A is for Arsenic (29 page)

In
Sad Cypress
, Christie describes a plausible situation that gives all of her chief suspects access to morphine. Nurse Hopkins had a tube of 20 half-grain morphine hydrochloride tablets in her bag, for use in treating a patient in the village who was suffering from carcinoma (skin cancer). The day before Mrs Welman's death, Nurse Hopkins found that she had lost the tube of tablets. Although she should have reported the loss, she did not do so at the time, as she thought she must have simply misplaced them. Later it was realised that the nurse's case had been left in the hall of Mrs Welman's house overnight, and anyone could have taken the morphine. The tube contained enough of the drug to kill several people not regularly using morphine or morphine-related products. A few of the tablets
could have been dissolved and injected, if the murderer had access to a syringe, or they could have been added to Mrs Welman's food or drink. In her incapacitated state she was unlikely to be able to protest if what she was consuming tasted unusually bitter. Therefore the list of possible suspects extends beyond those in the medical profession.

Compared to Mrs Welman's death, Mary Gerrard's murder seems clear-cut. The overdose of morphine had been consumed at lunch, and only three people were in the room at the time. The set-up mimics a real-life case, which Agatha Christie may have used as a source of inspiration. In 1930 Sarah Hearn was accused of putting arsenic in some salmon sandwiches she had prepared for herself and her friends, William and Annie Thomas. The couple became ill some time after eating the sandwiches, and Annie was particularly unwell. While they were recovering at home, Sarah Hearn visited them to prepare a meal for the invalid and her husband. Two days later, Annie Thomas was dead. Analysis of her body showed the presence of large quantities of arsenic. Meanwhile Sarah Hearn had disappeared, leaving behind a note that hinted at suicide. In fact she had changed her name, and taken a housekeeping job in a neighbouring county. When her trial eventually came to court, Hearn's defence barrister discredited the scientific evidence by showing that large quantities of arsenic were present in the soil where the bodies had been buried, and this could easily have contaminated the samples analysed at post-mortem. The jury acquitted Sarah Hearn, but many questions remained unanswered. For example, how could she have ensured that she did not eat a poisoned sandwich along with her friends? And how could Hearn have added arsenic (which was thought to be in the form of weedkiller, and therefore stained blue) to the sandwiches without the colour showing in the bread? If Annie Thomas
was
murdered, her killer was never brought to justice.

Explaining how a poisoner can kill only one person at a lunch where three people ate the same food without revealing
the murderer would result in some very convoluted descriptions. For the sake of clarity, this section contains a few major spoilers. If you do not want to know the result, look away now (or go to page
here
).

In
Sad Cypress
Poirot realises that, though Elinor had prepared the sandwiches, they had been left unattended in the kitchen for some time and anyone from outside could have tampered with them. If an outside agent had poisoned the sandwiches it seems likely that all three people eating lunch would have been taken ill. If this unknown murderer had poisoned only one of the sandwiches it was pure bad luck that Mary Gerrard chose to eat it. Poirot dismisses this theory, and decides that the murderer must have been one of the three at the lunch. The analysis of Mary's stomach contents cannot discern whether the morphine was in the sandwiches or in the tea that she had also consumed. Elinor had not drunk any of the tea, but Nurse Hopkins had. If the morphine had been in the tea then it should also have poisoned Nurse Hopkins.

There was one telling clue that the police appeared to have overlooked, or they had not appreciated the significance of it. This was a pin-prick mark on Nurse Hopkins's wrist. Elinor notices it when the pair are washing up after lunch. Nurse Hopkins claims she got the mark from a thorn on a rose bush, but Poirot's meticulous attention to detail finds that the rose bush in question is a thornless variety. The mark could have been made by the needle of a hypodermic syringe, and this ties up nicely with another clue the murderer unwittingly left on the kitchen floor. This was a tiny fragment of a label from a pharmaceutical prescription.

The police claim that the label fragment came from a tube of morphine hydrochloride tablets, the tablets that had gone missing from Nurse Hopkins's bag, but closer inspection shows that this is not the case. In fact the label was from a tube
of Apomorphine. The portion of the letter ‘m' visible on the fragment of label shows it was lower case, and therefore could not have been from a label of Morphine hydrochloride tablets.
⁷⁶

Fragment of label found on the kitchen floor in
Sad Cypress
.

The name apomorphine is slightly misleading, as it is structurally quite different from morphine. Apomorphine was originally synthesised by the method described by Agatha Christie in
Sad Cypress
: ‘Apomorphine hydrochloride is a derivative of morphine, prepared by saponifying morphine by heating it with dilute hydrochloric acid in sealed tubes. The morphine loses one molecule of water.' Christie is correct in these statements, but the molecules of morphine subjected to this process do more than lose two atoms of hydrogen and one of oxygen. The atoms in the molecule actually undergo a major rearrangement, resulting in a compound significantly different from morphine, though it still binds to opioid receptors. The side effects of the compound mean it is unlikely to lead to an addiction, but people using it sometimes fall asleep. In the past, apomorphine has been used in aversion therapy for the treatment of anxiety, alcoholism, homosexuality and drug addiction.
⁷⁷
The author William S. Burroughs felt it was the most effective treatment for opium addiction as it greatly
reduced the symptoms of withdrawal without being addictive. It was the only treatment, of the many that he tried, that gave him a lasting recovery from opiate addiction. However, outside of Burroughs's assertions, there is no evidence that apomorphine is a safe or effective treatment for opioid addiction.

Apomorphine is not a specific antidote to opioid poisoning as it can only remove any unabsorbed poison from the stomach. Administering apomorphine after the drug has been absorbed, or if it has been injected, would be of little benefit to the patient.

Nurse Hopkins added morphine to the pot of tea she prepared at lunch. Surprisingly, no one comments on any bitter taste to the tea – perhaps they were too polite to say anything. Mary Gerrard drinks some of the tea, as does Nurse Hopkins, but, by injecting herself with apomorphine shortly afterwards, Nurse Hopkins vomits violently to remove the poison before it can be absorbed into her body. Then, to ensure that Mary Gerrard succumbs to the effects of the morphine, Nurse Hopkins suggests helping Elinor turn out the clothes in a bedroom upstairs. Mary is left alone for an hour, so by the time her poisoning is ‘discovered' it is too late to save her.

Notes

⁶⁶
There are references to poppy plants, seeds, grains and stalks in several places in the Ebers papyrus, a collection of Egyptian medical knowledge. One application was for diseased toes. The poppy parts were to be incorporated into a poultice and held there for four days. Pods of the poppy plant were also recommended to stop the cries of a child, as well as to relieve pain. The authors seemed well aware of the poppy's analgesic and narcotic effects.

⁶⁷
The
spongia somnifera
may well have relieved the pain of surgery, but with these plants and the lethal hemlock in the mix it seems a thoroughly risky way of doing it.

⁶⁸
Formerly known as narcotine.

⁶⁹
Tincture of opium is also listed in the
United States Pharmacopeia.

⁷⁰
The conversion of codeine to morphine is slow. Codeine is therefore far less addictive than morphine or heroin (and is more moderate in its pain relief), but it can still be addictive if used regularly.

⁷¹
The amount in a ‘wrap' of drugs on the street varies enormously; street drugs are almost never pure. A typical batch of heroin bought on the street can be anywhere between 10 and 40 per cent heroin; the rest is by-products from the manufacturing process, or other substances deliberately added to dilute the heroin and increase the profit.

⁷²
Marketed under the names Narcan, Nalone and Narcanti.

⁷³
Equivalent to around £180 (or $270) per week now.

⁷⁴
From
Poisoner in the Dock
by John Rowland.

⁷⁵
Ptomaine poisoning is an old-fashioned term for food poisoning.

⁷⁶
Although the possibility that the label read Diamorphine does not seem to have been considered; diamorphine could also have caused the death of Mary Gerrard, and the toxicological analysis would be similar because of the swift metabolism of heroin to morphine in the body.

⁷⁷
Aversion therapy seeks to make the brain associate certain behaviours or actions with unpleasant stimuli, in an effort to wean the patient off them. For example, in alcohol aversion therapy, alcohol is administered with an emetic, causing vomiting. The individual associates alcohol with a deeply unpleasant experience; thousands of alcoholics have been treated since the 1930s, and there have been claims of significant success. Aversion therapy for homosexuals was mainly carried out in the 1960s, when homosexuality was still a crime in the UK; many people were referred for this through the courts. This involved injections of apomorphine to induce nausea and vomiting; images of men in various states of undress would then have been shown. Unsurprisingly, the treatment was unsuccessful. It also required hospitalisation, so the individual could be monitored and treated if dehydration occurred. There were doubtless deaths caused by the side effects of apomorphine treatment.

Dumb Witness

After some experiments made one day at my house upon the phosphorus, a little piece of it being left negligently upon the table in my chamber, the maid making the bed took it up in the bedclothes she had put on the table, not seeing the little piece. The person who lay afterwards in the bed, waking at night and feeling more than ordinary heat, perceived that the coverlet was on fire.

Nicolas Lémery

THERE are many ways that phosphorus, the 15th element in the periodic table, can kill you: it has something of a ‘Jekyll and Hyde' character. On the one hand, when combined with oxygen to form phosphate, phosphorus is essential to our existence; it forms the backbone of life. On the other hand, it has been described as the Devil's element, and the darker side of its nature was well known to Agatha Christie. White
phosphorus has been used in bombs, rat poison, matches and medicine, all with fatal consequences.