William Harvey

A contemporary of Galileo, Kepler, Bacon, Descartes and Shakespeare, William Harvey is another important figure in the establishment of the scientific method, this time in the field of medicine. His claim to fame is for demonstrating the circulation of the blood and the action of the heart as a pump driving this circulation. Through a series of clever experiments, he furthered the acceptance of experimentation for determining the workings of nature, rather than putting excessive reliance on authority. Most important, his primary achievement was inspired by a statement in the Bible.

Overt indications about Harvey’s personal faith are rare, though he did speak often of design, and felt that science was a godly vocation. Few of his manuscripts survive. Most were looted by rioters in the Civil War of 1642 when Harvey was 64 years old (a severe trial for him), and the extant works reveal little about Harvey the man. One short biography by a contemporary librarian divulges little else; Robert Boyle filled in one important blank. What is clear, however, is that Harvey believed in the divine authorship and authority of the Bible and the deity of Christ, and that the search for purpose in nature resulting from God’s creative wisdom was a strong motivation behind his work. One particular explicit reference to Scripture he made is particularly instructive for our purposes, and will provide the conclusion for this story.

Born in 1578 of “yeoman stock” in a family of Kentish farmers who had succeeded enough to move into commerce, William was eldest of six brothers, all of whom became successful merchants. His father was a man of means who became mayor of the town. From age 10, young William studied in Canterbury, then moved on to Cambridge on a medical scholarship. After graduating from Cambridge in 1597, he went abroad to further his studies in medicine at the best medical school of the day, the University of Padua. Having achieved his degree in Italy, he returned to England in 1602 and gave an impressive performance on his exams before the College of Physicians. A couple of years later he made a fortuitous marriage to Elizabeth Browne, daughter of the king’s physician, but they had no children.

William Harvey practiced medicine in London and in 1607 was elected to the Royal College of Physicians, where he received a lifetime post as a lecturer in 1616. His reputation as a leading physician in England was established and well earned. Around this time, he also was making his views on the circulation of blood known. Shortly thereafter, in 1617, he became the personal physician of King James I (of King James Bible fame), and later to King Charles in 1625, with whom he stayed during the Civil War of 1642-1648 (the Puritan Revolution and short-lived reform government of Oliver Cromwell). With the return of royal government, Harvey, now 69 years old, returned to London in 1647 to live out his days with his brothers. Most of his long career was spent at St. Bartholomew’s hospital in London. Late in life, Harvey was elected president of the Royal College of Physicians but refused the honor. He died in 1657, shortly before the careers of Robert Boyle and Antony van Leeuwenhoek took off.

Harvey’s lecture notes show him to be a witty and independent thinker.  Once he rhymed, “There is a lust in man no charm can tame: Of loudly publishing his neighbor’s shame: On eagles wings immortal scandals fly, while virtuous actions are born and die.”  Though his work on blood circulation is legendary, we should pause to observe that most scientific discoveries are elaborations of previous work.  While it is true that many physicians in Harvey’s time placed undue influence on classical authority, particularly of Galen, not all did; the popular maverick Paracelsus, for instance, declared his intellectual independence by burning the works of Avicenna and Galen.  Many read the classics only to critique them.  Harvey, like most in his time, was a staunch Aristotelian, but not slavishly so.  Furthermore, his experimentalism was heir to a long line of empirical work by his predecessors Vesalius, Fabricius and Colombo.  He was not, in other words, working on questions that had not already been matters of intense study, and he was not the only “discoverer” of blood circulation.  The Egyptian physician Ibn Al-Nafis had made significant headway 300 years earlier explaining pulmonary circulation.  Some of Harvey’s hypotheses later proved false, and his theory was incomplete in itself.   A recent book claims that the widespread story that Harvey predicted the existence of capillaries is a myth.  Nevertheless, his primary work An Anatomical Study of the Motion of the Heart and of the Blood in Animals (1628) was “certainly immeasurably influential on Western medical practice” according to historian Michael Hart, and his Essays on the Generation of Animals (1651) also formed the basis for modern embryology: Ex ova omnia, he wrote: “Everything from an egg.”

Diagram showing some of William Harvey’s experimental methods

Harvey’s clever experimental approach that demonstrated the circulation of blood from one side of the heart to the other, through the lungs and around the body making one big circuit, is well known. (Ironically, this paragon of experimental scientist was not all that impressed with the opinions of Francis Bacon, one of his patients.) Diagrams of Harvey pressing fingers at precise points on veins on the arm to illustrate his ideas are readily available. The details of how Harvey’s theory overcame classical and medieval concepts of the motion of blood, the function of veins and arteries, the action of valves in the veins, and the role of the heart, are all available in the secular literature. Students of history can unravel these details. What concerns us here is William Harvey’s place in the Christian influence on science. Some surviving references provide glimpses into his motivation and beliefs.

In a recollection by Robert Boyle, Harvey, shortly before he died, related to the young chemist the clue to his discovery. Writing 31 years after Harvey’s death, Boyle recalls how he had asked the eminent physician about the things that induced him to consider the circulation of the blood:

He answer’d me, that when he took notice that the Valves in the Veins of so many several Parts of the Body, were so Plac’d that they gave free passage to the Blood Towards the Heart, but oppos’d the passage of the Venal Blood the Contrary way: He was invited to imagine, that so Provident a Cause as Nature had not so Plac’d so many Valves without design; and no Design seem’d more probable than that, since the Blood could not well, because of the interposing Valves, be sent by the Veins to the Limbs; it should be sent through the Arteries, and Return through the Veins, whose Valves did not oppose its course that way.  (Emphasis added.)

Lest this design by “Nature” appear deistic, Emerson Thomas McMullen in Christian History (Issue 76, XXI:4, p. 41) stated that Harvey frequently “praised the workings of God’s sovereignty in creation—which he termed ‘Nature’.” We must not, in other words, read back 18th-century French concepts into 17th-century English terminology. McMullen, a PhD in the history and philosophy of science and a specialist in the life of Harvey, provides quotes that show Harvey’s provident Nature was an active, intelligent, wise, personal agent: Nature destines, ordains, intends, gives gifts, provides, counter-balances, institutes, is careful. Harvey spoke of the “skillful and careful craftsmanship of the valves and fibres and the rest of the fabric of the heart.” According to McMullen, Harvey’s primary achievement, the explanation of the circulation of the blood, was occasioned in part “by asking why God put so many valves in the veins and none in the arteries.” He believed that nature does nothing “in vain” (in Vein, perhaps, but not in Vain).

Red blood cells and other blood components circulate throughout the body in arteries, capillaries, and veins.

William Harvey also viewed natural philosophy as a sacred calling. This recurring theme in this series is clearly evident in a comment he made to a friend, “The examination of the bodies of animals has always been my delight; and I have thought that we might thence not only obtain an insight into the lighter mysteries of Nature, but there perceive a kind of image or reflex of the omnipotent Creator himself.” (McMullen, Ibid.). This glimpse into Harvey’s leitmotif shows him to be acting freely in a worshipful spirit as he undertook his scientific studies, not under compulsion as a naturalist trapped in a predominantly Christian culture. McMullen says that William Harvey was a “lifelong thinker on purpose” in anatomy and physiology, mentioning this throughout his writings in an effort to discern the final causes of things. This was not mere Aristotelianism. “Harvey was a Christian,” McMullen states unequivocally, “who believed that purpose in nature reflected God’s design and intentions.” The appeal of being able to glimpse something of the mind of God, to understand how he had made things work, in the hope of understanding more fully both God and his works, has been a frequent and productive force in the development of modern science.

To what extent Christian saving faith was realized in Harvey’s personal life is hard to say for sure, but McMullen claims Harvey was influenced by the Calvinist environment at Cambridge, and had George Estey, a clergymen and lecturer in Hebrew, as a tutor. A couple of anecdotes reveal his faith was more than cultural or intellectual assent to prevailing opinion. Once he referred to the Apostle John’s account of the crucifixion when discussing the pericardium, hinting at his familiarity with Scripture. On another occasion, when discussing childbirth, he spoke of Mary’s pregnancy. It’s interesting that instead of calling her child simply Jesus, he called him “our Savior Christ, of men most perfect.”

One other Harvey quote is particularly instructive on the relation of the Bible to science. Here is where a Scriptural passage can be cited as both a scientific fact corroborated thousands of years later, and also as a principle acting as a stimulus for scientific discovery. In Leviticus 17:11, Moses wrote, under divine inspiration, that “the life of the flesh is in the blood.” Again in verse 14, God says through Moses, “for it is the life of all flesh. Its blood sustains its life…. for the life of all flesh is its blood” (NKJV). Recall that the Greek doctrine of unbalanced body humors (fluids) as the cause of disease would not be discarded till the time of Pasteur 200 years later; for many more years, physicians would routinely perform blood-letting to try to restore the balance, often hastening death by removing the very life-giving substance God had set in circulation to nourish the entire body. Would that physicians had taken seriously this ancient Biblical insight recovered by Harvey. It was perhaps his most important finding. According to McMullen, Harvey concluded after demonstrating the circulatory system, that “life therefore resides in the blood (as we are informed in our sacred writings).” Harvey also quoted these specific passages from Leviticus when making a point about the beginning of life. There is a lesson for 21st century scientists here. If the Bible truly is the word of the Creator, it should provide clues that can open up new areas of research – even if it was not intended primarily as a science textbook. There could be many more scientific insights waiting to be discovered in its pages. Could the Bible again provide keys to unlock today’s greatest scientific questions? Could it steer us away from disastrous mistakes, like bloodletting? Let a new generation of scientists put the word of God to the test.

In the Bible, the heart is often symbolic of the innermost being of man: the mind and the will. Considering this chapter in the history of science, the counsel of Proverbs 4:23 is vital in both the figurative and literal sense: “Keep thy heart with all diligence,” Solomon wrote under divine inspiration, “for out of it are the issues of life.” Harvey could not have agreed more. The heart, he echoed, “is the household divinity which, discharging its function, nourishes, cherishes, quickens the whole body, and is indeed the foundation of life, the source of all action.”