Mad as a Hatter, An Adder, or An Oyster

Please give a warm welcome to my guest Mimi Matthews. She is an author, attorney, and animal advocate that still has time to research and write about 19th century romance, literature, and history. She is also a member of Romance Writers of America (PRO), the Beau Monde, and Savvy Authors.  She resides in Northern California with her family – which includes an Andalusian dressage horse, a Sheltie, and two Siamese cats. With that said, here is her post:

The mercury-based compounds used in 19th century hat making had unfortunate side effects for those engaged in the trade. Many today believe that these side effects – including slurred speech, unsteadiness, and paranoia – led to the popular phrase “as mad as a hatter.” It certainly makes sense. However, in actuality, the connection between such symptoms and exposure to mercury was not recognized until the 20th century. Where then did the phrase “as mad as a hatter” originate? As late as the 1890s, Victorian scholars were still attempting to puzzle this out. There were many theories and, surprisingly, few of them had anything to do with hats.

Alice’s Mad Tea Party by John Tenniel, 19th Century, Courtesy of Wikipedia

Alice’s mad tea party by John Tenniel, 19th Century. Courtesy of Wikipedia.

The 1889 edition of Beckwith’s Almanac traces the phrase back to the Anglo-Saxon word “atter” – meaning an adder or a viper. Beckwith’s states:

“The phrase, therefore, strictly means as ‘venomous as a viper,’ the old form, ‘mad as an atter,’ having been corrupted to ‘mad as a hatter.’”

An 1883 issue of Cheshire’s Notes and Queries posits a different theory:

“The French compare an incapable or weak-minded person to an oyster. ‘He reasons like an oyster’ (huitre). I would suggest, therefore, that through similarity of sound, the huitre may in the case before us have given occasion to the English ‘hatter.’ From Il raisonne comme une huitre may have come out ‘as mad as a hatter.’”

The Manufacture of Felt Hats, 1858, Public Domain

The manufacture of felt hats, 1858. Public domain.

Cheshire’s also mentions that, in some parts of England, the word “gnattery” was used to mean irritable. They suggest that, at some point in history, the phrase “as mad as a gnatter” might have been in use and, in time, corrupted into the phrase “as mad as a hatter.” Having exhausted adders, gnatters, and oysters, Cheshire’s then presents the following anecdote from 1876:

“William Collins, the poet, was the son of a hatter (not a hat manufacturer as some have said) at Chichester, Sussex. The poet was subject to fits of melancholy madness, and was for some time confined in a lunatic establishment at Chelsea. The other lunatics, hearing that his father was a hatter, got up the saying ‘Mad as a hatter.’”

Of course, since the phrase pre-dates the 1870s, it could hardly have originated with the madness of William Collins.

With the public still puzzling over the origins of the phrase, and many having absolutely no notion of what was particularly mad about hatters, an 1873 edition of Punch suggests comparable phrases for other trades:

“While on the subject, I might make a series of similes for trade and professional purposes: thus, Mad as a Hatter, Drunk as a Fiddler, Comic as a Cobbler, Mild as a Milkman, Bold as a Baker, Short as a Shoemaker (short, referring to his temper), Terrible as a Tanner, Fierce as a Photographer, Charitable as a Chandler.”

The phrase “mad as a hatter” was very rarely connected with the hazards of hat making itself.  However, on occasion, 19th century reports did come close to recognizing how dangerous the chemicals involved in the trade could be. A brief article in the March 26, 1892 edition of The Cheltenham Chronicle makes a humorous reference to the phrase in relation to actual hats. Unfortunately, still ignorant of the dangers of mercury poisoning, the article is primarily concerned with men who develop eczema on their foreheads as a result of the linings of their hats having been “whitened and glazed with arsenic.”

Cheltenham Chronicle, March 26, 1892

Cheltenham Chronicle article, March 26, 1892.

The 19th century hat making trade was excessively hazardous to the health of those who engaged in it. Mercury was used to stiffen animal fur, thus making it easier to remove from the hide. And the addition of liquids and heat created a mercury-infused mist that, if inhaled, could result in serious side effects. Nevertheless, these dangers had nothing at all to do with the 19th century phrase “as mad as a hatter.” So, the next time you are reading Lewis Carroll’s 1865 novel, Alice’s Adventures in Wonderland, you can rest assured that whatever madness Carroll intended to bestow upon the character of the Mad Hatter, its origins had nothing at all to do with the chemical compounds used to make his hat.

If you enjoyed Mimi’s article and wish to connect with her, you can find Mimi at


Or visit her great website by clicking here. Some of her top blog articles include:

  • The Cat Show at the Crystal Palace
  • The 19th Century Wire Cage Crinoline
  • The Beauty Rituals of 19th Century Empress Elisabeth of Austria 

Works Referenced or Cited in this Article:

  • Aikin, Arthur. Illustration of Arts and Manufactures. London: John Von Voorst, 1841.
  • Beckwith, George. Beckwith’s Almanac. Volumes 42-48. London: Peck, White, & Peck, 1889.
  • Lemon, Mark. Ed. Punch. Volumes 64-65. London: Punch Publications, 1873.
  • Martelle, Scott. The Madman and the Assassin. Chicago: Chicago Review Press, 2015.
  • “Mad as a Hatter.” Cheshire Notes and Queries. Volumes 3-5. Stockport: Advertiser, 1883.

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