Darwin and the Barnacle

by Rebecca Stott

  Species are mutable. Allied species are co-descendants of common stocks. This is what Darwin’s 231 secret pages amounted to – eleven simple words; a hypothesis; an idea in embryo. If this embryo was to survive, it would have to be adapted to the conditions into which it would be born. If Darwin was not to go the way of ‘Mr Vestiges’ or Lamarck, laughed off the scientific stage, he would have to find a way of persuading his audience that these eleven words were common sense, incontrovertible and, more than anything, plausible. He had to be plausible. He had to have authority – after all they had said about Mr Vestiges and his pie-in-the-sky ideas, his ideas had to be rooted in everyday things: common sense; empirically observable truths.

  This was where Mr Arthrobalanus fitted in. Life on the planet had begun with primitive creatures such as this; but barnacles were also everywhere, along every coastline in almost every part of the world. They were at once everyday objects and one of the strangest creatures in the world; and if he could show the relationship between living barnacles and fossil barnacles thousands and perhaps millions of years old, he could show that all these varieties of barnacles had once had a common ancestor and, more importantly, he could demonstrate why these first primitive forms had diversified.

  Mr Arthrobalanus was an orphan from a family of orphans – and an aberrant, too. In order to make sense of his deviance, Darwin had to understand what being a ‘normal’ barnacle meant and what the common ancestor might have looked like; and that was no easy matter. He began to send for specialist barnacle literature from specialist libraries and then he was hooked, reminded just how significant this zoological riddle was. Jenyns was right: the barnacle puzzles would not be solved in a few months’ work. He would be working at this particular problem for eight long years; but he didn’t know that in 1846, nor did he know at first that this extremely diverse genus would be the very epitome of mutability – a minute marine monument to mutability. He had been aware since 1837 of the need to show extreme mutability within one species; he knew how crucial it was to his theories. With Mr Arthrobalanus and his aberrant kin, he would bring down the fabric of fixed species and creationism once and for all: ‘Once grant that species … [of] one genus may pass into each other … & whole fabric totters & falls. – Look abroad, study gradation study unity of type study geographical distribution study relation of fossil with recent. The fabric falls.!’24

  By October 1946 the work on the house was complete and his study newly painted. Baby George was now walking; and although neither Emma nor Charles knew it yet, some time in early October husband and wife had conceived another child, who would be born the following July – a girl child, Elizabeth. On 2 October he wrote to Hooker with his new grand plan, a schedule that would take him until 1852 if he stuck to it:

  I am going to begin some papers on the lower marine animals, which will last me some months, perphaps a year, & then I shall begin looking over my ten-year-long accumulation of notes on species & varieties which, with writing, I daresay will take me five years, & then when published, I daresay I shall stand infinitely low in the opinion of all sound naturalists – so this is my prospect for the future.

  Are you a good hand at inventing names: I have a quite new & curious genus of Barnacle, which I want to name, & how to invent a name completely puzzles me.25

  The first job on this new zoological island was to map out Mr Arthrobalanus’s body parts. He would need to employ an artist to do this, but he struggled to find one. Joseph Hooker offered to help, so Darwin set off with Mr Arthrobalanus in his glass jar to London on 19 October, staying with his brother Ras in Grosvenor Square, and taking Mr Arthrobalanus on the omnibus to Kew the following day. Carrying a glass jar on an omnibus would not have been easy. The buses were usually crowded, with dirty straw on the floor and the journey through the busiest parts of London was often very slow. One traveller described the experience in the New Monthly Magazine: ‘Here we are … in all six and twenty sweating citizens, jammed, crammed and squeezed into each other like so many peas in a pod …’ There were no fixed bus stops, so passengers had to stop the bus from the roadside by banging on the roof or pulling on the horses’ reins.26

  Some time around noon Darwin reached Kew Gardens, where Hooker’s father, the famous botanist, Sir William Hooker, was the Director. The two men examined the internal organs of Mr Arthobalanus under Hooker’s microscope after lunch. Hooker was intrigued and began to draw. They discussed names – Hooker suggested Cryptophialus minutus, meaning ‘minute secret bowl’. Darwin was amazed at how much more he could see with Hooker’s microscope than with his own, so Hooker offered to order him a new lens from Alexander James Adie, an optician and instrument maker in Edinburgh.27 In the meantime he would lend him a lens. The new lens, which arrived in the post from Edinburgh a week later, cost Darwin three shillings and sixpence – a wise investment that would reap him substantial rewards over the following months. Hooker agreed to continue dissecting the specimen of Mr Arthrobalanus that Darwin left with him and to finish the drawings if he could. Then the two men took a walk in the gardens of Kew and Darwin, carrying his glass jar and microscope lens, walked back to the main road to flag down an omnibus to take him back to Grosvenor Square.

  This was an excellent start. Darwin was delighted with the finished drawings that the enthusiastic Hooker sent him a week later: at least twenty-one minutely sketched drawings of folds, jaws, muscles, valves, ‘coffin-shaped’ larvae and eggs. ‘The more I read, the more singular does our little fellow appear,’ he wrote enthusiastically to Hooker, enclosing the borrowed lens with thanks.28 The two men spoke about Mr Arthrobalanus now as if he were a creature they had hatched together. They often enclosed small presents with their letters: Hooker sent chutney and glass jars and porcupine quills in November that year. Darwin sent him a sheaf of carefully worded questions about what he had seen inside Mr Arthrobalanus such as: ‘Did you happen to notice, whether the cherotherium footsteps pointed upwards or to the base of the animal? I can look, if you do not remember.’29 Barnacle conversations had begun.

  12 Mr Arthrobalanus

  Throughout October Darwin dissected his specimens of Mr Arthrobalanus for several hours every day, supporting his wrists with blocks of wood.30 The heat from the fireplace made the wine spirits evaporate and it was too cold in October to ventilate the room properly. So Darwin worked in the heady smell of wine spirits, as sweet and spicy as fine brandy. By afternoon his head was swimming and his eyes strained with the close microscope work; for Mr Arthrobalanus was no bigger than a pinhead and so Darwin could only dissect him under the microscope. Once he had extracted the body part he needed, he transferred it in a drop of water on to a glass slide. Then he would take a spoonful of gold size – a thick glue – and draw a circle around the drop of water, sealing it by fixing another glass slide to the top. To his children’s eyes these glass slides, arranged in rows in the collecting drawer, were much less interesting than the jars containing shrews or lizards or octopuses curled up and floating in yellow liquid, eyes open, up on the shelves; but, for Darwin, the body parts of Mr Arthrobalanus began to be more important and frustrating than anything he had yet worked on. The more he looked, the less sense it made.

  By November 1846 he had made his first major breakthrough and he wrote immediately to Hooker: ‘I believe Arthrobalanus has no ovisac [ovary] at all!, & that the appearance of one is entirely owing to the splitting, & tucking up to the posterior penis, of the inner membrane of sack. I have just found a Cirripede with an indisputable abortive anterior penis; so that this chief anomalous feature (viz two penes) in Arthrobalanus is in some degree brought within bounds.31

  Barnacles are hermaphrodite, he knew they have both male and female organs; but they can’t fertilize themselves. In order to fertilize their neighbours they have a very large penis, the largest penis in the animal kingdom – proportionate to size, of course. So Darwin, assuming Mr Arthrobalanus to be a hermaphrodite, like all the mapped barnacles, had searched out a penis (and fou
nd two, he thought) but couldn’t find an ovisac.32 He searched and searched, discarding specimen after specimen, but there just wasn’t one. It didn’t make sense. Lunch that day must have been frustrating. Would Darwin have explained to Emma in front of the children? Could he have kept silent, aware of the import of the missing ovisac? Had he found a pure male barnacle? Or was it that he simply hadn’t searched hard enough for the ovisac that would establish its classification as a hermaphrodite? Where was it?

  By November 1846, Arthrobalanus partially mapped but not yet understood, Darwin had moved on to other barnacles, searching for answers to the puzzles Mr Arthobalanus’s strange body had produced. He could not understand the aberrance here, before he had come to understand the whole barnacle group; and that would take a long time. He had a theory to work with, however: Mr Arthrobalanus’s aberrance had allowed him to survive, and his survival had entailed adaptation to conditions. Other living barnacles were also prime survivors. He needed to map them against their ancestors to measure their divergence from a common starting point. For fossil and living barnacle specimens he would have to fish widely. If he were to stay put in Down, he would be dependent upon the goodwill of others to collect and loan him specimens. He wrote to Richard Owen asking for any barnacle specimens he might have; he wrote to Sir James Ross, who was setting off to search for the missing Franklin expedition in the Arctic, asking him to collect any northern barnacles: ‘Barnacles are so easily scraped off the rocks & put into spirits, that it would cause you but little trouble,’ he reasoned.33 He wrote to the trustees of the British Museum asking them to allow him to dissect their specimens in the privacy of his own home; and he prepared himself for months’ more close dissection by ordering a new microscope. This was going to take time – longer than he had thought.

  Down may have been, in Darwin’s eyes, on the ‘extreme verge of the world’ but he had made sure when he visited the house for the first time that the village had a post office. Darwin’s barnacle networks had their centre in the post office of chalky Down, one small village post office linked to the rest of the world through a reformed and increasingly efficient postal system. Rowland Hill, a British educator and tax reformer, had begun the postal reforms only in 1840, and now Darwin, like everyone else, paid a uniform rate of postage, regardless of distance. The postmaster who carried the packages up to Down House, the sound of his feet on the gravel path instantly recognizable to Darwin, carried letters and parcels with the new prepaid adhesive stamps.34 The mail coach took the letters and parcels Darwin posted to Bromley, where they joined up with the railway network. New specially adapted railway sorting carriages were speeding up delivery times enormously.

  Darwin’s barnacle network would eventually stretch across Britain to several barnacle collectors in London, including Hugh Cuming, a conchologist with a major collection of fossil shells, and the trustees of British Museum collection, but also to smaller-scale collectors such as Samuel Sutchbury in Bristol, Robert Fitch, a chemist and collector of fossil barnacles in Norwich and Albany Hancock in Newcastle. The network also extended beyond British shores and around the world. Darwin wrote and received correspondence and barnacles through international postal systems: from Augustus Gould and James Dwight Dana in Boston, Alcide d’Orbigny in Paris, professors in Germany, Holland, Denmark and Norway – even from Syms Covington, his former servant, and from the father of his former shipmate, Captain King, in Australia.

  A second railway boom in the mid 1840s was extending the length of the track in Britain from 2,000 to 5,000 miles. The new lines were being built by thousands of navvies, many of them Irishmen who had emigrated to England to find work during the famine.35 Their encampments, huts made of mud or wood with tarpaulin for the roof, which accommodated as many as fifteen hundred workers and their followers, were shanty towns built by the side of railway cuttings, with their own customs, hierarchies and traditions. The men were usually regarded by local villagers as a ‘race apart’ with a reputation for fighting, gambling, drunkenness, disease, and theft.36 However, survival was paramount in these communities and work was the key to survival. Most navvies worked from sixty to seventy hours a week, and work often had to be fought for. In 1846 Darwin read articles in The Times about riots and pitched battles amongst Irish, Scottish and English navvies at Penrith, Kendal, and Bathampton.

  In a couple of decades two hundred thousand navvies achieved a feat of engineering comparable to the construction of the pyramids of Egypt. They were expected to shovel about twenty tons of earth and rock a day, excavating, cutting, banking and tunnelling. For this they were paid twenty-two shillings a week in 1846. Three per cent of the labour force were killed, fourteen per cent injured. It was these men who made postal correspondence both possible and efficient.

  Railways were worth investing in for those with money to invest, as Darwin’s shrewd father advised him in 1846. Darwin began to speculate, to play the stock market. His first cautious investments began to pay off. He and Emma discussed further investments, using his money and the money from Emma’s trust fund. The railway boom was changing the landscape and making fortunes. The London to Brighton railway opened in 1841. Torquay was connected up to the railway network in 1848. The ten major seaside towns grew beyond all expectation in the first half of the nineteenth century as the volume of visitors encouraged entrepreneurs to build new lodging houses and the rich built their luxury summer villas. Seaside towns such as Brighton, Hastings, Margate, Torquay, Whitby and Blackpool increased in population by 254 per cent between 1801 and 1851, much higher than the rate of population growth of London during the same period.37 Hotels and fine houses were built along the shore or close to the railway line, in long rows, overshadowing sea cottages belonging to the fishermen and women. Sea views and drawing rooms with sea air were now luxuries.

  Darwin had good memories of childhood seaside visits, particularly one he made to Plas Edwards on the Welsh coast in 1819, when he was ten years old: ‘The memory now flashes across me, of the pleasure I had in the evening or on a blowy day walking along the beach by myself, & seeing the gulls and cormorants wending their way home in a wild irregular course. – such poetic pleasure, felt so keenly in after years, I should not have expected so early in life.’38 But no matter how much he wanted to replicate such rugged outdoor experiences for his own children, Darwin avoided the seaside after Edinburgh and the Beagle voyage. Perhaps it was the warmth and beauty of South Sea beaches that overshadowed his memories of the windy pleasures of the British coastline. Perhaps he simply didn’t need to go, now that he had sea-creature collectors posted around the world. He did not need to suffer the British sea winds. Emma had always enjoyed the Tenby excursions with her children, staying with her aunt Jessie Sismondi and Harriet Surtees in South Cliff House; but as the children got older and their numbers grew, South Cliff House grew too small and, as Charles was never keen to be dragged away from Down and from his study, Emma did not press for seaside holidays. They had so much at Down.

  All the bright young zoologists seemed to be settling down, Darwin reflected at the beginning of 1847. They were all looking for rocks upon which to fix themselves and reproduce. The sparkling and witty Edward Forbes, born on the Isle of Man and son of a small-time banker and timber merchant, had returned to England after following the marches of Alexander the Great across Asia Minor, discovering eighteen ancient cities and closely examining the sea creatures of the coast of Lycia, where Aristotle had walked. He had published an important and wittily illustrated book on British starfish in 1844 on his return. Now he was salaried, like Robert Grant. Edward Forbes was now Professor of Botany at King’s College, London and he had been appointed to the post before he had turned thirty. He spent his summers out on the sea with increasingly large and sophisticated dredges so as to probe deeper and deeper into the dark depths for new creatures. He was even leading a campaign for dredging committees to be established across the country to share dredge building and dragging techniques amongst marine zoologist
s.

  By 1847 Edward Forbes was in love, courting his future wife, the daughter of a general, whilst engaged day and night in writing up his new book, A Monograph of the British Naked-Eyed Medusae – minute luminous jellyfish, largely responsible for the phosphorescent waves Darwin had seen on the Beagle. Like the madrepore, like the sponge, like the sea anemone, these creatures had the most inventive ways of reproducing, only visible under a powerful microscope. They reproduced not only by producing gemmules, or eggs, but also by asexual reproduction – by budding. Suddenly a new creature would appear still connected to its parent, like a Siamese twin – food for thought for a man about to begin a family, Forbes reflected:

  What strange and wondrous changes! Fancy an elephant with a number of little elephants sprouting from his shoulders and thighs, bunches of tusked monsters hanging epaulette-fashion from his flanks in every stage of advancement! Here a young pachyderm almost amorphous, there one more advanced, but all ears and eyes; on the right shoulder a youthful Chuny, with head, trunk, toes, no legs, and a shapeless body, on the left an infant, better grown, and struggling to get away, but his tail not sufficiently organized as yet to permit of liberty and free action! The comparison seems grotesque and absurd, but it really expresses what we have been describing as actually occurring among our naked-eyed Medusa. It is true that the latter are minute, but wonders are not the less wonderful for being packed into small compass.39

  In fact, by late 1847 it seemed to Darwin, who now had five children (Emma had given birth to Elizabeth in July), that only Hooker was still unhooked, still unmetamorphosed; but even he was engaged: he had proposed to Henslow’s eldest daughter, Frances, before he sailed for the East. Darwin wrote to his botanist friend, who was collecting plant specimens in the Himalayas, to bring him up to date on the British news: Edward Forbes, he told him was newly married – ‘I almost grieve to think that I shall have no more of the old bachelor parties,’ he complained. Interestingly, many of these settling naturalists were also, like him, writing long monographs about sea creatures – starfish, jellyfish, molluscs, men-of-war – trying, like him, to puzzle out taxonomies and common anatomical and reproductive patterns in the undersea world. Asexual reproduction now appeared to be more common in nature than sexual reproduction. For the women they courted, hushed parlour conversations about undersea reproduction, the slime and tentacles of marine courtship, were doubtless piquant, grotesque and erotic.