William Harvey (1578-1657)

William Harvey was a medical doctor who first correctly described in exact detail the circulatory system of blood being pumped around the body by the heart. This developed the ideas of Rene Descartes who in his Description of the Human Body said that the arteries and veins were pipes and carried nourishment round the body. Many believe he discovered and extended early Muslim medicine especially the work of Ibn Nafis, who had laid out the principles and major arteries and veins in the 13th century.

Harvey also noted, as earlier anatomists, that fetal circulation short circuits the lungs. He demonstrated that this is because the lungs were collapsed and inactive. Harvey could not explain, however, how blood passed from the arterial to the venous system. The discovery of the connective capillaries would have to await the development of the microscope and the work of Malpighi. He was heavily influenced by the mechanical philosophy in his investigations of the flow of blood through the body. In fact, he used a mechanical analogy with hydraulics. He could not, however, explain why the heart beats. Furthermore, Harvey used quantitative methods to measure the capacity of the ventricles.

Harvey, oldest of seven children, was born in 1578 in Kent, England, at the halfway point of the reign of Queen Elizabeth I. He was a voracious student, earning his bachelor's degree in 1597 from Cambridge University. He continued his schooling at the University of Padua, the foremost medical school of the time, where he studied under the esteemed scientist and surgeon, Hieronymus Fabricius. Fabricius, an ardent anatomist, had observed the one-way valves in veins, but had not figured out exactly what their role was. The popular belief of the day held that blood was circulated by a sort of pulsing action of the arteries.

Harvey returned to England in 1602 and married Elizabeth Browne, who was the daughter of one of the Queen's physicians. Harvey himself obtained a fellowship at the Royal College of Physicians. In 1618 he was appointed as a physician to the court of James I.

His research into the circulatory system and his other lines of inquiry were generously sponsored and encouraged by James I's successor, King Charles I, to whom Harvey was later appointed personal physician. By studying animals given to him by his regal employer, Harvey eventually developed an accurate theory of how the heart and circulatory system operated. He published his theories in 1628 in his famous book "On the Motion of the Heart and Blood in Animals," which made him notorious throughout Europe.

But William Harvey was not satisfied with being the foremost anatomist of his day. He was intrigued by everything about the body, and at some point turned his attention to reproduction. He speculated that humans and other mammals must reproduce through the joining of an egg and sperm. No other theory made sense. It was 200 years before a mammalian egg was finally observed, but Harvey's theory was so compelling and so well thought out that the world assumed he was right long before the discovery was finally made.

Harvey remained a physician at St. Bartholomew's until 1643. He maintained his college lectureship until 1656, the year before his death, missing by a moment the dismantling under Cromwell of the monarchy that had supported his research throughout his life.

The major difference between Harvey and his predecessors, was -- methodology. Harvey determined to start out, so to speak, with a blank fact book and distinguished it from his theory book. Nothing would go down in his fact book unless tested and would readily remove it if it did not bear out on a re-test. Harvey went beyond mere superficial observation; and, he took deliberate steps so as not to be hampered by superstition or antiquated theories. Harvey was the first to adopt the scientific method for the solution of biological problems. Every true scientist, since, has followed Harvey's approach.