by Bill Hayes
The invention of spectacles as we know them today was made independently around the year 1285 in Florence by a man named Salvino degli Armati, a fact that, oddly, wasn’t made public until after his death some thirty years later. It seems that, like a well-guarded family recipe, he shared his creation with only a select group of friends. Subsequently, though, the use of eyeglass lenses took hold and spread throughout Europe. And it was only a matter of time before someone, rather than placing lenses side by side, arranged them one before the other, thus creating a compound magnifying instrument. Official recognition for the first microscope, however, is often ceded to a Dutch spectacle maker, Zacharias Jansen, who in 1590 combined two curved glass lenses in a small tube as a means for studying minute objects. Seventy-five years later an Englishman, Robert Hooke, stirred the public’s imagination with his startling book on microscopy, Micrographia (1665). In it Hooke described and illustrated what he’d observed using his own compound microscope—the hairs on fleas and snow crystals, for example. He also unknowingly coined a new scientific term when writing on why cork floats. Under magnification, the tiny air pockets he saw looked like the small rooms in monasteries, commonly called cells. Hooke had no idea at the time that he’d discovered plant cells.
One noteworthy person who picked up a copy of Micrographia was Antoni van Leeuwenhoek. Though it’s doubtful the Dutchman could have read the English text, the lush engravings of the small-made-big must have made his brain itch. He began to tinker. Rather than duplicating the elegant but complicated two-foot-tall microscope Hooke had drawn in the book, he went in the opposite direction. Borrowing the basic design of the magnifying glass he used in his shop to inspect the weave of fabrics, he crafted a lightweight, handheld device that housed a single lens. What to others may’ve seemed like a step backward was actually a great advance. The microscope lenses in common use at the time were made of poor-quality molten glass and had a power to magnify an item just twenty or thirty times. When viewed, objects appeared to be surrounded by fringes of color, and with each additional lens the optical defects multiplied. By using one spherical lens, ground and polished from a bead of purer glass, Leeuwenhoek found he got far clearer images and a magnification of more than two hundred times.
When I recently held a replica of one of Leeuwenhoek’s microscopes, my first thought was, It sure ain’t pretty. It was punier than I’d expected, and the lens was—no pun intended—microscopic. But I held my tongue. I did not want to offend the man who’d made it, Al Shinn, who sat across from me in his ramshackle cottage in Berkeley, California. Al, in truth, had done a magnificent job in re-creating this seventeenth-century microscope, I knew, basing it on a Leeuwenhoek original preserved in the Utrecht Museum in the Netherlands. A specialist in designing high-tech optical instruments, Al had spent years studying the Dutchman’s notes and designs, experimenting with different metals, even replicating the device’s tiny screws, scoring the threads by hand.
For all the excitement it generated in its time, the design is pretty simple. A tiny lens—a two-millimeter glass bead—is held between two thin brass plates, which are riveted together. By way of a long screw, you hold the device up to your eye like a rectangular lollipop. The object you want to view is affixed to a metal pin on the back that can be rotated or repositioned using a second screw. Leeuwenhoek produced more than five hundred variations on this design during his lifetime and bequeathed the bulk of them to his devoted daughter, Maria, who had never married and who’d assisted him till his dying day. Following her death in 1745, they were all sold at auction, as per Maria’s request, yet only nine are known to exist today. This is sad but not surprising. An untrained eye would never guess their purpose. The replica resting in my palm looked like an obsolete carpentry tool, something you wouldn’t hesitate to toss from a junk drawer.
When Al had greeted me at his front door—my first time meeting him in person—I’d immediately thought, It’s Doc, the scientist played by Christopher Lloyd in the Back to the Future movies, the inventor of the time-traveling DeLorean. Al, who’s sixty and gray, had the same detonated hair, lively eyes, and endearing smile, as well as a similar lankiness. Wearing a T-shirt, sweats, and flip-flops, he cleared a path back to the kitchen, where he made me a nice strong cup of coffee. Al’s house, like the physical manifestation of an active mind, was filled with stuff: projects that appeared to be just started, half finished, or long since abandoned. I even spotted boxed chemistry and ham-radio kits that could’ve been from his 1950s boyhood. While he shares the two-bedroom home with his wife and only child, a teenage daughter, I saw scarce evidence of their belongings. It was easy to imagine his many, many interests squeezing out any of their own. In the press for space between old computers and piles of books and laundry, a lampshade doubled as a bulletin board, covered with Post-it notes. I pushed aside some newspapers on the couch and sank into a cushion.
As if to explain away the surroundings, Al admitted, “I’ve always been a tinkerer. Even since I was little, I’ve been interested in the instruments of science—radios, telescopes, microscopes.” He’d first been inspired to try replicating Leeuwenhoek’s microscope about ten years ago, he continued, while he was working for a Bay Area ophthalmic equipment company, Humphrey Instruments. At the time, Al was a principal research scientist for the firm, a high-level position he’d reached more from raw skill than from schooling. A college dropout in the early 1960s, he had made his living for many years as a “hippie jeweler—pipes, earrings, artsy-craftsy stuff,” a line of work that had drawn him from Maryland to, go figure, the Berkeley area. After Al married, his new brother-in-law informed him that Humphrey was hiring. He got a job on the assembly line and rapidly worked his way up, the ascent fueled by a natural facility for designing and building complex optics systems.
When Al left the company a few years later to pursue freelance work, he found that his high-tech experience had in no way diminished his love of the low tech. He finally had a chunk of time to perfect his replica and to engage in a little hero worship. “Everyone else in his day was looking at small things and making them bigger,” Al explained, “but Leeuwenhoek was the first guy to look for the invisible—what’s there that can’t be seen. He started with things like pond scum.”
Al Shinn’s replica of a Leeuwenhoek microscope
“And blood, right?” I interjected. “Weren’t red blood cells among his earliest discoveries?”
That’s right, Al said.
“Well, um, do you think it would be possible for me to do that—to look at some of my blood through your microscope?” I was suddenly embarrassed that I was proposing myself as a specimen. “You know,” I added, “to see my”—I now thought it best to use the scientific term—“corpuscles? Would it work?”
His face lit up. “I’ve never tried it before. But there’s only one way to find out,” he declared, “and that’s to take the experimental approach!”
“I brought a needle,” I offered helpfully.
“Really? You brought a needle?”
“Yeah, a sewing needle. To prick my finger?”
For a brief second, nothing, then a smile swept across his face. “Excellent!
“Okay,” he added, “let’s see now, somewhere here I have some microscope cover slips . . .” And Al was off, as if he heard the pinging of a tracking device somewhere in the distant clutter. I, meanwhile, gave the Leeuwenhoekian lens a good long look.
In the year 1668, around the time he started experimenting with microscopes, Antoni van Leeuwenhoek began attending public meetings held weekly in Delft by a group of area doctors. Here he witnessed autopsies, heard lectures on new areas of scientific and medical investigation, and eventually submitted for consideration his own fledgling findings. His reports caught the attention of a participating doctor, Reinier de Graaf, who was also a member of the Royal Society of London, an association of progressive European scientists, including such illustrious figures as Sir Isaac Newton. The Royal Society had the standing prac
tice of urging its members to write with news of their important discoveries. In 1673 Dr. de Graaf happily obliged, his great discovery being not an idea or a technique or an innovation, but a man, “. . . a certain most ingenious person here, named Leeuwenhoek.”
With introductions made, Antoni was thereafter invited to correspond directly with the society, a practice he would continue for fifty years. His many letters, written in colloquial Dutch, were translated into English and published in the Royal Society’s prestigious journal. Although his reports were often rambling, there was no mistaking the originality of the amateur’s research. What came through just as clearly was how fearless Leeuwenhoek was in attempting to see what no one had seen before. And I do mean fearless. He had wished, for instance, to watch gunpowder explode under his microscope, so he devised a contraption for viewing the fireworks up close and, although he nearly blinded himself, succeeded. In another wild experiment, Leeuwenhoek determined to answer the question, Why is pepper so hot? He mashed peppercorns, soaked them in melted snow (thought to be 100 percent pure water), and, several days later, prepared a sample for his lens. As he wrote in the spring of 1676, he fully expected to discover in the magnified pepper particles “sharp little needles,” which literally lacerated the tongue. Instead, Leeuwenhoek found something wholly unrelated—four different kinds of “little animals” swimming in the sampling. The first three were protozoans, the organisms he’d previously seen in pond water, but the fourth set of creatures darting about was new, a separate and much smaller breed. They resembled tiny eels, he observed, “lying huddled together and wriggling” or “moving about in swarms.” Leeuwenhoek, we now know, had discovered bacteria. (The pepper’s heat, by the way, went undiagnosed.)
Leeuwenhoek found the same “little eels” in human saliva and other substances, he reported in later correspondence to the Royal Society. Soon scientists, clergymen, and common folk were making the trip to Delft to see for themselves the cloth merchant’s menagerie. That we are surrounded, covered, and filled with countless creepy-crawly microorganisms is such a commonplace understanding today that it’s difficult to imagine how radical—and grotesque—Leeuwenhoek’s images must have seemed three-hundred-odd years ago. His letters are a bracing reminder. “I have had several gentlewomen in my house, who were keen on seeing the little eels in vinegar,” he wrote in 1683, “but some of ’em were so disgusted at the spectacle, that they vowed they’d ne’er use vinegar again. But what if one should tell such people in [the] future that there are more animals living in the scum on the teeth in a man’s mouth, then there are men in a whole kingdom?”
Although Leeuwenhoek always strived to be hospitable, the flood of visitors intruded on his precious work time. During a single four-day period, he once bemoaned, he received twenty-six separate callers. But not all drop-ins were unwelcome. Leeuwenhoek’s makeshift laboratory became a mandatory stop for visiting royalty and heads of state, including King Frederick I of Prussia. Queen Mary of England arrived unannounced one afternoon, but the Delft shopkeeper was not at home. Leeuwenhoek was crushed. This missed meeting, he wrote, “will, and must, be mourned by me all my life.” Henceforth, appointments became mandatory. Another memorable visit came from Russia’s Czar Peter the Great, for whom Leeuwenhoek demonstrated all manner of “microscopical observations,” including, as a grand finale, the movement of blood through the newly discovered capillaries. This never failed to astound people. Leeuwenhoek had designed a special microscope to which he could fasten a small, live fish. Because some fish have transparent tails, one could see blood traveling through the microscopic “tubes” connecting the tiny arteries to the tiny veins. The Russian monarch, who spoke some Dutch, was “so delighted,” a local historian wrote at the time, “that in these and other contemplations he spent no less than two hours, and on taking his leave shook Leeuwenhoek by the hand, and assured him of his special gratitude for letting him see such extreme small objects.” Leeuwenhoek returned the compliment by presenting one of his microscopes as a gift, something he rarely did. Neither did he ever sell his microscopes or teach others how to make them. Anyone who wished to see a Leeuwenhoek microscope had to pay the man a visit.
“Here we go!” Al called out to me from the hallway. With a small box in hand, he returned to his seat and began fashioning a tiny slide from two thin pieces of clear plastic. “Okay, what we’re gonna do first is mount these on the pin with a little bit of beeswax. Oh, look at that!” he said, delighted, halting his work. “Newton’s rings.”
“Huh?”
Al held the plastic shards before me. “Do you see the rainbow-colored rings there, like oil in water?”
“Oh, yes,” I responded.
He smiled. “That’s caused by the interference of the light between the two surfaces. One of Newton’s discoveries.”
Even as he struggled to mount the plastic slide, Al remarked, “We have it so much easier than Leeuwenhoek did. What did he have to do to get a thin piece of flat glass? Window glass would be way too fat, so he had to make it himself!” The trouble Al was having made me realize why Leeuwenhoek got into the habit of leaving difficult-to-mount specimens permanently in place, then making a fresh microscope.
At last Al succeeded in getting the miniature slide onto the Leeuwenhoek replica, a process that had taken a good twenty minutes. And even then, Al wasn’t sure it would work. If the slide was too thick or not balanced just so, the specimen would be too far from the tiny lens and impossible to draw into focus. “I don’t want to waste your finger prick,” he said. “Let’s try some scummy water first.” He did not even have to leave his chair to find some—a vase on the coffee table held flowers that had been dead at least a month. “That looks good and slimy,” he said, raising a stem to retrieve a drop.
Its looks were deceiving, however, as Al could find no “wee beasties” swimming in the sample. Drop after drop of smelly water he tried but, alas, nothing surfaced. Yuck, I remember thinking. Is there really water so gross that even bacteria will refuse to move in? He did not look ready to surrender, so I spoke up. “Al,” I said. “Let’s go for blood.”
While he cleaned the slide with his shirtfront, I pulled out my pack of sewing needles, selected a medium-sized one, and poked my index finger. Though I’d pushed hard, no blood appeared. I tried another spot farther down. This triggered a fleeting flashback to high school biology, though it was my lab partner’s blood we studied, not mine—a lucky flip of the coin.
“Ah, there you go,” Al said, nodding, for he’d noticed before I did that both pricks were now bubbles of blood. “More than we’ll need.
“Okay,” he coached, “now get some of it on the end of the needle. Not much, just a bit.” I handed the dipped needle to Al, who smeared the blood on the slide and gingerly lifted the microscope to his eye.
In one of his very first letters to the Royal Society, dated April 7, 1674, Leeuwenhoek noted, “I cannot neglect this opportunity to tell you that I have endeavored to see and know, what parts the blood consists of; and at length I have observed, taking some blood out of my own hand, that it consists of small round globules driven through a crystalline humidity of water.” (By “water,” he was referring to what is now called plasma, the pale liquid in which blood cells are suspended.) Writing again two months later, Leeuwenhoek elaborated, not only describing “the red globules of the blood” but also measuring them. This was standard practice for Leeuwenhoek—he fastidiously measured everything he studied—and another of the man’s innovations, making him the founder of the science of micrometry. The impulse to measure seems to have been perfectly natural to him, a numbers whiz, as well as an extension of his years as a cloth merchant and surveyor. In order to measure particles on such a small scale, Leeuwenhoek had to devise new means of comparison, such as using a single hair or a grain of sand. Thus, he reckoned that one red cell was twenty-five thousand times smaller in volume than a fine grain of sand—or about 1⁄3,200th inch in diameter. Modern measurements indicate that he was
almost dead on.
Leeuwenhoek returned over and over to studying blood, constantly refining his understanding. He compared human blood to that of different animal species and noted, correctly, that the “globules” are the same size in all red-blooded creatures regardless of total blood volume, whether in a minnow’s thimbleful, say, or a whale’s many gallons. In addition to discovering red cells, Leeuwenhoek described the coagulant properties of blood and made preliminary observations of the colorless corpuscles now known as white cells, or leukocytes. None of which is to suggest that Leeuwenhoek didn’t make errors. Sometimes when you go out on a limb, the branch snaps. For instance, for the remainder of his life, Leeuwenhoek insisted that red blood cells were spherical when, in fact, they’re more like pinched balls of Play-Doh or, if you will, like sunken jelly doughnuts. Further, in attempting to explain where in the body blood cells originate, he theorized that they formed from minute particles of food that were built up then rounded in the steady rush of the bloodstream, like pebbles polished by the tumble of waves.
He never hesitated to share the smallest details of his findings, and at times, in his nearly four hundred letters to the Royal Society, Leeuwenhoek was forthcoming almost to a fault. “Whenever I found out anything remarkable,” he explained in 1716, “I have thought it my duty to put down my discovery on paper, so that all ingenious people might be informed thereof.” A noble credo, but he did make exceptions. He never divulged exactly how he ground and polished his amazing lenses, for instance, or, as important, how he so successfully illuminated his specimens. He even admitted to having a couple of microscopes with lenses of superior magnification, a private cache he showed no one. This last bit of withholding, I believe, is a forgivable indulgence. I’d like to think that, at least for a short while, before the next generation of microscopists brought forth their own innovations, Antoni van Leeuwenhoek had the best eyes in the world.