When it came to discovering how things worked, William Harvey cut right to the heart of the matter.

Literally.

He could often be found in his operating room, deftly cutting apart a deer, a chicken, a cow and even a cadaver to examine their various organs and systems. It was the best way, he knew, to determine how each part worked with another.

"I profess to learn and teach anatomy not from books but from dissections," he said, "not from the tenets for philosophers, but from the fabric of nature."

Superficial observation, however, wasn't enough for Harvey. He kept two books to log his research: a theory book and a fact book.

In his theory book, Harvey recorded his thoughts and inspirations, waging educated guesses about experiments.

Then he'd test the ideas to avoid relying on superstitions or old theories. Afterward, he carefully logged each experiment in his fact book, often fleshing out his meticulous descriptions with detailed drawings.

He'd later run the test again. If an experiment didn't bear out after a retest, he'd remove it from the fact book.

Harvey's deliberate approach changed the path of science — and history.

His painstaking work established him as the first practitioner of the scientific method, which is the foundation of modern research.

Every scientist since has followed his approach. He became the first to the outline how the human circulatory system works and to launch the science of embryology.

"Here for the first time a great physiological problem was approached from the experimental side by a man with a modern scientific mind, who could weigh evidence and not go beyond it, and who had the sense to let the conclusions emerge naturally but firmly from the observations," said William Osler, a Victorian physician called the father of modern medicine.

Learning Early

Born in Folkestone, England, to a prosperous yeoman, Harvey (1578—1657) showed a scholarly bent as a child. In a time when few people were literate, he studied hard with his tutors and kept copious journals. He became the first in his family to attend college, earning a degree at the University of Cambridge at 20.

Eager to keep learning, Harvey went to the University of Padua in Italy, then considered the best medical school in the world. There he sought medical masters to learn from, and apprenticed himself to renowned anatomist Hieronymous Fabricius. Harvey worked alongside him to glean lessons, then reflected on his experiences at day's end. Fabricius had observed valves in veins and arteries, but neither men knew how they worked. Harvey vowed that one day he'd discover their purpose.

He graduated with honors in 1602, but felt he still had more to learn. He returned to England to earn another medical degree from Cambridge.

After finishing his course work, Harvey married Elizabeth Browne, whose father was Queen Elizabeth's personal physician.

Harvey established a thriving practice. He eventually became a physician to King James I and personal physician to King Charles I, notes William Harrison's "Dr. William Harvey and the Discovery of Circulation." The doctor used any spare time for research.

Harvey tried to be ready for any opportunity. He kept his log books with him to write down observations and ideas. He also carried a dagger in case he had a chance to dissect something.

A determined scholar, Harvey welcomed unpalatable or difficult procedures. He kept working, noting that innovation is never easy.

"When I first gave my mind to vivisections. . . . I found the task so truly arduous, so full of difficulties, that I was almost tempted to think that the motion of the heart was only to be comprehended by God," he wrote in his groundbreaking 1628 book, "An Anatomical Study of the Motion of the Heart and of the Blood in Animals."

Take the way he often examined Viscount Montgomery's son, who had a hole in his chest from a poorly healed childhood wound. The wound was covered by a metal plate, but Harvey removed it to look into the boy's chest and watch his heart beating; others left the room when he performed the procedure.

He often used himself as a research subject as well as others. Harvey tied ropes around his subject's — and his own — upper arm to cut off blood flow. He saw the blood pool and the valves bulge in the upper arm, leaving the lower arm pale and cool. When he loosened the rope, the lower arm became warm and swollen, and the upper arm paled. He tried to push blood down the arm, but it didn't work.

Harvey observed the opposite effect in the neck's veins; blood flowed only down. The valves, he realized, regulated the direction of blood flow. He concluded that the blood circulated through the heart, which acted like a pump.

He relied on facts and figures to prove his theories. He weighed human and animal hearts and counted heartbeats to figure out how much blood was being circulated.

He drained animals of their blood and measured it against the size of the heart to gauge capacity.

In "An Anatomical Study," Harvey explained how the heart pumped blood throughout the body, returned it to the heart and recirculated. He outlined blood flow in two separate closed loops: pulmonary circulation, which linked the circulatory system to the lungs, and systemic circulation, which carried blood to tissue and vital organs.

He determined that contracting ventricles in the heart expelled blood in systolic contractions rather than sucking it in during the relaxation phase, or diastole.

He decried the practice of bloodletting, then thought by doctors as a cure for ailments. All his theories met with disdain, and he lost many patients. Harvey's theory flouted the then-popular notion set forth centuries before by Galen that the liver converted food into blood and then used it as fuel for the body.

" 'Twas believed by the vulgar that he was crack-brained, and all the physicians were against him," wrote an unnamed Elizabethan scholar.

Harvey ignored the criticism, pushing his theories in lecture after lecture, in face-to-face meetings with colleagues and letters.

He also ignored bad publicity, figuring any publicity spread knowledge of his cause.

Not content to be an anatomist, he began studying the development of chicks. By 1651, he'd put his expanded theories about the genesis of mammals in a book, "Essays on the Generation of Animals."

He believed that mammals were created by the joining of sperm and egg, although it would be another 200 years before a human egg would be observed. His work became the basis for modern embryology, notes Susan Wiegand in "Access Excellence," a publication of the U.S. National Health Museum.

Amid The Fighting

Setbacks that might stop others in their tracks didn't intimidate Harvey.

When his research notes were destroyed in London riots during the English Civil War, he simply vowed to re-create his experiments and take new ones.

He focused on the safety of others. During the Battle of Edgehill, he hid the royal children in a hedge and read to them in a whisper to keep them silent to evade enemies.

After the battle, he tended the dying and wounded regardless of what side they fought on.

BY JOANNE VON ALROTH