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Pontifications on Poison

Being some ramblings on events associated with poisonous plants.

Saturday 23rd June 2012

It is 100 years ago today that Alan Turing, the brilliant mathematician credited with playing a major role in UK code-breaking during World War II and making significant contributions to the development of computers, was born.

Unsurprisingly, this event has been widely marked, not least, because he didn’t receive the appreciation he deserved either during his life or after his early death at the age of 41. There are a number of meetings and conferences around today in several places in the UK as well as in India and the USA plus other foreign countries.

At the Turing’s World event in Oxford1 Prof. Jack Copeland, from New Zealand will be presenting his modern take on the events surrounding Turing’s death. A BBC report2 says that Prof. Copeland thinks Turing’s death, from cyanide poisoning, may have been an accident not suicide.

I want to stress that, unlike many of those who revisit the history of some event and categorically state that their take on it is the only possible truth, Prof. Copeland is clear that it will never be possible to know if his hypothesis, that Turing was sloppy during an experiment involving the use of cyanide and accidentally ingested enough to be slowly fatal, reflects what actually happened.

Though cyanide is always synthesised these days, it can be produced by plants. Prunus laurocerasus, cherry laurel, is the plant I detail on this site as an example of its presence but the centre of many fruit pips contain the cyanolipids from which cyanide can be produced.

If Turing did accidentally ingest some of the chemical he was working with he joins a number of other scientists who have done the same thing. Probably the most famous such incident came when Albert Hofmann, on April 16 1943, experienced strange feelings of intoxication whilst working with lysergic acid diethylamide tartrate, now very well-known as LSD.

Atropine, one of the active ingredients of Atropa belladonna, deadly nightshade, has been used for a long time for its ability to cause dilation of the pupils. This is helpful for an optician wishing to examine the inside of the eyeball and may also be used to treat a condition where the pupil does not have sufficient natural elasticity to respond to light changes.

Atropa belladonna, deadly nightshade

Atropa belladonna, deadly nightshade

An ophthalmologist once told me how he had, unknowingly, splashed a little atropine into one eye shortly before driving home on a wet, winter afternoon. He couldn’t understand why all the lights in the street was so bright and realised he was having difficulty driving safely because the glare was affecting his sight. When he pulled over, he looked at his face and could see that one pupil was fully dilated.

Though not a result of an error during a scientific experiment I also heard about a woman who accidentally ate ham sprinkled in atropine after a bottle in the fridge fell over and leaked. That story appears more fully on the plant page.

These, of course, are all accidental poisonings rather than the deliberate self-administration of substances sometimes undertaken as part of a research programme and, occasionally, resulting in the death of the self-experimenter.

Bringing atropine together with the notion of deliberate self-administration and unforeseen consequences reminds me of the Venetian women who are reputed to have used the extract of Atropa belladonna to dilate their pupils and make themselves more attractive and to have used arsenic as a means of bringing a marriage to a profitable end.

One can only imagine the unpleasantness of being in a crowded ballroom illuminated with thousands of flickering flames with pupils fully dilated. That thought led someone to suggest to me that these women were not motivated by greed when administering arsenic to their husbands but could not tolerate staying married to the ugly specimen they had saddled themselves with by being unable to clearly see their suitors’ features.


1.Turing’s Worlds University of Oxford
2.Alan Turing: Inquest's suicide verdict 'not supportable' BBC 23rd June 2012

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