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Mad as a hatter

Q From A Hansen: Can you enlighten me about the origins of mad as a hatter?

A These days we associate mad as a hatter with a bit of whimsy in Lewis Carroll’s famous children’s book Alice in Wonderland of 1865. Carroll didn’t invent the phrase, though. By the time he wrote the book it was already well known.

The earliest example known was discovered by Stephen Goranson of Duke University in Blackwood’s Magazine; a section called Noctes Ambrosianae featured imaginary conversations among Edinburgh wits of the time. In the issue of June 1829 this exchange occurs: “‘He’s raving.’ ‘Dementit.’ ‘Mad as a hatter. Hand me a segar.’” Although Blackwood’s Magazine was published in Edinburgh, the vocabulary (dementit and segar for cigar) suggests an attempt at an American origin. The next known example is from a work by Thomas Chandler Haliburton (Judge Haliburton), of Nova Scotia, who was well-known in the 1830s for his comic writings about the character Sam Slick; in The Clockmaker; or the Sayings and Doings of Samuel Slick of Slickville of 1836, he wrote: “Father he larfed out like any thing; I thought he would never stop — and sister Sall got right up and walked out of the room, as mad as a hatter”. As the author felt no need to explain it, by then it clearly was known in his part of North America. An early British reference is in Pendennis by Thackeray, serialised between 1848-50: “We were talking about it at mess, yesterday, and chaffing Derby Oaks — until he was as mad as a hatter”. Intriguingly, the character of Captain Shandon in the book was modelled by Thackeray on William Maginn, one of the creators of the Noctes Ambrosianae.

Note, by the way, that mad is being used in both these cases in the sense of being angry rather than insane, so these examples better fit the sense of phrases like mad as a wet hen, mad as a hornet, mad as a cut snake, mad as a meat axe, and other wonderful similes, of which the first two are American and the last two from Australia or New Zealand. But Thomas Hughes, in Tom Brown’s Schooldays, used it in the same way that Lewis Carroll was later to do: “He’s a very good fellow, but as mad as a hatter”.

Few people who use the phrase today realise that there’s a story of human suffering behind it; the term derives from an early industrial occupational disease. Felt hats were once very popular in North America and Europe; an example is the top hat. The best sorts were made from beaver fur, but cheaper ones used furs such as rabbit instead.

A complicated set of processes was needed to turn the fur into a finished hat. With the cheaper sorts of fur, an early step was to brush a solution of a mercury compound — usually mercurous nitrate — on to the fur to roughen the fibres and make them mat more easily, a process called carroting because it made the fur turn orange. Beaver fur had natural serrated edges that made this unnecessary, one reason why it was preferred, but the cost and scarcity of beaver meant that other furs had to be used.

Whatever the source of the fur, the fibres were then shaved off the skin and turned into felt; this was later immersed in a boiling acid solution to thicken and harden it. Finishing processes included steaming the hat to shape and ironing it. In all these steps, hatters working in poorly ventilated workshops would breathe in the mercury compounds and accumulate the metal in their bodies.

We now know that mercury is a cumulative poison that causes kidney and brain damage. Physical symptoms include trembling (known at the time as hatter’s shakes), loosening of teeth, loss of co-ordination, and slurred speech; mental ones include irritability, loss of memory, depression, anxiety, and other personality changes. This was called mad hatter syndrome.

It’s been a very long time since mercury was used in making hats, and now all that remains is a relic phrase that links to a nasty period in manufacturing history. But mad hatter syndrome remains as a description of the symptoms of mercury poisoning.

Page created 3 Mar. 2001
Last updated 2 Feb. 2008

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Last modified: 2 February 2008.