“I am not very skeptical…a good deal of skepticism in a scientific man is advisable to avoid much loss of time, but I have met with not a few men, who, I feel sure, have often thus been deterred from experiment or observations, which would have proved directly or indirectly serviceable.”
CHARLES DARWIN
Swammerdam was born in Amsterdam in 1637, almost a hundred years before Linnaeus. He was to be trained, according to his father’s wishes, to be a doctor. At the time, being a doctor was what one did when interested in the sciences. Although Swammerdam began to practice the era’s crude medicine, he found greater beauty in insects than in humans. For this and other reasons, he turned from medicine to his childhood love, the insects. He would write, “The body of a beast deserves as great admiration as the human body.”1 We should just “consider both in their kind and nature.”
Swammerdam was happiest when he was at work. He had a penchant for science but he felt he had been born into a world in which most important things were already known. He was melancholic in a way we now might call depressed. He sometimes walked to cure his sadness. In the morning, he would walk along the river and observe the creatures, moving largely unnoticed among people returning home from market or going to work. There, by the water, were snails and beetles. On the mulberry were silk moths. In the sky, swifts. He would return to his house and sit down at his wooden desk near a window. There he would open his case of tools, a fine pair of scissors, a saw made from a small piece of watch spring, a sharp-pointed penknife, feathers, glass tubes, tweezers, needles, and forceps.
One morning he sat down at his microscope to work on a bee. At the time, some things were known as certainties. Beehives were run by king bees. Insects were born spontaneously from rot and filth. The insides of insects were bags of goo, formless and certainly not intricately divided into organs.
He began to take the bee apart, piece by piece. This bee was the king, a male, and Swammerdam was sure he was the first ever to dissect one, “in the history of man.” In opening the bee, Swammerdam had cracked open a new world: The inside of the bee was filled with detail, not mush! Here was new information, mystery, where none was expected. He thought of it as the first decisive advance on Aristotle in hundreds of years. Anyone could have seen what he saw, but no one had carefully looked.
Most serious scientists occupied themselves with generating general theories of the world of life by scrutinizing human life. Although microscopes were relatively easy to make or buy, few used them. Few had ever looked to the world that Swammerdam found, and those that did were as peripheral, as strange, and as obsessed as he was. They almost needed to be. Microscopy was uncomfortable and the dissections were tedious. Nevertheless, Swammerdam worked at it relentlessly. What he discovered, building on the shoulders of his contemporaries, was the intricacy of smaller life. If these big insects had organs, so too might smaller life. He might, if he persisted, find much smaller life. His microscopes were good enough to see much smaller things than insects. Swammerdam was on the verge of discovering the biology of mites and then even, though they were not yet known, microbes. He was on the verge of peering through his microscope at the world and finding the details that everyone before him had missed.
Most of what Swammerdam did was very simple. He took a microscope made of a single glass lens and a support, and he looked at things. When this superficial approach was insufficient, he dissected—organ by organ, and vein by vein. At one point he held up a trachea he had unraveled from an insect. He had inserted a needle in the trachea and stretched it out, inches and then feet, all the tube-work of life, seemingly perfect and unexplored. He was awed. He moved from the bee to the fly, then to the silkworm, and then on to the snails in the swamps around his house. In a relatively short time, Swammerdam dispensed with a several-thousand-year-old idea about the insides of invertebrates and then kept working in the hope that he might learn more.
Scrutiny, it seemed, would resolve some of the greatest mysteries that had faced humans. And because so little was known about the biological world, it almost did not seem to matter what he was scrutinizing. He began to dissect the snails that flourished in the ditches and rivers of Holland. This snail species, much later named Viviparus viviparus by Linnaeus, consumed Swammerdam. He thought he knew about snails before, but now he met “many wonders and unheard-of things that perhaps have never even been imagined.” He found those wonders in the oviduct. As he cut through the muscled body of the snail, he found pearl-like spheres. He had no idea what such small jewels might be, but their presence and number delighted him.
As he continued his dissections, he found an abundance of elongate “worms” and within each of them still smaller worms. The larger worms were parasites of the snail, and modern scientists are left to wonder at the “still smaller” worms. With the worms and the pearls, he had to confess his “ignorance and blindness as to the reason for all of this.”2
As he proceeded, he would begin to understand what he was seeing. He had found the oviduct, and in the oviduct, smaller snails. Here, inside the mother, were more snails, waiting to be born. Removed from its mother, one miniature snail swam around. It had been alive and simply waiting, “perfect in all its parts.” As he continued to study the oviduct, he found smaller and smaller snails, until his microscope failed him and he could find no more. It seemed as though they might go on forever. These were to him, “nature’s unheard-of works of art,” both “astonishing,” and, ultimately, “inscrutable.” He sat back in his chair and watched the snails inside their eggs, inside their mother, moving about. The unknown had shown itself nowhere more forcibly than in this humble little snail of Holland’s gutters. “I think about it almost every moment,” God’s “unfathomable wisdom, inventions, and omnipotence.” He had revealed what he imagined were God’s workings, the machinery of life, and his only recourse was to investigate further.
Swammerdam would discover other secrets of development. In caterpillars, he would find the soon to be revealed organs of butterflies, already formed and simply waiting. These potential bodies in the caterpillars were remarkable to him because they spoke of the origins of things. Here before his microscope was beauty that had been unknown to all of humanity before him. Were these the things, he wondered, that were meant to be seen by humans? More than anything else, what Swammerdam was revealing was that there was more to be revealed. There were intricacies, whole species even, smaller than could be seen with the naked eye.
For Swammerdam the snail was a kind of metaphor. In squinting, one might see infinitely smaller and smaller snails in the oviducts of a snail. It is hard to imagine now, but no one knew for sure that there was more to see. So too might scientists reveal more and more features with more and more scrutiny. Swammerdam speculated that better lenses might reveal more complexities, more life.3
In retrospect it is clear that Swammerdam was destined for fame and glory. But his glory would not come easy, because his research was not in the scientific mainstream. True science focused on the human body, or more often it simply attempted to devise theories without observation. Rather than simply theorizing, Swammerdam looked to what logic dictated that he should find. Swammerdam was making big discoveries and so if he hung around and kept at it, others might listen. But he did not keep at it. Instead, in 1673, he met Antoinette Bourignon.
Antoinette Bourignon had one mission: to know God. One night, God told her to “Forsake all Earthly things. Separate thyself from the love of the creatures, of all creatures. Deny thyself.” She listened. She was still a teenager, but God had contacted her directly and so she decided to join a convent. A convent would not be extreme enough for Bourignon.
Her parents would have none of it. They removed her from the convent and married her to a wealthy merchant. Antoinette put off the wedding date once, then twice, and then a third time. The merchant bristled and her family begged. Finally, she ran away, sneaking into the darkness of early morning, dressed in the clothing of a hermit. She moved between the trees and past the swamps, deep into the great wood. She had brought just a penny for food. The voice came to her again and said, “Where is thy faith? In a penny?” She threw it away. Except for her hand-sewn smock, she was naked before the world.
As she walked among the trees, she was, as a disciple would later remark, “delivered from the burden of the cares and good things of this world.” She found her soul so satisfied that she no longer wished for anything. She heard God, preached, and asked for nothing else. She traveled across Europe proselytizing her religion, as directed to her through spirits. She carried with her a printing press. The wooden press was heavy, but it was the weight of her duty. She set it up in each town and manually produced 250 pages an hour of pamphlets promoting direct, personal experiences with God.4
Swammerdam met Antoinette when she came to Leiden. He found her mesmerizing. He wrote to her and they began a correspondence in which he confessed his sins. He confessed his hubris and, ultimately, the pleasure he took in his own achievements.* With these confessions, Antoinette convinced Swammerdam to give up science and to turn to God. To her his research was an “amusement of Satan.”5
Through Antoinette’s teachings, Swammerdam came to believe that he had been chasing his own pride, chasing fame, chasing understanding for its own sake. He saw mysteries, but only through his own ego. His joy, he would come to believe, was not the joy of knowing God, but the joy of knowing, a kind of heresy.
Swammerdam destroyed many of his notes at Antoinette’s urging. Perhaps unbeknownst to Antoinette, he had, however, sent the precious drawings from his silkworm studies to his colleague Malphigi (a great discoverer in his own right). He then moved to Antoinette’s commune on an island off the coast of Schleswig. The momentum of Swammerdam’s discoveries was lost. Now that he had abandoned his work, his discoveries and the whole field might just disappear back into the margins of oblivion. Malpighi would not pick up where the work left off. Malpighi was sick of microscopes. They literally, he believed, gave him ulcers.
The microscopic world was all but abandoned during the exile of Swammerdam to Antoinette’s island. Swammerdam would enventually return from exile, but he would die young, far short of finishing his work. Yet something big had been revealed. For the entire history of man, no one had looked at the things Swammerdam had seen, but now anyone with a simple tool could. It was just that no one seemed very willing. Many scientists believed that to look so closely at God’s creation would be sacrilege. Who better to dare than a draper—a humble, grumpy, cranky, busy man, who in his spare time would catch the first glimpses of microscopic life-forms. The astronomers looked up through telescopes and saw the sky in new detail. This draper, Leeuwenhoek, looked down and saw everything else. He saw that the world was mostly microscopic. All along, the biological story had seemed to be about humans, but Leeuwenhoek would show that we were enormous and oversized—the Big Gulps of life. Linnaeus would much later show that there were more big species than had been imagined. But it was Leeuwenhoek who showed that most life was many times smaller than us.
History produces unlikely revolutionaries. Leeuwenhoek was to be, without doubt, a revolutionary. In the traditional version of the story, which is to say, the one his peers told, Antonie van Leeuwenhoek did not seem particularly destined for scientific glory and fame. He was born to a basket weaver and brewer. He had little education. He spoke only “low Dutch” and did not read the languages of science at the time, English, Latin, or French. He has been called a simpleton, both in his time and ours. He owned no books but the Bible. He worked a variety of jobs. He surveyed. He was a draper. He did some of this, some of that, and the local government and his family provided sufficient funds for some free time.6
While this version of the story yields some to pressure (he did not read English, but did often have things translated, and he had read and owned a number of books), the generalities are true enough. Relative to the scientists with whom he would eventually find himself working, he was ignorant, poorly read, and ill-prepared. Although he was a central figure in the small-town life of Delft, Holland, to the broader world—the scientific world—he was an outsider.
Leeuwenhoek married young. His wife gave birth to five children. By the time he turned forty he had held half a dozen jobs and had not yet begun to do anything scientific. At this age, he could, given life expectancies of the time, expect to live only another few years.
When Leeuwenhoek began his work, he may have already read some of Swammerdam’s work. Based on Swammerdam’s work, Leeuwenhoek would have known that fleas were the smallest living organisms, thus their parts the smallest levers and fulcrums. But one night, at the age of forty, he appears to have begun reading a picture book by Robert Hooke, called Micrographia. He may have read it, tired, by the flicker of a candle in his room. His eyes would have been worn from parsing threads by day in his work as a draper in the bottom floor of his house. Hooke’s book was in English and so it had to be translated for him. The pictures in the book were of small things: the cells of cork, a bee, an ant, a silverfish, a daddy-long-legs. They were curious things, but ones that Leeuwenhoek could find around his own house. The words were interesting too, but once he knew what the pictures showed, the pictures might have seemed enough—a view of the New World, obscured by clouds but nonetheless breathtaking.
For Leeuwenhoek, these little things that he had for all of his forty years looked at, but not seen, were beyond intriguing. They were both wildly exciting and difficult to believe. Here were things that no one until Hooke, and maybe Swammerdam, had ever seen. Leeuwenhoek had long been engaged in experiments of different kinds. He was a generally curious person, by his own accounting. He had made some physics apparatuses that had come to no attention. He thought he could have been a scientist, that he had the mind for it, but he had not gotten the right education. Yet, truth be told, his physics experiments were crude.
Without any support and as a kind of obsessive hobby, he began to create lenses, perhaps to make observations akin to those of Hooke. Hundreds of other people read the same book, and many were excited by it, but no one else was inspired to make their own microscope. We are left to wonder what in the character of this man, with no training in microscopes, no training in science, and no history of such inquiry, led him on. Now we can look back and think, “I would have built a microscope.” But no one else did and no one else really would, either, for a hundred years after Leeuwenhoek’s death.
For his first microscope, Leeuwenhoek melted two slivers of glass together and then drew them, while still hot, quickly apart. A thin piece of glass was formed, which Leeuwenhoek then lowered over a flame, allowing the thin glass to melt into a larger and larger ball of molten glass. The glass ball was placed in his simple brass frame and would serve him for now. Many broke. Many were imperfect. He labored evening after evening until he was happy with a single lens.
Leeuwenhoek did not know it yet, but this would be the first of hundreds of microscopes he would build and the first of thousands of days he spent looking through them. At night, he would go to sleep seeing microscopic creatures on the backs of his eyelids. He would dream of fleas, ants, and smaller things. His lenses, combined with his abilities to observe and to experiment, were about to open up an entire world of life.
Late one night, after having already spent hundreds of nights at his microscopes, he lit a candle. He set himself some tea and then picked up one of his better microscopes. Leeuwenhoek mounted the piece of glass in a little frame. Before he looked through the lens, he might have thought about his situation. His father had made baskets; his was a family that worked with their hands, built things. His own hands were nimble, perhaps uncommonly so. Like any amateur, he would have wondered at the importance of what he was seeing as he worked with his microscope. Had others seen what he was seeing? Were his observations novel? Delft, too, was small. If he was discovering something new, whom could he ask?
Regnier de Graaf lived not far from Leeuwenhoek. De Graaf, too, was a kind of outsider. As a Catholic in a Protestant country, he could not work at the church-run university and was otherwise disadvantaged. The “scientific establishment” resided in London, where the Royal Society of England held court. The society—of which Robert Boyle, Robert Hooke, and later Newton were members—was the ultimate arbiter of scientific knowledge. If the society published a finding, it was so. De Graaf had recently been made a member based on his work on the human ovary. De Graaf was the most famous person Leeuwenhoek knew (albeit not well). He brought de Graaf a description of the “tiny animals he observed through a magic lens.” One imagines an awkward moment as de Graaf wondered whether Leeuwenhoek was mad.
Leeuwenhoek persisted. De Graaf sent a letter to the Royal Society recommending they “get Antony Leeuwenhoek to write you telling of his discoveries.” A few months later, de Graaf died at the age of 32. In Holland, biology did not seem good for one’s health.
De Graaf’s own contribution had been to document the function of the human ovarian follicle, an understanding he borrowed in part from Swammerdam’s dissections of snails. As the snail goes, so too the ovary. By the time de Graaf’s letter was fully considered by the Royal Society, he was already dead. Had the Society ignored de Graaf’s letter, Leeuwenhoek might never have been heard from.
The letter Leeuwenhoek sent was a meandering, comical, strange, and unprofessional creature entitled, “A specimen of some observations made by a microscope contributed by Mr. Leeuwenhoek, concerning mould upon the skin, flesh, etc.; the sting of a bee, etc.” The Royal Society was equal parts intrigued and dubious. Who was this strange man who, to have seen what he claimed, must have some of the best microscopes in the world? They wrote back for him to send more letters, but remained wary. They wrote him the way a scientist now might write an inquisitive child. Keep her encouraged; she could turn into something yet.
Many, many letters would follow. The letters were personal, chatty, and full of unscientific musings about neighbors, his health, his teeth, his feces, and nearly everything else. Leeuwenhoek has been said to have had “the silly curiosity of a puppy,” but it was more than just that. His was a singular, fanatical, obsessive curiosity. Some of his letters were ignored. Others were published. Some were, to the Royal Society, wondrous, others simply awkward.
Leeuwenhoek did not always know the significance of his discoveries, because he did not know much about the greater scientific world. He was cut off, except for his letters. With de Graaf dead, there were few other scientists in Delft. Leeuwenhoek seldom traveled, so what he saw of the world was only through his letters and his microscope. The letters confirmed for him what was novel and what was boring, what was worth investing and what was better left for later. It was through his correspondents at the Royal Society that Leeuwenhoek would begin to gain esteem, both across Europe and from himself. He was very pleased when the Society liked what he had seen; it made him want to see more. It brought him great joy, for example, that Hooke agreed with his observations on human hair.
The Royal Society slowly grew to appreciate Leeuwenhoek’s skills. They could direct him to investigate anything, and a report on the subject would soon follow. He was like a rover, sending back photographs from a distant planet. Those in the society, back on Earth, enjoyed the view. In April of 1676, Leeuwenhoek rounded a crest. Leeuwenhoek, the planetary rover, had gone over a hill. He believed he had discovered something truly new and unbelievable. He sent a letter on July 28, but did not appear to mention the new discovery. He first wanted to better document what he had seen. Also, he was wary of whether anyone would believe him, because it was simply too incredible. Previously, Leeuwenhoek had merely seen finer details of things that were small, but still visible to the naked eye: a flea’s leg, a bee’s puckered mouth. Here, though, were entirely new things, new kinds of life, all around him. When he saw this new scene his first response was to call someone else over to verify that he had not gone mad. He called to his teenage daughter, “Come here! Hurry! Look what I have done! There are little animals in this rain water…. They swim! They play around! They are a thousand times smaller than any creatures we can see with our eyes alone…. Look! See what I have discovered.”7
What Linnaeus would much later do was to name visible things, most of which had already been named by locals. He then cataloged, grouped, and inventoried those species. But Leeuwenhoek had discovered more, something no one had ever seen. He barely breathed. How big was this new land? Finally, on October 19, 1674, Leeuwenhoek wrote a new letter to the Royal Society. “I hope these new observations will not seem tedious to you and I hope you will communicate them to the curious.” Leeuwenhoek then wrote for sixty pages.
It is almost impossible to convey the grandeur of the unknown world Leeuwenhoek had chanced upon and how unprepared scientists were for its discoveries. When he found little animals in his rainwater playing around and swimming, he had discovered protists—microscopic single-celled creatures. In a series of days, he had added another dimension to a world full of both benign and malevolent creatures (though it would take a hundred years to discover the latter). The microscopic world was simply unknown. Leeuwenhoek would have to forgive the Royal Society if they were not initially convinced by his observations, if they did not at first even respond to his letter.
Leeuwenhoek constantly doubted himself. He looked again and again. He spent hundreds of hours observing the same scene over and over, adjusting the lens, mounting the slide, and watching. As he tried to confirm and elaborate on his observations, Leeuwenhoek had seen not just the protists, but something even smaller. This last kind “goes about, dashing over great distances in this world of his water-drop in the little tube. What nimble creatures! They stop, they stand still as ’twere upon a point, and then turn themselves round with that swiftness, as we see a top turn round, the circumference they make being no bigger than that of a fine grain of sand.” These were bacteria. In a period of days, Leeuwenhoek had discovered two of what we now recognize as kingdoms. Before there were animals and plants, now there would also be bacteria and protists (it would take many years for the kingdoms of life to be recognized by biologists, but it is nonetheless true that two of the kingdoms were first, in those days in Delft, seen by Leeuwenhoek).
After these initial observations of the New World, Leeuwenhoek would spend many hours, measuring, watching, and verifying. He didn’t quite believe what he saw. He never grew weary, for there was so much to find. He was as comfortable as someone in a lawn chair watching swifts and drinking a beer as he watched his creatures “swim about among one another gently like a swarm of mosquitoes in the air….” But still the Royal Society hadn’t written back. What would they think?
Leeuwenhoek, while waiting for the Society’s response, began to worry that they doubted him. He did not waste time. He gathered in his neighbors to see the tiny animals. He had them look through the microscope at the living creatures, “in a quantity of water as big as a grain of millet.” Leeuwenhoek then had them each write signed testimonials to what they had seen. Some saw 10,000 tiny animals, others 30,000, others still 45,000.
Then as if to reaffirm the wildness of what he was bearing witness to, he took another measure. There “were more than 1,000,000 living Creatures contained in one drop of Pepper-water. I should not have varied from the truth of it, if I had asserted that there were 8,000,000; for if according to some of the included testimonials, there might be found in a quantity of water as big as a millet seed, no less than 45,000 animalcules. It would follow that in an ordinary drop of this water there would be no less than 4,140,000 living creatures, which number if doubled will make 8,280,000 living creatures seen in the quantity of one drop of water, which quantity I can with truth affirm I have discerned.” Just imagine, it seemed to follow, how many of these animals there might be in the world.8
The Royal Society was skeptical. They wanted to see firsthand. Robert Hooke, whose book appears to have drawn Leeuwenhoek into looking through microscopes, took it upon himself to look. He had put his own microscopes away years ago. His eyes had grown strained. Yet it seemed worth pulling the old lenses out. He found his best one, cleaned it, and then proceeded exactly as Leeuwenhoek had. Hooke was sure that his microscopes were as good as Leeuwenhoek’s were, certainly good enough to see something the size of what Leeuwenhoek had claimed to have seen. He gathered river water and steeped black pepper in it (Leeuwenhoek had used black pepper because it had been at hand and because he wanted to know what made it spicy. It was one of a nearly infinite number of things he looked at, including “white salt”), as Leeuwenhoek had claimed to have done. He could not discover any of the creatures Leeuwenhoek had “seen.” Hooke wondered why. Leeuwenhoek might have lied. Alternatively, perhaps Holland is just a more productive area for tiny creatures. Maybe they do not exist at all in England.
A few days later, Hooke looked at the pepper infusions again. Now he saw them, “vast multitudes of those exceeding small creatures.” On November 15, 1677, Hooke brought his microscope to the Royal Society meeting. Leeuwenhoek, that ignorant Dutchman, had told the truth. The members, stodgy beyond reason, gathered around Hooke to look in his tiny microscope. They were not used to lining up so—clustered, bumping each other’s shoulders—but they saw and believed.
They sent Leeuwenhoek a plaque, a diploma of membership into their elite society, and he cherished it. He had been let in. Now to get back to work and show his new colleagues what he could do. Leeuwenhoek wrote back that he would serve them faithfully “for the rest of his life.”
Although the Royal Society had seen Leeuwenhoek’s little animals, there were still some worrisome issues. For example, they had seen the animals much less clearly than Leeuwenhoek claimed to have seen them. He had remarked upon details they could not see. Was it still just his imagination filling in the details? What of these “little feet” on the microbes? What had been lost in translation? The Royal Society decided again that they needed more information. They sent an emissary, Thomas Molyneaux (later the first man to speculate that species might go extinct), to Holland to see Leeuwenhoek and his microscopes. It was a long trip. Meanwhile, Hooke took to learning Dutch so that he might read Leeuwenhoek’s letters in the language in which they were written. These were persistent men.
Once in Holland, Molyneaux offered to buy one of Leeuwenhoek’s microscopes for the Society. Leeuwenhoek by this time had many microscopes, perhaps hundreds, but he said simply, “no.” He would show Molyneaux something through one of his lenses, but they would not leave his house. In the entire world, only in this room would the microscopic world be so clearly visible. It was as if Leeuwenhoek’s house was a kind of portal. Through it, life could be seen clearly, for the first time.
Molyneaux was awed by Leeuwenhoek’s microscopes, but indignant that he could not buy one. “But your instruments are marvelous.” They showed things a thousand times clearer “than any lens we have in England.” So it would remain for the next forty-five years of Leeuwenhoek’s life. Leeuwenhoek offered simply that he wished he could show Molyneaux his best lens, and his “special way of observing,” but that he kept “that only for [himself] and do not show it to any one—not even to [his] own family.”
Molyneaux returned to England. He was frustrated. The Royal Society, of learned men and big ideas, would have to wait for the reports of microscopic life from Leeuwenhoek. More of his curious letters would come. In each letter, Leeuwenhoek offered more tantalizing information about things that he uniquely saw. Swarms of subvisible beings in his mouth, on his body, on his neighbors.
As for Leeuwenhoek’s longevity, the Royal Society need not have worried. He lived another fifty years, outliving nearly all of them and seeing for the first time parasites, sperm (his own and that of others), microbes in his teeth swimming about like pike fish, and violently animated corkscrews. He never ran out of things to look at. Everyone in Delft had soon heard of the man and his little microscopes. At the same time that Dutch painters like Vermeer were thrilled with light and painted figures that seemed to glow in the juxtaposition of reflection and shadow,* Leeuwenhoek focused light through his microscope to see things of which they could only dream.
We will never know what made Leeuwenhoek so different, so obsessed with the microscopic world. Maybe it is enough to know that he loved it, that it was endlessly fascinating, that there were mysteries enough for his lifetime and more, and that the more he looked, the more he found. Maybe we ought to wonder about everyone else who, upon realizing that such a world existed, ignored it.
In Linnaeus’s categories of life, microbes were almost entirely absent. It would be easy to imagine that Leeuwenhoek and Swammerdam followed Linnaeus in time. Linnaeus gave just four names to all of microbial life, one of them being Chaos, and was done with it, unconvinced by the life-forms that were not to him immediately apparent. He had little more patience with the insects. Yet Leeuwenhoek (and Swammerdam, for that matter) lived a century before Linnaeus. Nor was Linnaeus alone. It would take many decades before the microbes were well incorporated into the Linnaean system. Even then, they would remain a different kind of life, more known for the problems they cause than for their ecological or evolutionary significance. The joy Leeuwenhoek felt in looking at the microbial world would be largely lost and replaced with a view of tiny life that emphasized its ills. Swammerdam’s discoveries were nearly lost when he turned to religion, but when Leeuwenhoek died, the loss was more serious. If Leeuwenhoek were a rover on the foreign planet of tiny life, with his death, the rover lost contact. It could be argued that we would not see the microbial world clearly again for two hundred and fifty years. It would take that long for science to find joy in the diversity of the microbial world again. There were, of course, exceptions, but few. Leeuwenhoek’s world was, like ruins grown over by the jungle, invisible, waiting rediscovery.
One day in Delft, Leeuwenhoek dissected the eyes of a dragonfly and looked through them at his world. He saw a hundred towers where there was one. He saw a hundred of his daughters. He saw the world like a dragonfly saw it, he thought. How many other ways, he wondered, were there to see? Hooke would say, of looking at microbes through lenses like Leeuwenhoek, I “was very much surprised at this so wonderful a spectacle, having never seen any living creature comparable to these for smallness: nor could I indeed imagine that nature had afforded instances of so exceedingly minute animal productions. But nature is not to be limited by our narrow apprehensions; future improvements of glasses may yet further enlighten our understanding, and ocular inspection may demonstrate that which as yet we may think too extravagant either to feign or suppose.”9 He could not have been more right.