Abraham Lincoln, the man who steered the United States through bloody civil war, was renowned for his composure under pressure. But the man widely regarded as his country's greatest president almost missed his place in history, afflicted with bizarre explosive fits of rage, whose cause has remained a mystery.
Scientists announced yesterday that they had finally found an explanation. They blamed the outbursts – from which Lincoln suffered in the years before he became president – to mercury poisoning from 19th century anti-depressants which contained 9,000 times the current safe limit for exposure to the metal.
In one incident when Lincoln was running for the US Senate in 1858, he caught hold of Orlando Ficklin, a political colleague, and shook him "until his teeth chattered".
Lincoln became so angry that his whole frame trembled and he only let go, when a bystander, who "feared that he would shake Ficklin's head off", broke his grip.
In 1861, a few months after his inauguration as the 16th President of the United States, Lincoln stopped taking the "blue mass" tablets doctors had given him because they made him cross, and subsequently developed the calm manner for which he became noted.
A study published in the journal, Perspectives in Biology and Medicine, said that if the toxic effects of the mercury had not been reversed, Lincoln might not have shown such leadership when civil war tore the country apart from 1861 to 1865. Dr Norbert Hirschhorn, a medical historian and co- author of the report, said Lincoln was wise enough to stop taking the medicine at a crucial time in US history.
"The wartime Lincoln is remembered for his self control in the face of provocation, his composure in the face of adversity," he said.
"If Lincoln hadn't recognised that the little blue pill he took made him cross and stopped the medication, his steady hand at the helm through the Civil War might have been considerably less steady."
Using a 19th century recipe, the scientists recreated the blue tablets which were commonly prescribed for depression, and found they contained enough mercury to kill.
"We wondered how a man could be described as having the patience of a saint in his 50s when only a few years earlier he was subject to outbursts of rage and bizarre behaviour, said Dr Hirschhorn.
He is now studying the effects of mercury on Charlotte Bronte, Robert Burns and Isaac Newton.Reuse content