Rush University, Chicago, Illinois, United States (Spring 2013)
|William Harvey (1578-1657)|
The impression that William Harvey (1578-1657) discovered the closed circulation of the blood is not entirely accurate, although after Harvey there was never any doubt about it. Regardless of what credit you ascribe to him, it is clear that his research benefited from more than two thousand years of observations about the circulatory system. As early as the 3rd century BC, Erastistratus, possibly the first experimental physiologist, described the heart as a pump and expressed a theory of the circulation of blood. Other predecessors who theorized about the circulation of blood included Ibn an-Nafis of Egypt and Syria in the 13th century, and in the 16th century, both the Spaniard Michael Servetus and the Italian Realdus Colombus. In the late 16th century, Andrea Cesalpino (1524-1603) described the pulmonary circulation, but not the systemic circulation.
Despite these earlier attempts to explain the circulation of the blood, Galen’s concept of the vascular system had prevailed for fourteen centuries. Galen believed that air passed from the lung into the pulmonary vein and into the left side of the heart (which was a reasonable assumption), but that waste gasses were passed back through the pulmonary vein to the lung to be expired. He also described blood as passing from the right to the left side of the heart through invisible pores in the interventricular septum. In the left ventricle, a vital spirit was postulated to have been formed from the mixture of blood and air and passed through the systemic arterial system into the rest of the body. The mitral valve would have prevented the vital spirit from passing back into the pulmonary vein and into the lungs with the waste air. The atria were supposed to be dilatations of large veins. Some blood from the systemic venous system passed through the right side of the heart, moved through the pulmonary artery to the pulmonary vein through fine openings.
It was Harvey, however, who, after many dissections of animals and human corpses, correctly described the mechanism of the heartbeat and the effects of lung motion:
When the right ventricle is contracting and expelling during systole its content of blood, the artery-like vein is pulsating and being dilated synchronously with the other arteries of the body …by the inthrust [of the right ventricle] the vessels and porosities of the lungs must be distended.
Blood moved through the pulmonary vascular system in one direction into the left side on the heart, from which:
Blood was forced out of the heart and driven by the beating of the left ventricle through the arteries into the body at its several parts …and that it returns through the veins into the vena cava and so to the right ventricle.
This sort of insight, of course, does not occur in a vacuum. Harvey was fortunate to live in a country where Elizabeth I had laid the groundwork for intellectual freedom through the Religious Settlement in the Acts of Supremacy and Uniformity. Michael Servetus, the Spaniard who was previously mentioned, was burnt at the stake, not by the Catholic Inquisition, but by the Protestants in Geneva for heresy!
An examination of his background and education shows that Harvey was a remarkable man who made the most of his times. He was a student at Caius College, Cambridge, from which he obtained a BA in 1597. He chose Padua for his medical training, the medical school of the great anatomist Vesalius. The anatomist Hieronymus Fabricius, who had succeeded Vesalius at the school, was a strong influence on Harvey in initiating his anatomic studies. Fabricius studied the valves of the veins, but Harvey understood that Fabricius falsely thought that these valves prevented overdistention of vessels and that there were no valves in the arteries because of the Galenic theory of ebb and flow of blood in the arteries. Harvey, through his studies, indicated that the function of the venous valves was to prevent reflux, assisting circulation of the blood.
In 1602, when he graduated in medicine at Padua, he was commended in his diploma as follows:
He had conducted himself so wonderfully well in the examination, and had shown such skill, memory, and learning that he had far surpassed even the great hopes which his examiners had formed of him.
After graduation, he also received an MD degree from Cambridge. Settling in London, he married the daughter of a physician to Queen Elizabeth and James I, which did not hurt his career. Within a few years, after becoming a member of the Royal College of Physicians, he was appointed to a position of honor as Lumleian lecturer, a position he held until one year before his death. Manuscripts of his lecture notes on anatomy and surgery are kept in the British Museum. Some of his notes follow:
It is plain from the structure of the heart that the passage of blood is from the arteries to the veins…It is shown by the application of a ligature that the passage of blood is from the arteries into the veins…Whence it follows that the movement of the blood is constantly in a circle, and is brought about by the beat of the heart.
|Image of veins from William Harvey’s De Motu Cordis|
His classic work, De Motu Cordis (Of the Motion of the Heart and Blood in Animals), published in 1628, was initially attacked by many of the conservative physicians of the time who still subscribed to Galen’s theories. Nonetheless, his contributions were recognized by many and he reaped the rewards. He held important offices in the Royal College of Physicians. It is also interesting to note that in the year that De Motu Cordis was published, Marcello Malpighi was born. It was Malpighi who eventually demonstrated the presence of capillaries though his microscopic anatomy studies. The circuit of the circulation was thus completed.
Two events of Harvey’s biography are particularly interesting. In 1634, Lancashire had an epidemic of witchcraft accusations provoked by a child’s testimony. Harvey was called upon to examine these so called “‘witches,” presumably to determine whether there was some supernatural quality about them. Because of his testimony, four of the seven women were spared. Once he was also ordered by Charles I to examine the body of a Thomas Parr, who presumably was 152 years of age when he died. Harvey concluded from the examination that he probably would have lived longer had he not altered his diet once he moved from his native Shropshire to London.
Harvey was close to James I and served as the personal physician to Charles I. Since Harvey was physician to two kings, he had the experience of taking on some other notable patients, one of whom was Francis Bacon. Bacon’s genius as a statesman, philosopher and scientist did not impress him though. He indicated that one of Bacon’s works on philosophy was written as if he was the Lord Chancellor. He also had the good fortune not to be persecuted with the deposition of Charles I, although many of his writings were destroyed in the civil war that followed in 1642. Early in the war, he was suspected of being a loyalist to the king, which he was, and a mob entered his home and scattered his papers, which were records of dissections and notes on comparative anatomy.
In 1645, several years after his home was attacked, he was made the warden of an Oxford College; he held the post for only one year, relinquishing it as a consequence of the continuing civil war. Eventually, in 1654, he had the honor of being chosen as President of the College of Physicians, an honor he did not accept because he was suffering from gout and other infirmities. He died in 1657 at age 79 of a cerebral hemorrhage.
In his 1967 Harveian oration Lord Platt related how even during his lifetime William Harvey was recognized as a great man, but not necessarily as someone one would want to be treating you. He was not practical, thought his contemporaries; his prescriptions were not worth threepence; and he was “too much governed by his phantasy … To have a Physician abound in phantasie is a perilous thing”.4
It is not entirely clear what the public expected from their physicians in 1650, at a time when therapeutic options were largely confined to bleeding, cupping, purging, clysters, and inducing vomiting. But what worried Lord Platt in 1967 was that too many bright young medical minds were being drawn into academic departments and working on esoteric projects rather than addressing the pressing problems confounding humanity. He argued that these academic departments, though staffed by the descendants of Harvey and Claude Bernard rather than of Sydenham and Osler, had made few contributions to medicine and that most of the great advances of his century had come from the laboratories of the pharmaceutical industry or from non-clinical scientists. Particularly incensed at what he called the hideous practice of referring to patients as clinical material for teaching and research, he was not impressed by modern investigators’ ability to “measure the blood flow to the liver in a patient with mitral stenosis who is being exercised on a bicycle ergometer.” Though admitting that his views might be viewed regarded as somewhat controversial and heretical, he stressed that the aims of the scientist and those of the physician are different: the object of the true scientist is discovery, that of the doctor to pursue the best approach for the individual patient. Being both, scientist and clinician was possible, but to many it did not come easily.
As we move half a century forward we find that many of Lord Platt’s fears have not been realized, and that indeed the pendulum seems to have swung in the opposite direction. No longer are young graduates beating down the doors of academia; bench research in many university departments has acquired a bad name; and research is now expected to be relevant and translational, even though in practice all too frequently concerned with” the trivial that you relevant and the obvious”5 —such as outcome studies designed to tell us what everybody knows. But on an optimistic note we join Lord Platt in concluding that perhaps “these defects may only be part of a temporary chapter in the history of medicine and, and a symptom of a more widespread ailment.4 ”
1. Willius FA, Keys TE. Classics of Cardiology. Volume I. William Harvey pp. 13-17. New York. Dovver Publications Inc. 1941.
2. Cournand A. Air and Blood pp. 3-70 in Circulation of the Blood. Men and Ideas. American Physiologic Society, Baltimore MD 1982.
3. Hamilton WF, Richards DW. The output of the heart. PP. 71-126, ibid.
4. Lord Platt: MedicalScience: Master or Servant? BMJ 1967; 2:439.
5. Editorial: Cui Bono ? BMJ 1967; 2433.
PHILIP R. LIEBSON, MD, graduated from Columbia University and the State University of New York Downstate Medical Center. He received his cardiology training at Bellevue Hospital, New York and the New York Hospital Cornell Medical Center, where he also served as faculty for several years. A professor of medicine and preventive medicine, he has been on the faculty of Rush Medical College and Rush University Medical Center since 1972 and holds the McMullan-Eybel Chair of Excellence in Clinical Cardiology.