Lab Girl

by Hope Jahren

  To this end, I posted sentry around several living hackberry trees in Minnesota and South Dakota in order to compare cold with (relatively) warm environments. I planned to collect the fruit periodically over the course of a year. Back in the lab in California, I would cut hundreds of these fruits into paper-thin slices, and then describe and photograph them under the microscope.

  When I looked through the microscope that magnified it by a factor of 350, the smooth surface of the hackberry pit resembled a honeycomb all stuffed full of something hard and crumbly. Using the concept of a peach pit as a place to start, I soaked several hackberry pits in an acid that I was sure could dissolve at least a bushel of peaches, and then examined what was left. The stuffing had dissolved out from within the honeycomb, leaving its lacy white scaffolding behind. When I placed the wee white structure in a vacuum and heated it to fifteen hundred degrees, carbon dioxide was released, which meant that there was something organic inside the white lattice—yet another puzzling layer.

  The tree had grown a seed, spun a stringy net around it, coated the net in some kind of skeleton, and then stuffed the holes full of the same material that makes up a peach pit. By doing so, it protected the seed, giving it a better chance of sprouting and therefore growing into a tree, and perhaps begetting ninety generations of additional trees. If we were going to get any long-term climate data out of these fossil seed pits, this lacy white lattice was clearly a strongbox of information. And once I knew what this most basic part of the seed pit was made of, I’d be on my way.

  Just as each type of rock forms differently, they each fall apart differently too. One way to distinguish among the different minerals that are the building blocks of rocks is to smash a sample thoroughly and expose it to x-rays. Each grain of salt in a saltshaker is a perfect cube when viewed up close. Grind one grain into a fine powder and you have shattered it into millions of tiny, perfect cubes. The inescapable cube shape of salt persists because the very atoms that comprise pure salt are bonded together in the shape of a square scaffold that outlines an endless number of cubes. Any break to this structure will occur along the planes of weakness that define these bonds, resulting in more cubes, all repeating the same atomic pattern right down to their smallest components.

  Different minerals have different chemical formulas, reflecting differences in the number and type of atoms they contain and the way those atoms are bonded together. Such differences give rise to differences in shape that persist even in powder form. If one can figure out the tiny shapes present in a pinch of mineral powder—even the heterogeneous powder from an ugly, complicated rock—one can also determine its chemical formula.

  But how to see the shape of these tiny crystals? After an ocean wave hits a lighthouse, a ripple bounces back across the ocean. The size and shape of this reflective ripple carry information about both the wave and the lighthouse. If we are anchored in a rowboat far away, we can distinguish a lighthouse with a square base from one that is rounded by the way the ripple hits us, provided that we have a very good idea of the size of the wave, its energy and timing, and the direction it has traveled. This is similar to how we work out the tiny shapes within mineral powder, using the ripples that bounce back, or diffract, from very small electromagnetic waves known as x-rays. A piece of film catches the ripples at their peaks, and their spacing and intensity allow us to reconstruct the shape off which they bounced.

  In the fall of 1994, I asked permission for access to the x-ray diffraction laboratory that was situated across campus from my usual lab, and I was allotted some hours during which to use the x-ray source. I looked forward to my analyses with the same happy anticipation one brings to a baseball game: anything might happen, but it will probably take a long time.

  After much deliberating, I had chosen to reserve the machine at night, but I wasn’t sure that I had made the best choice. There was a creepy post-doc who worked in that lab, and I was uncomfortable with his surly demeanor. I’d seen how the slightest look or question could set this guy off on a rage, and he seemed particularly menacing toward the odd female who stumbled into his orbit. Thus I had a dilemma: If I came during the day, I’d be sure to see him, but there would be people around who might serve as human shields. At night, I’d likely have the place to myself, but on the odd chance that he did come in, I’d be an easy mark. In the end I signed up for a midnight shift and brought a three-quarter-inch ratcheting wrench along with me. I wasn’t quite sure how I would actually defend myself with the tool if something happened, but just having the weight of it in my back pocket made me feel better.

  When I got to the x-ray diffraction laboratory, I placed a glass sample slide onto the countertop, covered it in fixating epoxy, and sprinkled it with powder from the ground hackberry pit. I placed the slide into the diffraction machine and oriented everything carefully, and then activated the x-ray source. After lining up the strip chart, I said a silent prayer that its unobservable inkwell was full enough to last the entirety of the run, and then I settled in to watch and wait.

  When a lab experiment just won’t work, moving heaven and earth often won’t make it work—and, similarly, there are some experiments that you just can’t screw up even if you try. The readout from the x-ray displayed one clear, unequivocal peak at exactly the same angle of diffraction each time I replicated the measurement.

  The long, low, broad swoop of ink was totally unlike the stiff, jerky spikes that my advisor and I thought we might see, and it clearly indicated that my mineral was an opal. I stood and stared at the readout, knowing that there was no way I had—or anybody could have—possibly misinterpreted the result. It was opal and this was something I knew, something I could draw a circle around and testify to as being true. While looking at the graph, I thought about how I now knew something for certain that only an hour ago had been an absolute unknown, and I slowly began to appreciate how my life had just changed.

  I was the only person in an infinite exploding universe who knew that this powder was made of opal. In a wide, wide world, full of unimaginable numbers of people, I was—in addition to being small and insufficient—special. I was not only a quirky bundle of genes, but I was also unique existentially, because of the tiny detail that I knew about Creation, because of what I had seen and then understood. Until I phoned someone, the concrete knowledge that opal was the mineral that fortified each seed on each hackberry tree was mine alone. Whether or not this was something worth knowing seemed another problem for another day. I stood and absorbed this revelation as my life turned a page, and my first scientific discovery shone, as even the cheapest plastic toy does when it is new.

  I didn’t want to touch anything, because I was just a visitor. So I stood and looked out the window, waiting for the sun to come up, and eventually a few tears ran down my face. I didn’t know if I was crying because I was nobody’s wife or mother—or because I felt like nobody’s daughter—or because of the beauty of that single perfect line on the readout, which I could forever point to as my opal.

  I had worked and waited for this day. In solving this mystery I had also proved something, at least to myself, and I finally knew what real research would feel like. But as satisfying as it was, it still stands out as one of the loneliest moments of my life. On some deep level, the realization that I could do good science was accompanied by the knowledge that I had formally and terminally missed my chance to become like any of the women that I had ever known.

  In the years to come, I would create a new sort of normal for myself within my own laboratory. I would have a brother closer than any of my siblings, someone I could call any hour of the day or night and gossip with more shamelessly than I ever had with my girlfriends. Together, we would devote ourselves to exposing the absurdity of our endeavors and continuously remind each other of particularly ridiculous examples. I would nurture a new generation of students, some of whom were just hungry for attention, and a very few who would live up to the potential that I saw in them. But on that night, I wiped my face
with my hands, embarrassed to be weeping over something that most people would see as either trivial or profoundly dull. I stared out the window and saw the first light of the day spilling its glow out upon the campus. I wondered who else in the world was having such an exquisite dawn.

  I knew that before noon I would be told that my discovery was not special. An older and wiser scientist would tell me that, in fact, what I had seen was something that he himself might have assumed. While he explained that my observation wasn’t a true revelation, only a confirmation of what should have been an obvious guess, I listened politely. It didn’t matter what he said. Nothing could alter the overwhelming sweetness of briefly holding a small secret that the universe had earmarked just for me. I knew instinctively that if I was worthy of a small secret, I might someday be worthy of a big one.

  By the time that the sunrise had burned through the Bay Area fog, I felt lifted out of my maudlin mood as well. I walked back to the building where I usually worked in order to start my day. The chilly air smelled of eucalyptus in a way that will always remind me of Berkeley, though the campus was quiet as death. I let myself into the lab and was surprised to find that the lights were on. I then saw Bill, who was sitting on an old lawn chair in the middle of the room and staring at a blank wall while listening to the static of talk radio on his little transistor.

  “Hey, I found this chair in the Dumpster behind McDonald’s,” he told me as I walked in. “It seems to work.” He examined it with satisfaction while still sitting upon it.

  I felt deeply happy to see him. I had anticipated at least three more lonely hours of waiting for someone to talk to.

  “I like it,” I told him. “Can anybody sit in it?”

  “Not today,” he said. “Maybe tomorrow.” He considered and then added, “But maybe not.”

  I stood and thought about how every single thing that came out of this guy’s mouth was just a little on the weird side.

  Against my Scandinavian instincts, I decided to tell Bill about the most important thing that I had ever done. “Hey, have you ever seen an x-ray of an opal?” I asked, holding up my paper readout.

  Bill reached for his radio and silenced it by pulling out its nine-volt battery—the on-off switch had stopped working long ago. After he finished, he looked up at me. “I knew I was sitting here waiting for something,” he told me. “Turns out it was that.”

  ***

  After I discovered that the hackberry pits contained opal, my next goal was to discern a way to back-calculate the temperature that governed its formation within the seed. While the scaffolding of the hackberry shell was indeed made of opal, the crumbly stuffing was made from a carbonate mineral called aragonite—the exact same mineral found in a snail’s shell. Pure aragonite is easy to precipitate in the laboratory; one just mixes two supersaturated fluids, and the crystals rain out of the clear mixture like mist condensing within a cloud. The isotope chemistry of the crystals is strictly controlled by temperature, which means that by measuring the oxygen isotope signature of a single crystal, we could predict the exact temperature at which the solutions were mixed. I could make this work in the lab one hundred times out of a hundred. It was foolproof. My next task was to show that it also worked within a tree, that the same process was happening inside the fruit, where aragonite crystals formed as tree-sap solutions mixed.

  My advising professor had pitched this idea as a fifteen-page grant proposal to the National Science Foundation, the peer-reviewers had liked it, and we were recommended for funding. And so, in the spring of 1995, I was headed back to the Midwest to look for the perfect trees to study. I decided upon three full-grown hackberry trees that I found growing on the banks of the South Platte River near Sterling, Colorado, less than a day’s drive from a couch where I was always welcome. Under what felt like the biggest, bluest sky in the world I calculated how the composition of the river, taken with the composition of that summer’s fruit, would allow me to solve for the average temperature of the season. Confident of success, I corded off the trees and began to monitor them like an expectant father—delighted in anticipation of the gift, but tangential to the proceedings. I also became similarly bewildered during the thick of things, because during that particular summer none of the hackberry trees at or near the site flowered or bore fruit.

  Nothing in the world exposes human helplessness and folly quite like a tree that will not bloom. Unaccustomed to people—let alone things—that wouldn’t eventually do what I wanted them to do, I took it hard. I analyzed the situation with my only friend in Logan County, Colorado: a guy named Buck who worked behind the counter in a liquor store at the highway crossing. I had gone into the store more desperate for air-conditioning than for beer, truth be told, but after Buck carded me he grudgingly admitted that I was “holding up pretty good for an old lady,” and I took it as an invitation to hang around. As the summer wore on, Buck was increasingly bemused that he was having more luck with his scratch-offs than I was with my trees, but he refrained from rubbing my nose in the irony of my prior lectures on lottery statistics.

  Buck had grown up on a ranch nearby, and so I vaguely felt he was a party to the whole fruit debacle, or at least that he should be answerable to it. “But why didn’t they bloom? Why this year?” I urged the question on Buck. I had pored over the local climate records and found nothing conspicuous in the weather.

  “It just happens sometimes. Somebody around here could have told you that,” he said, dispensing the grim pity that is rarely to be had from cowboys.

  I was convinced that the trees were giving me a sign and that my future career was unraveling. I was panicking, picturing myself on the assembly line, trimming the jowls off of dismembered hog heads, one after the other after the other, for six hours a day, just as the mother of my childhood friend had done for nearly twenty years. “That’s not good enough,” I answered. “There has to be a reason.”

  “Trees don’t have a reason, they just do it, that’s all,” Buck snapped. “In fact, they don’t do anything, they’re just trees, they just are. Shit, they’re not alive, not like you and me.” He had finally gotten fed up, and something about me and my questions was irritating him.

  “Ke-rist-on-a-crutch,” he added in frustration, “they’re just trees.”

  I left the shop and never went back.

  I returned to California in failure. “Well, if I had a car that I thought could make it over the Concord Bridge I’d say let’s go set one of those trees on fire,” Bill said as he concentrated the crumbs from the bottom of his Lay’s potato chip bag using one of the lab’s funnels. “We’ll let the others watch that one burn for a while and then ask them if they don’t feel a little more inclined to bloom.”

  Bill had become a fixture in my advisor’s laboratory. He appeared sometime around 4:00 p.m. each day and then stayed for eight or ten hours, as his spirit and our needs moved him. He couldn’t see how the fact that he was given pay for only ten hours a week was relevant, and he was surprisingly content to listen to me talk obsessively about my trees for hours each night while we worked. Before my last trip to Colorado, Bill had urged me to take a BB gun and indulge in a couple of afternoons of shooting at leaves and branches.

  I declined. “Not that I’m an arborist or anything, but I don’t think it will help.”

  “It will make you feel better,” he said emphatically. “Trust me.”

  That whole summer in Colorado was a data-gathering bust, but it taught me the most important thing I know about science: that experiments are not about getting the world to do what you want it to do. While tending to my wounds that fall, I shaped a new and better goal out of the debris of the disaster. I would study plants in a new way—not from the outside, but from the inside. I would figure out why they did what they did and try to understand their logic, which must serve me better than simply defaulting to my own, I decided.

  Every species on Earth—past or present, from the single-celled microbe to the biggest dinosaur, daisies, tre
es, people—must accomplish the same five things in order to persist: grow, reproduce, rebuild, store resources, and defend itself. At twenty-five, I could already see that my own reproduction was going to be complicated, were it ever to take place at all. It seemed outrageous to hope that fertility, resources, time, desire, and love could all come together in the right way, and yet most women did eventually walk that path. While in Colorado, I’d been so focused upon what the trees weren’t doing that I hadn’t made any observations of what they were doing. Flowering and fruiting must have taken a backseat to something else that summer, something that I had failed to notice. The trees were always doing something: when I kept this fact placed firmly in front of me, I got closer to making sense of the problem.

  A new mind-set became imperative: perhaps I could learn to see the world as plants do, put myself in their place, and puzzle out how they work. As a terminal outsider to their world, how close could I come to getting inside? I tried to visualize a new environmental science that was not based on the world that we wanted with plants in it, but instead based on a vision of the plants’ world with us in it. I thought of the different labs that I had worked in and the wonderful machines, chemicals, and microscopes that gave me so much happiness…What kind of hard science could I bring to bear on this weird quest?

  The perversity of such an approach was seductive; what was there to stop me, aside from my own fear of being “unscientific”? I knew that if I told people I was studying “what it’s like to be a plant,” some would dismiss me as a joke, but perhaps others might sign on just for the adventure. Maybe hard work could stabilize scientifically shaky ground. I didn’t know for sure, but I felt the first delicious twinges of what would be my life’s enduring thrill. It was a new idea, my first real leaf. Just like every other audacious seedling in the world, I would make it up as I went along.