centenarian contain the earliest known description of cirrhosis of the liver. Had he published his treatise, he would be considered more important than the Belgian anatomist Andreas Vesalius, whose influential textbook On the Fabric of the Human Body appeared in 1543. But he never did.
Heart of the matter
Yet arguably Leonardo’s most brilliant scientific insights occurred after Marcantonio’s death from the plague in 1511, when the great polymath fled political turmoil in Milan and took shelter in the family villa of his assistant Francesco Melzi, 15 miles (24km) east of the city. It was here that he became obsessed with understanding the structure of the heart.
The heart surgeon Francis Wells, who works at Papworth Hospital in Cambridge and recently published The Heart of Leonardo, recalls coming across Leonardo’s studies for the first time as a medical student. “I remember thinking that they were far better than anything we had in modern textbooks of anatomy,” he says. “They were beautiful, accurate, absorbing – and there was a liveliness to them that you just don’t find in modern anatomical drawings.”
During his investigations, Leonardo discovered several extraordinary things about the heart. “Up until and after his time, because of course he never published, the heart was believed to be a two-chambered structure,” Wells explains. “But Leonardo firmly stated that the heart has four chambers. Moreover, he discovered that the atria or filling chambers contract together while the pumping chambers or ventricles are relaxing, and vice versa.”
In addition, Leonardo observed the heart’s rotational movement. “If you look at a heart, it is cone-shaped,” says Wells. “But it’s a complex cone in a geometric sense, because