by Janet Browne
Wallace visited Darwin at Down House in June or July 1862, although no record of the meeting exists other than Wallace’s statement that it took place.5 Further contact was interrupted by Leonard Darwin’s catching scarlet fever, followed by a long convalescent stay by the Darwin family in Southampton and Bournemouth, during which Emma also developed scarlet fever. “We are a wretched family,” Darwin declared to Fox, “and ought to be exterminated.… There is no end of trouble in this weary world.” Then Wallace fell ill with pleurisy. If nothing else, these illnesses provided a convenient talking-point, and the gloomy exchange of news about ailments helped consolidate their developing relationship. The following winter Wallace and Darwin met at Erasmus’s house in London for a brief, well-mannered event which confirmed the cordiality each felt towards the other.
Meanwhile, Wallace made himself known to Lyell and Huxley in London, both of whom were eager to meet him. Wallace’s originality and fresh perspective appealed enormously to them. As a co-founder of natural selection, he would also, they anticipated, become an invaluable addition to the crusading ranks of biology. These expectations deepened into esteem as they became familiar with Wallace’s collecting exploits, his intellectual curiosity, and his courteous character. Lyell valued Wallace’s opinion on evolutionary matters almost as if it were Darwin’s—sometimes precisely because it was not Darwin’s. For Lyell remembered how much Wallace’s early articles had stimulated his imagination and inspired him to start a private scientific journal about the problem of species, and he welcomed Wallace’s willingness to talk about the human condition and other absorbing topics that Darwin sometimes seemed reluctant to probe. Wallace spoke freely with Lyell about archaeology, primitive culture, language, biogeography, geological astronomy, and the purpose of the universe. The appreciation was mutual. Wallace said of Lyell that “I saw more of him than of any other man.… my correspondence with him was more varied in the subjects touched upon, and in some respects of more general interest, than my more extensive correspondence with Darwin.”6
Huxley brought Wallace up to date with the gorilla wars. Wallace soon considered Huxley’s specialist knowledge of the anatomical side of natural history to be unrivalled. He was gratified when Huxley coined the expression “Wallace’s line” to describe the biogeographical boundaries between the Pacific and Asiatic faunas.7 Swept along in Huxley’s current, Wallace became a member of the Zoological Society and began enjoying some of the most forward-looking scientific company in nineteenth-century Britain.
His circle also included Henry Walter Bates, back in England from his travels in the Amazon. Hesitantly the two travellers wondered what, if anything, they still had in common, and their relationship, while remaining close, was never again as sympathetic as it had been in Leicester or in the South American jungle. Together they made an appointment to meet Herbert Spencer, whose First Principles they read in 1862 and admired. Wallace’s and Bates’s thoughts were full of the great unresolved problem of the origin of life, “a problem that Darwin’s Origin of Species left in as much obscurity as ever,” announced Wallace, as they went to see Spencer.
Underneath the welcome that Wallace received from the scientific establishment, however, there lurked a hint of rapacity. These men-about-town fell on him with alarming speed, seemingly impatient to suck him dry. They wanted to know what he could offer, which sword he could rattle.
In actual fact Wallace found it hard to identify any suitable role for himself in Britain in the post-Origin years. At times it may have appeared to him that he was hardly needed. Much of the evolutionary flare-up had already passed him by. Darwin seemed fully in command of spreading the word at home and overseas, and the public business of defence lay in the hands of individuals like Huxley, who dominated nearly every corner of the controversy and appeared unwilling to share the limelight. Furthermore, Darwin’s name was becoming an acknowledged synonym for the theory of natural selection. Any chance of an evolutionary movement called Wallacism—even if Wallace wished for such a thing—had probably disappeared. Several years afterwards when reflecting on his return to England, Wallace said quietly of the theory that Darwin “had already made it his own.”
He may have been content to let it go. For a while he concentrated on distributing and classifying his Malaysian collections—three thousand bird skins, twenty thousand beetles and butterflies—and spent the better part of the next five years writing highly informative articles based on these specimens. He contributed important papers to the Zoological, Entomological, and Linnean Societies. Nor did he lose sight of natural selection. In private, he began to probe some of the most enigmatic aspects of his and Darwin’s evolutionary scheme, thinking hard about the protective colours of animals, the mental capacities of mankind, and the emergence of early human societies.
But he was unsettled by London’s superficial existence. With a start, he remembered exactly why he had abandoned the metropolis for the impenetrable green of Malaysia. “Talking without having anything to say,” he later wrote in his memoirs, “and merely for politeness or to pass the time, was most difficult and disagreeable.” Lady Lyell’s impression when she met him in 1863 for the first time, at a London lunch party hosted by Lyell in their home in Harley Street, was of a very retiring figure, “shy, awkward and quite unused to good society.” If truth be told, Wallace was overawed by the Lyells’ style of living, with its daunting array of silver forks and high-table conversation. He preferred Lyell to walk over to visit him in his lodgings. He felt more at ease in Huxley’s home, a modest villa in St. John’s Wood, at that time a cheap suburb of London, where Henrietta Huxley and the children unpretentiously bustled round. Huxley’s son Leonard recalled Wallace’s unassuming manner during these visits. All in all, Wallace found it increasingly more convenient to shut himself up with his bird skins than to accept dinner invitations.
Darwin was relieved to find him so agreeable—perhaps, as well, so unlikely to be troublesome. He did what he could to smooth Wallace’s path over the next few months, helping him submit articles to those scientific societies of which Wallace was not a member and writing supportive letters. They became strong friends, a friendship rooted in goodwill towards each other, their common travelling experiences, and the intellectual rigours of what was now a mutual enterprise far larger than either man individually. Darwin genuinely admired Wallace’s mind and always treated him with deference and respect. He hated to differ from Wallace on natural history points. If he did so, he would become anxious about his own powers of reasoning. From time to time, he protested that the theory of natural selection was “as much yours as mine.”
Yet it was an odd relationship, as tricky to negotiate as any arranged marriage, and both men felt inclined to tread slowly. Darwin did not let their promising new connection, for example, interrupt his continuing research and writing projects. They never appeared on a scientific podium together, never composed an article together, never rose united to defend their combined theory against detractors or opponents, never sat for a double portrait, although one shrewd photographer with an eye to posterity asked if they would be prepared to do so. United well enough on that single point, they both spontaneously refused the request.8 Although theirs was a noteworthy partnership, they never performed as a duo. This surely had much to do with a deep-seated wish to acknowledge the other’s independent creativity. They affirmed the ties that bound them and, for the most part, went their individual ways.
II
With his orchid book published, Darwin turned to what he considered his proper task for the future—presenting the full evidence for natural selection. He had promised to supply this evidence in the preface to the Origin of Species, and his sense of fair play told him he ought to fulfil the obligation, however much he found it a chore. Yet it was to turn into a massive, unfinished, perhaps unfinishable project. From 1862 until 1868, when the first in this planned trio of books was published, he pushed himself relentlessly. He began with variation in domestic organis
ms, an amorphous and difficult subject. “Oh Lord what will become of my book on variation,” he had exclaimed to Hooker in the middle of his happy experiences with orchids. Now his voice became doleful, as if the fun had stopped and real work was to begin. “It is so much more interesting to observe than to write.”
The longstanding theme of variation drew him back into the world of animal breeders, dog handlers, farmers, and horticulturists and allowed him to consolidate all the disparate facts he had been collecting for decades. The result was a two-volume study called The Variation of Animals and Plants Under Domestication, published in 1868. He intended following it with a matching volume discussing variation under natural conditions, a book that was never written.
Darwin’s friends were admittedly a little bewildered by his self-imposed labours. As with the orchid researches, they wondered whether peas and chickens were worth all that effort. Even Darwin himself, who was dogged by bad health during these years, came to feel that his life might “hardly be long enough” for everything he hoped to achieve. And yet these volumes, and the home-based experiments on which they rested, set him on a new path.9 He was led to fresh insights that influenced the way he would subsequently think about animals and plants—and humans too. To a large extent he reworked existing material. Details from his earliest notebooks reappeared almost unchanged in the book, and relevant parts of the old manuscript of “Natural Selection” were plundered into oblivion.10 But Darwin also reformulated his understanding of the processes of reproduction, fertilisation, heredity, and variability, setting out problems that would occupy his mind for years to come.11
Most of all, he intended using the new book to provide an extended response to critics of the Origin of Species. As countless reviewers told him, he had not explained the cause of variability, how the individual differences in organisms came about. In the Origin, Darwin said openly, “Our ignorance of the laws of variation is profound.” So in Variation he intended explaining what he knew about the source, stability, and transmission of variations, in essence making an attempt to understand the phenomena of heredity some thirty or forty years before the modern science of genetics emerged. Although Darwin had not yet devised the theory of “pangenesis” that would ultimately take pride of place in the book, he felt sure that the origin of variability lay in the unsettling of the reproductive system brought about by factors such as domestication, the processes of out-crossing and interbreeding, changing conditions of life, and sexual procreation (as distinct from parthenogenesis and various forms of vegetative reproduction). He reminded Hooker that “variation is the base of all.”12 He regarded the book on variation as an essential sequel to the Origin of Species.
It was a project for him, moreover, that could only be carried out in his home and garden. Much underestimated by Victorian readers, the practical work that lay behind this book on variation was extraordinary. Darwin’s book was crammed with experimental results that were derived either from his own investigations in his greenhouse and aviary or gathered by correspondence from associates scattered across the globe. For it, he depended on his circle of correspondents, his library, his friends, his household staff, and his family. Everything was verified by correspondence, reading, and experiment. “You need not believe one word of what I said about gestation of dogs,” he told Lyell at one point. “Since writing to you I have had more correspondence with the master of hounds, & I see his record is worth nothing—it may of course be correct, but cannot be trusted.” Perhaps even more than when he had composed the Origin of Species, he transformed his daily activities into scientific knowledge.
Despite Darwin’s calling them “trifling observations,” these researches were more sophisticated and to the point than usually supposed. Few authors of the period, for example, troubled to say in what respect offspring resembled their parents, so Darwin undertook cross-breeding experiments in which he tried to break down each plant or animal’s defining characteristics into those features that were acquired relatively recently and those that were more ancient, like the black bars on pigeon wings. At other times, he sought information on reversion to the ancestral type by allowing free mating between different breeds of chicken. He looked for atavism (a term first defined in relation to plants and only later applied to animals and humans), in which a well-marked variety produces a throwback, revealing the hereditary past, using his garden laburnums as an example. When considering farm animals, he asked gentlemen farmers of his acquaintance about secondary sexual characteristics and features that were transmitted by one sex alone or were apparent only at particular stages in the life cycle. He thought deeply about potency, believing that older, well-established breeds were more likely than recent variants to transmit their characteristics unchanged, a fact of life that apparently governed the stud books of pedigree cattle.
As for himself, most of his practical investigations now lay in plants. He experimented on plant sterility and fertility, investigated hybrids and hybridization, the effects of inbreeding and outbreeding, the impact of good or poor conditions of life, and phenomena connected with the grafting of plants, monstrosities, and the way highly developed varieties of garden plants rarely reproduce true to kind. Throughout, he read and reread authoritative sources, especially those by Thomas Andrew Knight and Carl Gärtner on inheritance and hybridity. He corresponded with experimental hybridizers of the period, including Charles Naudin, renowned for his interbreeding studies on plants, and the Swiss botanist Carl Wilhelm von Nägeli, who worked on plant hybridity in Munich. Soon he came in touch with August Weismann, in Freiberg, who was interested in similar topics, and began writing to him. Like Naudin, Gärtner, and Gregor Mendel, each of whom investigated the same broad spectrum of hereditary phenomena during the 1860s, Darwin hoped that information derived from careful experimentation with plants—ideal experimental organisms for the period—would open up at least some of the mysteries of inheritance.
Interestingly, he included mankind in his research, regarding human beings as self-evidently variable domesticated organisms. Over these years he consulted anthropologists, medical men, statisticians, anatomists, missionaries, and a variety of printed sources, ranging from travel literature to the Lancet, on the question of human variability. When his notes on mankind became too unwieldy, even for a big book like this, he put them aside for a separate future volume, although he did incorporate some of the most striking human examples in relevant places in Variation—anatomical variations like polydactyly (multiple fingers or toes), abnormalities like harelip and deaf-mutism, and inherited medical conditions like gout. Darwin’s correspondence with medical men such as James Paget was crucial here. It also pleased him to mention some of the cases that his father had discussed with him before his death in 1848.13
Notwithstanding the solid intellectual aims underpinning the work, an indisputable air of Gulliver’s Travels crept in. His letters inquired about geese or goldfish, cross-bred pheasants, cucumbers, or abortive roses. Nothing seemed too absurd to contemplate, however briefly. “What do you say to wheat being grown from oats in the second year?” asked John Innes in 1862. Darwin was specially exercised over honey bees. The presence of neuter bees in every colony made it troublesome to understand how variation and selection (which depend on reproduction) could possibly take place. The drones could not pass their characteristics on to progeny because they left none.14 “I am half mad on subject.”
When he inquired in the Journal of Horticulture whether bees could vary, a flurry of negative replies forced him to think hard. Beekeepers from all over the country told him that there were no obvious variations in native stock. As Darwin’s web of inquiries spread outwards, even the eminent German apiarian Johannes Dzierzon informed him that variation was negligible. Only one man, a Mr. J. Lowe, an amateur beekeeper from Edinburgh, thought he had once seen a light-coloured variety visiting his hives. In desperation Darwin turned the question on its head: if there were no physical differences, perhaps there might be variations in behaviou
r? He urgently asked Lubbock to look out for fields of clover.
I write now in great Haste to beg you to look (though I know how busy you are, but I cannot think of any other naturalist who wd. be careful) at any field of common red clover (if such a field is near you) & watch the Hive Bees: probably (if not too late) you will see some sucking at the mouth of the little flowers & some few sucking at the base of the flowers, at holes bitten through the corollas—All that you will see is that the Bees put their Heads deep into the head & rout about.—Now if you see this, do for Heavens sake catch me some of each & put in spirits & keep them separate.—I am almost certain that they belong to two castes, with long & short probosces. This is so curious a point that it seems worth making out.—I cannot hear of a clover field near here.—Pray forgive my asking this favour, which I do not for one moment expect you to grant, unless you have clover field near you & can spare 1/2 hour.15
Domestic rabbits gave him trouble too. Digging around in his old notes, he unearthed details about rabbit breeds collected for him by Abraham Bartlett, the senior keeper at the London Zoological Gardens. Long ago, Darwin and Bartlett had together pondered the inheritance patterns of the so-called Himalayan rabbit, a good-looking show breed, with white coat and black ears, nose, tail, and feet. At Darwin’s request, Bartlett now began to carry out selected crosses between the Himalayan and other breeds. These crosses sometimes produced coloured animals called blues, a mystifying result that would not be fully explicable until the advent of Mendelian genetics. Darwin was at a loss. “The effects of crossing are sometimes marvellous in bringing out old & lost characters or in producing new characters.”16 But he visited the British Museum’s backroom collections to examine pelts. He came to believe the black markings (points) were ubiquitous, as seen in cats, dogs, Chillingham cattle, deer, and horses, and that the silver, bluish-grey coats were reversions to an aboriginal, wild colouring.