A is for Arsenic (9 page)

Pilocarpine eyedrops were used on the Exford ward to treat several patients who suffered from glaucoma. All the medicines were stored in a room that was supposed to be locked, but in reality it rarely was. It was suggested that the drug had been added to the evening meal, but when everyone had finished eating the leftovers had been disposed of and the plates and cutlery washed up by the kitchen staff. There were only a few scraps of cottage pie left for the forensic team to analyse for traces of poison, but nothing was found. It was eventually determined that the pilocarpine had been added to the soup, because many of the patients had noticed a bitter taste and eaten very little of it. This accounted for the fact that not everyone was taken ill, and that most survived; just four drops of pilocarpine would be enough to kill an elderly patient.

The average age of the patients on the Exford ward was 88 and many were in an advanced stage of dementia; others had difficulty communicating because of their particular form of psychiatric disorder. The police struggled to question the patients, but it emerged that one woman had been upset when two others took her customary place at the dinner table. There were also disagreements among the staff that had resulted in one member being dismissed. Despite these tentative leads,
whoever it was that added the poison to the soup, and the motive behind it, remains a mystery.

Pilocarpine has specialised medical applications and would not be part of most people's medicine cabinet, nor would it be carried by doctors on their rounds. Even if the doctor attending Geoffrey Denman in the Christie story had recognised the symptoms of atropine poisoning, it is unlikely that he would have had pilocarpine to hand. However, in cases of atropine poisoning other stimulants have been used, even caffeine.

As well as being an antidote for muscarin and pilocarpine poisoning, atropine is an antidote for poisonings from organophosphorus compounds. There are a huge number of compounds in this category of chemicals; they all contain phosphorus, carbon, hydrogen and oxygen atoms in various combinations and arrangements. These were initially developed in Germany in the 1930s as pesticides, but it was soon clear that some of them had serious effects on human health, including difficulty breathing and a dimming of vision as the pupils contracted to pinpoints. The Nazis went on to develop several of these compounds as chemical weapons; they were given names such as sarin, tabun and soman, but thankfully none were used during the Second World War.
³³

The best-known of these organophosphorus chemical weapons is sarin; sadly it
has
been used since the Second World War. Sarin is a relatively simple molecule that can be manufactured easily and stockpiled without its potency deteriorating over time, making it a popular choice for oppressive regimes and terrorist groups. Sarin interacts with cholinesterase, the enzyme that breaks up acetylcholine after it
has done its job of activating muscarinic receptors (the ones that slow the heart rate, and increase the output of fluids like tears and sweat). If the acetylcholine molecules are not removed they continue to stimulate the receptors; the target organ then goes into spasm, eventually becoming paralysed, and death occurs because the muscles required for breathing stop working. Atropine opposes sarin poisoning; it blocks the muscarinic receptors without stimulating them, so the excess acetylcholine has only a limited effect.

Sarin was used in 1995 in attacks on the Tokyo subway by members of the Aum Shinrikyo doomsday sect. Thirteen people died, and several thousand required hospital treatment. The sect had previously carried out a smaller-scale attack, which alerted the authorities to its intentions. When the second attack was carried out doses of atropine were available, and many lives were saved because of this. Soldiers deployed in situations where they may encounter organophosphorus compounds, such as in the case of nerve-gas attack, carry doses of atropine with them.

Some organophosphorus compounds, organophosphates, also have a beneficial role and are widely used as pesticides in agriculture today. These compounds are considerably less toxic than those used as chemical weapons, and they are also less toxic than the organochlorine-based pesticides such as DDT that they replaced. Accidental and intentional poisonings with agricultural organophosphates do occur, and they have the same symptoms as the organophosphorus compounds of warfare. Fortunately atropine can again be used as an antidote in emergency situations, and these symptoms can be treated. However, studies are ongoing into the health effects of long-term exposure to low levels of organophosphate pesticides.

Some real-life cases

Real-life atropine murders are very rare, even though plants containing significant quantities of the poison grow wild in many countries. This is probably due to the ease of identifying and treating the symptoms. However, there have been some
atropine poisonings, and one bungled murder attempt may have been inspired by one of Agatha Christie's stories.

Atropine was used in a failed murder attempt in Scotland. In 1994 Alexandra Agutter was poisoned by her husband Paul, a biology lecturer at Edinburgh University. He had added atropine to a bottle of tonic water that he used to make his wife a gin and tonic. Alexandra complained of the bitter taste and only drank some of the tipple but she had ingested around 150mg, more than enough to kill her. She soon felt very ill, and five minutes later tried to stand but felt dizzy and collapsed on the floor. She had a pain in her throat, and started to hallucinate. Paul promised to ring for help but called their local doctor rather than the emergency services. The doctor was out, so he left an urgent message for him. When the doctor picked up the message he immediately rang for an ambulance and set out for the Agutters' home. When the doctor and the ambulance arrived it was obvious that Alexandra was gravely ill, and they suspected she had been poisoned. The ambulance man took possession of the drinks for analysis. Alexandra was rushed to hospital, and though she was very ill for some time, she recovered.

Although it was clear that Alexandra had been poisoned with atropine, no immediate suspicion fell on her husband. Paul Agutter had been very careful in his planning. He had chosen atropine for a number of reasons: he was well aware of its lethal properties, it was easy for him to obtain by stealing it from the research lab where he worked, and the bitter taste would, he thought, be disguised by the bitter taste of the tonic water. He also took great pains to leave a trail of red herrings that would divert attention from himself.

Agutter added atropine to a number of tonic-water bottles, not just the one he used to make his wife's drink. These bottles contained between 11mg and 74mg of atropine, not enough to kill, but enough to make anyone who drank them very ill. Paul left the bottles on the shelf of a local supermarket. His plan was to make the authorities believe that a psychopath was deliberately tampering with bottles of tonic water. But CCTV
in the supermarket captured him in the store, and one of the employees remembered him placing bottles of tonic water on the shelves.

Eight people were subsequently admitted to hospital with atropine poisoning after drinking tonic water from the same shop. All the bottles of tonic water were taken from the shelves and tested; six more were found to contain atropine, and a nationwide alert asked people to return bottles of tonic water bought from the same supermarket chain. The story became front-page news, and Paul Agutter took part in a press conference with the police asking for help to find the culprit.

Agutter's mistake was failing to tidy up the evidence in his own home. The amount of atropine in the bottle of tonic water he used for Alexandra's drink was far higher (300mg) than the amounts he added to the other bottles. Had he substituted the bottle with the lethal dose for one intended for the supermarket and disposed of it before the ambulance arrived he might never have been suspected. Paul Agutter was found guilty of attempted murder and served seven years in prison.

One of the most interesting – but now almost forgotten – cases of atropine poisoning occurred in 1977 in Créances, France. Roland Roussel, a 58-year-old office worker, plotted to kill a woman he thought responsible for the death of his mother. He added atropine from an eyedrop solution to a bottle of Côtes du Rhone wine that he left at his uncle Maxime Masseron's house, where the woman frequently visited. Roussel's uncle and aunt abstained from drinking alcohol outside of the holidays, but his intended victim was known to drink wine at the house. Unfortunately Uncle Maxime decided to keep the wine for a special occasion, and he opened the bottle on Christmas Day, pouring a glass for himself and his wife. Maxime died at the scene, but Mme Masseron (whose full name has unfortunately been lost in the mists of time) fell into a coma, and was rushed to hospital by neighbours.

It was thought that the couple had been victims of accidental food poisoning, and the police were not alerted until a few days later when a local carpenter and the victim's son-in-law went to the house to place Maxime's body in a coffin. Finding wine on the table from Christmas Day, both men decided to drink a glass, and they quickly became violently ill. Within an hour they had both fallen into a coma, but thanks to medical treatment their lives were saved. The police quickly turned their attention to Roland Roussel, and they found a copy of Agatha Christie's
The Thirteen Problems
in his apartment, along with other magazine and newspaper articles on poisons. A gendarme stated that ‘I'm not saying Roussel was inspired by the book, but we found it in his apartment with the relevant passages on poisons underlined, and it was with that poison that the victim was killed.'

Agatha and atropine

In Agatha Christie's short story
The Cretan Bull
, Hugh Chandler displays all the symptoms of atropine poisoning, which a doctor would easily be able to recognise and treat. But instead of consulting a doctor, Diana Maberly, Hugh's fiancée, consults Hercule Poirot; fortunately for Hugh, Poirot's little grey cells are up to the challenge.

For the past year Hugh has been suffering from hallucinations, and a series of macabre incidents at his home mean drastic action had to be taken by Hugh's family. Hugh suffered from terrible, vivid dreams, and wandered around at night. To stop him or his family from coming to any harm Hugh was locked in his bedroom at nights, but sometimes he managed to escape. When he woke in the mornings he would find blood on his hands, and the bodies of slaughtered sheep were found in fields adjacent to the grounds of the house. Hugh was threatening to break off his engagement to Diana because he was worried for her safety.

When Poirot arrives on the scene he asks Hugh to describe his symptoms, which include a dry mouth and difficulty swallowing. Hugh also describes a feeling of flying, a sensation
often experienced with atropine; belladonna and mandrake were the key ingredients in witches' flying salves because of the presence of atropine in these plants. These salves were prepared using fats to dissolve the atropine and increase its absorption into the bloodstream when the salve was rubbed onto the skin. The effect of atropine on the central nervous system, and specifically the brain, creates hallucinations that often take the form of dissociation; the feeling of the mind leaving the body gives a sensation of flying. Women accused of witchcraft often genuinely believed they had flown.

While Hugh talks to Poirot he describes a vivid hallucination of a skeletal figure standing nearby. Hugh is bewildered, terrified and clearly believes himself to be going mad, but Poirot has his doubts. Poirot believes the hallucinations and other symptoms Hugh is experiencing are due to deliberate poisoning with atropine, and he sets out to prove it.

Hugh had a shaving rash and was using a cream to soothe the skin. Poirot takes a sample of the cream, and analysis shows that it contains atropine sulfate, a compound that had been prescribed to Hugh's father for an eye condition. By having the prescription copied the poisoner could obtain the atropine sulfate and avoid awkward questions from the pharmacist. In 1947, when the book was written, this compound was likely to have been dispensed as a solution of 260mg of atropine sulfate dissolved in one ounce (approximately 30ml) of water. This would be enough to kill an adult man if given in a single dose, but the prescription would be expected to last for a month if used daily for both eyes. The daily dose would be approximately 4mg per drop, roughly the level at which toxic symptoms might start to appear. The atropine sulfate obtained by the poisoner in
The Cretan Bull
would have been mixed with the cream, which wouldn't have changed its appearance, apart from perhaps making it a little runny. Poirot suggests that the atropine sulfate was extracted from the medicine before being added to the cream. Extracting the atropine sulfate, or concentrating it, could easily be achieved by evaporating the water from the eyedrops to leave a solid residue. Face creams,
or cold creams, are a mixture of oils in water, and if the poison was added as solid atropine sulfate it would dissolve in the water already present in the cream.