Q&A With A is for Arsenic author, Kathryn Harkup


This year chemist, author and Agatha Christie fanatic, Kathryn Karkup, releasedA is for Arsenic, a book celebrating the use of science by the undisputed Queen of Crime. A is for Arsenic examines the poisons used by the murderer in fourteen classic Agatha Christie mysteries. It looks at why certain chemicals kill, how they interact with the body, the cases that may have inspired Agatha Christie, and the feasibility of obtaining, administering and detecting these poisons.

We caught up with Kathryn Harkup to find out how she discovered Christie and what is was that inspired her to write this insightful book.

How did you discover Agatha Christie?

I think I first started reading Agatha Christie when I was a teenager, I particularly liked the Poirot stories. Since then she has never really left me. There were the fantastic films, I love Peter Ustanov's interpretation of the famous sleuth, and of course there was the Poirot TV series where David Suchet became the definitive Poirot. Later, after becoming interested in poisons and toxicology, I noticed Christie's name cropping up in various science books I was reading. I then went back to novels and formed a new appreciation for Christie's scientific accuracy.

When was the first time you remember reading or watching your first Christie?

It's almost as though Christie stories have always been there, somewhere in the background. She is one of the few writers that almost everyone has heard of even if they haven't read her books. Poirot would be delighted that his name is still so well known.

What was it that inspired you to write a book on the poisons used in her novels?

I had been working in science communication for a while, talking to school students to encourage them to study science and engineering subjects at a higher level. When you want to engage bored teenagers in science, anything dangerous or disgusting usually grabbed their attention. You can talk about a lot of science while they are still marvelling at a gruesome detail you have dropped in to the talk. Poison is perfect subject for gross detail and interesting science. When I was asked to write a book, poisons was an obvious choice, and if you are going to write about poisons, then the Queen of Crime is a fantastic starting point and compliment to the subject.

Were you interested in poisons before you were interested in Agatha Christie, or the other way round?

That's a bit of a chicken and egg question for me. Although my interest in Christie stories probably dates back further, I didn't associate her with poisons until after I had become interested in toxicology. The two interestes ran parallel to each other for a long while. Writing the book forced me to make the link.

How did you choose which books to focus A is for Arsenic on?

Christie used over thirty different compounds to kill her characters so I was spoiled for choice. The poisons she used all have fascinating histories, modern uses and intriguing effects within the body. I only had space in the book for fourteen poisons so I chose compounds that interested me and in some cases they only appear in one story, such as nicotine in Three Act Tragedy, or phosphorus in Dumb Witness, so the choice was easy. When it came to strychnine and arsenic there are so many stories to choose from I ended up going for those that had the most detail about the effects of the poison, or a novel method of administering it. When it came to cyanide, even though it was Christie's favourite method of bumping off a victim (she killed nineteen characters with cyanide compounds), the choice had to be Sparkling Cyanidejust because of the perfect title, but there are also a lot of details about symptoms of cyanide poisoning and different places it could be obtained.

Using your knowledge of poisons, were you always able to guess whodunit?

Knowing the effects of poison, or time taken for symptoms to appear, was of limited use. In a few cases it narrowed down the list of possible suspects but in truth I am rubbish at guessing 'whodunit'. After reading every single Christie story I have only ever correctly guessed once. Full credit to Christie for plotting such brilliant puzzles and disguising clues. She has a real talent to deceive.

If you could recommend one Christie novel to demonstrate her understanding and clever use of poisons, which would it be?

There are so many brilliant examples to choose from but I think the most impressive for me is Five Little Pigs because the symptoms of poisoning provide vital clues to solving the crime. The novel has brilliant plotting, clearly signposted clues but you still won't guess the culprit. It's only when the murderer is revealed and Poirot describes how he worked it out that you can appreciate just how well constructed the story is.

Find out more about A is for Arsenic here.

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