The Mad Hatter and Fish
by Scott Moeller
You can learn so many lessons from Lewis Carroll’s “Alice’s Adventures in Wonderland:” Things like: “don’t drink from bottles of mystery liquid,” and “call animal-control at the first sign of a floating cat” spring to mind. But, one lesson that is never fully explained is why the Mad Hatter acted so crazy.
It turns out, the phrase “mad as a hatter” goes back a couple hundred years to the time when beaver felt hats were the global fashion craze of the day. Hat-makers, or “Hatters,” used a solution of mercury nitrate in the process of turning beaver fur into the felt they used for making these hats.
It was not fully understood at the time, but inhaling the mercury vapors caused symptoms of uncontrolled muscle movement, drooling, incoherent speech, and impaired mental faculties. Of course, I exhibit any number of these symptoms upon waking every morning -- but they usually go away. The Mad Hatter, on the other hand, had chronic systemic mercury poisoning.
Now, there’s nothing that I find more endearing in a fictional character than heavy-metal-induced psychosis. But, the fact is that mercury is a potent neurotoxin and, in high doses, is nothing to mess around with.
It’s only in recent decades that we have come to take mercury exposure more seriously. My parents tell me that, when they were in their high school science classroom, they were allowed to explore the unique properties of liquid mercury by playing with it in their bare hands. I assume they followed this up with learning mammal biology by wrestling grizzlies, and playing dodgeball in gym using live grenades.
Today, not only have we stopped actively encouraging our children to splash around in pools of liquid mercury, but we have all but eliminated mercury from thermometers, thermostats, batteries and other household items.
But with this newfound caution comes the danger of being overly cautious and reactionary. For example, because they contain mercury, some people still refuse to use those spirally compact fluorescent lightbulbs (CFLs), despite the fact that CFLs result in less mercury in the environment than a standard bulb. Read more about mercury in CFLs.
Similarly, recent reports about mercury in fish have prompted some people to stop eating fish entirely, but they too may be doing themselves more harm than good. Nearly all fish contain some mercury, but fish also contain valuable nutrients and oils found in few other foods. Before deciding how often you should eat fish, it’s important to compare the risks and benefits carefully. MinnAqua Lesson 6:5 - Eating Fish is a nice primer on how to weight the benefits and risks of eating fish, and on how bioaccumulation of chemicals happens in our environment.
There is risk in every facet of life, but you shouldn’t overreact. Driving a car is risky, but do I stop driving because of it? No. Bathing can be risky, but do I wear a snorkel in the bathtub? Almost never.
Eating some delicious fish every now and then will not turn you into the Mad Hatter. You can balance the health benefits and risks of eating fish by following these sensible guidelines found at the Minnesota Department of Health website.
And, if your hobby is making authentic 19th-century-style felt hats in your poorly-ventilated basement… switch to stamp collecting.