The Best American Science and Nature Writing 2018 Read online

  To know what it is like to live as people lived for most of human history, you would have to find one of the places where traditional hunting-and-gathering practices are still alive. You would have to spend a lot of time there, to make sure that what you were seeing wasn’t just a snapshot, and that you had a real sense of the texture of lived experience; and, ideally, you would need a point of comparison, people with close similarities to your hunter-gatherers but who lived differently, so that you would have a scientific “control” that allowed you to rule out local accidents of circumstance. Fortunately for us, the anthropologist James Suzman did exactly that: he spent more than two decades visiting, studying, and living among the Bushmen of the Kalahari, in southwest Africa. It’s a story he recounts in his new book, Affluence Without Abundance: The Disappearing World of the Bushmen.

  The Bushmen have long been of interest to anthropologists and scientists. About 150,000 years ago, 50,000 years after the emergence of the first anatomically modern humans, one group of Homo sapiens was living in southern Africa. The Bushmen, or Khoisan, are still there: the oldest growth on the human family tree. (The term “Bushman,” once derogatory, is now used by the people themselves, and by NGOs, “invoking as it does a set of positive if romantic stereotypes,” Suzman notes, though some Khoisan prefer to use the term “San.”) The genetic evidence suggests that, for much of that 150,000 years, they were the largest population of biologically modern humans. Their languages use palatal clicks, such as a tsk, made by bringing the tongue back from the front teeth while gently sucking in air, and the “click” we make by pushing the tongue against the roof of the mouth, then bringing it suddenly downward. This raises the fascinating possibility that click languages are the oldest surviving variety of speech.

  Suzman first visited the Bushmen in 1992, and went to stay with them two years later, as part of the research for his Ph.D. The group he knows best are the Ju/’hoansi, between 8,000 and 10,000 of whom are alive today, occupying the borderlands between Namibia and Botswana. (The phonetic mark /’ represents a tsk.) The Ju/’hoansi are about 10 percent of the total Bushman population in southern Africa, and they are divided into a northern group, who retain significant control over their traditional lands, and who therefore still have the ability to practice hunting and gathering, and a southern group, who were deprived of their lands and “resettled” into modern ways of living.

  To a remarkable extent, Suzman’s study of the Bushmen supports the ideas of Against the Grain. The encounter with modernity has been disastrous for the Bushmen: Suzman’s portrait of the dispossessed, alienated, suffering Ju/’hoansi in their miserable resettlement camps makes that clear. The two books even confirm each other’s account of that sinister new technology called writing. Suzman’s Bushman mentor, !A/ae, “noted that whenever he started work at any new farm, his name would be entered into an employment ledger, documents that over the decades had assumed great mystical power among Ju/’hoansi on the farms. The secrets held by these ledgers evidently had the power to give or withhold pay, issue rations, and determine an individual’s right to stay on any particular farm.”

  It turns out that hunting and gathering is a good way to live. A study from 1966 found that it took a Ju/’hoansi only about 17 hours a week, on average, to find an adequate supply of food; another 19 hours were spent on domestic activities and chores. The average caloric intake of the hunter-gatherers was 2,300 a day, close to the recommended amount. At the time these figures were first established, a comparable week in the United States involved 40 hours of work and 36 of domestic labor. Ju/’hoansi do not accumulate surpluses; they get all the food they need, and then stop. They exhibit what Suzman calls “an unyielding confidence” that their environment will provide for their needs.

  The web of food sources that the hunting-and-gathering Ju/’hoansi use is, exactly as Scott argues for Neolithic people, a complex one, with a wide range of animal protein, including porcupines, kudu, wildebeests, and elephants, and 125 edible plant species, with different seasonal cycles, ecological niches, and responses to weather fluctuations. Hunter-gatherers need not only an unwritten almanac of dietary knowledge but what Scott calls a “library of almanacs.” As he suggests, the step-down in complexity between hunting and gathering and domesticated agriculture is as big as the step-down between domesticated agriculture and routine assembly work on a production line.

  The news here is that the lives of most of our progenitors were better than we think. We’re flattering ourselves by believing that their existence was so grim and that our modern, civilized one is, by comparison, so great. Still, we are where we are, and we live the way we live, and it’s possible to wonder whether any of this illuminating knowledge about our hunter-gatherer ancestors can be useful to us. Suzman wonders the same thing. He discusses John Maynard Keynes’s famous 1930 essay “The Economic Possibilities for Our Grandchildren.” Keynes speculated that if the world continued to get richer we would naturally end up enjoying a high standard of living while doing much less work. He thought that “the economic problem” of having enough to live on would be solved, and “the struggle for subsistence” would be over:

  When the accumulation of wealth is no longer of high social importance, there will be great changes in the code of morals. We shall be able to rid ourselves of many of the pseudo-moral principles which have hag-ridden us for two hundred years, by which we have exalted some of the most distasteful of human qualities into the position of the highest virtues. We shall be able to afford to dare to assess the money-motive at its true value. The love of money as a possession—as distinguished from the love of money as a means to the enjoyments and realities of life—will be recognized for what it is, a somewhat disgusting morbidity, one of those semi-criminal, semi-pathological propensities which one hands over with a shudder to the specialists in mental disease.

  The world has indeed got richer, but any such shift in morals and values is hard to detect. Money and the value system around its acquisition are fully intact. Greed is still good.

  The study of hunter-gatherers, who live for the day and do not accumulate surpluses, shows that humanity can live more or less as Keynes suggests. It’s just that we’re choosing not to. A key to that lost or forsworn ability, Suzman suggests, lies in the ferocious egalitarianism of hunter-gatherers. For example, the most valuable thing a hunter can do is come back with meat. Unlike gathered plants, whose proceeds are “not subject to any strict conventions on sharing,” hunted meat is very carefully distributed according to protocol, and the people who eat the meat that is given to them go to great trouble to be rude about it. This ritual is called “insulting the meat,” and it is designed to make sure the hunter doesn’t get above himself and start thinking that he’s better than anyone else. “When a young man kills much meat,” a Bushman told the anthropologist Richard B. Lee, “he comes to think of himself as a chief or a big man, and he thinks of the rest of us as his servants or inferiors . . . We can’t accept this.” The insults are designed to “cool his heart and make him gentle.” For these hunter-gatherers, Suzman writes, “the sum of individual self-interest and the jealousy that policed it was a fiercely egalitarian society where profitable exchange, hierarchy, and significant material inequality were not tolerated.”

  This egalitarian impulse, Suzman suggests, is central to the hunter-gatherer’s ability to live a life that is, on its own terms, affluent, but without abundance, without excess, and without competitive acquisition. The secret ingredient seems to be the positive harnessing of the general human impulse to envy. As he says, “If this kind of egalitarianism is a precondition for us to embrace a post-labor world, then I suspect it may prove a very hard nut to crack.” There’s a lot that we could learn from the oldest extant branch of humanity, but that doesn’t mean we’re going to put the knowledge into effect. A socially positive use of envy—now, that would be a technology almost as useful as fire.

  SIDDHARTHA MUKHERJEE

  Cancer’s Invasion Equa
tion

  from The New Yorker

  Over the summer of 2011, the water in Lake Michigan turned crystal clear. Shafts of angled light lit the lake bed, like searchlights from a UFO; later, old sunken ships came into view from above. Pleasure was soon replaced by panic: lakes are not supposed to look like swimming pools. When biologists investigated, they found that the turbid swirls of plankton that typically grow in the lake by the million had nearly vanished—consumed gradually, they could only guess, by some ravenous organism.

  The likely culprits were mollusks: the zebra mussel and its cousin the quagga mussel. The two species—Dreissena polymorpha and Dreissena bugensis—are thought to have originated in the estuarine basins of Ukraine, notably that of the Dnieper River. In the late 1980s, cargo ships, traveling from the Caspian Sea and the Black Sea, had dumped their ballast water into the Great Lakes, contaminating them with foreign organisms.

  At first, the mollusks seemed like relatively innocuous guests. Then things took a turn. By the mid-1990s, they were hanging from ship keels, turbines, and propellers in bulbous, tumorlike masses, encrusting docks and piers, clogging water pipes and sanitation systems, and washing ashore in such numbers that, on some beaches, you could walk on a solid bar of shells. Eventually, the water clarity began to increase, the effect at first picturesque and then eerie.

  By 2012, the Dreissena population in parts of southern Lake Michigan had reached a density of 10,000 per square meter. By one estimate, there were 950 trillion mussels in the lake, its bottom a crackling carpet of calcium. By 2015, the density was 15,000 per square meter—more mussels, by weight, than all the fish in the lakes. Billions of dollars in damage had accumulated. Ships and boats had to be decontaminated, and water-cleaning equipment dismantled and stripped. Dire warning signs (“DON’T MOVE A MUSSEL!”) were placed throughout the lake system, yet the invaders—the quaggas, ultimately, in the greatest numbers—continued to spread.

  What made the mussels such malignant invaders? Some of their aggression is a feature of their biology. The Dreissena are champion breeders, each churning out more than a million eggs a year. Yet in the basins and the deltas of Ukraine these mussels seldom reach even a fifth of their peak density in the Great Lakes. They rarely invade depths below 30 meters, clump on boats, clog marine equipment, or form calcified masses. They are, in short, a relatively docile species—restricted, perhaps, by the quality of the water, by their natural predators and pathogens, by the shallowness of the river basin, or by factors we haven’t yet identified.

  Solving the quagga conundrum requires cracking two halves of a puzzle. Half the story lies in the mussel’s intrinsic biology—its genes, its morphology, its nutritional preferences, its reproductive habits. The other half involves the match between that biology and the environment. It is a basic insight that an undergraduate ecologist might find familiar: the “invasiveness” of an organism is always a relative concept. The Asian carp—another fierce aggressor in American waters—is not particularly invasive in parts of Asia. The Japanese knotweed, now colonizing the cherished gardens of the English, is hardly known as a weed in Japan. An aggressor in one environment is a placid resident in another. The meek are only circumstantially meek; when conditions change, they might suddenly inherit the Earth.

  One evening this past June, as I walked along the shore of Lake Michigan in Chicago, I thought about mussels, knotweed, and cancer. Tens of thousands of people had descended on the city to attend the annual meeting of the American Society of Clinical Oncology, the world’s preeminent conference on cancer. Much of the meeting, I knew, would focus on the intrinsic properties of cancer cells, and on ways of targeting them. Yet those properties might be only part of the picture. We want to know which mollusk we’re dealing with, but we also need to know which lake.

  A few weeks before the ASCO meeting, at Columbia University’s hospital on 168th Street, I met a woman with breast cancer. Anna Guzello, a supermarket cashier from Brooklyn, had noticed a small lump in her left breast a few months earlier. (I’ve changed some of her identifying details.) A mammogram then revealed a hazy, spidery mass, and a biopsy confirmed that the tumor was malignant.

  Guzello had a total mastectomy of the breast—a simple lumpectomy would not have sufficed, given the size and the location of the mass—and planned to have surgical reconstruction. On an afternoon in May, she came to see Katherine Crew, a breast oncologist at Columbia, to discuss the next steps in her treatment.

  Crew’s office, on the 10th floor of the hospital, is a small, square, sparsely furnished room. The light from a fluorescent desk lamp was flickering, and Crew switched it off. She wanted no distractions. Guzello, her hair coiled into a tight bun, leaned forward, frowning intently, as Crew drew pictures and wrote notes on a sheet of paper.

  “Can you read my writing?” Crew asked. “You can keep the notes and always come back with questions.” Her tone was gentle, but it was as if the weight of every word were multiplied.

  Guzello nodded. She drummed her fingernails on the table, producing a staccato, military sound—click-click-click—a nervous tic that seemed to calm her.

  “First, the good news,” Crew said. “There’s no visible cancer left in your body.”

  The surgeons had removed the tumor, with wide margins on all sides. The lymph nodes in the armpits—a frequent site of cancer metastasis—also contained no sign of cancer. In oncology parlance, Guzello would be classified as NED: “no evidence of disease.”

  But that’s a squirrelly phrase: “evidence” refers to the state of our knowledge, not the state of the disease. Breast-cancer cells could have escaped and settled in Guzello’s brain, spinal cord, or bones, where they might be invisible to scans and tests. Women with complete mastectomies and “no evidence of disease” can relapse with metastatic breast cancer months, years, or even decades after the removal of the primary cancerous mass. Patients who succumb to cancer generally die of these metastases, not of their primary tumors. (Notable exceptions are brain cancers, which can kill patients by occupying the skull, and blood cancers, in which the cancerous cells are inherently metastatic.)

  “So we treat with medicines to decrease the chance of metastasis—the growth of cancer cells in sites outside the breast,” Crew told Guzello. She explained that the medicines came in three main categories: cell-killing chemotherapy; targeted therapies, like Herceptin, that specifically go after the products of misbehaving genes in cancer cells; and estrogen-blocking pills, which are typically prescribed for five or ten years.

  Guzello moved her hands over her hair, her lips tightening. The hormonal pills were fine. But she balked at the cell-killing chemotherapy.

  “If I don’t have those metastases, then I’ll be taking risks for no reason,” she said. The nails drummed on the table again. The risks were substantial: hair loss, diarrhea, infections, a small possibility of permanent numbness that would leave her hands feeling as if she were wearing leather gloves, yet exquisitely sensitive to cold. The chemotherapy protocol meant that she would be yoked to an IV pole at an infusion center for several hours once a week, for nearly half a year. She had a mother with a severe disability to care for, and few vacation days. Was there any way to know whether she was likely to suffer metastasis? “Then I’d be able to assess the risks and benefits more realistically,” Guzello said.

  The question has echoed through oncology for decades. We aren’t particularly adept at predicting whether a specific patient’s cancer will become metastatic or not. Metastasis can seem “like a random act of violence,” Daniel Hayes, a breast oncologist at the University of Michigan, told me when we spoke at the ASCO meeting in Chicago. “Because we’re not very good at telling whether breast-cancer patients will have metastasis, we tend to treat them with chemotherapy as if they all have potential metastasis.” Only some fraction of patients who receive toxic chemotherapy will really benefit from it, but we don’t know which fraction. And so, unable to say whether any particular patient will benefit, we have no choice b
ut to overtreat. For women like Guzello, then, the central puzzle is not the perennial “why me.” It’s “whether me.”

  There are deep roots to the idea that a cancer’s metastases depend on local habitats. In 1889, an English doctor named Stephen Paget set out to understand cancer’s “primary growth and the situation of the secondary growths derived from it.” The son and nephew of prominent English doctors—his father, James Paget, was one of the founders of modern pathology; his uncle was a Cambridge professor of medicine—the younger Paget might have been burdened by the deadweight of inherited wisdom. Cancer, in Paget’s time, was thought to diffuse from its primary site like a malignant inkblot. Surgeons, believing this “centrifugal theory”—cancer’s stainlike, outward spread from a central mass—advocated ever-widening surgical extirpations to eliminate cancer. (This theory would form the intellectual basis for William Halsted’s “radical” mastectomy.) But when Paget collected the case files of 735 women who had died of breast cancer, he found a bizarre pattern of metastatic spread. The metastases didn’t appear to spread centrifugally; they appeared in discrete, anatomically distant sites. And the pattern of spread was far from random: cancers had a strange and strong preference for particular organs. Of the 300-odd metastases, Paget found 241 in the liver, 17 in the spleen, and 70 in the lungs. Enormous, empty, uncolonized steppes—anatomical landmasses untouched by metastasis—stretched out in between.