The Reluctant Mr. Darwin

by David Quammen

  Charles and Emma left Staffordshire that day. By way of matrimonial celebration, they shared sandwiches and a bottle of water on the train down to London. It was their chosen style. A quiet pair, disinclined toward ebullient display. And he had to get back to work.

  The Kiwi’s Egg

  1842–1844

  7

  Think of it as a bird’s egg, taking form slowly inside him. Ovulation had occurred. Fertilization had occurred. Now came growth, from the microscopic scale of a single ovum to…well, to whatever size it would reach before laying. Don’t think of a hen’s egg or a goose’s, or even the hefty egg of an avian lummox like the ostrich. Since the ovum was natural selection and the bird was Charles Darwin, think of it as the egg of a kiwi.

  The kiwis are long-beaked, globular, flightless birds, strange creatures with hairlike feathers who run around at night eating insects and worms. There are several species and subspecies, all embraced by the genus Apteryx, all endemic (that is, native there and nowhere else) to New Zealand. They belong to the ratite group, meaning that ostriches, rheas, emus, and cassowaries are their closest living relatives. The elephant birds of Madagascar and the moas of New Zealand, two sets of extinct giants, were part of that group, too. If these birds are all related and all flightless, you might ask, how did they arrive in such remote and disconnected places as South America (rheas), Australia (emus and cassowaries), New Guinea (more cassowaries), Madagascar, and New Zealand? The answer seems to be that they walked. The ratite lineage dates back to an era before the ancient southern supercontinent, now known as Gondwanaland, separated into its continental and island fragments. Traveling on foot, the ancestral ratites dispersed all across Gondwanaland and then, sometime later, the land fragments drifted apart. The giant birds rode away like penguins on an iceberg.

  Compared with other ratites, the kiwis are small—no bigger than an overfed chicken. Taxonomists have disagreed about just how many species to recognize, under just what scientific names, but currently the consensus seems settled on four: the North Island brown kiwi (Apteryx mantelli); the tokoeka (Apteryx australis); the great spotted kiwi (Apteryx haastii); and the little spotted kiwi (Apteryx owenii). The last was named for Richard Owen, who in 1838 presented a multi-part paper titled “On the Anatomy of the Apteryx” to the Zoological Society in London. Darwin, having heard at least some of Owen’s paper, referred to it in his notebook “D.” The most remarkable thing about the apteryx, Darwin thought, was its small respiratory system, suggesting that in the wild this must be a shy, patient, creepy little bird, with little inclination to exert itself much and therefore little need to breathe heavily. Owen had only a single specimen to examine, a male, and he was an anatomist, not a physiologist or a field naturalist; so he missed some kiwi traits just as peculiar as the reduced lung capacity. An extraordinarily acute sense of smell. A low body temperature, unusually cool for a bird. An odd mix of furtive and aggressive behavior. Darwin missed them, too, along with the single most notable fact about kiwi biology: These little birds lay humongous eggs.

  A female brown kiwi weighs less than five pounds. Her egg weighs almost a pound—constituting, that is, about 20 percent of her total weight. Among some kiwis, the egg-to-body weight ratio reportedly reaches 25 percent. A female ostrich, by contrast, lays an egg weighing less than 2 percent as much as herself. Certain other avian species—hummingbirds, for instance—lay more ambitious single-egg packages than ostriches, but few if any match kiwis. Relative to her body size, on a standard with other birds, the brown kiwi’s egg is about six times as big as it should be. It contains also a disproportionate allotment of yolk, on which the chick will survive just after hatching. This egg takes twenty-four days to develop and, once it has, fills the female like a darning egg fills a sock. Having gorged herself for three weeks to support the growth of such a large embryo, during the last two days she stops eating. There’s no room in her abdomen for another cricket. “Sometimes the egg-bearing female will soak her belly in puddles of cold water,” according to one source, “to relieve the inflammation and to rest the weight.” She is painfully replete with motherhood.

  An X-ray photo of a gravid female kiwi, taken fifteen hours before laying, shows this: a skull, with its long beak; a graceful S-shaped neck; an arched backbone; a pair of hunched-up femurs; and at the center of it all, a huge smooth ovoid—her egg—like the moon during a full solar eclipse. She herself is now just a corona. It seems impossible. How can she carry this thing? How can she deliver? Will it reward her efforts and discomforts, or rip her apart?

  The size of the kiwi’s egg raises interesting evolutionary questions. For starters: Why is it so big? What are the adaptive advantages for kiwi females (and for males, who do much of the incubating) of such heavy investment in a single chick? How has the kiwi lineage changed over evolutionary time? Did the egg evolve toward largeness? Or did the bird itself evolve toward smallness—a shrinking ratite, descended from moa-sized ancestors—while the egg stayed as it was? If the bird shrank and the egg didn’t, why not? Those questions could take us into a discussion of allometry (the study of growth rates and size disparities within organisms) and kiwi evolution, which might be amusing. But allometry isn’t the point here.

  The point is simply metaphor. Every time I see that X ray of the mama kiwi, I think: There’s Darwin during the years of gestation.

  8

  By spring of 1842 he was a famous author, thanks to the surprising success of his Journal from the Beagle voyage (published in 1839), and a father of two, thanks to Emma. He had been elected a Fellow of the Royal Society, Britain’s foremost scientific club. But he was still stuck in an ugly little row house in filthy, raucous London, and still slogging his way through the less glorious, more technical publishing chores that had followed from the five-year expedition. As for his transmutation theory, nothing. Nothing published, anyway. Nothing written except those disjointed notes and an occasional coy hint, in a letter to a friend, that he was working on the question of species and varieties. To his close colleague Lyell he had let drop his doubt that species have a divinely decreed beginning. In his Journal he had mentioned the Galápagos mockingbirds and finches, different species on different islands, but declined to speculate further on such a “curious subject.” He wanted to tell people about his theory, and he didn’t. It wasn’t ready. He wasn’t ready. He had finished with his transmutation notebooks, three years earlier, and let them sit. Among his more overt reasons for inaction on the “curious subject” were that he had been too hectically busy and too often sick.

  The mysterious vomiting, headaches, and other knockdown symptoms continued to afflict him intermittently. He had resigned from his secretaryship of the Geological Society, citing bad health, a legitimate excuse but also one that allowed him to immerse himself more fully in his own work. Intellectual hobnobbing was fine for those with the stomach; he found it literally nauseating. He was over the loneliness he’d felt aboard the Beagle, satiated with the sort of chirpy socializing his brother enjoyed, and had begun the process of retreating from London scientific circles into a reclusive life of research, writing, and invalidism. His marriage to Emma, entered in such a pragmatic and passionless spirit, had started developing toward what it would eventually be: an extraordinarily close mutual devotion and an asymmetric dependency, with her serving as his chief nurse and protectress. Even before the later children (eight more of them) arrived, those roles were enough to keep Emma busy—and, it seems, satisfied. She didn’t need to function as her husband’s intellectual sounding board, or as his transcriber, or his copyeditor, to feel fully engaged with his life.

  Besides, there was still that “painful void” between his thinking and her beliefs, which neither of them cared to accentuate. They knew that their disagreements about God, scripture, creation, and afterlife were wide and irresolvable. Three years earlier, not long after their marriage, Emma had written Charles an earnest letter, describing her struggle to come to terms with his science-driven imp
iety. She was ambivalent, she admitted. She wanted to feel that “while you are acting conscientiously and sincerely wishing and trying to learn the truth, you cannot be wrong.” On the other hand, she couldn’t always give herself that comfort. She worried that “the habit in scientific pursuits of believing nothing till it is proved” had blinded him to the importance of revelation. She wondered whether Charles hadn’t been unduly influenced by his careless, doubting brother, Erasmus. She warned him gently of the danger to his immortal soul if, rejecting dogma, betting against orthodox views of spiritual reward and punishment, he was wrong. “Everything that concerns you concerns me,” Emma wrote, “and I should be most unhappy if I thought we did not belong to each other for ever.” He didn’t want her to be perpetually unhappy, not in this life, let alone any other. So he preferred to let the matter drop—at least until he published his theory, whenever that might be.

  But he never forgot her letter. He saved it among his private papers, in fact, and occasionally pulled it out to reread.

  For the present, he needed to focus himself on immediate tasks and conserve strength. His volume on coral reefs would be published any month. He was offering an ingenious, well-supported explanation for how they are formed. Next he would do a book on volcanic islands. Both of those had been added to his original ambitious plan for the Zoology of the Beagle series. Eventually he would write three complete volumes of geological observations from the voyage, plus editing five volumes on the zoology. All this took time; years. Where did the days go? In his diary he tried to keep track. The coral reef book alone, Darwin figured, cost him twenty months of effort. That was spread across four years during which he had worked also on the Zoology, the Glen Roy paper, some other geological projects, and (marginally) transmutation, losing the rest of his workdays to illness. Being a husband, a father, and a householder also took time, notwithstanding the help supplied by a butler, a cook, a nurse for the children, and other servants, as well as Emma’s own indulgence of his detached, contemplative habits. In May, he and Emma bustled their gang off to Staffordshire for a vacation at her family home. After a month there, he shuttled over to stay with his father and sisters in Shrewsbury, leaving Emma and the kids behind.

  He had left his notebooks behind too, in London, but that didn’t stop him thinking. The holiday from other work became a chance to put something on paper about transmutation. During those summer weeks of 1842, amid Emma’s family and then his own, he found enough quiet hours to write a dense précis of his ideas and of the evidence and arguments he’d collected to support them. He worked in pencil. This “sketch,” as he called it, came to thirty-five pages. Unlike the notebooks it was carefully structured, moving from topic to topic in a way meant to build his case clearly and cogently; but like the notebook entries it was elliptical, with phrases and sentences suggesting much more (at least to him) than they actually said. It was an outline, an extensive one, of the book he intended to write.

  He began with the topic of variation among domestic animals, noting the obvious point that individuals differ slightly from one another in size, weight, color, and other ways. Because some of those differences are heritable, human breeders have been able to perpetuate and even amplify desirable traits by carefully selecting which animals to pair. With enough selection over long stretches of time, breeders even produced new races—speedy horses versus dray horses and tallow cows versus beef cows, for instance. This was the setup for Darwin’s crucial analogy.

  From variation among domestics he moved to variation among wild creatures, and to what he called here “the natural means of selection.” Variation in the wild might not be as common or as extreme as variation among domestics (so he thought), but under certain circumstances it did occur. What caused it? He didn’t know—and, for the present, that didn’t matter. Some of those variations, like the ones among domestic animals, were heritable. Given the inherent rates of population increase and the enormous excess of insupportable offspring, to which Malthus had awakened him, wild creatures would be subjected to an automatic sort of culling, based on their capacities to compete for survival and for mating opportunities. By now he had hit upon not just his analogy, with domestic breeding, but his chosen term: “natural selection.” The net result over thousands of generations, he wrote mutedly, would be to “alter forms.”

  He had described a physical mechanism (or at least, part of it) by which new species could be produced. But was there empirical evidence that they had been produced, one from another, through any such pageant of organic change? Yes, and in the second half of his draft he sketched that evidence, category by category: the fossil record, geographical distribution, systematic classification of species based on morphological resemblances, rudimentary organs (such as the wings of the apteryx), all of which tended to affirm the idea of transmutation and to belie special creation. Then he wrote a conclusion, highlighting as a sample case three species of Asian rhinoceros—those from Java, Sumatra, and India—and noting that a creationist would believe all three originated, with their “deceptive appearance” of close kinship, from separate acts of divine will. As for himself, Darwin wrote, he could just as well believe that the planets revolve in their orbits “not from one law of gravity but from distinct volition of Creator.” If all species are handmade by God, then a person might also assume that Mars and Jupiter fly around because He’s playing them like yo-yos. That’s unlikely. Maybe even blasphemous. Wasn’t the deity, if any existed, too sublimely transcendent for what we’d now call micromanagement? Darwin was suggesting an idea even larger than natural selection: that the universe is governed by laws, not by divine whim, and that the transmutation of species by natural selection is merely one of those laws.

  He finished the rough sketch with a burst of eloquence. It was oddly consoling, Darwin noted, that from the hard Malthusian struggle involving “death, famine, rapine, and the concealed war of nature” had come a great good, the creation of the higher animals. “There is a simple grandeur,” he wrote,

  in the view of life with its powers of growth, assimilation and reproduction, being originally breathed into matter under one or a few forms, and that whilst this our planet has gone circling on according to fixed laws, and land and water, in a cycle of change, have gone on replacing each other, that from so simple an origin, through the process of gradual selection of infinitesimal changes, endless forms most beautiful and most wonderful have been evolved.

  He had made a big move toward putting his thoughts forward. But it was only a private memo to himself. And even in private he had fudged on one thing: no mention of the origins of man.

  9

  Late that summer London was a mess, more so than usual, with police and Guards units on alert against possible rioting by Chartist demonstrators. A radical editor was tried and convicted of publishing “impious doctrines” such as atheism and socialism, as flavored in his news rag with a vague, political version of transmutationism. Across the country, half a million workers had gone out on a general strike for the Chartist demands, and military units were moving north to restore order in mill cities like Manchester. Troops in London faced off, with fixed bayonets, against hollering protesters not far from where the Darwins lived. It seemed the right time to do what Charles and Emma had been contemplating for a year: buy a home in the country and get away.

  After some careful house-hunting, they chose a place in a somnolent little village called Down, in Kent, sixteen miles southeast of central London. Sixteen miles then meant two hours by horse and carriage, distance enough to give them tranquility but allow Darwin to commute back on special occasions for scientific business. The property itself, known as Down House, had once served as the village parsonage; lately it stood vacant, musty and unsold. It was a big house with multiple bedrooms, a fixer-upper at a bargain price, and it came with 18 acres of land. Helped by a loan from Darwin’s father, they grabbed it. By late September they were in residence, not knowing that this would be their sole home and treasured refug
e for the rest of their lives. Darwin himself may have hoped exactly that. The Beagle voyage had sated his appetite for travel and he felt ready to be a homebody. His wife was less enthusiastic about this drab house and the flat Kentish landscape around it, neither of which were impressive to a young woman raised on a fancy Staffordshire estate; but she figured she could adjust to it. The first major event in the new location was cheery, when Emma gave birth to a girl, their second daughter, christened Mary Eleanor. The next came like a bad omen, three weeks later, when the baby died. They buried Mary Eleanor in the Down churchyard. Now, in a grim way, they were rooted here.

  The village Down later became Downe, with a spelling change meant to make it more distinctive. Darwin transmogrified himself, too, though not in order to stand out. On the contrary, he settled into village life as though it were a witness protection program. Assuming the trappings of a minor country squire, he planted flowers, bought a few milk cows, started an orchard, hired a handyman, took a seat on the parish council, established his private workspace in a study filled with books and files, and commissioned renovations for the rest of the house. Outside one window he attached an inconspicuous mirror, angled so that he could see people coming up the drive before they saw him. Visitors were hell on his weak gut, plus they cost him time that he needed for work. He didn’t want company, except in very limited doses and on his own controlled terms. Lively chat made him excited and excitement made him sick. His study included a little lavatory nook behind a curtain, where he could vomit. From now on, most of his scientific conversations would be conducted through the mail.

  He’d always been an exceptionally good letter writer, in a letter-writing age. Telephones didn’t yet exist, after all, and any literate Victorian necessarily scrawled lots of missives to family, colleagues, and friends. Having a dinner party? Invitations went by note. Gossip and professional chat were largely epistolary, even among those who lived not far apart. After the move to Down House, Darwin took that a step further. Self-sequestered inside both his home and his sense of frail health, he became very dependent on written correspondence and very disciplined in his use of it. He wrote letters for friendship, letters for business, letters for love (to his “dear old Titty” or his “dear Mammy,” as he variously called Emma, when they were apart), letters for good deeds and scientific politicking, letters asking parental advice and (later, with his sons away) giving it, letters for the sheer joy of prattle, and most of all, letters seeking scientific information. He peppered friends, acquaintances, and strangers with questions, requests for data, little assignments of experimentation that they might perform for him if, ahem, it wasn’t too much trouble. He was unctuous and apologetic, but demanding.