Editing William Harvey (section)

== Views of the circulation of blood before Harvey ==
At the time of Harvey's publication, [[Galen]] had been an influential medical authority for several centuries. Galen believed that blood passed between the ventricles by means of invisible pores. According to Galen's views, the venous system was quite separate from the arterial system, except when they came in contact through the unseen pores. Arabic scholar [[Ibn al-Nafis]] had disputed aspects of Galen's views, providing a model that seems to imply a form of [[pulmonary circulation]] in his Commentary on Anatomy in [[Avicenna]]'s Canon (1242). Al-Nafis stated that blood moved from the heart to the lungs, where it mixed with air, and then back to the heart, from which it spread to the rest of the body.<ref>{{cite journal | pmc = 1390327 | pmid=17856795 | volume=104 | year=1936 | journal=Ann. Surg. | pages=1–8 | author=Haddad SI, Khairallah AA | title=A Forgotten Chapter in the History of the Circulation of the Blood | issue=1 | doi=10.1097/00000658-193607000-00001}}</ref> Harvey's discoveries inevitably and historically came into conflict with Galen's teachings and the publication of his treatise ''[[De Motu Cordis]]'' incited considerable controversy within the medical community. Some doctors affirmed they would "rather err with Galen than proclaim the truth with Harvey."<ref>{{cite web |url=http://biology.about.com/library/organs/blcircsystem2.htm |title=William Harvey – Father of Cardiovascular Medicine |author=Regina Bailey |publisher=about.com |access-date=26 September 2010 |archive-date=12 June 2011 |archive-url=https://web.archive.org/web/20110612043835/http://biology.about.com/library/organs/blcircsystem2.htm |url-status=dead }}</ref><ref>{{cite book |title=The Animal's defender and zoophilist, Volume 13 |author=National Anti-Vivisection Society (Great Britain) |year=1894 |publisher=The Victoria Street Society for the Protection of Animals from Vivisection |location=Victoria Street, London, S.W.|page=297 |url=https://books.google.com/books?id=gIrNAAAAMAAJ&pg=PA297}}</ref> Galen incompletely perceived the function of the heart, believing it a "productor of heat", while the function of its affluents, the [[arteries]], was that of cooling the blood as the [[lungs]] "...fanned and cooled the [[heart]] itself".<ref>William Osler, [https://books.google.com/books?id=blzPRNNiKf8C ''The Evolution of Modern Medicine''], Kaplan Publishing, 2009 {{ISBN|1607140535}}</ref> Galen thought that during [[Vasodilation|dilation]] the [[arteries]] sucked in air, while during their contraction they discharged vapours through pores in the flesh and skin.

Until the 17th century, two separate systems were thought to be involved in blood circulation: the ''natural'' system, containing [[venous blood]] which had its origin in the liver, and the ''vital'' system, containing [[arterial blood]] and the 'spirits' which flowed from the heart, distributing heat and life to all parts. Like [[bellows]], it was thought the lungs fanned and cooled this vital blood.

Independently of Ibn Al-Nafis, [[Michael Servetus]] identified pulmonary circulation, but this discovery did not reach the public because it was written down for the first time in the Manuscript of Paris in 1546.<ref>[http://www.michaelservetusresearch.com/ENGLISH/works.html Michael Servetus Research] Website with graphical study on the Manuscript of Paris by Servetus</ref> It was later published in the theological work which caused his execution in 1553, almost all copies of which were destroyed. In: ''Christianismi Restitutio'', Book V, the Aragonese Miguel Servet (Michel de Villeneuve, 1509?–1553) wrote: 'The blood is passed through the pulmonary artery to the pulmonary vein for a lengthy pass through the lungs, during which it becomes red, and gets rid of the sooty fumes by the act of exhalation'.<ref>{{cite book |last=Rooney |first=Anne|author-link=Anne Rooney |year=2016 |title=The Story of Biology |publisher=Arcturus Publishing |isbn=978-1-78428-734-4}}</ref> Ideas on circulation of blood were also proposed by the Spanish veterinarian-farrier [[Francisco de la Reyna]] in 1546.<ref>{{Cite journal|last=Izquierdo|first=J. J.|date=1937|title=A new and more correct version of the views of Servetus on the circulation of the blood|url=https://www.jstor.org/stable/44438194|journal=Bulletin of the Institute of the History of Medicine|volume=5|issue=10|pages=914–932|jstor=44438194|issn=2576-4810}}</ref><ref>{{Cite journal|last=Trueta|first=Josep|date=1948|title=Michael Servetus and the Discovery of the Lesser Circulation|journal=The Yale Journal of Biology and Medicine|volume=21|issue=1|pages=1–15|issn=0044-0086|pmc=2598790|pmid=18103720}}</ref><ref>{{Cite journal|last=Wilkinston|first=Ronald Sterne|date=1968|title=The First Edition of Francisco de la Reyna's LIBRO DE ALBEYTERIA, 1547|url=https://academic.oup.com/jhmas/article-lookup/doi/10.1093/jhmas/XXIII.2.197|journal=Journal of the History of Medicine and Allied Sciences|language=en|volume=XXIII|issue=2|pages=197–199|doi=10.1093/jhmas/XXIII.2.197|issn=0022-5045}}</ref>

Pulmonary circulation was described by [[Renaldus Columbus]], [[Andrea Cesalpino]] and [[Vesalius]], before Harvey would provide a refined and complete description of the circulatory system.