When Abraham Lincoln led the nation during the Civil War, he appeared composed and dignified. That's a far cry from the Lincoln of earlier years--when he was prone to mood swings, outbursts of rage, insomnia, and forgetfulness. Researchers now theorize that Lincoln for years was being poisoned by mercury-laden pills he was taking for depression.
Norbert Hirschhorn, a retired physician and medical historian in New York City, says his interest was piqued when he read a 1993 Gore Vidal essay that quoted Lincoln's law partner as saying Lincoln "ate blue mass." "That tickled something from my medical school training," he says. Blue mass was a drug commonly prescribed to treat "hypochondriasis," a vague term that included melancholia. It contained mercury that was believed to benefit the liver by countering the buildup of "black bile." Hirschhorn says Lincoln may have started taking the pills as early as 1841, at the age of 32, when he became deeply depressed after he and Mary Todd broke off their engagement.
To see just how toxic blue mass was, Hirschhorn and colleagues recreated the pills from a 19th century recipe calling for mercury, liquorice root, rose water, honey, sugar, and dead rose petals. They compounded the ingredients with an old-fashioned mortar and pestle and rolled the pills on a 19th century pill tile. As they report in the summer issue of Perspectives in Biology and Medicine, at a dosage of two to three pills a day, Lincoln would have taken in about 9000 times more mercury than the Environmental Protection Agency deems safe.
Lincoln reportedly stopped taking the pills 5 months into his presidency because he said they "made him cross." Mercury poisoning is reversible, and his odd behavior disappeared, which probably altered the course of history, Hirschhorn says. But there's no way to verify that Lincoln had mercury poisoning, he says, because there are no hair samples from the years he was taking the pills.
"What this may mean to an evaluation of Lincoln's achievements is mind-boggling," says Lincoln historian Robert Johannsen at the University of Illinois, Urbana-Champaign. From now on, "no study of Lincoln that does not take his mercury poisoning into account can be complete."