A is for Arsenic (20 page)

Agatha Christie goes into some detail when she describes the death of Amyas Crale. He was found slumped in front of his easel, sprawled on his seat with his arms flung out. He appeared to be staring at the picture he was painting. It was a position his friends and family had often seen him in, and those who had observed him from a distance that day didn't think anything was amiss. When it was finally realised that something was seriously wrong, no one could be sure that he was dead, so a doctor was called. ‘He looked – almost natural. As though he might be asleep. But his eyes were open and he'd just stiffened up.' The doctor duly arrived, but it was too late.

Amyas's death might have been taken as natural causes, perhaps due to sunstroke, if it had not been for Meredith. On the morning of the murder, Meredith had noticed that the bottle containing his preparation of coniine was almost empty, when the day before it had been almost full. Concerned that someone might have taken the coniine without realising how dangerous it was, Meredith went to Amyas's house, to talk the matter over with his brother Philip. As he walked up towards the house he waved to Amyas, who had set up his easel in the garden to paint a portrait of Elsa Greer. Meredith watched Crale walk back to his easel and saw him stagger a bit. He thought Amyas was drunk, but in fact the poison had already begun to take effect.

Coniine leaves no distinctive signs at post-mortem, but the disappearance of the poison from Meredith's laboratory would have given the pathologist a clue as to what to look for. Enough poison was extracted from Crale's remains, probably using the Stas method, to prove that he had died of coniine poisoning. Once extracted from the body coniine could be easily identified, not only by smell but by characteristic chemical colour tests. These colour tests were crude, and unreliable by today's standards, but they would have left little doubt for pathologists and jury members in the 1920s. Today,
coniine could easily be identified using chromatographic techniques. Even if coniine is not specifically tested for as part of a post-mortem examination, it would be picked up by more general tests for plant alkaloids, which are standard procedure in forensic toxicological screenings.

The doctor in the Crale case believed the poison had been administered two or three hours before the body was discovered. From the post-mortem findings it was easy to reconstruct the final hours of Amyas Crale's life. Agatha Christie was well aware of the symptoms of coniine poisoning, and describes the paralysing effects taking over Amyas's body. After the others had gone to lunch he would have dropped down and relaxed in his seat. Muscular paralysis would then have set in. Agatha trusted Plato's description of the death of Socrates saying that there was no pain, but as we've seen this may not have been the case. Amyas may have been in
considerable
pain, and would certainly have been distressed at his growing physical incapacity; the poison would have kept him conscious and alert until his final moments, though unable to call out for help.

In front of Amyas's body an empty glass and beer bottle were found, and they were taken away for analysis. Initially it was thought Amyas might have committed suicide. He had argued with his wife, but this was not an unusual occurrence and, therefore, there appeared to be no motive for him to take his own life. As the circumstances of the day were investigated by the police, suspicion fell on Caroline, Amyas's wife. An empty bottle of jasmine scent was found in a drawer in her bedroom. Analysis of the bottle revealed traces of coniine hydrobromide. Meredith must have prepared the hydrobromide salt of coniine in his laboratory, and stored it in a solution. It was thought that Caroline decanted some of the coniine into her emptied scent bottle when she visited Meredith's laboratory, while no one was looking. She claimed she had taken the poison to commit suicide, but she was not believed. In addition, it was Caroline who took the bottle of beer to her husband. It was assumed she had added the coniine to the beer with a pipette normally used
for refilling fountain pens; the pipette was found crushed to splinters on the path between Amyas's easel and the house. This instrument would hold approximately 1–2ml of liquid. Assuming Meredith had produced a fairly concentrated solution of coniine hydrobromide, the pipette would have had more than enough capacity to carry a lethal dose.

Caroline was arrested and tried. She put up no defence, was found guilty and was then hanged. Many years later, it is up to Poirot to find out if Caroline really was guilty of the murder. He interviews the ‘five little pigs', and reconstructs in his mind what happened on the fatal day. Of course, Poirot realises the true significance of many clues that the police investigation had overlooked, and is able to use his little grey cells to discover the truth.

There is no question that Amyas died of coniine poisoning, and it seemed reasonable that the coniine in his body was the same as that taken from Meredith's laboratory. But precisely who took it, and who administered it to Amyas, was less clear. The case against Caroline was stark; no one seemed in any doubt that she was responsible. One fact, however, proves to Poirot that Caroline could not have been the murderer; analysis of the beer bottle and glass found in front of Amyas revealed coniine only in the glass. Caroline had taken her husband the beer but, so far as anyone knew, she had not touched the glass. Another fact in Caroline's favour was that the poison must have been given to her husband before she brought him the beer. The time taken for the poison to act and the evidence from Amyas himself indicated that he had already tasted the bitter flavour of coniine before his wife arrived – when he drank the beer he commented that ‘everything tastes foul today'.

But if Caroline wasn't guilty, who was? Anyone could have taken the poison from the laboratory, or observed Caroline taking it, then stolen it in turn from the scent bottle she had hidden in her drawer. Caroline believed her younger sister Angela had taken the poison, and put it into a beer bottle for Amyas to drink. Angela had a row with Amyas on the day of the murder, and was seen fiddling with a bottle of beer that
Caroline took from her and gave to Amyas. When his body was found Caroline was observed wiping fingerprints from the beer bottle and wrapping her husband's hand around it, in an attempt to suggest suicide and divert suspicion from Angela; she had not known that the coniine was only in the glass. Believing Angela to be guilty and wishing to protect her, Caroline offered no defence when she stood trial for murder. Poirot is therefore able to eliminate both Caroline and Angela from his list of suspects. But that still leaves four little pigs … and to find out ‘whodunit' you will have to read the book.

Notes

⁵⁴
None that I have been able to find, anyway.

⁵⁵
Entitled
Murder in Retrospect
in the United States.

⁵⁶
These being γ-coniceine, coniine, N-methyl-coniine, conhydrine, psuedoconhydrine, conhydrinone and N-methyl-psuedoconhydrinone.

4.50 from Paddington

… Learn this, Thomas,

And thou shalt prove a shelter to thy friends,

A hoop of gold to bind thy brothers in,

That the united vessel of their blood,

Mingled with venom of suggestion,

(As, force perforce, the age will pour it in)

Shall never leak, though to do work as strong

As aconitum or rash gunpowder.

William Shakespeare,
King Henry IV Part 2

THE title of Agatha Christie's 1957 novel
4.50 from Paddington
(entitled
What Mrs McGillicuddy Saw
in the United States) refers to a journey taken by Mrs McGillicuddy after a shopping trip to London. During the journey two trains travel alongside each other, and for a brief moment they move at the same speed. Mrs McGillicuddy looks through the
window to the carriage opposite, and sees a woman being strangled. She believes she has witnessed a murder, and goes on to tell the station-master and the police. With no missing person being reported and no corpse discovered, no one believes the old lady. Only Miss Marple is convinced that her friend has witnessed a crime, and she resolves to investigate further.

The first task is to find the body. A curve in the train track a little further along the route encloses a large estate, Rutherford Hall, the residence of eccentric biscuit baron Luther Crackenthorpe. The train embankment slopes down into the grounds, providing a convenient spot for the disposal of a body from a moving train. Miss Marple asks her friend, Lucy Eyelesbarrow, to act as housekeeper at Rutherford Hall, so she can root around in the shrubbery for a dead body when no one is looking. The discovery of a recent corpse hidden in a sarcophagus in an outbuilding is the start of a murderous campaign against the Crackenthorpe family; two more characters are bumped off before Miss Marple can solve the crime.

Christie used two notorious poisons to dispatch members of the Crackenthorpe family: arsenic and aconitine, poisons that have been used to murder for millennia. But while arsenic is still well known and is used almost as a by-word for poison, aconitine has been more or less forgotten. By the 1950s aconitine's time in the limelight was almost up, but it had not disappeared completely. Aconitine-containing plants grow wild in much of the northern hemisphere, and several species are cultivated in gardens. Some of these plants have been given saintly names such as monkshood, but they all have a dark and sinister side.

The genus
Aconitum

Aconitum variegatum
– monkshood – is considered to be the most poisonous plant in Europe; it has been called the ‘Queen Mother of Poisons'. The genus
Aconitum
occurs across the northern hemisphere, often in mountainous regions. All these plants contain aconitine, an alkaloid, in addition to a number
of related compounds. The genus contains around 250 species, of which some of the common names include monkshood (named after the shape of its flowers), wolfsbane, leopard's bane and Devil's helmet. ‘Bane' means ‘poison', and this refers to the use of the plant as an arrow-poison for hunting wolves and other dangerous carnivores. As these names suggest, these plants have something of a reputation. In Ancient Greece they were believed to have been spawned from the drool of the hound of hell, the ferocious three-headed dog, Cerberus. Hercules was challenged to bring the hell-hound from the Underworld to the surface. As he wrestled with the beast, saliva from its three mouths scattered over the rocks; where the drool fell, the poisonous flowers grew.

Preparations of
Aconitum
plants have been used in witchcraft medicine for centuries for the treatment of gout, probably as an analgesic to ease the intense pain of the condition. The roots of the plants were also a common ingredient in witches' flying salves; alkaloids within the roots have a ‘local anaesthetic' action, giving a feeling of numbness, and this may have contributed to a sensation of the body losing contact with the ground.

The use of
Aconitum
species and their extracts persisted in medicine until the early twentieth century. They were formerly used in drops to reduce heart rate, fevers and elevated blood pressure, and to promote sweating. Extracts could also be applied externally as a liniment for the relief of pains such as neuralgia, rheumatism, sciatica, migraine and toothache. The numbing effect produced by the alkaloids would have relieved localised pain, but the margin between a dose producing numbness and one causing serious toxic effects is dangerously narrow. The safety margin was too narrow for a Dr Meyer who, in 1880, prescribed aconitine drops to a young boy. After treatment the boy became ill with chills and convulsions, and his mother went back to see the doctor, blaming the medicine for the child's illness. Dr Meyer was so outraged at someone daring to question his prescription that he took a dose from the boy's medicine bottle to prove that it was perfectly safe. Five hours later Dr Meyer died of aconitine poisoning.

The high toxicity of these compounds means there are no modern medical uses for either the plants or the individual alkaloids they contain. However, aconitine is still used in Chinese traditional medicine as a pain-relieving analgesic, and for its anti-inflammatory properties. The roots are processed by soaking and boiling to reduce their toxicity before use. Poisonings still occur, either because more than the prescribed dose has been consumed, or because the processing of the root has not been carried out effectively. Most cases of aconitine poisoning in recent years have taken place in Japan and China. These cases are usually accidental or suicide. Murder cases are exceptionally rare, but not unheard of. To find a case of large-scale poisoning we have to look back to 1857, during the Indian Mutiny. Regimental chefs added
Aconitum
root to a soup that was to be served to a detachment of British officers. When the chefs refused to taste the soup one of the officers, John Nicholson, force-fed some of the food to a monkey, which died immediately. The chefs were hanged without trial.