A is for Arsenic (3 page)

In more recent times, arsenic-poisoning was a popular murder method in Renaissance Europe, and was a particular favourite of the Borgia family. It was claimed that the Borgias spread arsenic on the entrails of a slaughtered pig, which were then left to rot. The resulting mess was gently dried to a powder which they called
La Cantarella
, a pale solid that was added to food or drink. If the arsenic did not claim the victim, the toxins from the rotting entrails would probably finish them off. The benefits of using arsenic were twofold. First, arsenic had no taste that could alert the potential victim to their being poisoned. And second, the symptoms of arsenic poisoning are very similar to those of food poisoning, cholera and dysentery, all of which have been common at various times through the ages.

Throughout the sixteenth and seventeenth centuries, poisoning was considered a peculiarly Italian art, owing in part to the reputation of the Borgias,
¹²
as well as Toffana (a professional poisoner who labelled her deadly cosmetics with the images of saints) and the Council of Ten, one of the governing bodies of Venice. The Council of Ten maintained its position of power by killing off potential rivals, and even went to the lengths of actively advertising for poisoners, as well as maintaining its own reliable stock of poisons for nefarious purposes.

By the seventeenth century the popularity of arsenic poisoning had spread to the French royal court. Members of the aristocracy were found to be conspiring with La Voisin, a notorious poisoner who was also alleged to have taken part in black masses. The investigation became so widespread, and involved so many prominent figures in French society, that a special court was convened, the
Chambre Ardent
or ‘Burning Court', named after the method commonly used for executing those who the twelve judges found guilty. To save embarrassment and potential repercussions the court met in secret and reported only to the King. ‘Human life is up for sale, and cheaply,' wrote Nicolas Gabriel de la Reynie, one of the judges; ‘Poison is the sole solution to most family problems.'
And arsenic, of course, was the poison of choice; its use had become so common that it was referred to as
poudre de succession
– ‘inheritance powder'.

Prior to the seventeenth century, many powerful and influential people took to employing official tasters, and there was understandable caution over who was allowed to prepare their food and drink. There are many stories of methods of murder that circumvented the tasters. Tales of gloves and riding boots laced with poison that would kill by contact with the skin are probably exaggerated, but tests have shown that a poisoned shirt is at least a theoretically viable method of administering arsenic. The garment in question would have the tail soaked in a solution of arsenic before being allowed to dry. The material would appear slightly stiff but otherwise there would be no obvious sign of anything wrong with the fabric. Contact via the skin of a naked bottom could potentially allow enough arsenic to be taken in to kill, especially if a blistering agent was added to the arsenical mixture to break the skin and allow faster absorption into the bloodstream.

Arsenic poisoning was long the preserve of the rich and powerful. Those on more restricted means had to find other ways to kill each other. However, the Industrial Revolution brought with it huge demands for metals such as iron and lead, and when extracted from the ground as ores these metals are often contaminated with arsenic. To obtain the pure metal, the ore was roasted in fires, and the arsenic reacted with oxygen in the air to form arsenic trioxide. This would condense in the chimneys as a white solid, which had to be periodically scraped off to prevent the chimney from getting blocked. Instead of dumping the white arsenic as waste, industrialists realised a profit could be made by selling the arsenic as poison, for rats, bedbugs, cockroaches or any other vermin infesting the home (including humans). Prices plummeted, and soon anyone and everyone could afford enough arsenic to dispatch an unwanted relative or inconvenient enemy.

Unsurprisingly, the number of arsenic poisonings began to rise. Anyone reading a nineteenth-century British newspaper
would think that arsenic murders had reached epidemic proportions, with working-class women being the most likely culprits. In reality the number of poison trials was very low; even at the peak of the media hysteria there were only two or three trials per year in the whole of England and Wales. There was sometimes suspicion when there were sudden deaths, but this was often fuelled by local gossip from folks who might have had reasons to hold a grudge, and by sensationalist reports in the newspapers. For example, of the 20,000 suspicious deaths in England in 1849, 415 were linked to poison, but only eleven of those were possibly murder, and not all resulted in a guilty verdict. What did not help these early cases was that, if arsenic was involved, the victim's symptoms could be attributed to natural causes, and there was no way to detect arsenic in the body. It became apparent that something needed to be done, and various methods were trialled to allow the detection of arsenic in human tissue. None of these early methods was reliable, and they did not produce results that could easily be discussed, or even shown in a court case. The case of John Bodle illustrates this well.

In 1832 James Marsh (1794–1846), a British chemist, was asked to investigate the death of an 80-year-old farmer named George Bodle. Marsh found arsenic in the dead man's intestines and in a cup of coffee he had drunk from, but the samples he prepared for the trial did not keep too well, and the jury found Marsh's technical descriptions of his experiments incomprehensible. As a consequence the suspect, John Bodle – the farmer's grandson – walked free. John Bodle later confessed to the murder, but he could not be re-tried. Marsh was furious and set about devising a test for arsenic that even the most stupid jury member could comprehend. He wanted jury members to see the arsenic for themselves.

Marsh made a U-shaped glass tube with one end open and a tapered nozzle at the other. In the nozzle he suspended a piece of zinc. The fluid to be examined was placed in the open end, and acid was added. When the fluid level reached the zinc even a minute trace of arsenic would be converted to arsine
gas (AsH
3
) that would be ignited as it left the nozzle. A cold porcelain bowl was held against the flame; pure metallic arsenic was then deposited on its surface. The apparatus would be further refined, but it was still in use in Agatha Christie's time – indeed, in preparation for her apothecary's examinations she and a colleague practised the Marsh test using their ‘Cona' coffee machine, blowing it up in the process.

Marsh Test apparatus as it was in 1921. (A) flask containing zinc and acid for generating hydrogen; (B) calcium chloride for drying the gas produced; (C) glass tube; (D) arsenic mirror. From
An Introduction to Chemical Pharmacology
by Hugh McGuigan.

The Marsh test was first used in a criminal trial in 1840, by the celebrated toxicologist Mathieu Orfila (1787–1853). Orfila had been asked to investigate the death of Monsieur Charles Pouch-Lafarge. When Marie Capelle married Charles in 1839, both believed they were marrying into serious wealth. In reality Marie had a modest dowry, but she had ideas above her station. She had been educated at elite schools and believed herself to be descended from royalty. Charles claimed to be a wealthy iron-founder, but he really lived in a tiny hamlet, in a damp, rat-infested house on a dilapidated estate, part of which he had converted into a foundry; the expense of the conversion had left him almost broke. The marriage did not get off to the best of starts, and things did not appear to improve until Marie persuaded her husband to change his will in her favour. Charles went away to Paris over the Christmas period to seek out
financial backers for a new business venture, and Marie sent him a parcel as a Christmas gift. Members of the Lafarge household had witnessed Marie placing five small cakes in a box, with a portrait of herself and a loving letter. When the package arrived in Paris it contained one large cake that made Lafarge very unwell when he ate it. He recovered enough to travel back home, but was again taken ill and died shortly afterwards. Arsenic poisoning was suspected, and Marie was known to have purchased arsenic, supposedly to kill the rats in the house. Orfila was called in to determine if arsenic had indeed been the cause of Charles's death. Orfila's testimony and the results of his Marsh test provided enough evidence for the jury to find Marie guilty of murder.
¹³

There are still doubts over Marie's guilt in the Lafarge case. No one could prove that she had switched the cakes, or even that she had had the opportunity to do so. Another toxicologist, François-Vincent Raspail (1794–1878), also threw doubt on the forensic evidence. Raspail showed that the zinc Orfila had used when carrying out the Marsh test had been contaminated with arsenic and would have given a positive test for the poison even if
none
had been present in Charles's remains. Raspail's evidence came too late, though, and Marie had already been sentenced to life imprisonment before his arrival at the court. Raspail had highlighted the only real drawback of the Marsh test – it was perhaps a little too sensitive. Being able to detect 0.02mg of arsenic would normally be considered an advantage in forensic science, but this element is widespread in the world, and was particularly so in nineteenth-century
European households. Arsenic was soon found to be almost everywhere.

As its name suggests, white arsenic is a white powder. It is very similar in appearance to sugar or coarse flour, and mistakes sometimes occurred. Food adultery was fairly common in Victorian England. Sweet-makers would add ‘daft', an inert substance such as plaster of Paris or powdered chalk, to bulk up their sweets, because it was cheaper than sugar. In 1858 one sweet-maker in Bradford went to what he thought was a barrel of daft, scooped up the white powder within, and proceeded to make his sweets. Unfortunately, he had taken the powder from a barrel containing white arsenic. When some children ate the sweets the mistake was soon realised and the deadly candy was recalled, but not before 200 people had become seriously ill and twenty had died. Extraordinarily to modern eyes, no one was prosecuted over the incident.

By contrast, in 1836 Eliza Fenning, a cook, was executed for the attempted poisoning of the household she worked in. The whole family, and Eliza herself, had become seriously ill after eating dumplings she had prepared (though they all recovered). A packet of arsenic had disappeared from the house some weeks earlier. Eliza was convicted on the flimsiest of evidence. Others in the household had had the opportunity to add poison to the dumplings, or – perhaps more likely – it was all a terrible mistake.

Eighteenth-century industrialists found other uses for the growing amount of waste arsenic from the iron smelters, besides rat poison. Several arsenic compounds are brightly coloured, and these have been used as pigments for thousands of years, such as orpiment (As
2
S
3
), an intense yellow, and realgar (AsS), a ruby red mineral. In 1775 Scheele's green (CuHAsO
3
), invented by Carl Wilhelm Scheele (1742–1786), was added to the list of arsenic-based pigments. These arsenic compounds were a huge improvement on the vegetable dyes that had been used in the past as their colours did not fade so readily and
they were cheap and easy to manufacture. The great popularity of the colours red and green in Victorian England meant that arsenic was used to dye almost anything and everything, from wallpapers and clothes to toys and even food, such as sweets and cake icing.
¹⁴

Arsenic dyes in wallpaper were directly dangerous only to those manufacturing the paper, who would be exposed to the arsenic dust. In the home it was clear that bedrooms with arsenical wallpaper had fewer bedbugs. This was initially seen as a bonus, and sales increased. The problem was that whatever was affecting the bedbugs soon began to affect the human occupants of the room, too. To stick wallpaper to a wall a simple flour paste was used. In the damp climate of the British Isles this provided the perfect environment for mould to grow. Mould is also adversely affected by arsenic but some moulds could adapt to their environment by chemically processing and removing it. In 1893 Bartolomeo Gosio (1863–1944) was the first to show that
Penicillium brevicaule
(now known as
Scopulariopsis brevicaulis
) was attacking the starch paste and releasing an arsenic gas, which he could not identify but which had a distinctive garlicky smell. The gas became known as Gosio gas; it was in fact trimethylarsine gas (As(CH
3
)
3
), identified in 1933. Trimethylarsine is highly toxic, and recommendations were made to reduce the amount of arsenic used in wallpapers. Unfortunately these recommendations came too late for one famous Frenchman.