Ole Corneliussen himself doesn’t paint, so his appreciation is purely for the pigments–‘mainly for the colour, but it’s not always very easy to describe’–and for the occasional thrill of tracking down some rare oddity. One of his favourites is the sugary cobalt violet I had noticed in the shop. It is both bright and intense, ‘one of very few colours to have that quality, it’s a very deep violet even though it is light in tone–very hard to describe without using the word fluorescent’.
I leave him to attend to an order from the artist Anish Kapoor for a tonne of calcium carbonate whiting–‘Goodness knows what he’s making.’
Inheritance Powder
Arsenic, wrote Gustave Flaubert in his Dictionary of Received Ideas, ‘Can be found anywhere (remember Mme Lafarge). There are certain populations that eat it regularly!’
As usual, Flaubert, the surgeon’s son, is sharp on scientific matters. Arsenic is widespread and abundant–so much so that it is never mined for itself but is obtained in plenty from the waste of other mining activity–and for all its deserved reputation as a poison it is essential to human biology. It is not only eaten, particularly in shellfish, but has a long and distinguished history as a medicine that continues to this day. By the nineteenth century, arsenic compounds were employed as pigments and dyes, in many medicinal preparations, alloyed with lead in shot, and in glass-making and fireworks.
But it is as the classic poison agent that arsenic is best known, and of the many tales of poisoning by arsenic, both imagined and true, that which surrounds the death of Napoleon on the remote South Atlantic island of St Helena is surely the most contentious. The story shows once again how colour and toxicity are bound together in nature. When the deposed emperor died in May 1821, the autopsy conducted by his personal physician, one of the retinue who had accompanied him into exile and a fellow Corsican, found a stomach ulcer and gave the cause of death as stomach cancer. It was not until the diary of the emperor’s valet was published much later, in 1955, that doubts began to be raised. To Ben Weider, a Canadian Napoleon enthusiast, the descriptions it gave of the emperor’s deteriorating condition in the early months of 1821 seemed remarkably like the symptoms of poisoning. In 1961, Sten Forshufvud, a Swedish toxicologist, performed analytical tests on samples of hair–many of Napoleon’s loyal servants had been prescient enough to snip off an imperial lock–and found they did indeed contain high levels of arsenic. The two men eventually teamed up and conducted further tests in pursuit of the theory that Napoleon had been a victim of deliberate poisoning, and, through a tortuous series of murder-mystery deductions, came to a definite conclusion as to whodunit. Neglecting to ask themselves too many more questions, Weider and Forshufvud amplified their theory in a series of books.
The ensuing publicity led the chemist David Jones–the author of the Daedalus column of conceivable scientific fancies in New Scientist–to wonder whether in fact the wallpaper at Longwood House, where Napoleon had been kept prisoner on St Helena, might not be a more plausible source of the poisonous arsenic than an assassin. Green shades in wallpaper of the time were frequently made by using compounds of arsenic, following the discovery by Carl Scheele of copper arsenite, a colour that became known as Scheele’s Green. By the time of Napoleon’s exile, a bright new green was also available, based on the aceto-arsenite of copper–the lucky product of colourmen’s natural urge to see what would happen if you combined copper acetate, the long-used pigment known as verdigris, with Scheele’s murkier tone.
This colour is so striking that it was marketed under the name Emerald Green. Because of its poisonous properties, it is no longer sold, but I find a small tube of it among my father’s paints, its label translucent from sixty years’ absorption of linseed oil. To my surprise, the knurled metal cap yields immediately and the paint inside glistens willingly. The colour is lurid and has a bluish grey undertone, which marks it out as quite alien from any shade in nature. This eye-aching, sickly green makes me wonder if, when we refer to a ‘poisonous shade’, it is not these arsenic pigments that are responsible for the phrase.
Jones knew that under the right conditions the arsenic in such materials can be chemically converted into gaseous forms such as the hydride arsine. Speaking by chance on a radio programme about this phenomenon, and how it might account for many mysterious illnesses and deaths throughout the nineteenth century, he speculated that perhaps Napoleon’s death on his humid prison island was also hastened in this way. If only the colour of the Longwood wallpaper were known, it would help to establish the facts. To Jones’s great surprise, he received a letter in response to the broadcast from a woman who not only knew the colour of the paper, but had a sample of it in a scrapbook recording the travels of a family ancestor. In the scrapbook was a page of souvenirs from a visit to St Helena in 1823, among them ‘a piece of paper taken off the room in which the spirit of Napoleon returned to God who gave it’. Jones published the results of a chemical analysis of the green-and-gold star-patterned paper in 1982 in Nature, confirming the presence of arsenic–a not unexpected result given the popularity of the colour at the time. At the same time, doubts were thrown on to Forshufvud’s original analysis. New tests on the emperor’s hair using more sophisticated equipment showed high levels of antimony and other potentially harmful elements as well as arsenic. The antimony probably came from a standard emetic administered to Napoleon, and it is quite likely that the medicine did him more harm than good.
Nearly 200 years later, it is impossible to establish cause and effect with any certainty, and even the basic precaution of a DNA test to authenticate the sampled hair remains to be done. Nevertheless, recent biographies of Napoleon concede that his symptoms were consistent with arsenic poisoning, and that arsenic from whatever source may have been one factor in the former emperor’s death. The consensus is that there probably was some attempt on the part of his British custodians to disguise the real cause of death as part of a wider cover-up–their mismanagement of the island had allowed dysentery to run rife–but that there is no need for wild assassination theories.
The most recent re-examination of the evidence in 2008 found that Napoleon’s hair from periods of his life predating his exile, as well as the hair of his wife, Josephine, and other family members, all had levels of arsenic that would be regarded as elevated by today’s standards. There was no evidence of a sudden rise in the arsenic concentration following his incarceration, as would have been produced by deliberate poisoning. However, rather than putting themselves to the trouble of rounding up Napoleon’s locks for analysis, the authors of this latest study might simply have surveyed the toxicological literature. They would have found that human remains of this period in general can exhibit levels of arsenic that would be classified as dangerous by today’s standards, reflecting nothing more than the fact that the element then was indeed ‘found anywhere’.
Arsenic may or may not have contributed to the death of Napoleon, but it has certainly been the chemical agent responsible for many other cases of poisoning, both deliberate and accidental. The one that most closely follows the Longwood wallpaper scenario concerns Clare Boothe Luce, the United States ambassador to Italy in the 1950s, who was slowly poisoned–accidentally, it was later established–by flakes of paint falling from the ornate ceilings of the ambassadorial residence. She retired due to illness and made a recovery later. Luce was an unlucky latterday victim of a widespread danger. Green paint, colour printing and coloured papers, green in wallpaper, green dyed furnishings and clothes, and especially the green colouring used for the foliage in artificial flowers all contained compounds of arsenic and probably accounted for many mysterious deaths in damp bedrooms and nurseries. There were rising suspicions during the Victorian period that these materials were to blame. The Lancet and the British Medical Journal sounded the alarm and campaigned vigorously against arsenic, but while a few companies began to advertise arsenic-free papers, the decorating industry for the most part decried the idea that their products could relea
se any harmful substance at ordinary room temperatures. It was not until 1893 that it was shown that arsine gas could be generated by the reaction of mould from wallpaper paste with the green colorant. In an essay on the art of dyeing in that year, the designer William Morris railed against synthetic dyes–among which were the arsenic greens–for ‘doing great service to capitalists in their hunt after profits’ but leaving the domestic craft ‘terribly injured’ and ‘nearly destroyed’. Morris fought noisily for the survival of traditional vegetable dyes in wallpapers and textiles. Odd, then, to find that recent X-ray analysis of Morris’s own wallpaper designs has revealed that his green came from copper arsenite, while a red rose in the pattern was the vermilion of mercuric sulphide–‘a very dangerous piece of art!’
Others took arsenic knowing full well what they were doing. Romantic before his time, the teenage poet Thomas Chatterton used arsenic to commit suicide in 1770. At Tulle in the Limousin region of France, Marie Lafarge was tried and found guilty of poisoning her husband with arsenic in 1840. The case was such a cause célèbre that Flaubert could safely include it in his dictionary more than thirty years later, knowing that his readers would remember the episode. The author had more than a passing interest in desperate housewives, of course: his own creation, Emma Bovary, also uses arsenic to commit suicide. Madame Lafarge was convicted when the evidence of the brilliant toxicologist Mathieu Orfila, called by the lawyer in her defence, showed there to be arsenic in her husband’s exhumed body and in food residues. It was the first case in which forensic chemistry was used to secure a verdict.
Both in fact and in fiction, where it became a staple of detective stories, arsenic was generally obtained from pharmacies, where it was widely sold as everything from medicine to rat poison. The form of the element used in these cases is likely to have been the sugar-like oxide known as white arsenic, a colourless substance of no interest to the decorative arts. This became so well known for its use in family murder cases that it soon acquired the nickname ‘inheritance powder’. As for Emerald Green, Winsor & Newton stopped manufacturing the colour around 1970 after a patient at Broadmoor high-security psychiatric hospital amassed enough of it in prison art classes to kill himself.
While searching for deaths attributed to arsenic poisoning, I was startled to come across the story of Mary Stannard of New Haven, Connecticut. In 1878, she was murdered in her twenty-second year by her lover, the Reverend Herbert Hayden, when it appeared she might be pregnant. He administered a large dose of what she took to be a treatment to induce an abortion but was in fact arsenic. He then bludgeoned her to death and slit her throat. This gory tale was not what brought me to a halt, though. No, what stopped me was that Mary and Stannard are the two forenames of my own mother, Connecticut-born in 1930. Was this a branch of my own family tree that had been so brutally severed?
Before the twentieth century, public access to arsenic was largely unrestricted. Today, white arsenic is more closely guarded, but still widely used in medicine: the United States Food and Drug Administration recently approved it for use in treating patients with leukaemia. Arsenic in nature is less readily corralled, and here its compounds quietly do great harm. The drinking water of up to 100 million people around the world may be tainted with it. Surveys of the water, soils and rice grain of Bangladesh have shown levels of the element far above the limits judged safe in the West, themselves rather arbitrarily set in response to public outrage at the wallpaper deaths. The phenomenon is recent and has been traced to the changeover from deep-water wells to so-called tubewells driven into shallow river sediments. These produce potable water for millions of people, but the water contains arsenic washed out of natural deposits upstream. Some scientists believe that a cancer epidemic is now inevitable as a result. It is not what Flaubert had in mind, but it is unfortunately true, and on a far larger scale than he imagined, that there are populations who eat it regularly.
Rainbows in the Blood
Slipped in among Lee Chong’s grocery and the Palace Flop-house, one of the varied emporia of Monterey that John Steinbeck describes in Cannery Row is the laboratory of Western Biological, where you could buy ‘the lovely animals of the sea, the sponges, tunicates, anemones, the stars and buttlestars, and sun stars, the bivalves, barnacles, the worms and shells, the fabulous and multiform little brothers, the living moving flowers of the sea’, and much more.
Specimen collectors have always marvelled at forms of life from under the sea, which are so often beautiful and puzzling, uncertainly poised at the junction of the animal, vegetable and mineral worlds, and only delivered up from the depths at irregular intervals by stranding storms. The most mysterious items on Steinbeck’s list are the tunicates, a class of animal that includes the sea squirts, which normally live on the seabed in colourful clusters of bag-like organisms. I once arranged to borrow a tunicate specimen from the Natural History Museum for an exhibition. It came in a squarish tank of thick glass filled with preserving liquor like the specimens at Western Biological. The creature, or creatures, or growth–scientists still aren’t really sure how to classify the things–was a chaotic eruption of shapes and colours like some absurd dinner-table centrepiece. Each ‘bag’ wears its own transparent tunic like a plastic mac as it puffs gently in and out, pumping seawater in order to extract nutrients. The organisms are dependent for some biological functions on the cluster as a whole, but manage nevertheless to express their individuality in blue, green, purple, pink, yellow and white.
In 1911, a German physiologist named Martin Henze, who was curious to learn why they adopt these seemingly indiscriminate hues, drew some tunicates from the Bay of Naples and was surprised to discover extraordinary quantities of the element vanadium in their blood. Positioned one place before chromium in the periodic table, vanadium, like chromium, forms compounds that exhibit a wide range of colours. Vanadium in these creatures can be a hundred times more concentrated than in the seawater from which they suck their food, and, according to scientists at the University of Hiroshima, tunicates may possess the highest concentrating ability for any metal of any animal. It seems reasonable to assume the vanadium is harvested for some purpose, but despite pinpointing the green cells, known as vanadocytes, where the element collects in the blood and identifying various proteins that bind to it, the scientists are still unsure what that purpose is. At first it was thought that the vanadium might have a function analogous to the iron in our own blood, but this notion has been discounted; it is possible that the element plays a part in the animals’ immune system.
This bizarre anomaly of nature came to the attention of military officials during the Second World War. Vanadium produces a much tougher steel than other metals and was therefore in demand for use in soldiers’ helmets and armour plating as well as in machinery. The United States War Department approached Donald Abbott of Hopkins Marine Station–the research outpost of Stanford University at Monterey that Steinbeck used as the model for Western Biological–wanting to know whether tunicates might be gathered or even farmed for the exotic metal. The government men flattered the scientist that the vanadium was needed not for conventional armour, but for the top-secret atomic bomb project. Abbott presumably set to work on the problem, but nothing more was said about it. Asked about the episode many years later, Abbott’s widow, Isabella, also a scientist at the station, confirmed in the obscure technical bulletin Ascidian News: ‘Such a request was made of Don, but he showed them how much vanadium was in the tunicates that took it up, and it was just too small to bother with, and as I remember that was the end of it.’ But perhaps vanadium was not the real goal. During the war, ‘vanadium mining’ was the code term used to describe the search for uranium ores needed for the atomic bomb. (The two elements occur together in some minerals, a fact noted in the name of Uravan in western Colorado, one of the mining sites where this subterfuge was in operation.) It may be that the War Department wondered whether the tunicates might be used to concentrate uranium too.
Vanadium was dis
covered twice and was named on both occasions in homage to its colourful chemistry. In 1801, only three years after Nicolas-Louis Vauquelin had discovered chromium in Paris, Andrés Manuel del Río, a Spanish-born mineralogist at the School of Mines in Mexico City, identified the new element in one of the many unfamiliar minerals that came into his laboratory. Delighted by the many colours of its salts, he named it panchromium. A couple of years later, the explorer and naturalist Alexander von Humboldt visited Mexico and took back samples of the mineral to be tested in Paris. One of Vauquelin’s colleagues analysed the substance and declared that it was nothing more than chromium. Del Río bowed to this judgement, unaware for many years afterwards that the French science was flawed, and that documents he had sent separately, which would have provided stronger support for his claim to discovery, had been lost in a shipwreck.
Periodic Tales Page 30