William Harvey and the Discovery of the Circulation of the Blood
2019; Lippincott Williams & Wilkins; Volume: 124; Issue: 10 Linguagem: Inglês
10.1161/circresaha.119.314978
ISSN1524-4571
Autores Tópico(s)Health, Environment, Cognitive Aging
ResumoHomeCirculation ResearchVol. 124, No. 10William Harvey and the Discovery of the Circulation of the Blood Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBWilliam Harvey and the Discovery of the Circulation of the BloodPart III Roberto Bolli Roberto BolliRoberto Bolli Correspondence to Roberto Bolli, MD, Institute of Molecular Cardiology, University of Louisville, KY 40292. Email E-mail Address: [email protected] From the Institute of Molecular Cardiology, University of Louisville, KY. Originally published9 May 2019https://doi.org/10.1161/CIRCRESAHA.119.314978Circulation Research. 2019;124:1428–1429These 3 articles on William Harvey (which are published in 3 consecutive issues of the journal) are an edited version of 3 President's Letters that I wrote about 10 years ago for Heart News and Views, the news bulletin of the International Society for Heart Research (the source articles can be found in volume 17, numbers 1, 2, and 3, 2009–2010 of the newsletter). Three books have been used to provide specific information and quotes: Doctors: The Biography of Medicine, by Sherwin B. Nuland and Alfred A. Knopf, New York 1988; The Personality of William Harvey, by Geoffrey Keynes, Cambridge University Press, 1949; and Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus by William Harvey, translated by Chauncey D. Leake and Charles C. Thomas, Springfield, IL, 1970.Herewith is the third part of my account of William Harvey's life and work.Part IIIIn the final part of his book, De Motu Cordis, Harvey addressed how blood flows from the right to the left side of the heart. He was not the first one to describe the pulmonary circulation. At least 2 scholars described this before him. One was a Syrian physician, Ibn al-Nafis, who lived in the 13th century and correctly described the circulation of blood from the right ventricle to the lungs and then back to the left ventricle. However, since his writings were never translated into Western languages, these concepts were unknown to the Western world. The second person who described the pulmonary circulation was Michael Servetus, who did it about a century before Harvey. He published these ideas in a religious book, not a scientific book, which is one of the reasons they were unknown at Harvey's time. The second reason they were unknown was that Servetus was accused of heresy by John Calvin and burned alive in Geneva. Many of his books were burnt with him and disappeared. Long after their death, Harvey rediscovered what Ibn al-Nafis and Michael Servetus had discovered. He showed clearly that there are no such things as pores in the ventricular septum (as Galen had asserted) and that blood flows from the right ventricle to the lungs, and then back to the left ventricle.The only thing that was missing to complete the loop (no pun intended) was the answer to the question: how does the blood go from the arteries to the veins? Harvey struggled with this gap but could not fill it, since he did not have the tools to address the question. So, he postulated the existence of pores in tissues, but it was not until 1660 (3 years after Harvey's death) that Marcello Malpighi, using the microscope—which was not available at the time of Harvey—discovered the existence of capillaries in tissues.In De Motu Cordis, Harvey summarized his new paradigm thus: "For a long time, I turned over in my mind such questions as, 'How much blood is transmitted and how short a time does its passage take?' Not deeming it possible for the digested food mass to furnish such an abundance of blood … unless it somehow got back to the veins from the arteries and returned to the right ventricle of the heart, I began to think whether there might not be a movement, as it were, in a circle. Now this I afterwards found to be true; and I finally saw that the blood, forced by the action of the left ventricle into the arteries, was distributed to the body at large, and its several parts, in the same manner as it is sent through the lungs, impelled by the right ventricle into the pulmonary artery, and that it then passed through the veins and along the vena cava, and so round to the left ventricle in the manner already indicated."These ideas were a revolution in medicine, for they directly contradicted 1500 years of Galenism. As is usually the case when an entrenched paradigm is challenged, they set off a storm in medical and philosophical circles. Harvey was attacked viciously. For example, the University of Paris opposed his ideas for at least 50 years after De Motu Cordis was published. Apparently, his medical practice also suffered from the publication of De Motu Cordis. Harvey himself was trepidant because he wrote: "It is of a so novel and unheard-of character, that I not only fear injury to myself from the envy of a few, but I tremble lest I have mankind at large for my enemies, so much does want and custom, that has become as another nature, and doctrine once sown and that has struck deep root and rested from antiquity, influence all men." Interestingly, he did not hold the media in high regard, lamenting a problem that was a harbinger of much worse things to come. He wrote: "The crowd of foolish scribblers is scarcely less than the swarms of flies in the height of summer and threatens with their crude and flimsy productions to stifle us as with smoke." Things have not changed much, for today almost everything that is reported by the media is grossly distorted, crassly inaccurate, maliciously fabricated, or blatantly false.What is William Harvey's legacy? I believe it is 2-fold. Of course, he discovered the circulation of the blood. This was a turning point for medicine because it enabled us to understand the human body in a manner that was impossible before. But this is not his major contribution. I think his major contribution has been the establishment of the scientific method in biomedical research. Much has been said about Francis Bacon being the inventor of the scientific method in biology. Bacon established experimentation as the principal means for biological research, an approach that we refer to as inductive reasoning or experimental method, as opposed to believing blindly what Aristotle, Galen, and others had said, or following one's personal ideas or preconceptions. Harvey must be regarded as one of the founders of modern science because he was the first to adopt the scientific method for the solution of biological problems and to study biology in a quantitative manner. This was an enormous paradigm shift, a paradigm that every scientist has followed since then and that has become the foundation of modern biology. Harvey was to physiology what Vesalius was to anatomy. Vesalius had debunked Galenic anatomy with his Fabrica. Harvey did the same thing in physiology with De Motu Cordis. Thanks to these 2 Galen "bashers," medicine awoke from a long sleep and shook off the shackles of ignorance and authority. And what a long sleep it was—from the 2nd century AD until the 17th century.In De Generatione Animalium, Harvey writes: "Nature herself must be our advisor; the path she chalks must be our walk. For as long as we confer with our own eyes, and make our ascent from lesser things to higher, we shall be at length received into her closet-secrets." So, we must always rely on our own observations and our own reason, making small but solid steps from "lesser things" to "higher things"; if we do so, we will gradually begin to unravel the mysteries of nature.I want to close this essay by citing some marvelous and eternally inspiring words written by Harvey in the preface to De Motu Cordis: "True philosophers ("philosophers," at Harvey's time, was a term for "scientists"), who are only eager for truth and knowledge, never regard themselves as already so thoroughly informed, but they welcome further information from whomsoever and from whencesoever it may come; nor are they so narrow-minded as to imagine any of the arts or sciences transmitted to us by the ancients in such a state of forwardness or completeness that nothing is left for the ingenuity and industry of others; very many, on the contrary, maintain that all we know is still infinitely less than all that still remains unknown; nor do philosophers pin their faith to others' precepts in such wise that they lose their liberty and cease to give credence to the conclusions of their proper senses." The clause that I italicized is one of the most important statements I have ever seen. Everybody should keep it in mind, particularly those modern scientists who arrogantly think that they know—and can explain—everything or almost everything. Yes, as I pointed out in my Manifesto,1 we must never forget that all we know is infinitely less than all that remains unknown, a concept reminiscent of Socrates, who used to say: "I am wise because I know that I do not know."This is Harvey's immortal legacy, as precious and relevant now as it was 400 years ago. He advises us to be critical, to be skeptical, to challenge what we are taught, to rely on our observations, and to follow our reason. Above all, he tells us that a true scientist knows how limited our understanding of nature is. Our minds can grasp only small fragments of reality. And the experience of scientific inquiry teaches us that the process of answering a question inevitably creates even more questions; this has not changed in the 400 years since Harvey and will not change in the future. For all the progress we have made, a true scientist today must have the humility to always keep in mind that "all we know is still infinitely less than all that still remains unknown."Download figureDownload PowerPointFigure. Robert Hannah's portrait of William Harvey demonstrating a deer's heart to Charles I. The original is at the Royal College of Physicians, London. Photograph: Getty Images/Universal History Archive.DisclosuresNone.FootnotesThe opinions expressed in this article are not necessarily those of the editors or of the American Heart Association.Correspondence to Roberto Bolli, MD, Institute of Molecular Cardiology, University of Louisville, KY 40292. Email [email protected]eduReferences1. Bolli R. The New CirculationResearch: a manifesto.Circ Res. 2010; 106:216–226.LinkGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetailsCited By Craig D, James A, Wang Y, Tavian M, Crisan M and Péault B (2022) Blood Vessel Resident Human Stem Cells in Health and Disease, Stem Cells Translational Medicine, 10.1093/stcltm/szab001, 11:1, (35-43), Online publication date: 3-Mar-2022. Chen T and Maslow A (2021) Right Ventricular Diastolic Dysfunction: "The Missing Link", Journal of Cardiothoracic and Vascular Anesthesia, 10.1053/j.jvca.2020.10.052, 35:3, (807-810), Online publication date: 1-Mar-2021. Luo X, Liu J, Chen H, Li B, Jin Z, Zhao M, Xie Y, Yu C, Zhou X, Zhao B and Yan H (2020) The feasibility and survival mechanism of a large free flap supported by a novel hybrid perfusion mode, Oral Oncology, 10.1016/j.oraloncology.2019.104506, 101, (104506), Online publication date: 1-Feb-2020. May 10, 2019Vol 124, Issue 10 Advertisement Article InformationMetrics © 2019 American Heart Association, Inc.https://doi.org/10.1161/CIRCRESAHA.119.314978PMID: 31071006 Originally publishedMay 9, 2019 Keywordspersonalityinventorscirculationbiomedical researchbiologyPDF download Advertisement SubjectsBasic Science ResearchHemodynamicsPathophysiology
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