Charles Darwin

by Janet Browne

  In saying this, Darwin joined a long line of thinkers stretching back to Buffon, Maupertuis, and beyond who believed the visible structure of organisms rested on an invisible arrangement of elementary units and that these units somehow contained a memory that could be passed to the next generation—a “mould,” Buffon had called it, more than a hundred years before. Since Buffon’s day, the notion of cells had become current, and the organising functions of the cell nucleus were appreciated if not precisely understood. Yet Darwin was unusual in thinking in such realist terms, almost as if gemmules were letters in the postal system, individually conveying a specific packet of information. The ovules, spermatozoa, and pollen grains each “consist of a multitude of germs thrown off from each separate atom of the organism.”2

  Offspring would therefore receive a collection of parental gemmules, some from the mother, some from the father, which mingled and were expressed in different ways in the child. Some gemmules, he proposed, could remain dormant for many generations. Some lost their distinguishing characteristics. Others were routinely carried by all offspring but perhaps only one or another might be expressed, or a certain combination was needed to allow full representation. Some blended. Every child was therefore the fruit of its parents’ loins—built up from a mixture of the parents’ and grandparents’ gemmules coming from either side. Using a metaphor close to his rural heart, Darwin likened this to gardening; a flowerbed could be sprinkled with seeds, “most of which soon germinate, some lie for a period dormant, whilst others perish.” His awareness of the longlasting vitality of seeds—their fertility, superabundance, and longevity—gave him confidence that his ideas might be valid.

  New as these ideas were to him, they rested in impressions he had been turning over in his mind for decades. All his life Darwin had puzzled over the phenomena of breeding, by which he meant not so much natural selection, although that usually entered his deliberations somewhere or another, but rather the whole complex of biological phenomena connected with reproduction, pedigree, sexual identity, fertility, mating patterns, embryology, and inheritance. Even before Malthus had illuminated his understanding of the natural world, he had been intrigued by animal and plant breeding, seeing it (like his grandfather Erasmus Darwin) as the underlying rationale for nature, the essential moving stimulus that drove each and every living being. “Why such high object generation?” he had asked himself when first opening his earliest notebook on the evolution of species. His answer sprang from the following page: “Generation to adapt & alter the race to changing world.”3 Sex governed all, as he had said in these secret notebooks. As soon as he then hit upon natural selection as a working concept, he plunged into investigations on fertilization, hybridity, inheritance, courting rituals, sexual choice, selfing, and crossing, all of which became highly relevant researches because his new theory turned reproduction into the mechanism responsible for both maintaining and varying living structures. For thirty years, his interest had never wavered. Although it is commonly said that Darwin aimed primarily to explain the meaning of adaptation in living beings, this underestimates the scope of his continuing programme. He was instead a lifelong “generation” theorist.4 It could legitimately be claimed that the origin of species was not even his primary focus in life when compared with the dedicated attention he lavished on sexual and reproductive concerns. To understand breeding was a fundamental objective.

  Darwin’s assumptions about the society in which he lived inevitably played a part. These researches into reproduction had always carried a touch of autobiographical interest. On the one hand, he was more anxious than ever before about unmasking the facts of heredity. The possible transmission of ill health from parents to children was an issue of all-consuming worry. His own health was as bad as it ever had been, and the health of his children was constantly present in his thoughts. During this period, he wondered, not for the first time, whether he might be the source of their disorders, and whether his marriage to Emma, his first cousin, had played any significant part in this inherited burden.

  And on the other, he lived in a world in which heredity was an obvious organising principle. The upper reaches of Victorian society were, after all, built on the notion of human pedigree and good breeding, not only in the sense that an individual’s position in the existing social order depended to a large degree on birth, but also in the heightened emphasis then laid on manners and the cultivation of taste and intellect.5 Family wealth was transmitted along lines of descent, marriages were contracted according to well-known social codes, and increasing numbers of diseases and disorders were recognised by doctors as hereditary “taints.”

  Darwin had every reason to muse on good and bad breeding among humans. His personal circle belonged to a close-knit stratum of society, the intellectual aristocracy of the high Victorian era, sympathetic to Mill’s idea of a “learned elite” and Carlyle’s “aristocracy of talent.” Most members of this intellectual elite associated themselves with the rising ideologies of meritocracy, utilitarianism, and personal “character,” a Smilesian sense of personal effort and determination under adversity, while for the most part enjoying inherited private incomes and status by birth. Darwin’s position as a gentleman was secure. Expansively, he felt free to value gentlemanly qualities in others who might not have been born into favoured families like his own, regarded himself as an egalitarian, applauded merit and industry, promoted civic duty and progress, and appreciated the attributes of refined society. He felt no guilt about being an elitist, and yet he managed most of the time not to be too much of an obvious snob. He made room in his life for the conviction that effort, manners, intellect, and hard work could make a difference.

  Assumptions like these could smoothly feed into ideas about family lines of inheritance. Any walk through his village community might reveal local families that had existed on the same spot for generations, the same names on the gravestones beside the church, the same fields, shops, and public houses running in families, the great houses like High Elms passed down from father to son, although these patterns were never quite as stable as pastoral nineteenth-century imagery might suggest. Everywhere he looked he might see sequences of marriage and heredity, whether dynastic unions between royal princes and princesses or the small-scale reinforcements of social identity that took place in his own circle. The family was the primary Victorian institution in which the meaning of individual lives and lines of descent were constructed and transmitted over the generations—the repository of personal history.6 Embedded as he was in his own family connections, these notions surely seemed a natural basis for his researches into animal and plant inheritance.

  And reproductive advice washed around him, not just in medical texts and household manuals but also in the romantic fiction of the period. It would not be going too far to suggest that during these years of ill health the sentimental novels read to him by his wife Emma put mating and heredity in the spotlight.7 The love plot suddenly mattered, ranging from the tangled nets of courtship and marriage in Eliot’s Middlemarch or Daniel Deronda to the darker writings of Thomas Hardy, who, although an author unread by Darwin, declared himself one of “the earliest acclaimers of the Origin.” The novels that Darwin best liked to hear were liberally embroidered with squandered fortunes, obscure births, unusual lineages, misplaced inheritances, ancestral maladies, inappropriate marriages, and the transmission of family “temper.” In effect, the biological ideas at the heart of evolutionary theory turned human genealogy into palpitating drama. Much of Darwin’s interest in good and bad breeding and his sympathetic concern for the travails of pretty heroines consequently reflected the wider preoccupation of his class with marriage, position, manners, wealth, and the fear of congenital ill health. No wonder he insisted on a happy ending.

  His attention to the transmission of wealth was significant too. While Victorian aristocrats criticised the law of entail that turned an eldest son into a merely temporary custodian of a landed estate, and country landowners squealed
at the erosion of their patrimony, the newly affluent ranks of society claimed an increasing share of the country’s financial and political power, sometimes through paper wealth alone. The old order was breaking down. Darwin’s interest in the subject was profound, and it probably acquired vivid personal meaning through his own experiences as an investor and a financially supportive husband, brother, and father. He went to elaborate lengths to ensure financial security in the form of an inheritance for his loved ones. The circulation of capital, in this sense, and particularly the accumulation of interest on that capital, could easily serve as a metaphor for the inheritance of characteristics in living beings.8

  Hereditary disease naturally bothered him too. While he was ill, Darwin lingered on the topic with morbid unease. His own afflictions supplied an alarmingly personalised case study, although his fears about the children having inherited his “wretched constitution” have to be taken in due proportion. Many families experienced at least some comparable congenital disabilities or fears about such. Bad stomachs, melancholia, early senility, hypochondria, stillborn babies, gout, mysterious “fits,” and idiocy regularly appear in the medical records of the century. Even so, his children’s disorders seemed to him like variants of his own. Perversely, no matter what the children suffered from, Darwin always thought he could identify something of his own failings in each and every illness. “When we hear it said that a man carries in his constitution the seeds of an inherited disease,” he was to write in Variation, “there is much literal truth in the expression.”9

  Time after time, the topic of inbreeding arose. An undercurrent of worried self-interest ran through his researches into plants and animals, for he was never sure if reproduction between close relatives might inadvertently bequeath to the offspring a series of innate weaknesses, infertility, or a tendency towards disease (“diathesis” in the terminology of the period). In human affairs, consanguineous marriages were at that time prohibited by civil law, prohibitions that extended from blood relatives in the immediate line (fathers and daughters, for example) to relatives by marriage. Even though the prohibition did not include marriages between first cousins, as in the case of Darwin and his wife, Darwin knew there were sufficient medical warnings about such marriages to cause concern. He had carefully studied Alexander Walker’s book on intermarriage when first hoping to propose to Emma, a book which addressed “the causes why beauty, health and intellect result from certain unions, and deformity, disease and insanity from others.”10

  Moreover, in England, continued newspaper agitation about repealing the laws prohibiting marriage with a deceased wife’s sister rose and fell in the nation’s consciousness. He wondered about the marriages between cousins that were so common in his personal circle. No fewer than three of his or Emma’s siblings had married cousins, not counting himself, and whose offspring he had an opportunity to observe at Down House on a regular basis. Cousin marriages were commonplace in his wider sector of society, at times seemingly the preferred norm. In fact, Victorian notions about cousin marriages were nearly the opposite of those of the modern day. Given the restrictive social structure of the day and constraints on marriage, cousins were often the only members of the opposite sex whom young men or women could come to know with any intimacy. Such familiarity and shared social background were often regarded as the best possible start to a marriage, as Darwin’s own experience showed. The advantages of cousin marriages for retaining land, money, or titles in the family were also well understood. So Darwin was caught in a dilemma that is not easily understandable in modern terms. He did not necessarily regard cousin marriages as a bad thing. Few people, other than a handful of medical authors or social commentators, worried about cousin marriages as a likely source of inbreeding or inherited defect, and even those warnings would have been perceived as mostly applicable to aristocracy or royalty, or to geographically isolated populations in areas of Britain like the Welsh hills or the East Anglian fens, where long-continued intermarriage over many generations was known to result in a number of recognisable congenital physical and mental disorders. Yet he could not help but be anxious about the possible medical consequences of his own actions for his children.

  Plants and pangenesis were his salvation. The breeding experiments he performed at Down House during this period were designed in part to test this assumption and—perhaps unsurprisingly—helped him come to the conclusion that the deleterious effects from inbreeding were not nearly as pernicious as supposed.

  To this end, he made crosses between individual plants that were closely related, especially back-crossing descendants to their parents, and putting brothers to sisters, techniques much used by Naudin and Gärtner; and he consulted animal breeders and other agriculturalists who knew about the same kind of mating patterns in pedigree animals among which it was important to conserve and emphasise particular bloodlines. In an era when foxhounds or racehorses could be more highly bred than members of the Houses of Parliament, he found plenty of experts to help him on the point. William Tegetmeier carried out similar breeding experiments for him on poultry, pigeons, and even a few turkeys. Darwin studied the results of European specialists, returning again and again to Gärtner’s Versuche und Beobachtungen, as well as Nägeli’s Botanische Mittheilungen (1866) and Naudin’s Nouvelles recherches sur l’hybridité dans les végé-taux (1863). All three books were in his library and carried on every page evidence of his attention.

  The results were suggestive. He noted that inbreeding was primarily a feature of the domestic kingdom. Farmers would consolidate their stock-lines by putting father to daughter, brother to half sister. Continued inbreeding of this kind between blood relations certainly diminished the “constitutional vigour, size and fertility of the offspring; and occasionally leads to malformations but not necessarily to general deterioration of form or structure.”11 Under the intensive conditions of domestication, with assisted matings and supplementary feeding, even the weakest offspring could survive and reproduce.

  It is unfortunately too notorious that man and various domesticated animals endowed with a wretched constitution, and with a strong hereditary disposition to disease, if not actually ill, are fully capable of procreating their kind.

  These situations would not generally arise in the wild. Taking advice from the anthropologist Edward Tylor, Darwin suggested that there must be in nature a form of incest taboo. If by chance there were such matings, natural selection would weed out any malformed offspring.

  The surprise came with his realisation that matings between first cousins did not necessarily fall into these deleterious categories. His research into Victorian farming practice showed him that farmers considered cousins sufficiently far apart to present little risk to the viability of the offspring. As often as not these matings were regarded as good procedures for conserving, say, the prime features of champion bulls.

  Pangenesis looked to him as if it might supply the answer. Darwin proposed that some limited effects from the environment might become embedded in an individual’s constitution and thus be liable to be transmitted, via the gemmules, to the offspring. If two very closely related individuals, who had grown up under rather different external circumstances, were paired, these small differences would make each sufficiently distinct from the other to bear normal offspring.

  There is good reason to believe that by keeping the members of the same family in distinct bodies, especially if exposed to somewhat different conditions of life, and by occasionally crossing these families, the evil results may be much diminished, or quite eliminated.12

  As he would acknowledge in Variation, the point was of “high interest, as bearing on mankind.”

  Even so, he remained uncertain. The philosophical difficulties and practical consequences of cousin marriages troubled him for years afterwards. There was no other theme in Darwin’s science that more clearly reflected the personal origins of his intellectual achievement. He could scarcely have arrived at pangenesis without this attention to his mar
riage, his children’s ill health, and his own sickness.

  II

  Significantly, he also thought pangenesis resolved some of the more important criticisms brought up by reviewers of successive editions of the Origin of Species. While he was ill, and then while writing the book on Variation, he composed his answers.

  One of these criticisms went to the nub of the matter. In 1867 the Scottish engineer Fleeming Jenkin pointed out in a long review of the Origin of Species in the North British that any individual variation, however favourable, could hardly maintain a secure foothold in a large, freely breeding population, at least not in sufficent numbers to produce a new species.13 Jenkin was one of the most original thinkers of his generation, a friend of Robert Louis Stevenson, and greatly interested in population studies and political economy. Although it took Darwin a full year to discover who had written this review in the North British, he took the objection seriously and admitted, “Fleeming Jenkin has given me much trouble, but has been of more real use to me than any other essay or review.”

  At the centre of the review lay a concrete problem. Calling on archetypal Victorian racial assumptions, Jenkins gave the hypothetical case of a white-skinned sailor shipwrecked on an island inhabited only by black-skinned tribes. Free reproduction between “civilised” and “savage,” said Jenkin, would not lead to the preservation and spread of the white man’s characteristics. Quite the reverse. The European’s supposed advantages would be blended or “swamped” in the larger population.

  Our shipwrecked hero would probably become king; he would kill a great many blacks in the struggle for existence; he would have a great many wives and children … but can anyone believe that the whole island will gradually acquire a white, or even a yellow, population, or that the islanders would acquire the energy, courage, ingenuity, patience, self-control, endurance, in virtue of which qualities our hero killed so many of their ancestors, and begot so many children?14