Witches, tree-rings, and LSD

In the moonlight mothers and fathers watched the shriveled toes of a poor beggar swing from the gallows. They placed their faith in God that the death of this "witch" might take away the torment, fits, and visions that plagued their children. That somehow through supernatural forces the sensations of ants crawling underneath their skin, delusions of bursting into flames, and frenzied shrieks of terror in the night would cease. As the the seasons brought new harvests the number of swinging bodies dwindled. But bouts of bewitchment would visit the same valleys for centuries.

This was a typical scene in the medieval villages that lined the Rhône and Rhine rivers. Here, and in other curiously coincidental micro-climates all over Europe something dark and treacherous lurked in the farm fields.

During the cold, wet harvest seasons a deep purple fungus Claviceps purpurea reared its ugly sclerotium amongst the ears of rye. Looking much like the rooster's spur the killer was given the french name - erogot. When rye was milled the flour could contain up to 30% ergot by dry weight. And so it goes that the biochemistry of bewitchment had its origins under the millstones of fifteenth century Europe. 

During this age the peasantry ate an enormous proportion of the darker cheaper rye; upwards of three pounds a day. As the chemicals made by the ergot made their way into the blood and brains of those apparently seized by demons, the unaffected were left to assume they had been bewitched. The linguistic fossil preserved in the very word - seizure - describes the uncontrolled fits the affected displayed. A condition known at the time as "St Anthony's fire"  (aka Ignis Sacer) did not become known as ergotism until 1853 when the clinical connection to the fungus was finally made.

Mycotoxins are poisons produced by fungi and mold. The variety of mycotoxins contained in ergot-infested rye cause two distinct varieties of ergotism - gangrenous or convulsive ergotism. Ergotamine, a powerful vaso-constrictor, prevents blood flow to the extremities and is the main culprit in gangrenous ergotism.  Whereas ergine and lysergic acid hydroxyethylamide cause convulsive ergotism. These lysergic acid compounds found in the ergot fungus have similar effects on the human brain as the psychoactive drug - LSD.  Both LSD and the ergot alkaloids induce hallucinations by a similar and yet poorly understood mechanism.  Structurally similar to serotonin these compounds bind serotonin receptors in the brain. It is not known how this induces hallucinations but it is thought that agonist activity to serotonin releases higher concentrations of the neurotransmitter glutamate in the brain's cortex exciting neurons in random ways.  This would explain the varied psychological effects reported by individuals under the influence of this class of drugs.

By their activity these compounds were known long before their chemical makeup was uncovered. Ergotamine had been used for nearly two centuries in midwifery to stop hemorrhaging after birth and also to induce abortion. In the first half of the 20th century the other ergot alkaloids were probed for alternative medical uses such as blood pressure and migraine treatments.  A young chemist named Albert Hofmann working for Sandoz pharmacueitcal company in Basel, Switzerland literally stumbled across LSD while performing organic synthesis of ergot alkaloids.  His wild bicycle ride is a story of scientific lore worthy of its own post.

But here we are focused on the science behind medieval bewitching. The connection between ergotism and witch trials was first proposed by Linda Caporael in 1976 where she hypothesized in the Journal Science that Ergot could have been the real world cause of the supposedly supernatural events that transpired in the village of Salem, Massachusetts in 1692.  
 

In her paper Caporael outlines the evidence for ergotism being the scourge that set off the string of hangings accompanying the infamous witch trials in Salem.  She points out that the symptoms of ergotism; spasms, the sensation of ants crawling under skin, and the feeling of being disemboweled - were all recorded by the court clerk when taking the testimony of the affected teenage accusers.  Indeed the very fact that the accusers were female and in their teens also implicates ergotism as these are the most susceptible individuals in any community where there is an outbreak.  Lastly, she turns to the geographic distribution of the bewitchment. Here she reconstructs a map of Salem village where she hypothesizes that a contamination of grain grown on the eastern bank of the Wolleston river could have been the only source of ergot and still affected all the families involved.
  

Caporael's work inspired historian Mary Matossian to conduct further investigations into the possible connection between witch trials and ergotism outbreaks throughout the middle ages up until the 19th century.  In her book Poisons of the Past Matossian lays out an incredibly convincing argument that outbreaks of ergotism indeed correlate to increased incidence of witch trials throughout the medieval period.  She explains how tree ring thickness measurements compiled for every year from 1269 - 1977 C.E. can be compared to an annual index of number of witch trials with statistical correlation in southwestern Germany and the Swiss alps. 

 

Years in which the growing season was cool and wet correspond to thicker tree rings and therefore seasons in which the amount of fungus growing amongst the rye was high.  These long wet seasons directly preceded autumns with more witch trials. Like the medieval trials the Salem affair was also preceded by two years of unusually cold spring weather.

I was and still am utterly fascinated by the potential connection between a nefarious fungus and the waves of witch trials throughout the middle ages. So fascinated that I have continued seeking further evidence for this biochemical culprit in primary sources.  As I have said, the mid-wives of medieval Europe knew how to use ergot to treat hemorrhaging after birth, but did they know they could use this fungus to induce abortion? Surely they must have, and this would only have placed them higher on the list of public enemies by church rulers. Interesting observation, but how can I use this bit of information to test the claim that the presence of ergot in the diet of medieval peoples lead to witch trials?

There was a guide-book to hunting witches written in Germany in 1486 and approved by the papcay - the Malleus Maleficarum. Translated to English from Latin this means "the hammer of the witches."

The main purpose of the Malleus was to attempt to systematically refute arguments claiming that witchcraft does not exist, discredit those who expressed skepticism about its reality, to claim that witches were more often women than men, and to educate magistrates on the procedures that could find them out and convict them.

Might I use this primary text to hunt for clues connecting ergot to geographic regions affected by witchcraft?   Ergot can induce abortion in humans, right? Well, ergot in rye can also induce abortion in cattle. With this fact in mind I went to the text of the Malleus which is available through Google Books and project Gutenberg. When I searched in the book for the word "cattle" I found several references and even a whole chapter on how witches injure cattle in various ways. To my astonishment, there was even mention of bewitched cattle spontaneously aborting their calves! To the witch-hunters and inquisitors of the middle ages this phenomenon was a sign of witchcraft but the reality was most likely a rotten rye crop!

Thanks for reading! I hope you liked this story. If you did please share it! I would like to make this part of a storytelling series I am planning on you tube. Stay tuned here in the coming weeks for more biochemistry of Halloween content! You can subscribe to Tom Paine's Ghost at the link in the upper-right sidebar. If you like what you read here please make a donation of any size so I can continue to do what I love :)  Donate button also in the sidebar.

I would like to thank Nick Clark for our many discussions and collaboration on this topic and George Hudler for his kind advice and additional references.


Caporael, L. (1976). Ergotism: the satan loosed in Salem? Science, 192 (4234), 21-26 DOI: 10.1126/science.769159  

Schweingruber, Fritz H., BrÄker, Otto U. & SchÄr, Ernst (1979). Dendroclimatic studies on conifers from central Europe and Great Britain Boreas, 8, 427-452