33. Arsenic: It’s Not Easy Being Green

Considering how synonymous this episode’s element is with “poison,” it’s astounding how eager people have historically been to ingest the stuff.

Featured above: A typical label found on an arsenic-based medicament.

Show Notes

What an appropriate element this is for us to cover around St. Patrick’s Day, eh?

Anyway, it’s always a good time to watch The Princess Bride. Of all the iconic scenes in that film, let’s recall this one now:

“What you do not smell is called iocane powder. It is odorless, tasteless, dissolves instantly in liquid, and is among the deadlier poisons known to man.”

With the pedantic nitpick that arsenic dissolves much better in hot liquids than in cold ones, this describes element 33 to a T! And arsenic was most frequently available as a powder, as well. But the most remarkable similarity is the one that sounds most outlandish: It is, in fact, fully possible to develop an immunity to arsenic by slowly consuming sub-lethal doses over long periods of time! (Please note that I am in no way advising this.)

In fact, a population of peasants in the Austrian province of Styria gained a degree of infamy in the 19th century for being “arsenic eaters.” They would start by consuming tiny doses of arsenic once a week, then up the frequency to several times a week, then daily. From there, they would slowly increase the dosage they took every day, until these folks were fully capable of consuming a dose of arsenic that could kill a man three times over, and suffer no ill effects whatsoever. The claims that arsenic was good for complexion and could provide a little pep in your step were not entirely unfounded, and those were the reasons the Styrians claimed.

This also happened to immaculately preserve a person’s body after death.

For more on the subject, you can read excerpts of John Parascandola’s book Arsenic: King of Poisons online.

I was under considerable pressure to get this episode out on time this week, so I’m actually still adding my sources to the transcript! Do check back in a day or two for the complete citations, as well as perhaps a few additional stories here in the show notes. (e.g., why arsenic makes a rather ironic rat poison.)

Episode Script

For over half the twentieth century, one lone British woman was responsible for murders literally too numerous to count. Her victims died in many different ways — they were variously shot, stabbed, electrocuted, and defenestrated — but this woman was especially fond of poisons. She had picked up this nefarious proficiency while working as a pharmacist in both World Wars. Her fatal prescriptions included cyanide, strychnine, hemlock, and arsenic.

Being so brutally prolific, it’s no surprise that this woman became world-famous. But the papers weren’t crying for her to be brought to justice. If anything, she was celebrated for orchestrating these murders in ways that were endlessly clever and surprising.

The twist, of course, is that all the victims of these murders were fictitious persons, and you can read their tales in the collected works of Agatha Christie.1

You’re listening to The Episodic Table Of Elements, and I’m T. R. Appleton. Each episode, we take a look at the fascinating true stories behind one element on the periodic table.

Today, we’re building up an immunity to arsenic.

Poisonous substances are often complex compounds with long names, but a handful of elements the periodic table are quite deadly right off the shelf, too. Among them, perhaps none is more famous than today’s subject: Arsenic.

Certainly, part of the reason is because we’ve known about the substance for thousands of years, but more importantly, you could hardly design a more perfect poison. Even in small amounts, this colorless, odorless, and tasteless element can kill, inducing effects that mimic the symptoms of prevalent and deadly diseases.

For the chemically literate like ourselves, the periodic table provides a clue as to how arsenic kills. Take a look at the slot directly above arsenic, and you’ll find phosphorus. You might remember that as a critical ingredient in the chemical adenosine triphosphate, which the body requires any time it makes a movement, big or small.

But our bodies aren’t very good at distinguishing elements that share a group on the periodic table, especially when one of them is far more abundant than the other. Since we rarely encounter element 33 in the wild, Arsenic can wear the molecular equivalent of a fake mustache to slip past our cellular defenses, where it gets swept up into our ATP molecules. That’s where the trouble starts. Arsenic belongs in ATP about as well as a thick wad of chewing gum belongs in a clock tower’s sprockets.

What happens next is rather complicated, and wholly unpleasant, but unless an antidote is administered in time, systemic organ failure leads to death.

At least, that’s the case for most life on earth. The biology community was consumed by a considerable brouhaha in 2010, when scientists discovered a species of bacteria that actually can thrive in an arsenic-rich environment. Later research revealed, however, that even these microbes would rather deal with phosphorus when given the chance.2

Historically, people were well aware of how dangerous arsenic is, but they also appreciated its many other qualities. For some applications, there weren’t many alternatives they could turn to — so arsenic’s toxicity was seen as an acceptable risk.3

One such application was invented by Carl Wilhelm Scheele. If the name rings a bell, it’s probably because he’s briefly appeared in prior episodes. He did important work investigating oxygen, fluorine, phosphorus, and other elements in the late 18th century.

Sadly, for all of his contributions, he rarely received the credit he was due. But there was one notable exception: In 1775, he concocted a particularly vibrant arsenic-based green pigment, much brighter than anything else that was available at the time. It became known as “Scheele’s Green,” and it was all the Before long, Scheele’s Green was slathered on every available surface: wallpaper, paint, clothes, children’s toys, and even food coloring.4

To our modern sensibilities, none of these sound like particularly good ideas. And indeed, living in an arsenic-tinted world occasionally had tragic consequences. But out of the many green-hued goods in Victorian Europe, the one that caused the most widespread panic was the wallpaper.

After a few decades of sitting in lounges and parlors colored brightly with Scheele’s Green, people noticed that there seemed to be some adverse health effects — especially when those rooms were damp, dim, and stuffy. When Italian doctor Bartolomeo Gosio investigated, he discovered that certain varieties of fungi were able to absorb the arsenic from the wallpaper, convert it to a volatile form, and disperse it in the air as trimethylarsine gas.

Naturally, Scheele’s Green quickly fell out of favor, since nobody was too fond of breathing arsenic aerosol, and it certainly provided an explanation for the many mysterious illnesses people occasionally died from. In the 1980s, following advances in forensic science, a British chemist named David Jones proposed that Napoleon Bonaparte was one such casualty, killed by his wallpaper while in exile on the island of St. Helena.

The facts all seemed to add up, at least on the surface. The symptoms Napoleon displayed in the final weeks of his life were consistent with arsenic poisoning, and the wallpapers in his island estate were colored with arsenic-based pigments. Jones even got his hands on a sample of Napoleon’s hair, and chemical analysis showed extremely high levels of element 33.5

It’s a tempting theory, but it ignores some critical context. First of all, it was the 19th century, and everyone’s body was stuffed to the gills with arsenic. See the earlier note about how it was present in the clothes and the toys and the food. There’s also the fact that Napoleon’s autopsy, conducted immediately after he died, concluded with great confidence that stomach cancer was the cause of death. Just as it had been for Napoleon’s father and two of his sisters.

And then, in 2004, the Journal of Environmental Monitoring published a paper titled, “The Toxicity Of Trimethylarsine: An Urban Myth.” It specifically investigated the theory originally proposed by Bartolomeo Gosio, and using the benefit of modern tools, thoroughly debunked it. While Gosio had proven that wallpaper fungi could theoretically fill the air with trimethylarsine, he never actually demonstrated that this happened in the real world. According to the authors, gas production would be “extremely unlikely,” even under optimal conditions. And the kicker? “All of the above reasons,” they write, “pale into insignificance in view of the very low toxicity of trimethylarsines.”6

So why were people dying in all those dark, moldy rooms? The simplest explanation seems likely. They had probably contracted diseases that everyone was already familiar with: Typhoid, cholera, pneumonia, and the like, which were far from uncommon at the time.

So it turns out that Scheele’s Green wallpaper probably didn’t kill Napoleon. In fact, it probably didn’t kill anyone at all.

Anyone, that is, except for the eponymous Carl Wilhelm Scheele. The man had an unfortunate habit of using his nose and tongue as laboratory instruments throughout his career, exposing him to hazardous substances like hydrofluoric acid, lead, mercury, and, obviously, arsenic. Even for an Enlightenment-era chemist, his death at the age of 43 was tragically premature.

Of course, this is not usually what people mean when they talk about death by arsenic. They mean murder.

Arsenic in particular has seen such widespread use as a weapon throughout history that one of its long-standing nicknames is “inheritance powder.” In the period between 1750 and 1914, British poisoners were nearly five times more likely to use element 33 to do the deed than the second-most-popular choice, opium. And we only have those kind of statistics for those murderers clumsy enough to get caught.7

Poison has long had a reputation as a women’s weapon, especially in works of popular fiction, from the witch in Snow White to Poison Ivy in Batman’s rogue’s gallery. But perception and truth, in this case, are severely out of alignment with each other. Over 60% of convicted poisoners are men, in the present as well as the past.

In a 2014 article for The Hairpin, Meredith Haggerty speculates as to why the myth might endure:

Ladies have long been tasked with cooking, cleaning, and nursing, and poison can be drizzled into coffee, applied to the inside of freshly laundered shirts, or administered as an “accidental” overdose. … Poison is a hands-off, elegant means to someone’s end; it’s not showy or vainglorious, like stabbing or shooting. It doesn’t require muscle like, say, beating a human to death. Poison is a weapon for people who just need a job done.”8

And to be fair, women accounting for 40% of poison-based murders is much higher than any other method. In modern American society, women are only responsible for 6.8% of all felony murders.9 10 In this light, science historian Daniel Kevles points out that it is not the gun that is “the great equalizer,” as is commonly claimed, but poison.11

And if you seek out history’s most prolific poisoner, you will find a professional woman catering to an exclusively female clientele.

Like nearly every other time and place in history, Renaissance Italy was not especially kind to women. All too often, a woman could find herself trapped in a loveless marriage and treated as property — or worse. With divorce prohibited by the Church, many women saw widowhood as their only salvation.

By the mid-17th century, Giulia Tofana had earned a significant reputation as the person to turn to if you were a woman in such dire straits. Her own mother had been executed in 1633 for poisoning her husband, and Giulia picked up the family trade soon after. Disguised as cosmetic products or as a kind of holy water called Manna of St. Nicholas, Tofana would provide lethal doses of her proprietary arsenic-based formula to women in need — often for a price, but occasionally as an act of charity for the truly desperate.

Employing the assistance of her daughter and other trusted confidants, Giulia sold “Aqua Tofana” to many aspiring widows. By 1655, the number of customers served may have been as high as 600 — which would make her one of the most successful poisoners of all time. A dubious honor, to be sure.12

Records from the time are rather messy, though, and facts have blended with rumor and fantasy over time. It’s likely that Madame Tofana was something of a composite figure, encompassing the illicit careers of several women across Italy for over a century. But her reputation was so widespread that as Mozart laid on his deathbed in 1791, he wondered if he had been dosed with the notorious Aqua Tofana.1314

For the record, historians agree that Mozart was almost certainly not poisoned. But until relatively recently, even a skilled medical examiner would have no way of knowing if a victim was murdered by arsenic. It wasn’t until 1840 that James Marsh devised a chemical test that could accurately determine the presence of element 33.

But the Marsh Test didn’t definitively close the book on the era of arsenic murders, because if there’s anyone craftier than scientists, it’s lawyers. “Of course, no one is disputing the presence of arsenic in the victim’s body,” defense attorneys would say. “But none of us can say beyond a reasonable doubt how it came to be there.” And that wasn’t an argument that was entirely without merit. Aside from the myriad ways in which a body might inadvertently absorb arsenic, it was just as likely to be deliberately consumed for medicinal purposes.

It sounds utterly daft to us now, but it’s true — all manner of tinctures and tonics loudly advertised their arsenic content, most famously Thomas Fowler’s Solution, which claimed to do everything from beautifying one’s complexion to instilling the spirit with vim and vigor.15

Rarely did people die from these self-administered doses. Think of it as kind of a corollary to what Paracelsus said: Any substance can be a poison at a high enough dose, sure, but in minuscule enough quantities, any poison can also be rendered harmless. And arsenic was far from the only toxic chemical that was sold as a cure for all sorts of ailments. Just wait till we get to antimony — that one’s a riot.

It’s easy for us to scoff at such foolish behavior, but we’re just as likely to riddle our bodies with substances that will cause future humans to gasp in shock, even for reasons as frivolous as vanity. For instance, take botulinum, a protein produced by the Clostridium genus of bacteria. So lethal is this substance that one milligram dispersed in the air would be enough to kill well over one thousand people.16

As an outpatient procedure, you can voluntarily have this same stuff injected directly into your face to smooth wrinkles away under the brand name Botox. So perhaps we should think twice before assuming any sense of modern, enlightened superiority.

Nonetheless, public infatuation with arsenic did eventually cool off. As a sign of the times, Britain introduced the Sale Of Arsenic Regulation Act in 1851, which required sellers to record their buyer’s names and addresses in a ledger that became known as The Poison Book.

Since then, arsenic hasonly become more difficult to acquire. Even twenty years ago, arsenic was more readily present in everything from our lumber to our chicken wings than it is today. As for the former, arsenic was a key ingredient in the chemicals typically used to treat wood for use in construction. More worryingly, farmers have included arsenic in chicken feed for decades, since the element helps poultry plump up nice and big. Regulations passed in recent years have made both of these practices less common.

Perhaps the only non-villainous individuals who could be disappointed by this information are the element-collectors of the world, but fret not. Even in 2019, society is completely comfortable reserving mass, arsenic-based murder for one last demographic: Rats.

There’s no shortage of ways in which the frustrated homeowner can attempt to stave off rodent infestation, and arsenic is as popular a solution as ever. Even the highly sensitive nose of a rat can’t detect its presence in a lump of peanut butter. So once again, we have an element that can easily be added to our collections by a trip to the hardware store. Just make sure to heed the numerous warnings on the label, and keep out of reach of pets and children.

Thanks for listening to The Episodic Table of Elements. Music is by Kai Engel. To learn why “iocane powder,” from The Princess Bride, is actually just arsenic by another name, visit episodic table dot com slash A s.

Next time, our hearts will go on with selenium.17

Until then, this is T. R. Appleton, reminding you to never go up against a Sicilian when death is on the line!


  1. History Extra, Arsenic: A Brief History Of Agatha Christie’s Favorite Murder Weapon. Kathryn Harkup, January 7, 2016.
  2. National Geographic, Arsenic-Life Discovery Debunked — But “Alien” Organism Still Odd. Richard A. Lovett, July 10, 2012.
  3. Racked, The History Of Green Dye Is A History Of Death. Jennifer Wright, May 17, 2017.
  4. A delightful and well-researched account of this can be found at The Pragmatic Costumer: Historical Costuming For The Rest Of Us.
  5. Is Arsenic An Aphrodisiac? The Sociochemistry Of An Element, p. 146. William R. Cullen, 2008.
  6. The Toxicity Of Trimethylarsine: An Urban Myth. The Journal Of Environmental Monitoring, December 6, 2004.
  7. Huffington Post, Arsenic: The Near-Perfect Murder Weapon. Sandra Hempel, December 6, 2013.
  8. The Hairpin, That Girl Is Poison: A Brief, Incomplete History Of Female Poisoners. Meredith Haggerty, December 16, 2014.
  9. Wired, The Imperfect Myth Of The Female Poisoner. Deborah Blum, January 28, 2013.
  10. As opposed to misdemeanor murder, which is when culpability can be shown, but motive cannot.
  11. Slate, Don’t Chew The Wallpaper. Daniel J. Kevles, April 6, 2006.
  12. Hayes’ Principles And Methods Of Toxicology, p. 15. Edited by A. Wallace Hayes and Claire L. Kruger, 2014.
  13. Toxicology In The Middle Ages Ad Renaissance, Chapter 6. Mike Dash.
  14. Aqua Tofana: Slow-Poisoning And Husband-Killing In 17th-Century Italy. Mike Dash, April 6, 2015. Ordinarily I wouldn’t link to a blog as a source, but this is exhaustively well-researched and worth reading in its own right.
  15. Dartmouth Toxic Metals Superfund Research Program, Arsenic: A Murderous History.
  16. The Conversation, Handle With Care — The World’s Five Deadliest Poisons. April 12, 2016.
  17. Thanks to my own dad for inspiring this dadliest of dad jokes.

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