Carroting, you must understand, was a process by which animal fur is bathed in a solution of mercury nitrate, in order to render the hairs more supple, thus producing a superior felt." At this last word, he threw a significant glance in my direction. "Felt," I repeated. "You mean, for the making of hats?" "Precisely. The solution is of an orange colour, hence the term carroting. However, this process had rather severe side effects on those who worked with it, which is why its use today is much reduced. When mercury vapours are inhaled over a long enough period of time-particularly, for our purposes, in the close quarters of a hat-making operation-toxic and irreversible effects almost inevitably follow. One develops tremors of the hands; blackened teeth; slurred speech. In severe cases, dementia or outright insanity can occur. Hence the term mad as a hatter.
( Douglas Preston )
[ White Fire ]
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