IV (fig. 1), where he illustrates the passage in which he explains in painstaking detail the pulmonary artery system of the frog. These drawings are the few by Swammerdam I know of in which color is used. This had a practical reason: the drawings represent, as Swammerdam put it, ‘graphically’ (‘graphice exprimit’) how the structure within the lungs had been made visible by injecting colored wax. Hence, what we see is a representation of a preparation interacting with a text.

The point is, of course, that without the accompanying letter, the images become meaningless, and vice versa. Some of Swammerdam’s letters and images are still at the archives of the Royal Society (now separated, to be sure). They remind us that in the scientific culture of the 1670s the boundaries between words and images, and between science and art, were still rather fluent ones.