Agatha Christie: Murder in the Making

‘Since I was surrounded by poisons, perhaps it was natural that death by poisoning should be the method I selected.’

From her experience as a hospital dispenser in both world wars, Agatha Christie had a professional knowledge of medicines and poisons. Starting with her first book, she used poison as a murder method more often than any of her contemporaries. The use of strychnine in The Mysterious Affair at Styles is a vital element of the murder plot; in fact the success of the conspirators depends on it. She uses not just the usual poisons – arsenic (Murder is Easy), morphine (Hickory Dickory Dock), cyanide (Sparkling Cyanide), but also the more esoteric – nicotine (Three Act Tragedy), thallium (The Pale Horse), taxine (A Pocket Full of Rye).

Notebooks 52 and 53 both include notes on the properties of a number of poisons. The former Notebook, dating from the early 1960s, contains notes for The Mirror Crack’d from Side to Side and The Clocks; the latter, from ten years earlier, has notes for After the Funeral and A Pocket Full of Rye, both published in 1953. Despite the fact that she had been dispatching her victims with poison for over 30 years, these notes show that Christie still researched new and ingenious methods of literary murder.

The notes are telegrammatic in style but most of the detail is scientifically accurate; I imagine that she was taking notes from a textbook. I have had to omit a few words whose illegibility defeated me and I include brief comments on some of the entries. The first list is from Notebook 53:

Notes on Poison

Taxine from leaves and berries of yew tree – salts soluble in water

Symptoms

Suddenly taken ill – fainting – face pale – pulse almost imperceptible – pupils contracted – eleptiform [resembling epilepsy] convulsions – stertorous breathing – slowing of respiration. Died within hour of illness, 2 hours after taking leaves. In another case died in eleptiform fit.

Possible sequence – quick pulse – fainting – collapse – nausea, vomiting; convulsions, slow respiration, death sudden and unexpected – death due to rigid paralysis of respiration and suffocation.

Taxine is used in A Pocket Full of Rye, the notes for which are contained in the same Notebook, and the details of Rex Fortescue’s death follow this outline.

Arsenic

Acute form similar in action to cholera; in district where cholera epidemic – no suspicion. Diarrhoea absent sometimes and death from shock

Rare form – nervous form – no diarrhoea or vomiting – narcotism – delirious – acute mania even eleptiform convulsions

Rare cases – symptoms delayed for 9 hours – fell suddenly and expired.

Murder is Easy features the use of arsenic and, in the 1950s, Alfred Crackenthorpe succumbs to arsenic poisoning in 4.50 from Paddington.

Ouabain

Arrow poison – of extract of root of ouabai tree [found in Africa]

Tasteless, odourless, sol[uble] boiling water – almost insol[uble] in cold. V[ery] poisonous if injected – (Diabetes?)

Colchicine

Colchicine (meadow saffron) – Colchicine wine (sherry) or schnapps or madeira – leaves consumed with salad – less than a 1 gr. fatal. Mrs. Soames killed by Margaret [should be Catherine] Wilson 1862). Burning pain in throat and tummy

Death 2nd day to 5th

Although colchicine was not adopted as a murder method by Christie, the true-life Wilson case is mentioned in Chapter 12 of Anthony Berkeley’s The Wychford Poisoning Case (1926).

Digitalis

Symptoms appear not less than 3 hours after. Red coal fire appears to be blue – sometimes blindness.

Digitoxin is the poison used to despatch Mrs Boynton in Appointment with Death.

Helleborus

From root of Christmas Rose, Helleborus Niger and other hellebores. Death under 8 hours – root boiled in wine? Heart poison – symptoms as digitalis

Oleandrin from oleander leaves

Saponin

40 grams subcutaneously – lethargy – weakness of heart – extracted from bread or flour. Sol[uble] in water – frothy – in lemonade? Sherbet? Etc.

As can be seen, even as she jotted the above notes Christie was thinking of a plot involving a frothy drink to camouflage the poison, although she never used it in a story.

Santonin (for worms?!) Max dose . . . 6 gr.

Tetanic convulsions and death – 15 to 48 hours; everything looks yellow (sometimes violet). ‘Woman in yellow dress?’

Daphne Mezereum

Burning taste in mouth – sudden narcosis – convulsion – dev[eloped from] fresh leaves? Berries?

Water hemlock

In flower in August – root like parsnip – stalk like celery. Semi-comatose – legs dragged

Coniine, another name for hemlock, is the poison stolen from Meredith Blake’s laboratory and used the following day to kill Amyas Crale in Five Little Pigs.

Hyoscyamine

1 gr. fatal – quiets excitement – muscular motion enfeebled – flushed face – pupils dilate. Distinction from atropine as latter causes delirium and excitement

The following list is from Notebook 52. In the 15 years between use of this Notebook and the end of her career, Christie used poison as a murder method in a further seven novels, and mood-altering drugs are a major plot feature of Third Girl:

Poisons Possibilities for book

Pentanol (Amyl Alcohol) C3H11OH [should be C 5 H11OH]

Ethylene Glycol CH2OH [formula should be twice this (CH2OH) 2 = C2H6O2]

Colourless sweet taste – substitute for glycerine – freeze – preserving substance – 100 grams drunk in “Schnapps” was fatal

Diethylene alcohol

Solvent for paints – Sol. of sulphanilamide in diluted diglycol caused 100 cases poisoning in America

Look up veronal, phanodorm, curral, somnifen, noctal, phenocton [more probably phenytoin], nirvanol (phenyelhydantoin) – (barbiturate derivatives)

Look up pyrazolone derivatives – in partic[ular] pyramidon (sol. 1 in 2 alcohol central paralysis) cardiazol – coramine etc.

Strophanthin (Heart tonic)

Strophanthin is used and identified in ‘The Case of the Caretaker’ and ‘Triangle at Rhodes’ as well as Verdict.

Nitrobenzene

1 gm. fatal

Tri-ortho-cresyl phosphate

Paraffin-like, colourless, odourless tasteless – insol. in water – used as adulteration of ginger extract – produces similar sensation to alcohol. In 1929 20,000 died of ginger paralysis – ten weeks before symptoms developed – ending with paralysis of arms and legs – (taken as liquid paraffin).

This adaptation of a patent medicine, popular during Prohibition because of its ‘alcohol’ effect, was later shown to have an adverse effect on some nerve cells in the spinal cord. The paralysis Christie notes was not fatal, although in many cases it was permanent.

Sodium fluosilicate

Sometimes mistaken for baking powder or sod[ium] bic[arbonate] – suicidal agent

E.605 plant protection agent – freely sold to public – epidemic of suicides in Germany

Neurotoxin affects regulation of parasympathetic system. Death through cardiac and respiratory paralysis after agonising pain and convulsions – a few minutes or up to half an hour. Christa Lehman poisoned a number of people

Christa Lehman was convicted in September 1955 in Germany of the murder of two members of her own family and a neighbour, using E605. Incongruously, it is thought that the publicity surrounding the case caused the ‘epidemic of suicides’, as the chemical, now banned, was then freely available.

Kava-kava

Narcotic pepper – peaceful joyous sensation – drowsiness

In her Autobiography Agatha Christie writes: ‘Dispensing was interesting for a time, but became monotonous – I should never have cared to do it as a permanent job.’ Fortunately for the world of detective fiction it did not become a permanent job; but the knowledge gained in that Torquay dispensary not only stood her in good stead in her future career but also inspired the poem ‘In a Dispensary’, published in the 1924 edition of her poetry collection, Road of Dreams. In one prophetic verse she writes:

From the Borgias’ time to the present day, their power has been proved and tried!

Monkshood blue, called Aconite and the deadly Cyanide!

Here is sleep and solace and and soothing of pain – courage and vigour anew!

Here is menace and murder and sudden death! – in these phials of green and blue!