London, 1860. This is Sarah. She’s twenty-one years old. And she can’t stop shaking. Sarah is a fur puller. She works in a hat factory, preparing fur for felt hats—top hats for wealthy gentlemen. The process is called “carroting”: ∙ Take rabbit pelts ∙ Brush them with mercury nitrate solution ∙ The mercury makes the fur separate from skin easily ∙ It also turns the fur orange—like carrots ∙ That’s where the name comes from Sarah’s job is pulling the treated fur from the pelts. Her hands are in mercury solution for ten hours a day. She breathes the mercury vapor constantly. The room has no ventilation. Mercury is poison. It attacks the nervous system. After six months: Sarah noticed her hands shaking. Just a slight tremor. Then it got worse. After a year: The personality changes started. She’d fly into rages over nothing. Cry uncontrollably. Her coworkers started avoiding her. “Mad as a hatter”—that’s what they called workers like Sarah. After eighteen months: Her teeth started fal...