William Harvey

Hello. My name is William Harvey. I want to tell you the story of how my curiosity about the world led to a discovery that changed medicine forever. I was born on April 1st, 1578, in a little seaside town called Folkestone, England. Even as a boy, I was fascinated by how things worked, especially living things. I loved watching the animals around my town and wondering what was happening inside them.

My curiosity led me to study medicine. First, I went to the University of Cambridge in England. But to learn from the very best, I traveled all the way to Italy in 1599 to study at the famous University of Padua. There, I learned so much about the human body. My teacher, Hieronymus Fabricius, had discovered little flaps, or valves, inside our veins, but he wasn't sure what they did. This puzzle stuck in my mind. I graduated as a doctor in 1602 and returned to London, excited to start helping people and solving mysteries.

Back in London, I became a successful doctor, even for the king. But I couldn't stop thinking about the heart and the blood. At that time, for over 1,400 years, doctors believed the ideas of an ancient physician named Galen. He thought that the body constantly made new blood in the liver and that it was used up like fuel. But this didn't make sense to me. How could the body make so much blood all the time? And what about those little valves in the veins? I knew there had to be a different answer.

To find the truth, I started doing my own experiments. I carefully studied the hearts of many different animals. I observed how the heart squeezed and relaxed, like a pump. I realized the valves in the veins, which my teacher had shown me, made sure the blood only flowed in one direction—toward the heart. I even did a simple math problem. I calculated how much blood the heart pumped in an hour and realized it was far too much for the body to be constantly making. The only explanation was that the same blood must be going around and around in a circle, or a circuit. The heart was the pump that pushed it all around the body.

In 1628, I was ready to share my discovery with the world. I published a book called 'Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus', which is a long Latin name that means 'An Anatomical Study of the Motion of the Heart and of the Blood in Animals'. At first, many people didn't believe me. My idea was so different from what everyone had been taught for centuries. But my careful experiments and clear evidence eventually convinced them.

My discovery of how blood circulates completely changed our understanding of the human body. It became the foundation for all modern medicine and physiology. I lived a long and curious life, and I passed away on June 3rd, 1657. I lived to be 79 years old. Today, when doctors listen to your heartbeat or check your pulse, they are using knowledge that started with my simple questions about how our amazing bodies work.