The circulation of blood from the heart through arteries and back through veins may seem trivial and obvious now, but William Harvey’s discovery during the 17th century was remarkable because it was at odds with the accepted view of anatomy.
The circulation of blood from the heart through arteries and back through veins may seem trivial and obvious now, but William Harvey’s discovery during the 17th century was remarkable because it was at odds with the accepted view of anatomy.
It was a major milestone on the long road to understanding the human body.
After graduating from Cambridge University, Harvey (1578–1657) studied medicine at the University of Padua, Italy, one of Europe’s best medical schools at the time.
He returned to England to be a doctor and became fascinated by the function of the blood and the way it moves through the body.
He worked out that the heart pumps more blood every half hour than all the blood the body contains. This could only be explained by blood circulating.
What Harvey could not work out was how blood made its way from the ends of the arteries to the beginning of the veins, the start of its journey back to the heart.
The arteries just keep on dividing, getting smaller and apparently disappearing into flesh.
This makes Harvey’s continued conviction about the idea of circulation even more amazing.
At the time, understanding of anatomy was rapidly advancing.
The Flemish anatomist Andreas Vesalius (1514–1564) had stepped up the pace almost a century earlier.
Also a graduate of Padua University, he had begun a revolution in thinking about the human body with his book De Humani Corporis Fabrica (On the Fabric of the Human Body) in 1543.
At the time European ideas about the body were dominated by the teachings of an ancient Greek physician called Galen, full name Claudius Galenus (129–200).
He made major contributions to the science of anatomy and was revolutionary in his own day.
As a physician, he attempted brain surgery, removed cataracts and promoted the patient-centred approach of Hippocrates (c.460–377 BC).
Galen discovered the basic functions of many systems within the body, including the kidney and the nervous system.
But many of his ideas were mistaken, partly because he carried out his research on pigs, apes and goats.
Galen thought blood ebbed and flowed like ocean tides – out and back through the same blood vessels. When the blood returned to the heart, it rid itself of impurities.
The pioneering work of Vesalius and Harvey encouraged fellow anatomists to re-evaluate the function of other human organs.
The introduction of the microscope in the 1620s gave access to the body at a new and daunting level of detail.
One of the pioneers of microscopic anatomy was Italian Marcello Malpighi (1628–1694), who discovered the existence of capillaries, the tiny blood vessels that complete the circuit between arteries and veins.
Sadly for Harvey, the discovery came four years after his own heart stopped pumping.
