Dr's Casebook: Dr William Harvey and his discovery of how blood circulates the body

I visited Edgehill in Warwickshire the other day. This was the site of the first major battle of the English Civil War. This period of history has always intrigued me. As a doctor I am also fascinated by the history of medicine. At Edgehill these two interests merged, since Doctor William Harvey the discoverer of the circulation of the blood was present at the battle.

Circa 1625, English doctor who discovered the circulation of blood, William Harvey (1857 - 1657) (Photo by Hulton Archive/Getty Images)

Dr Keith Souter writes: Harvey was not a combatant, but King Charles I tasked him with looking after his two young sons, Charles and James. Respectively they would become Kings Charles II and James II. Clearly, Doctor Harvey performed the task well.

William Harvey (1578–1657) was a physician and anatomist who was court physician to three kings of England. After graduating from Cambridge University, he went to study medicine and anatomy at the University of Padua.

At that time the current theory was that blood was manufactured by the heart and used up in the liver. He did not think this was logical. Simple arithmetic showed that a huge amount of blood would have to be produced and used up in a short period of time.

After extensive experimentation on animals, he came to the conclusion that there was a constant amount of blood and that it was in continual circulation, pumped by the heart through the blood vessels.

Harvey published his work in 1628. It was the most significant piece of medical research ever written and laid the foundation for the scientific study of medicine. He proposed that blood flowed through the heart in two separate loops, a pulmonary circulation going to the lungs and another, the system circulation, going to the organs and extremities.

Harvey’s work in Padua helped him to understand the function of the valves in veins. They only work in one direction, so Harvey concluded that they were designed to allow blood to flow towards the heart, but not in the other direction. This suggested that the blood flowed around the body and that the two circulations were in some way linked.

At Edgehill Doctor Harvey had a narrow escape. He was almost struck by a bullet. Had he been killed his great discoveries about the circulation of the blood would not have been made.