A disease common among hat makers in the seventeenth century was caused by their direct contact with mercury and this disease was known as mad hatter disease.
The mad hatter diseases were very common in seventeenth century England due to the exposure of hat-makers to mercury vapours which arose from the mercury for felting.
Felting was a process in which the wool was stabilised using mercury and in this process, the hatters got exposed to the toxic mercury vapours leading to several behavioural changes.
