The middle of Abraham Lincoln’s shoe wore out faster than the heel or toe.
Most people would not find this fact of great interest, but to medical historians, it represents a clue.
Three researchers published an article, Abraham Lincoln’s Blue Pills: Did Our 16th President Suffer From Mercury Poisoning? Tuesday in “Perspectives in Biology and Medicine.” The article builds a case that the pills Lincoln took for depression gave him mercury poisoning until he stopped taking them a few months after his inauguration in 1861.
The idea for the investigation came after medical historian Norbert Hirschhorn, who was then a visiting University professor, read an essay about Lincoln by Gore Vidal. The essay mentioned Lincoln taking a substance called “blue mass,” a common medication made with mercury.
Hirschhorn became curious about possible mercury poisoning and asked School of Public Health Dean Ian Greaves about typical mercury poisoning symptoms.
The two agreed Lincoln might have had mercury poisoning and enlisted the help of Robert Fledman, a professor of neurology at Boston University, to study the neurological effects of mercury.
The researchers used small facts about Lincoln’s life to help with their diagnosis. They found old pharmacy records, analyzed Lincoln’s handwriting for evidence of tremors and read accounts of Lincoln’s behavior written by close friends, such as the unusual wear on his shoes.
The way Lincoln wore out his shoes demonstrates the way he walked: flat-footed. This stride is typical of people who are unsure of their footing, which can be a symptom of nerve damage from heavy metal poisoning, according to the paper.
Some Lincoln scholars disagree with the diagnosis, but Greaves said while it is only right to be skeptical about new information, the evidence suggests Lincoln suffered from mercury poisoning.
Lincoln’s symptoms included erratic behavior, outbursts of rage, insomnia, forgetfulness and hand tremors – all typical signs of mercury poisoning, according to the paper.
University pharmacy professor Cheryl Zimmerman contributed to the paper and re-created the pills to determine the exact amount of mercury used.
Making the pills was both “interesting and challenging,” Zimmerman said. The formula called for ingredients such as “confection of rose,” making it necessary to consult old books to find modern equivalents of the ingredients. “Confection of rose” turned out to be dead rose petals. Zimmerman used precautions to avoid contact with the mercury.
The re-created pills showed the amount of mercury in each pill was 9,000 times greater than the allowable amount to avoid poisoning.
Greaves said the study of Lincoln’s poisoning offers an “interesting message for the past and present.”
Lincoln’s medical treatment was appropriate for the time, Greaves said, and speaks to a question all doctors ask themselves: “Do I give medicine to improve health knowing about the side effects?”
Greaves added that he finds parallels with some treatments given today, such as chemotherapy.
“Sometimes the treatment can be more harmful than the cure,” Greaves said. This might be true in Lincoln’s case since his behavior changed after he stopped taking the pills because he believed they were causing him to behave strangely.
It was fortunate Lincoln stopped taking the pills before the Civil War, Greaves said, because the long term effects of mercury poisoning include permanent nerve damage, paralysis, dementia and the onset of a coma.
Lincoln’s behavior during the war shows he probably had no residual effects of mercury poisoning after he stopped taking the blue pills, said Greaves.
The evidence suggesting Lincoln had mercury poisoning in no way diminishes his status as an icon, Greaves said. Instead, it adds more dimension to his personal difficulties and makes his achievements more impressive, he added.
Liz Kohman covers the Academic Health Center. She welcomes comments at [email protected]