How Many Apple Pips Will It Take To Kill You?


Regular readers of detective fiction will soon discover that many of the stories are laced with poison, cyanide, arsenic, and strychnine being especially favoured. It is a useful device because administering a poison, while requiring a certain degree of guile and some planning, does not require much in the way of brawn. Whereas a form of murder which requires the application of physical force may preclude many a fair damsel, the ability to pour surreptitiously a poison into the drink or meal of the intended victim presents no bar to gender. The poison can be administered in one go or drip fed, the latter method favoured if the victim has underlying health conditions, particularly gastric complaints.

It was a case of art imitating real life, as poisoning was a regular way of dispatching a victim from the mid-19th until the early 20th century. And it was not surprising as poisonous substances were relatively easy to get hold of. In a sensational trial in 1857, Madelaine Smith was accused of murdering her former lover turned blackmailer, Pierre Emile L’Angelier, with arsenic. An astonishing 88 grains of the poison were found in his stomach at the post-mortem. She admitted buying it but stated that she used it “in washing, as a cosmetic…[and] for the alleged purpose of killing rats”. The jury may have enjoyed the irony in her statement as they recorded a verdict of “Not Proven”.

Patent tonics openly available to give you that extra spring in your step contained strychnine, opiates in the form of laudanum could be bought over the counter, and potassium cyanide was to be found in many a gardener’s shed, useful for removing pests and weeds. Arsenic was mixed with vinegar and chalk and eaten by women desperate to lighten their skin or rubbed over their faces and arms to “improve their complexion”. It was also used as a dye for wallpapers, producing the type of bright green colour to die for, as some unfortunately did from inhaling the poisonous fumes that emanated from the material. Poisons only disappeared from the shelves when the authorities started to regulate products and introduce tighter legislative controls.

Poisons, though, can be found in many a common or garden foodstuff. Take the fruits in the Rosaceae family. I rarely eat an apple these days but when I do, I studiously eschew that thin fibrous band in the centre harbouring the pips. It is not the change in taste and texture that puts me off and I know that I am wasting part of the fruit and that if I eat it vertically, it is barely noticeable; I just do not want the pips stuck in my colon. Perhaps there is an innate self-preservation instinct at work too.

Apple pips contain molecules called cyanogenic glycosides, one of which is amygdalin. If you inadvertently chew or break the hard coating of the pip, the enzymes in your digestive system cut off the sugar part of the molecule, leaving the rest to decompose in your stomach and make the poisonous gas, hydrogen cyanide.

This discovery was made by a Swedish chemist, Carl Willhelm Scheele, in 1782 when he was dissolving pips and seeds. Hydrogen cyanide and its compounds went on to be used in industrial processes to harden metals, such as iron and steel, and to make ink for pens. Ironically, Scheele himself was a victim of toxins, dying at the age of 43 from mercury poisoning, almost certainly as a consequence of his scientific experiments.

Before you get too alarmed, though, it is worth putting the latent toxicity of apple pips into context. Humans experience some form of cyanide toxicity after consuming a dosage of at least 0.5 milligrams per kilogram of body weight. A fatal dose, it is reckoned, will need to be greater than 1.5 milligrams per kilogram of body weight. There are approximately 3 milligrams of amygdalin in a gram of apple pips, a recent study revealed, each pip weighing approximately 0.7 grams. Of course, because of the action of the digestive system’s enzymes, not all the amygdalin is converted into cyanide.

I weigh 78 kilograms and assuming a dosage of 1.5 milligrams per kilogram of body weight is required to finish me off, then 117 milligrams of cyanide would do the job. To achieve this, my putative poisoner would need 39 grams of apple pips or 557 individual pips. If we assume that there are eight to an apple, that means seventy apples would be needed.      

Other members of the Rosaceae family have higher concentrations of amygdalin. The greengage has almost six times as much in its seeds as an apple, 17.5 milligrams per gram, and the apricot, a fruit I have never got on with, almost five times the concentration, at 14.4 milligrams. A red cherry has almost a third as much as an apple, at 3.9 milligrams. My advice is to play safe and avoid biting into their stones.

If I ever decide to unleash my inner Richard Osman, it is safe to say that my murderer would not be using apple pips!

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