The Motion Of The Heart

WILLIAM HARVEY’S RADICAL THEORY OF CIRCULATION

- Maria Parrott-Ryan

Today, it’s no secret that the heart pumps blood in a circle throughout the body. It’s called the circulatory system, after all. But several hundred years ago, this wasn’t common knowledge. Even doctors didn’t know!

William Harvey helped change that. He was one of the few physicians in the 1600s who was willing to question old ideas about the human body. His search for answers exposed a truth hidden inside every human who ever lived.by Maria Parrott-Ryan

◉ Reasonable Doubt

In the early 1600s, almost everything experts thought they knew about the human body was based on theories that were over a thousand years old. Many of these theories came from one man who lived in the Roman Empire—a physician named Galen.

Unfortunately, many of Galen’s theories were way off. This isn’t surprising when you consider that, during Galen’s time, there were no tools for looking inside a living human body, like ultrasounds or x-rays. Also during his time, it was illegal to dissect a human corpse. Galen based his theories mainly on dissections of dead animals and lots of philosophical (not scientific) thinking. When William Harvey began studying medicine nearly 1,400 years later, Galen was still considered the world’s foremost medical authority.

As a physician and anatomist, Harvey performed many dissections of the human body (which were no longer illegal). What he saw during those dissections made him doubt some of Galen’s theories.

Harvey set up a lab in his home and began conducting experiments to test his theories. In the 1600s, this was odd. Most physicians dismissed any theory that didn’t come from the ancient authorities. But Harvey knew that to discover the truth, he had to do his own thinking and experimenting.

◉ A Criminal’s Heart