Stephen McWilliams
Dublin, Ireland

Few works of fiction are as original as Lewis Carroll’s masterpiece Alice’s Adventures in Wonderland. Replete with singular characters such as the White Rabbit, the King and Queen of Hearts, the March Hare, the somnolent Dormouse, and the infamous grinning Cheshire Cat, the novel also boasts one of the true icons of literary history—the Mad Hatter.

In the novel he is simply “the Hatter,” although at one point the Cheshire Cat refers to him and March Hare alike as “both mad.” Still, popular culture has played upon the phrase “mad as a hatter” (which predates Carroll’s work) to give the character his more familiar name. Despite the Hatter’s infamy, he appears only briefly in the book—mostly in the seventh chapter, entitled “A Mad Tea-Party.”¹ Here, we learn that the Hatter, the March Hare, and the Dormouse have been condemned to afternoon tea in perpetuum because of the Hatter’s failed attempt to regale the Queen of Hearts with his singing. She accuses him of “murdering the time” and characteristically shouts, “Off with his head!” The Hatter thankfully avoids decapitation but, in retaliation, Time deliberately stands still at 6pm so that the Hatter, the March Hare, and the Dormouse must forever have tea.

Of course, poor Alice finds it hard to tolerate even a brief period at the table. The Dormouse keeps falling asleep, everyone must switch places clumsily at a moment’s notice, and unanswerable riddles are the order of the day. Most famously, the Hatter asks, “Why is a raven like a writing-desk?” When Alice admits she does not know, the Hatter responds that he himself has not the slightest idea either. Alice soon tires of the Hatter’s rudeness and departs in disgust, only to encounter the Hatter later at the public trial of the Knave of Hearts.² Here, the King warns the Hatter not to appear nervous, or he will have him “executed on the spot.”

Lewis Carroll was, of course, a nom de plume. He was born Charles Lutwidge Dodgson at Daresbury Parsonage, near Warrington, Cheshire on January 27, 1832. The eldest son of Reverend Charles Dodgson, he had three brothers and seven sisters. Like some of his siblings, he had a stammer that he retained into adulthood—although he would often lose this impediment while speaking with children, which he enjoyed.³ He was educated in Richmond, Yorkshire and Rugby School, Warwickshire, before he was accepted to Christ Church College, Oxford. He went on to become a Fellow of the College, their Lecturer in Mathematics, and a Church of England deacon, but, in due course, he settled down as a full-time writer. During his lifetime, he wrote over 250 books on topics as varied as billiards, tennis, mathematics, and medicine, but it is for his fiction that he is best known, including the sequel Through the Looking Glass (1872). Thought of as a kind and modest fellow, he was described by Mark Twain as “the stillest and shyest full-grown man I have ever met except Uncle Remus.”³ Carroll listed John Ruskin, Alfred Lord Tennyson, Lord Salisbury, and Arthur Hughes among his friends and was, moreover, a talented photographer who exhibited at the Photography Society in London, with Frederick Crown Prince of Denmark counted among his sitters. Carroll died in Guildford, Surrey on January 14, 1898.

The inspiration for Alice’s Adventures in Wonderland is thought to be Alice Liddell, the daughter of Henry George Liddell, who was Dean of Christ Church. Carroll initially regaled Alice and her sisters Lorina and Edith with the tale while on a river trip from Oxford to Godstow on July 4, 1862. The original handwritten manuscript, entitled Alice’s Adventures Under Ground, was a mere 18,000 words long and took Carroll some eight months to write, such was its complexity. An expanded version was published four years later by Macmillan and Co., with forty-two illustrations by Sir John Tenniel. Of note, Alice Liddell grew up to be courted briefly by Prince Leopold, son of Queen Victoria, although she would go on to marry one of Carroll’s pupils, Reginald Gervis Hargreave. Tragically, two of their three sons would die in the Great War. In 1928, Alice sold her manuscript copy of Alice’s Adventures Under Ground for the record sum of £15,400.³

So, how might Carroll have conjured up so unique a character as the Hatter? Millinery was a thriving trade in nearby Stockport when the writer was a boy, and it might not have been unusual to see local hatters appearing somewhat confused. Nineteenth-century milliners commonly used mercury to stabilize wool during felting, and industrial hat makers would have been exposed to the mercury vapors over a long period of time. Nevertheless, Carroll is thought to have based his character on an eccentric furniture dealer from Oxford called Theophilus Carter, whose tendency to stand at the door of his shop wearing a top hat earned him the nickname “the Mad Hatter.”

It is therefore a little disappointing to note that the fictional Hatter does not display many of the features of mercury poisoning. Medically termed erethismus mercurialis, the disorder is relatively rare, although notably, mercury is listed by the World Health Organization (WHO) as one of the top ten chemicals of major public health concern.⁴ There is nothing new about it; Hippocrates, Pliny the Elder, Galen, and others all made reference to mercury poisoning in their respective writings, according to Leonard J. Goldwater in his 1957 review.⁵

Mercury exists in a few different forms, namely elemental (or metallic), inorganic (mercuric chloride, for example) and organic (such as methylmercury), all of which have different toxic effects on the nervous, digestive, and immune systems, as well as the lungs, kidneys, skin, and eyes. Exposure in utero to methylmercury is especially dangerous for the fetus, while inorganic mercury salts are corrosive to the skin, eyes, and gastrointestinal tract and can lead to toxicity of the kidneys if ingested.

But, with reference to the Hatter, what are the neurological and psychiatric symptoms of mercury poisoning? The former are comprised of tremor, headaches, insomnia, neuromuscular effects, and motor dysfunction. Psychiatric symptoms, meanwhile, can include depression, anxiety, poor concentration, memory loss, intense shyness, and—in the worst-case scenario—agitation, delirium, and hallucinations. Although the Hatter is clearly eccentric and sometimes speaks in riddles, he pays careful attention to every word Alice says and appears otherwise jovial, logical, and of relatively sound memory. He is also quite self-confident, notwithstanding some understandable nerves in court.

It is worth mentioning that not only hatters are at risk of mercury poisoning. Eating large amounts of fish and marine mammals that accumulate methylmercury in their muscles is a notable source of human exposure to the toxin.⁶ The WHO has also expressed concern about skin lightening and bleaching products that involve exposure to mercury salts to inhibit melanin production.⁴ Indeed, mercury-containing skin lightening products have been banned in many countries, although they can still be obtained in some regions via the internet. Finally, dental amalgams, which have been used to treat tooth decay for around two centuries, are also a source of concern, given that cheap fillings contain up to 50% mercury. One of the targets of the WHO Global Oral Health Action Plan 2023–2030 is that by 2030, 90% of countries will have implemented measures to phase out the use of dental amalgams as stipulated in the Minamata Convention on Mercury.⁴

Either way, given his assumptions about mercury poisoning, Lewis Carroll might easily have cast a fishmonger, beautician, or dentist over a hatter in Alice’s Adventures in Wonderland. This leaves us with one question: can it be treated? While prevention is obviously better than cure, acute cases of toxicity can be ameliorated with chelation therapyto bind to the offending mercury so that it can be excreted via the kidneys. But, as this technology was not available in the 1860s, it is just as well that the Hatter is unlikely to have had mercury poisoning in the first place.

References

1. Carroll, Lewis. Alice’s Adventures in Wonderland (With Forty-Two Illustrations by John Tenniel). London: Macmillan and Co., 1866. Chapter VII, “A Mad Tea-Party,” p. 95.
2. Carroll, Alice’s Adventures in Wonderland. Chapter XI, “Who Stole the Tarts?” p. 162.
3. Bryant, Mark. Private Lives. London: Cassell & Co. 2001: p. 62-64.
4. World Health Organization. Mercury fact sheet. October 24, 2024. https://www.who.int/news-room/fact-sheets/detail/mercury-and-health. Accessed March 4, 2025.
5. Goldwater LJ. The Toxicology of Inorganic Mercury. Annals of the New York Academy of Sciences. 1957;65(5):498-503.
6. Kang B, Wang J, Guo S, Yang L. Mercury-induced toxicity: Mechanisms, molecular pathways, and gene regulation. Science of the Total Environment 2024; 943. https://doi.org/10.1016/j.scitotenv.2024.173577.