The Mad Hatter
Many will remember the Mad Hatter from Lewis Carroll’s Alice in Wonderland. The Mad Hatter was based on a real character, or rather many real characters. There is debate over whether Lewis Carroll’s Mad Hatter suffered from mercury poisoning; he was portrayed as an eccentric extrovert who was obsessed with time - not typical features of mercury poisoning. [1] Nevertheless, hatters of the 19th century most certainly were regularly poisoned by this harmful metal. Unsurprisingly, hatters made hats, and during the 19th century felt hats were especially popular. The haters had to brush a mercury-containing solution onto animal fur as part of the hat-making process. The hatters inevitably breathed in the mercury, a problem made worse by the poorly ventilated workshops in which they worked. They developed tremors and twitching (“hatter’s shakes”) as well as slurred speech, irritability, shyness depression, confusion, memory loss and other personality changes - all symptoms of mercury poisoning.
These symptoms became known as ‘Mad Hatter Syndrome’ which was, in effect, one of the early industrial occupational diseases - mercury poisoning. [2]
 
[1]  Waldron HA. Did the Mad Hatter have mercury poisoning? British Medical Journal Clinical Research Ed. 1983; 287(6409): 1961.
[2]  Goldman LR. Shannon MW. American Academy of Pediatrics: Committee on Environmental Health. Technical report: mercury in the environment: implications for pediatricians. Pediatrics 2001; 108(1): 197-205.