Mad about Mad Hatter Disease
April 23, 2017


I’m a big fan of medical history so I was surprised when I heard the term “Mad hatter disease” recently and I was unfamiliar with it. The only Mad Hatter I was aware of until recently was the silly top hat-wearing gentleman in Alice in Wonderland. When I discovered that the disease actually related to hats, I got even more excited.

(I love me a good old-timey hat.)

In the late 1500s in Europe, tall hats became the fashion. The capotain, commonly worn by both men and women, was usually black. Width and height varied with time but the vertical portion was usually more conical toward the top and the sides of the hat usually curved into the top, rather than ending at a sharp edge like the top hat we know today. The rim was also sometimes wider and less stiff than a top hat’s.

The Puritans were real big fans of the capotain, so much so that it became a symbol of Puritanism. The black hat with the belt buckle on the front? Yeah, that’s a capotain. These hats eventually went out of style, later reappearing as an early form of the top hat in the late 1700s. Its popularity was probably helped along by Beau Brummell, friend and personal stylist to Prince George, the future George IV. Brummell is credited with several different men’s fashion, including the modern suit and necktie.

Abraham Lincoln

Abraham Lincoln

The top hat still remains a symbol of the 1800s today. They were worn by men of all classes. The tall, “stove pipe” top hat was immensely popular during the first half of the 1800s, particularly during the Victorian era. The trend wasn’t limited to the UK though, as President Abraham Lincoln was also a fan of the stove pipe style hat and helped it become popular in America. Back in England, Prince Albert adopted the top hat and it became a mark of a gentleman.

During the latter half of the 1800s, the height was reduced a bit and a sleek ribbon was added at the bottom of the cylinder.

Prince Albert and Queen Victoria

The best hats worn by those in the upper classes were made from felted beaver fur. (Fellow Canadians might know all about that beaver pelt fever, as it is a major part of Canadian history.) Rabbit hair was sometimes used as well. Silk, linen and flannel were also used, especially as the trend spread to lower classes.

When producing a top hat, a milliner would use a mixture to separate the fur from the skin and keep the hair together. The mixture was orange, the process was called “carroting” and the mixture contain mercuric nitrate—i.e. mercury. Then the fur could be molded into the shape of a hat or brim.

Since the effects of mercury poisoning were unknown, these milliners would often times work in enclosed spaces and wouldn’t wear protective equipment. There is some evidence that the creation of hats was effecting the milliners, as evidenced by the use of the phrase “mad as a hatter,” but the practiced continued for, well, way too long. Different methods for separating the animal fur from the skin became popular by the late 1800s and legal regulations were introduced in France 1898 to ban the use of mercury in hatmaking. In the United States, however, mercury was still being used until 1941.

What did Mad Hatters Disease look like though?

Mercury poisoning, caused by the mercury in the vapors of the carroting solution, had a long list of symptoms, many involving the nervous system.

  • hair loss
  • tooth and nail loss
  • muscle spasms
  • drooling
  • slurred speech
  • unfocused thoughts and speech
  • depression and suicidal thoughts
  • insomnia
  • irritability
  • loss of memory
  • fatigue
  • hallucinations
  • skin discoloration
  • increased heart rate
  • rashes
  • sensitivity to light
  • kidney problems
  • trembling hands

Danbury, Connecticut was, during the 1800s, in the hat making capital of the world, producing five million hats in one year at the peak of the trend. The trembling hands symptom came to be known as the “Danbury Shakes” since so many people in the area showed signs of poisoning.

Links of interest:

Jillianne Hamilton is a history enthusiast and the author of The Spirited Mrs. Pringle (historical fiction), The Hobby Shop on Barnaby Street (historical romance), and The Lazy Historian’s Guide to the Wives of Henry VIII (non-fiction). Jill launched The Lazy Historian in 2015. She lives in Charlottetown on Canada’s beautiful east coast. Learn more.

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  1. Thank you very interesting to learn about mad hatters illness. I also love books about womens history during the biblical era have you read the red tent? Great read


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Hi, I'm Jillianne.

I'm a historical fiction writer, a lover of history, and a hoarder of books. I'm the author of The Spirited Mrs. Pringle, The Hobby Shop on Barnaby Street, and The Lazy Historian's Guide to the Wives of Henry VIII.

The Lazy Historian is a history blog featuring stories from the past with sass. With a focus on Western European and women's history, I delve into anything fascinating. Learn more.