A is for Arsenic (6 page)

‘Gastroenteritis' describes a set of symptoms – vomiting, diarrhoea and stomach pain – rather than a specific illness, and these are due to inflammation of the gut. The symptoms can be brought about by a large number of causes, usually a virus such as the norovirus or a bacterial infection, or, more rarely, by a parasite, but they can also be due to food intolerances – or even arsenic poisoning. An infection might normally be expected to clear up after a few days or a few weeks. Mrs Horton was described as having a long illness, so we can assume she was ill for at least a number of weeks and must have been suffering from chronic arsenic poisoning, with a larger dose administered shortly before she died.

Symptoms of chronic arsenic poisoning, Mees lines and skin effects such as pigmentation and dermatitis, for example, may not have had time to present themselves during Mrs Horton's illness. Nails grow at approximately 3mm per month, and though arsenic can be deposited in hair and nails within hours
of ingestion, it would take several weeks for the deposit to grow out from the nail matrix and past the cuticle, where it would become visible. In the Agatha Christie novel
They Do It with Mirrors
²³
the would-be murderer carefully cuts the victim's nails so they cannot be analysed for arsenic. However, this plan would not have succeeded; the poisoning would have to have been carried out a long time in the past, or the whole nail would have had to be removed to prevent detection. Even then, the hair of the victim could also have been analysed and would have shown signs of arsenic.

Even with no obvious outward signs of arsenic poisoning Mrs Horton was convinced she was being poisoned by one of her nurses, and had her dismissed. No one else seemed to take her seriously, and dismissing the nurse did not improve her condition. Someone else was administering the arsenic.

There are plenty of suspects to consider, chief among them being Mrs Horton's husband, Major Horton. Agatha Christie may have taken her inspiration for this character from a real-life arsenic-poisoner, Major Herbert Rowse Armstrong, dubbed ‘The Dandelion Killer'. In 1921 Armstrong was working as a solicitor in Hay-on-Wye. His wife had died after a long illness that involved her being treated in a lunatic asylum, shortly after she had made over all her property to her husband. Her treatment in the hospital appeared to have been successful and she was well enough to return home, where she suffered a relapse and died a month later. No suspicion was attached to her death, even though the doctor could not determine the exact cause. But Armstrong's behaviour after her death did cause some alarm.

Oswald Martin was a solicitor at a rival legal firm in Hay-on-Wye. Martin and Armstrong were both involved in a land dispute, and were acting for opposing sides. The legal arguments had been going on for some time and were becoming increasingly acrimonious, which made Armstrong's behaviour all the more surprising.

Martin received an invitation to tea at Armstrong's house, which he accepted. He ate a tasty buttered scone, which Armstrong had selected and placed on a plate. Later Martin became very ill, but he recovered. He then recalled receiving a box of chocolates, sent anonymously, which had made a guest of his very ill. Martin was by now suspicious, and he decided to alert the police. The chocolates were analysed along with a sample of Martin's urine, and both were found to contain arsenic.
²⁴

The results of the tests were enough to interest the police and they agreed to investigate, but did not want to alert Armstrong to what was going on. Tea invitations continued to pour in to the Martin household from Armstrong, and Martin did his best to find excuses. Eventually Armstrong was arrested for the attempted murder of his rival; after his wife's body was exhumed and his house searched for arsenic, he was tried for the murder of his wife. Arsenic was found in the body, and packets of arsenic were discovered in the house. Armstrong claimed the arsenic was for poisoning dandelions in his lawn. The jury didn't believe him, and he was hanged.

In
Murder is Easy
, Major Horton seems more concerned about the health of his dog than the death of his wife, but the lack of an appropriate emotional response is not evidence of murder. There are also plenty of other suspects to consider. Mrs Horton seems to have been popular; she had several visitors when she was ill, and one of them, Lydia Pinkerton, would enquire about the food and drinks she was being given. She was clearly suspicious, and the murderer later pushes Miss Pinkerton in front of a car before she can reach Scotland Yard to tell the police of her concerns, although luckily she has
already shared her suspicions with a retired detective, Luke Fitzwilliam.

Another resident in the village, Lord Whitfield, showed his concern for the invalid Mrs Horton and sent her peaches and grapes from his hothouse. Mrs Horton complained that the fruit was bitter but the nurse never repeated the assertion. A bitter taste is sometimes a sign of a plant-based poison such as morphine or strychnine, but the symptoms Mrs Horton suffered from were not consistent with this type of poisoning. Arsenic poisoning would explain the symptoms, and it has no taste. The fruit could have been naturally bitter and still have had arsenic added to it. Arsenic applied to the skins of the fruit would have shown as a white powder, which would probably have been washed off if it was noticed. Alternatively, a solution of arsenic could have been injected into the flesh of the fruit. Relatively small doses could have been administered this way over a number of weeks.

Another method that could have been employed was adding arsenic to the patent medicines Mrs Horton was known to take. These medicines were supplied to Mrs Horton by the local antiques dealer, who appeared to have no motive for killing Mrs Horton, but his dabbling in black magic certainly made him a suspicious character. By the 1950s arsenic was no longer being used in tonics as its effects were ‘unpredictable and uncontrollable' but in 1939 these remedies were still available, though their use was declining. Getting hold of arsenic in 1930s England would have been considerably more difficult than 50 or even 20 years earlier, but not impossible. No mention is made in the book of how the poison was obtained, but in 1935 ten grains of weed-killer contained seven grains (454mg) of arsenic, enough to kill two or three people. The weedkiller would have had a bright blue dye added to it to prevent accidental ingestion, and the dye would have been clearly visible if weedkiller had been added to Mrs Horton's food, drinks or patent medicines.

In
Murder is Easy
, Luke Fitzwilliam, the retired detective, can only speculate over the cause of Mrs Horton's death. He is not
investigating any of the crimes in an official capacity and therefore cannot order an exhumation and post-mortem, which could have confirmed his suspicions. Even a year after burial, arsenic would have been easy to detect in a corpse. Hair takes a long time to decompose, and it would have held on to the arsenic deposits from chronic poisoning for many more years. Fortunately the murderer confesses, and even goes on to explain how the deed was done; the poison was added to Mrs Horton's tea by one of her visitors. Arsenic trioxide is poorly soluble in cold water, but it is much more soluble in hot water. By dissolving the arsenic in tea the killer was able to ensure that no suspicious gritty powder was left at the bottom of the cup.

Notes

⁸
Entitled
Easy to Kill
in the United States.

⁹
On the boundary between a metal and a non-metal, with characteristics of both.

¹⁰
Christie of course used the British spelling, ‘sulphur', whenever she mentioned the element or its compounds in her work. Since 1990 the scientific community has agreed that the spelling to use is, in fact, ‘sulfur', which is the one I'll be using in this book; this will look perfectly acceptable to American eyes but may jar a little with British ones, and I can only apologise. The
Oxford English Dictionary
still lists the British spelling as ‘sulphur', so there's a good case for using either.

¹¹
For the rest of this chapter, the word ‘arsenic' refers to arsenic trioxide unless otherwise stated.

¹²
Although they were in fact Spanish in origin.

¹³
This case may have inspired Christie's use of arsenic-laced cake in
After the Funeral
. In the novel a slice of arsenic-laced wedding cake was delivered to a suspect in a murder case. The suspect ate some of the cake but placed the remainder under her pillow, following the tradition that she would then dream of her future husband. Although the suspect grew very ill she survived because she didn't eat all of the cake.

¹⁴
Agatha Christie makes reference to Scheele's green and its use in wallpaper in the novel
They Came to Baghdad
. When one of the characters is taken ill with ‘Bad gastro-enteritis', arsenic poisoning is suspected. ‘I'm wondering', says Sir Rupert, ‘if it might be a case of Scheele's green …'

¹⁵
g/m
2
= grams per square metre.

¹⁶
At the time the recommended safe limit was between 0.001 and 0.005gm
-2
.

¹⁷
Charles Darwin is known to have taken Fowler's solution, initially as an undergraduate to treat his eczema, but he continued dosing himself for much of his adult life. This may go some way to explaining the poor health he experienced as an adult.

¹⁸
There doesn't seem to have been an equivalent law passed in the United States. A survey in 1877 revealed that the sale of poison was still unregulated in the US, though things are rather different today.

¹⁹
Agatha Christie was well aware of the Maybrick case and she describes soaking fly-papers to obtain poison in her novel
The Mysterious Affair at Styles
.

²⁰
The sulfur is often in the form of a sulfydryl group, a sulfur atom bonded to a hydrogen atom (–SH).

²¹
TV and films often portray poison victims swallowing a mouthful of tainted food, choking a bit and collapsing in seconds. This is far from accurate, and has often resulted in my shouting at the screen with frustration. I am surprised I haven't been banned from my local cinema yet.

²²
As recently as the early 1960s, employees at poison-treatment centres were known to start work by burning toast to prepare the day's supply of charcoal.

²³
Entitled
Murder with Mirrors
in the United States.

²⁴
The Marsh test is equally effective on samples, such as urine, from living people; today, the test for arsenic would involve using atomic absorption spectroscopy, where a sample is placed in a flame that causes it to emit light in colours characteristic of the elements present.

The Labours of Hercules

Belladonna, n. In Italian a beautiful lady; in English a deadly poison. A striking example of the essential identity of the two tongues.

Ambrose Bierce,
The Devil's Dictionary

BELLADONNA is a poisonous plant with a long history of use by humans as a beauty aid, as a medicine and as a murder weapon. All three applications were described by Agatha Christie in several of her stories, resulting in two attempted murders and one that was successful. In some respects belladonna is the perfect poison, as the plant grows in the wild. The principal poisonous component of belladonna is a chemical called atropine, which leaves no signs at post-mortem and is widely distributed throughout the body. Atropine is also rapidly broken down after death and may no longer be present at all a few weeks after burial, making it difficult to trace.
However, the bitter taste of this poison alerts many would-be victims, and the symptoms of atropine poisoning are easily recognised and treated.

Belladonna takes a starring role in
The Cretan Bull
, the seventh of the twelve short stories that make up the 1947 collection
The Labours of Hercules
. The premise of the book is that the great Belgian detective, Hercule Poirot, has decided to retire from detective work, but before he moves to the country to grow ‘vegetable marrows', he elects to take on twelve cases that have a connection to the labours of Hercules, his namesake in classical Greek mythology. The legendary Cretan Bull was seduced by Pasiphae in disguise, leading to the birth of the Minotaur (in some versions of the tale the bull was Zeus in disguise, and he did the seducing, with Europa the target of his affections). The seventh labour of Hercules (the Greek, not the Belgian) was to overpower the Cretan Bull, which was playing havoc with crops and boundary walls on Crete, and bring it to King Eurytheus.

In Agatha Christie's version of the myth, Hercule Poirot captures Hugh Chandler and returns him to his fiancée, Diana Maberly. Hugh is a ‘young bull of a man' whose erratic and frightening behaviour certainly causes havoc at his home, Lyde Manor. Hugh's symptoms of vivid dreams and hallucinations are blamed on a family history of insanity. His madness has almost pushed him to the point of suicide before Poirot's intervention. There is plenty of insanity on display, but it perhaps isn't Hugh who is afflicted.