Darwin and the Barnacle

by Rebecca Stott

  Zoonomia came in two volumes, ran to 586 pages and weighed four pounds. But of all those pages it was the fifty-five-page chapter on generation that excited Grant the most, for in it Erasmus Darwin argued that every living organism on the Earth had descended from one common ancestor, a microscopic aquatic filament, and that from this beginning of life all other forms had transmuted and diverged to form all the variety of forms now present on the Earth: ‘In some this filament in its advance to maturity has acquired hands and fingers, with a fine sense of touch, as in mankind. In others it has acquired claws or talons, as in tygers and eagles. In others, toes with an intervening web, or membrane, as in seals and geese.’6 Erasmus Darwin, who had postponed publishing his ideas about the development of species for twenty years, fearful of the consequences, was tentative in his conclusions, even hesitant, carefully honing his ideas into rhetorical questions:

  Would it be too bold to imagine, that in the great length of time since the earth began to exist, perhaps millions of ages before the commencement of the history of mankind, would it be too bold to imagine, that all warm-blooded animals had arisen from one living filament, which THE GREAT FIRST CAUSE endowed with animality, with the power of acquiring new parts, attended with new propensities, directed by irritations, sensations, volitions, and associations; and thus possessing the faculty of continuing to improve by its own inherent activity, and of delivering down these improvements by generation to its posterity, world without end!7

  The nature that Erasmus Darwin described was entirely self-sufficient, self-regulating and self-generating; all of its changes could be explained without reference to God and it was still changing, mutating, improving. The word – the dangerous word – was ‘transmutation’. The world was still in its infancy, he argued, and the patterns of structure that Grant had seen in animal bodies were, according to Erasmus, the result of common parentage; but when Grant enthused about the brilliance of Zoonomia to fellow students and teachers, they either dismissed the book as mere speculation or warned him against the blasphemous ideas that it contained. It was a book by a poet for poets, others said – those with a vivid imagination. Who else could believe that man had grown from primitive aquatic filaments? The man was an inventor of ideas not a researcher, nor an anatomist, nor a dissector. Where was his evidence?8

  Grant graduated as a doctor in 1814. His father, a solicitor, had died in 1808 when Grant was fifteen years old, unusually dividing up the family fortune in his will equally between the surviving children. Grant was now financially independent, but his money would not finance intellectual independence for more than a few years; so his professors encouraged him to go abroad – Germany and France were the places to go with the questions about anatomical patterns that pressed him. Paris was the centre of comparative anatomy and in 1815, at the end of the Napoleonic Wars, the year after Grant graduated, the great city was accessible again. The seventh son to leave home, Grant’s departure caused few worries to his family. His health was good, his professors encouraging, family funds available.

  Grant arrived in Paris at the beginning of the winter of 1815–16 when he was twenty-two. The war was over but the city, with its wide boulevards and green parks, was still full of men in uniform: Prussian victors swaggered about the city, boastful and ebullient, filling the nightclubs and dance halls; the British soldiers were more sober and disciplined; even Scottish soldiers in kilts were to be seen on street corners buying lemonade from the street sellers. Grant was one of only a few British medical students in the city, but they lodged together and met in cafés, comparing notes, gossiping about the charismatic and argumentative French professors.

  There were many more corpses for dissection in Paris than in Edinburgh. Reforms to medical practice, research and hospital management in the wake of the French Revolution had made Paris the heart of the new medicine, characterized by systematic close observation of human anatomy. The vast Parisian hospitals, no longer in the hands of the Church but in the hands of the republic, had become places of research and teaching and the new generation of doctors was being trained to spend hours sawing, cutting, looking, describing the insides of bodies in order to determine the structure and patterns of disease, only visible beneath the skin. Thirty thousand people a year were treated in the hospitals of Paris and of those who died four fifths were dissected. Body parts on marble slabs, anatomic diagrams on chalk boards, maps of disease, autopsies, microscopes – like a detective, the medical student was trained to watch, listen and record and to trust the evidence of his senses, particularly his eyes, above the authority and abstract, untested theory of old medical textbooks.9

  Grant spent his first winter studying comparative anatomy in the Musée d’Histoire Naturelle at the Jardin des Plantes, attending lectures by the most famous French comparative anatomists of his day and improving his French so that he could follow their arguments more closely. Carrying letters of recommendation from Professor Jameson, he was immediately admitted into the salons of three French professors: Baron Georges Cuvier, Geoffroy St Hilaire and the elderly Jean-Baptiste Lamarck, Professors of Comparative Anatomy and Zoology at the Jardin des Plantes. Like Grant and Jameson, all three French professors were gathering detailed information about human and animal anatomy. They were trying to understand why there were structural and functional similarities between legs, fins and wings, for instance. Cuvier taught that species were fixed and that any observable similarities between organisms belonging to different zoological families – or embranchements, as he called them – were explained by their similar functions. Geoffroy, on the other hand, believed in structural relationships that revealed blood relationships across the various groups. He was convinced that there was a unity of type and that natural laws could explain the connected body parts of humans and other animals right across the spectrum of creation, but he was not much concerned with transmutation as a way of explaining these common structures.

  There was a transmutationist in Paris, however. Lamarck, Professor of Worms and Invertebrates in Paris, was in his seventies in 1815 when Grant arrived and was just completing his seven-volume work Histoire Naturelle des Animaux sans Vertèbres, Like Erasmus Darwin before him, he believed that the structural similarities between different animals were due to the development of different species from a common ancestor; and that this common ancestor was not a man called Adam, but a primitive marine creature that had appeared through a kind of spontaneous generation. These were controversial ideas because they implicitly questioned the centrality of God in the creation of the Earth, implying that humankind had evolved from a primitive creature and therefore had not been made in God’s image. In addition, for these theories to be true, the Earth would have to be hundreds of millions of years old, much older than biblical history allowed. But Lamarck was not setting out to topple the Church or the authority of the Bible – these things were far from his mind. He was looking for a key to nature’s riddles and secrets. It was a simple hypothesis: if life started in water and single-celled marine organisms were the first life forms, then, as the ‘parents’ of all living things, marine invertebrates were the key to understanding the complicated biological processes of all ‘higher’ animals.10

  Grant, already seeing nature and transmutation through Erasmus Darwin’s eyes, gravitated towards the Lamarck transmutationism, staying in Paris long enough to improve his French, study the contents of the natural history museum and its rich sea-sponge collection of over a hundred different species, and pick up the latest radical philosophical theories shaping zoological interpretation. He read voraciously in Greek, French, German and Italian. The writings of Geoffroy and Lamarck in particular confirmed his belief that marine invertebrates were the key to understanding the origins of life. In this climate of philosophical speculation underpinned by rigorous scientific experiment and observation, Grant determined to find a small corner of the natural world that he could make the subject of his own research, an unknown territory to map. In this way he could work throu
gh some of these philosophical problems for himself.

  Of all the marine invertebrates discussed in the salons and lecture theatres of Paris, the sea sponge, an aquatic organism full of holes, gave comparative anatomists perhaps the most trouble. The discovery of fossil sponges suggested that this creature was one of the most ancient organisms on the planet, but what kind of creature was it – animal or vegetable? If animal life was to be measured in terms of sensation, movement and the existence of a stomach, then the sea sponge appeared to have few discernible signs of such things – few discernible signs of anything. In fact it was so immobile and apparently insensate that many zoologists until the 1820s had categorized it as a plant. Under a stick a sea mouse would roll, a cuttlefish squirt, a sea anemone retract its tentacles; but prod, poke or pierce a sea sponge and nothing happened. Calm, nerveless and permanently attached to rocks on the seabed, they had been studied by few people. Taken out of the water they quickly died, their prismatic vibrant colours faded. They were an enigma.

  The sea sponge was to be Grant’s unknown continent. With a clear set of philosophical problems in mind he set off for southern Europe to collect new specimens and to visit as many European marine invertebrate specialists, libraries and natural history collections as he could before his inheritance ran out. These questions took him to Rome, Florence, Pisa, Padua and Pavia, not for paintings or ruins but for books and articles in French, German and Italian – books on marine invertebrates and now sea sponges in particular. He collected and dissected Mediterranean sea sponges on the seashores of Leghorn, Genoa and Venice. He read all the journal articles and books on marine invertebrates in French and German he could find. He took copious notes on the books he read and the creatures he dissected. He asked to speak to marine invertebrate specialists in every city he visited and he found them. He spent eighteen months in Germany, then travelled through Prague, Munich, Switzerland, back down to the south of France and the University of Montpellier. In 1820 he returned to Paris, then visited the natural history and anatomy collections in London, arriving back in Edinburgh by the end of the year with boxes of notebooks, specimens and papers. He was careful with his emerging conclusions, however – careful not to give away his ideas to others.11

  Grant’s actions from 1820, on his return to Edinburgh, are those of an obsessively driven and secretive man, determined to prove a theory, and aware that his time was running out. His inheritance was diminishing and soon he would cease to be a man of science with independent means. Once back in Edinburgh he prepared himself for earning a living as a doctor and as a part-time lecturer in comparative anatomy. He enrolled in Dr Barclay’s private anatomy school in 1821, which had the best supply of corpses in Edinburgh, and for two years he was seldom away from the dissection rooms until a friend in 1823 give him the use of his high-walled house on the beach in Prestonpans, a village to the east of Edinburgh, where he could conduct his research in complete privacy.

  Dr Barclay’s anatomical theories were a long way from the exciting ideas Grant had heard in Paris in conversations with Geoffroy and Lamarck. Barclay, a former clergyman, had set himself against these materialist French ideas. He deplored ‘the overweening conceit of the sceptic’, and for him those who spoke of ‘established laws’ were bigots. His own published work was a determined attack on all mechanistic explanations of life. ‘Those physiologists who are inclined to favour materialism have never attempted to explain how the first parents of the different species of animals and plants might have been formed,’ he complained in 1822.12 Barclay did not suspect that he had a materialist interloper in his dissecting rooms, or that the beautiful sea sponges stored in Grant’s jars were being used as the foundation for a materialist philosophy of nature. He was so impressed with his apprentice’s knowledge that in 1824 he asked Grant to give the invertebrate lectures for the comparative anatomy series he had been asked to deliver at the University. During the summer, Grant used the income from these lectures to fund further sponge-collecting expeditions around the coasts and caves of Scotland and Ireland.

  The seven sea-sponge essays that Grant finally published in 1825–7 tell a tale of obsession – not the obsession of the collector, determined to add more and more rare specimens to his collection, but that of a natural philosopher. He wanted to understand the complex anatomy of the sea sponge in order to form a cornerstone for a daring philosophy of nature, based on the premise that the sea sponge was an almost unchanged descendant of the very first living forms on Earth. The sea sponge would be the first proof of a philosophy of transmutation, providing a lineage from which higher forms had emerged. So he dissected sea sponges by night, winter night after winter night, for almost the entire five-year period between his return from Europe and his first published sponge essay in 1825. Adult and embryo human body parts by day; adult and larval sponge body parts by night.

  Grant’s winter residence, Walford House, a large house with a high-walled garden built on the edge of the shore of Prestonpans, was rented from a friend in Dalkeith who used it for his family summer holidays. Prestonpans was established in the twelfth century for the production of salt from water dredged from the Firth and boiled in enormous salt pans. In the eighteenth century, at the Battle of Prestonpans, Highland Jacobite soldiers, carrying scythes and eight-foot-long claymores, massacred hundreds of English soldiers at dawn, mowing them down, and severing limb from limb. The ground was strewn with legs, arms, hands, noses, and mutilated body parts, the ground soaked with gore. By the nineteenth century, however, Prestonpans was a picturesque tourist attraction, offering newly fashionable bathing machines to the summer tourists who rented the large sea-front houses. Surrounded by a high wall and opening on one side through a narrow wooden door, which led down four steep steps directly on to the black rocks and sand, Walford House was the perfect place for Grant to house and dissect his sea sponges through the winter months.

  Prestonpans Bay was especially rich in sea sponges. If the Firth was full of sea sponges, the bay, only a matter of feet from Grant’s living room, through the garden wall and down the narrow steps on to the rocks, was uniquely structured to gather them, as Grant himself described: ‘In Prestonpans Bay, the tide has excavated, in many places, the beds of soft slate-clay from beneath the outgoings of the sand-stone strata, and has thus formed innumerable small caves that are sheltered from the direct force of the waves, by lofty ridges of trap-rocks extending to a great distance from the shore.’13

  In the spring of 1825 Grant was ready to unveil the results of his five-year investigations. He moved back to Edinburgh. First he decided to test some of the basic premises of his philosophy on the members of the Wernerian Natural History Society, run by Professor Jameson. He turned up to give his very first paper to the Society on 2 April 1825 with several buckets of dead cuttlefish recently dredged from the Firth of Forth: Loligo sagittata. Cuvier had argued that no invertebrates had a pancreas; Grant opened up the stomach of one of his Firth cuttlefish and revealed to his audience that what had been thought to be the creature’s ovarium was in fact a pancreas. Then he opened another and another, male and female, until the room was filled with the smells and discarded body parts of warm dead cephalopods. There could be no doubt. This proved, he claimed, that the pancreas was to be found much lower in the scale of animals than had previously been believed. There was a pattern to be found running through the entire animal kingdom: humans had pancreases; so had cuttlefish. A few weeks later he was back with buckets of gastropods and sea slugs. These had a pancreas too. Grant was using cuttlefish and sea slugs to call Cuvier’s influential map of nature, fixed and divided into absolute embranchements, into question.

  The Society presentations had been generally uncontroversial, but no one yet realized where Grant’s observations about marine invertebrates were leading. He was now prepared to unveil the conclusions he had reached about the ancient, inert, borderline sea sponge. He began to publish his research in serial essay form in 1825 in the journal run by Professor Jameson,
the Edinburgh Philosophical Journal, which was superseded halfway through the sponge series by the Edinburgh New Philosophical Journal. Effectively Grant’s seven essays formed a small book, but instead of publishing it in one volume, Grant controlled the stages of his reader’s understanding of his work, allowing people time to fully absorb each of the premises from which he would draw his radical conclusions. Each article concluded with the words ‘To be continued’.

  His very first published essay began: ‘Sponges are aquatic productions’ – a strange phrase. Stating the obvious, perhaps; but with these words Grant implied, subtly and gently, that the sponge had been produced not by God but by its aquatic environment over eons of time. He was careful with his words, taking his time, careful to imply philosophical conclusions but not to state them bluntly. He built up his seven-part philosophy slowly, layer by layer, premise by premise, taking the reader deep inside the body of the sea sponge with all its mysterious holes and catacombs, to reveal its secrets.

  During his years in the libraries of Europe, Grant had read the works of all the eighteenth- and nineteenth-century marine zoologists who had specialized in sea sponges or polyps. His essays are filled with their lyrical European names: Zeller, Lamouroux, Gmelin, Peyssonel, Ellis, Montagu, Pallas, Guettard, Jussieu, Blumenbach, Lichtenstein, Schweigger and Marsigli; but he also returned to ancient knowledge and read Aristotle’s work on sea sponges in the original Greek. Aristotle, the natural historian of ancient Greece, was also a specialist in sea sponges, recording, for instance, that the helmet of Achilles had been lined with dried sea sponge. Grant discovered, in returning to this ancient work, that Aristotle, dissecting sea sponges without a microscope on the shores of the Adriatic in 300 BC, had been closer to these creatures than the eminent nineteenth-century professors. He – Robert Grant – would walk in Aristotle’s footsteps, not on the shores of Lycia but on the windblown shores of the east of Scotland: ‘It is pleasing to observe, that our forefathers, at such a remote period, were occupied, like ourselves, among the rocks of the sea shore, experimenting on this humble and apparently insignificant being.’14