Eye of the Beholder: Johannes Vermeer, Antoni van Leeuwenhoek, and the Reinvention of Seeing

by Laura J. Snyder

  As one microscopist of the eighteenth century would remark, this was a world that, with its monsters of bizarre form and motion, was more eccentric even than the distant Indies. Volvox, a tiny globe of five hundred to five thousand cells, perpetually rolling through the water with no fins or other obvious source of motion; amoeba, a membrane filled with crystalline globules—microscopic objects such as these prompted the question “Now will you call such thing an animal?” When a Swiss tutor in Holland named Abraham Trembley observed freshwater hydra with a microscope in 1740—rediscovering a creature Leeuweenhoek had already seen at the start of the century—he astounded the world with his tales of the almost magical property of the organism: self-regeneration. “We cut them with scissors and knives, turned them inside-out like a stocking or a glove,” observed another natural philosopher, and yet from their pieces offspring arose. As Baker remarked of such oddities, “these are truths the Belief whereof would have been looked upon some Years ago as only fit for Bedlam.”

  The existence of such strange creatures opened up new areas of scientific study and new possibilities for understanding subjects such as human anatomy and medicine. Van Leeuwenhoek had a kind of affection for the little animals he saw, even in his own drinking water and in the plaque of his teeth, and resisted the suggestion of Hans Sloane of the Royal Society that “tiny animals” might be found in the fluid exuded from smallpox pustules. Even when he found these creatures in his excrement while suffering from an intestinal disorder, he refused to believe that the animals might have made him sick. But others shuddered to think of the dangers that lurked, unseen, all around them. In 1696 a student at Leiden expressed his amazement that anyone could escape such prevalent and invisible contagion. An anxious Nicolaas Hartsoeker steeped himself in tobacco smoke, hoping to ward off the poisonous insects that, he thought, caused the plague, while the French naturalist René-Antoine Ferchault de Réaumur wondered about the creatures of profound smallness that might be ravaging his insides at that moment. The eighteenth-century Swedish botanist Carl Linnaeus, the founder of modern taxonomy and the system of identifying organisms by reference to their genus and species, would later propose that such little beings had caused more carnage than had all the wars of the past. What we cannot see, it turns out, can hurt us. Yet although natural philosophers fretted over these pathogens, and some of them “rediscovered” bacteria seen first by Leeuwenhoek, a sustained research program of seeking microscopic causes for disease would not come until the nineteenth century—when Filippo Pacini proposed that the cholera that terrorized cities like London was caused by a microorganism (he published his work in 1854, but it was not widely known or accepted until several decades later).

  This newly unveiled world of minuscule creatures lit up the imagination of writers. Huygens’s friend Margaret Cavendish wrote an ode to “a world in an Eare-Ring,” imagining a multitude of unseen worlds on earth. William Blake advised his readers “to see a World in a Grain of Sand,” while Joseph Addison, the essayist and founder of The Spectator, remarked,

  Every part of matter is peopled, every green leaf swarms with inhabitants. There is scarce a single humour in the body of a man or of any animal, in which our glasses [microscopes] do not discover myriads of creatures. The surface of animals is also covered with animals which are, in the same manner, the basis of animals that live upon it.

  The poet James Thomson reveled in “worlds in worlds,” noting that God’s wisdom kept the invisible animals that lurk everywhere from our naked sight because otherwise we would not eat or drink anything.

  Where the pool

  Stands mantled o’er with green, invisible,

  Amid the floating verdure millions stray.

  Each liquid too, whether of acid taste,

  Potent, or mild, with various forms abounds.

  Nor is the lucid stream, nor the pure air,

  Tho’ one transparent vacancy they seem,

  Devoid of theirs. Even animals subsist

  On animals, in infinite descent;

  And all so fine adjusted, that the loss

  Of the least species would disturb the whole.

  Stranger than this th’ inspective glass confirms

  And to the curious gives th’ amazing scenes

  Of lessening life; by WISDOM kindly hid

  From eye, and ear of man: for if at once

  The worlds in worlds enclos’d were push’d to light,

  Seen by his sharpen’d eye, and by his ear

  Intensely bended heard, from the choice cate,

  The freshest viands, and the brightest wines,

  He’d turn abhorrent, and in dead of night,

  When silence sleeps o’er all, be stun’d with noise.

  The discovery of this previously invisible world upset the faith of some—why would God spend so much effort on the intricate parts of animals that could not even be seen by man’s naked vision? But for most believers, the new microscopic discoveries provided further fodder for their convictions. The unseen world offered an opportunity to experience a greater awe toward God, who had created even the lowly louse with such intricacy and beauty that men must wonder at the sight—and could wonder, now that they had microscopes with which to see it. Surely such complexity could not exist in a chaotic, godless universe, many theologians argued. The tiny beings and minuscule structures seen under the microscope became, just like the existence of distant planets and stars seen through telescopes, further proof of God’s existence. In the nineteenth century, when a debate about the “plurality of worlds” raised questions about the existence of life elsewhere in the universe, the discovery of previously unseen worlds here on Earth was used to show that faith could survive the realization that the creatures we see with our naked eyes are not the only inhabitants of God’s creation.

  The discovery of microscopic life—coming sixty-four years after Galileo’s most astounding telescopic observations—in a sense set things right in the cosmos. Galileo’s discovery of lunar craters, Jupiter’s four moons, and a multitude of previously unseen stars proved Copernicus’s heliocentric theory and upended the universe as it had been thought to exist for millennia. Once again, after Van Leeuwenhoek, humans inhabiting Earth were located in the center of God’s creation. Not physically in the middle, as they were when it was believed that every other body in the universe circled around our planet, but metaphysically. Humans were now understood as hovering, visibly, between the two parts of God’s creation that were invisible to the naked eye: those faraway stars seen with Galileo’s telescopes, and those tiny creatures seen with Van Leeuwenhoek’s microscopes.

  *1 Leeuwenhoek did not specify who the “two women” were whose teeth he examined, but since he stated that he knew they cleaned their teeth every day as carefully as he did, it is reasonable to assume they were women of his household.

  *2 Leeuwenhoek may also have been introduced to the camera obscura in his work as a surveyor.

  *3 This loss was discovered in April of 1855, when a member of the Royal Society requested to see the microscopes and was told they could not be found.

  PART 12

  New Ways of Seeing

  * * *

  -1-

  IN DELFT’S OUDE Kerk, the graves of Van Leeuwenhoek and Vermeer lie close together. The two men, who had been baptized a week apart across the Market Square in the Nieuwe Kerk, and who had spent their lives in such proximity, were close in death as well.

  Like many of the artists and natural philosophers in Delft, both men had been engaged in optical experiments. Van Leeuwenhoek had devised a method of observation that was, in a sense, circular, just like the globules he had seen in his blood. After making an initial investigation of a part of an organism, or discovering a new kind of creature in a particular kind of liquid, Van Leeuwenhoek would return, again and again, to the same body part, or the same liquid, circling back multiple times. He discussed microscopical observations of optic nerves in ten letters to the Royal Society between 1674 and 1700
alone; he observed not only the optic nerve of cows but also that of horses, codfish, flies, shrimp, sheep, pigs, dogs, cats, hares, rabbits, and birds. He boasted that he had access to human eyes—perhaps from his friend the city anatomist ’s Gravesande—and he examined the cornea of those as well, noting that there was a yellowish color to them that he had not observed in the eyes of cattle.

  Van Leeuwenhoek observed the same or similar specimens multiple times with different microscopes and using different light sources—sunlight and candlelight—in order to ensure that he was viewing them with the correct instrument, and under the best light conditions. As he told the Royal Society, “I generally notice that we come closer to the truth the more often we concentrate our investigations on one and the same thing at different moments.” It was a way of coming to better understand the object of study, but it was also a technique for learning more about the instruments being used and how they functioned under various optical conditions.

  Van Leeuwenhoek, unlike others of his contemporaries who were using microscopes, was primarily interested not in anatomy, or in microscopic life, or in generation; his main scientific preoccupation was with the microscope as an optical instrument and the practical optics of the device—the way he could make light work with his vision to enable him to see the hitherto unseen world with tiny glass lenses. Although he never studied mathematical theories of optics, his interest was with visual perception itself. That is why, while other natural philosophers like Nehemiah Grew and Robert Hooke tired of the microscope, moving on to other investigative tools, Van Leeuwenhoek never did. And it is why he examined anything anyone brought him, from the vermin found in the grain stocks of the Dutch East India Company, to the hair he collected from barbers, to whatever animal parts were brought to him by the local butcher, to blood, skin, callouses, earwax, vomit, excrement, and other bodily effusions he could get his hands on from his own body and from family, maidservants, neighbors, and others he would meet on the streets.

  Vermeer’s “experimental method” was like Van Leeuwenhoek’s, so much so that Van Leeuwenhoek himself must surely have noticed this while inventorying the painter’s work as executor of his estate. Vermeer’s way of returning, again and again, to similar scenes and similar compositions, was itself an experimental technique, like the astronomer’s looking again and again at the same part of the sky, night after night, to record what remained the same and what changed, or like Van Leeuwenhoek’s returning again and again to the optic nerve, to sperm, to his little animals in different kinds of infusions. Vermeer depicted a solitary woman, engaged in a domestic task, no fewer than fourteen times. He painted maps in nine of his pictures. He explored the theme of a woman writing, or reading, or receiving a letter six times. He painted scenes of a man and woman engaged in some kind of meeting or transaction—perhaps monetary, perhaps not—six times. Music playing was another constant theme, occurring in eight pictures. He painted tronien, or portrait-like pictures of heads—including the famous Girl with a Pearl Earring—four times in a burst of energy in two to five years (between 1665 and 1667 or 1670). Vermeer set scenes in rooms with black and white tiles ten times, and depicted oriental carpets in eleven paintings, a blue-yellow-green tablecloth in fourteen, a yellow satin mantle in ten, a blue-gray robe in seven, a yellow-brown maid’s jacket in six, and a yellow-black jacket in five.

  This repetition does not evince a lack of imagination on Vermeer’s part, but rather a desire to experiment with the optics involved in seeing the same object under different lighting conditions. Like Van Leeuwenhoek, Vermeer did not study formal optical theory, but explored the way the world appears to us through lenses as a way of understanding visual perception. This is why we need not posit that Vermeer traced his camera obscura image. He was using the device not as a drawing instrument but as an experimental apparatus, not so different from the way Van Leeuwenhoek used his microscope.

  By returning again and again to the same subjects, themes, and compositions, Vermeer was exploring how different light conditions could change the emotion of a picture, as well as the colors of its parts. This method helped Vermeer learn more about how we see under different optical conditions and how paint can depict the same object under diverse circumstances of light and shadow. Recurring motifs are painted in different ways in each picture. Flesh tones, for example, are depicted in different colors depending on the light of each scene. The same is true for the tiled floors, which are not rendered identically in the ten paintings in which they appear. And we saw that Vermeer paints the same map (the Berkenrode-Blaeu map of Holland and West Friesland) three different ways in three pictures: Cavalier and Young Woman, Woman in Blue Reading a Letter, and The Love Letter. Each time he portrayed the map, Vermeer changed its position within the composition, and altered the lighting and the color. The result is that it appears at first glance that Vermeer has painted three entirely distinct maps. But on closer inspection we realize that each representation is faithful to the original in its descriptive content and relative scale. It is, in fact, the same map, illustrated under different experimental—optical—conditions.

  -2-

  Both Vermeer and Van Leeuwenhoek were employing optical instruments as “artificial eyes” to supplement the natural organs of sight. Van Leeuwenhoek used his microscopes, and Vermeer lenses, mirrors, and the camera obscura, to see beyond the surfaces, beyond the immediately apparent—to see more than meets the eye. Both recognized that there was more to the natural world than what lay on the surface—and believed that it was part of his task as an “investigator of nature” to look deeper, to see what lies underneath. Both men were, in different ways, looking inside living things.

  Francis Bacon had instructed the natural philosopher to “vex Nature”—in a Latin phrase sometimes translated more provocatively as “torture Nature”—in order to induce her to reveal her secrets. And in Bacon’s day the study of organisms had usually involved something like torture, cutting animals open, often while still alive. Robert Hooke had expressed the hope that the microscope would do away with the need for cutting open living things. He had been repelled—as are we today—by his own investigation of respiration on living dogs, which involved cutting open a living dog, placing a tube down its throat, and pumping air through the tube while observing what happened in the dog’s lungs. The victim suffered immensely; it had to be held down firmly by at least two assistants so that its desperate squirming would not impede the investigation. As Hooke admitted, “when we endeavour to pry into [Nature’s] secrets by breaking open the doors upon her, and dissecting and mangling creatures whil’st there is life yet within them, we find her indeed at work, but put into such disorder by the violence offer’d.” Hooke hoped that the microscope would do away with the violence of vivisection, noting that “it may easily be imagin’d, how differing a thing we should find, if we could, as we can with a Microscope, in these smaller creatures, quietly peep in at the windows, without frighting her out of her usual bias.”

  It turned out, however, that the microscope encouraged looking inside living things, either through vivisection or dissection. As other investigators soon realized, it was necessary to cut open specimens—sometimes while still living—in order to learn much about them, even at the microscopic level. In at least some instances, Van Leeuwenhoek engaged in vivisection, as when he says he “took the testicle of a live rat.” One poor mite lived for “eleven weeks and one day” impaled on the specimen pin behind Leeuwenhoek’s microscope. More often, Leeuwenhoek looked inside creatures when they were already dead; he became a master at microdissection. He possessed an astonishing manipulative skill that enabled him to cut the thinnest slices of the smallest creatures; even today observers can hardly reproduce some of his dissections with the more advanced instruments and techniques available. Although Van Leeuwenhoek was cutting slices of optic nerves as early as his first letter to the Royal Society in 1673, his skill at dissection was more obvious later, in the 1680s and 1690s, when he was between for
ty-eight and sixty-eight years old. His 1680 dissection of the mite Aleurobius and the flea were among his first efforts to dissect tiny, living creatures. In 1683 and 1693 he was able to dissect the flea’s trachea, male genital organs (this may have been the gut), ovary, and parts of the mouth. In 1685 he dissected a sheep fetus at three days, the size of a grain of sand, and at seventeen days—about the diameter of a standard number two pencil. Of the latter, Van Leeuwenhoek told the Royal Society that he carefully stretched it out and was able to distinguish all the vertebrae of the spinal column, the jawbone, blood vessels, nerves, and “quite distinctly saw the brains.” He also opened the tiny abdomen, from which he “extracted several portions of the intestines.”

  Van Leeuwenhoek dissected the cornea of a calf’s eye, taking off layer after layer of membrane, until he found that each cornea consisted of at least a hundred membranes overlapping each other like scales. He dissected oysters and found their sexual organs, as well as their tiny larvae—he afterward ate his subjects, noting that they were “as savoury as ever I saw or tasted Oysters in my life!” Once he began his investigations into generation, he dissected reproductive organs of nearly every type of animal imaginable: roosters, hares, insects, fish, and dogs. Far from doing away with the violence of vivisection, the microscope offered new opportunities to cut open creatures and look inside. Nature was still being interrogated; parts of it were being tortured. But this seemed necessary in order to peer inside living things, to see what was otherwise invisible. Van Leeuwenhoek hoped that “those who investigate natural things will delve up those hitherto hidden matters deeper and deeper.”