A is for Arsenic (2 page)

Agatha Christie broke nearly all of the rules, most spectacularly in
The Murder of Roger Ackroyd
, which caused consternation at the time of publication, and columns of newspaper screed declaring Christie to be a cheat. Today the novel is regarded as one of the best detective stories of all time. When not actually breaking the rules, she strained them to their absolute limit. In spite of this Christie was one of the founder members of The Detection Club, a dining club for writers of detective fiction
whose members included G. K. Chesterton, Dorothy L. Sayers and the writer of the Decalogue himself, Ronald Knox. Knox's rules were adopted by the club's members as a kind of code of ethics among detective-fiction writers. Members also had to swear an oath as part of an elaborate initiation ceremony.

Do you promise that your detectives shall well and truly detect the crimes presented to them using those wits which it may please you to bestow upon them and not placing reliance on nor making use of Divine Revelation, Feminine Intuition, Mumbo Jumbo, Jiggery-Pokery, Coincidence, or Act of God?

Christie showed only slightly more regard for the oath than for Knox's rules, yet she still managed to maintain fairness to her readers. Christie was proud of the fact that she never ‘cheated'. The clues were presented, but it was for the reader to spot and interpret them correctly.

In terms of poisons, Christie invariably played with a straight bat. She never used untraceable poisons; she carefully checked the symptoms of overdoses, and was as accurate as to the availability and detection of these compounds as she could be. But there were a few notable exceptions. Serenite (
A Caribbean Mystery
), Benvo (
Passenger to Frankfurt
) and Calmo (
The Mirror Crack'd from Side to Side
⁶
) are drugs that are pure Christie inventions, though the properties she attributed to them are very similar to those of barbiturate drugs. In fairness to Christie, she only used one of her invented drugs to kill a character, in
The Mirror Crack'd from Side to Side
; otherwise, these drugs were not critical to the plot.

Her use of poison was not just a convenient way to dispose of a character. Although her novels are liberally sprinkled with classic poisons such as arsenic and cyanide, Christie used a huge variety of killer compounds in her novels – too many to fit into this book. Many of the poisons she described were the drugs she was familiar with from her dispensing days. Toxic
compounds and chemicals such as strychnine, phosphorus, coniine and thallium were still in use in 1917 in medical preparations. They have long since disappeared from the
British Pharmacopoeia
, due to their high toxicity and low therapeutic value. Other compounds, however, such as morphine, eserine, digitalis, atropine and barbiturates, still have applications in modern medicine. As the physician and founder of toxicology Paracelsus (1493–1541) pointed out, ‘Poison is in everything, and no thing is without poison. The dosage makes it either a poison or a remedy.' Christie understood this well, and made use of unusual and unexpected poisons, such as nicotine and ricin, to great effect. The symptoms, availability and detection of the poisons contributed clues and plot points to her stories. For example, the brilliantly plotted novel
Five Little Pigs
makes use of hemlock – the way it acts on the body, its taste, and the time it takes to act all match perfectly with the timeline of the novel (see pages
here
–
here
).
⁷

Real-life inspiration

Agatha Christie did not just rely on an accurate and detailed knowledge of poisons. She read about real crime extensively, and was well versed in the sensational murders of the past. She referred to many real-life murders and poisoners in her books, killers such as Herbert Rowse Armstrong, Frederick Seddon and Adelaide Bartlett. She even used the circumstances of murder cases as inspiration for her plots.

Mrs McGinty's Dead
is a novel based around the infamous murderer Dr Hawley Harvey Crippen. He was found guilty of poisoning his wife, and was hanged in 1910. Human remains were discovered buried in the cellar of the Crippens' London home. The portions of flesh, wrapped in Crippen's pyjamas, were found to contain lethal quantities of hyoscine hydrobromide. Meanwhile, Crippen had fled aboard a ship
bound for Canada with his mistress, Ethel le Neve, who was disguised as a boy. The disguise didn't fool the ship's captain, who alerted the British police by wireless telegram. Inspector Dew boarded a faster ship and was able to arrest Crippen and le Neve when their ship docked at Montrose. In
Mrs McGinty's Dead
several murders are committed to hide the murderer's secret – their mother was the mistress of a man who had killed his wife and buried her in a cellar.

The novel
Ordeal by Innocence
tells the story of Jacko Argyle, who was found guilty of murdering his mother. Years later, after Jacko had died in prison, a stranger turned up at the Argyle house with proof that Jacko was innocent. If Jacko did not kill his mother, who in the family did? The story was inspired by the Bravo case, a real-life poisoning that occurred in 1875. Charles Bravo married a wealthy young widow, Florence Ricardo, after a whirlwind courtship. Just four months into their married life Charles was taken ill after eating dinner with his wife and her live-in companion, Jane Cox. He died three days later after being attended by Dr James Gully, his wife's former lover. Post-mortem analysis revealed he had been poisoned by a single dose of antimony. An inquest into the death decided on an open verdict, though it was widely suspected that Charles Bravo had committed suicide.

Subsequent reports in the press revealed that Jane Cox and Charles Bravo had been on bad terms, and that Cox had overheard an argument between the married couple over Florence's association with Dr Gully. A second inquest was opened which effectively became a trial of the two women. A verdict of ‘wilful murder' was returned, but with insufficient evidence to suggest who had administered the fatal dose of antimony. By this time the two women were no longer friends. The common suspicion was that Mrs Bravo had laced her husband's wine with poison and attempted to cast suspicion on her companion. Charles Bravo's murderer was never identified. To quote Agatha Christie, ‘And so Florence Bravo, abandoned by her family, died alone of drink, and Mrs Cox, ostracised, and with three little boys, lived to be an old woman with most of
the people she knew believing her to be a murderess, and Dr. Gully was ruined professionally and socially.' As Christie eloquently put it, ‘Someone was guilty – and got away with it. But the others were innocent – and didn't get away with anything.'

*

I first read Agatha Christie's books when I was a teenager. I loved the stories, but I doubt if I appreciated the scientific content at the time. Re-reading the novels and short stories during my research for this book has only increased my appreciation, not only of Christie's scientific knowledge, but also of the way she incorporated it into her work. Many find science off-putting, but Christie explained all the detail necessary to understand the significance of a poison without distracting the reader from the plot. In this book, I'll examine fourteen of the poisons Christie employed during her writing career, as well as the real-life cases that could have inspired her, or may have been inspired by her work. It is a celebration of Christie's inventiveness, her brilliant plotting, and her attention to scientific accuracy.

Notes

¹
Chemists, pharmacists and similarly qualified people may be able to eliminate certain possibilities early on in the novels, but the revelation of the murderer is just as surprising to them as it is to anyone else.

²
i.e. one part drug per hundred in total.

³
Christie used grains throughout her stories, but in this book I'll give equivalent measurements in grams (g) or milligrams (mg, thousandths of grams); one grain is equivalent to 64.79891mg.

⁴
Christie was able to write twelve complete novels during the war years.

⁵
Knox was a priest, theologian, BBC broadcaster and writer of detective stories. His books featured the detective Miles Bredon.

⁶
Shortened to
The Mirror Crack'd
for publication in the United States.

⁷
Incidentally, for much of the time that Christie was developing the plot she was planning to have the murder victim shot, though how this would have worked in the final novel is difficult to imagine.

Murder is Easy

The poison of Kings and the King of poisons.

Anon.

THE name ‘arsenic' has become almost synonymous with poison – it could be argued that it represents the gold-standard of criminal poisoning. Arsenic has a long and illustrious history of murder and assassination, stretching from the time of the Ancient Greeks to the present day. This is often the poison people most associate with Agatha Christie, but in fact only eight characters, in four novels and four short stories, were dispatched using this infamous element and some of these die ‘off stage' with little description of their symptoms. They form a relatively small proportion of the more than 300 characters Dame Agatha bumped off in her career. In fact, her use of arsenic is relatively low-key given its infamy. However, it does get a mention in many of her books, and some of these
often fleeting references reveal her deep knowledge of the poison.

The 1939 novel
Murder is Easy
⁸
features an arsenic murder with some details of symptoms, as well as discussions about how the arsenic could have been administered. The novel has a stereotypical ‘Agatha Christie' setting, with mass murder being carried out in a quiet English village. Luke Fitzwilliam, a retired detective, takes on the task of solving the crimes. Fitzwilliam is drawn into the case by an elderly spinster, Lavinia Pinkerton, whom he meets on a train journey to London. She tells him she is on her way to Scotland Yard to report three suspicious deaths in her home village: Amy Gibbs, who died after drinking hat paint (yes, a paint for changing the colour of a hat) that she mistook for cough medicine; Tommy Pierce, who died after falling from a roof when he was cleaning windows; and Harry Carter, who fell from a bridge and drowned after a night out drinking. Did they fall, or were they pushed? Miss Pinkerton is convinced that these were no accidents, and she assures Fitzwilliam that Dr Humbleby will be the next victim.

Initially, Fitzwilliam dismisses the old lady's story, but when he later reads both Miss Pinkerton's and Dr Humbleby's obituaries in the newspaper he decides to take a closer look. He travels to Miss Pinkerton's village and investigates every recent death in the village, of which there have been a number. All of them appear to have been accidents, or due to natural causes, but the unprecedented demands on the local undertaker have meant that it was either a very unlucky village or something more sinister was going on. One of the deaths Fitzwilliam is most concerned about is that of Mrs Horton, the wife of Major Horton, who died the previous year after a long illness. She had been in hospital for some time suffering from acute gastritis. Although her symptoms could be explained by natural causes, they could also have been due to arsenic poisoning …

The arsenic story

Arsenic (As) is the fourteenth most common element in the Earth's crust, though it occurs naturally as a compound rather than as the pure element. It was first isolated in the thirteenth century, and was found to be a grey metalloid.
⁹
The name ‘arsenic' comes from the Persian word z
arnikh
, which means ‘yellow orpiment', a brightly coloured compound of arsenic and sulfur.
¹⁰
Zarnikh
was then translated into the Greek word
arsenikon
, which was related to another Greek word,
arsenikos
, meaning ‘masculine' or ‘potent', before we finally arrive at arsenic. When people refer to arsenic as a poison they are usually referring to ‘white arsenic' or arsenic trioxide (As
2
O
3
), or other deadly compounds of arsenic. In its pure elemental form, arsenic is far less toxic than arsenic trioxide, because the body cannot easily absorb it.
¹¹

The poisonous properties of arsenic compounds have been known since at least the time of Cleopatra. When the Egyptian queen decided to end her life she wanted to ensure her death would cause her as little pain as possible, and that she would leave an attractive corpse. It is said that she tested various poisons on her slaves, and watched the results. One of the poisons she tested was arsenic, but it was clearly too unpleasant a way to die, so she opted for the asp (though this would have been far from pain-free, and her cadaver would also have needed some cosmetic retouching).