TabulaThe body, as it was written.

A tour · 6 plates

The circulation of the blood

In Galen's physiology, blood was made continuously in the liver from digested food, carried outwards by the veins and consumed by the body, and some of it passed from the right side of the heart to the left through pores in the septum. Ibn Sina's Canon repeated the teaching.1 This tour follows the long argument that took the picture apart. In Cairo, Ibn al-Nafis rejected the pores and sent the blood through the lungs.2 In the 1550s three Europeans described the same route, and who deserves the credit is still argued over.3 Fabricius described the valves of the veins but thought they were brakes; his student Harvey turned them into evidence and argued in 1628 that the blood must circulate.4 The last missing link, the vessels between arteries and veins, was seen by Malpighi in 1661.5 Almost everyone on this tour was partly right. Watch the red ink of the septal pores fade as the heart fills in.

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  1. Tab. VI: Arteries carry blood (c. 160s–190s)
  2. Tab. IX: No pores in the septum (c. 1242)
  3. Tab. XII: Three Europeans and a suppressed book (1553 · 1556 · 1559)
  4. Tab. XIV: Perfectly described, completely misread (1603)
  5. Tab. XVI: The blood goes round (1628)
  6. Tab. XVII: The missing link (1661)

Sources for this introduction

  1. In Galenic physiology blood was made continuously in the liver from digested food, carried outwards by the veins and consumed by the body; Galen taught that blood passes from the right to the left side of the heart through pores in the septum, and Ibn Sina's Canon repeated the teaching.

    • Galen, De usu partium (On the Usefulness of the Parts). 2nd c. CE. primary
    • Neuss, Blood money: Harvey's De motu cordis (1628) as an exercise in accounting. 2018. British Journal for the History of Science. Link · Archive scholarly · details pending
    • Stanford University, History 13 course reader, William Harvey (1578–1657). n.d.. Link · Archive secondary
    • M. Akmal, M. Zulkifle, A. H. Ansari, Ibn Nafis – a forgotten genius in the discovery of pulmonary blood circulation. 2010. Heart Views 11(1):26–30. Link · Archive scholarly

  2. Ibn al-Nafis rejected the septal pores and described blood passing from the right ventricle through the lungs to the left.

    • Ibn al-Nafis, Sharḥ Tashrīḥ al-Qānūn (Commentary on the Anatomy of Avicenna's Canon). c. 1242. primary
    • M. Akmal, M. Zulkifle, A. H. Ansari, Ibn Nafis – a forgotten genius in the discovery of pulmonary blood circulation. 2010. Heart Views 11(1):26–30. Link · Archive scholarly
    • Hektoen International, Ibn al-Nafis and the pulmonary circulation. 2017. Link · Archive secondary

  3. In Europe the lung route was described by Servetus in a suppressed theological book of 1553, by Valverde in print in 1556, and by Colombo in 1559.contested

    Priority among the three, and any link to Ibn al-Nafis, is debated.

    • Michael Servetus, Christianismi restitutio. 1553. primary
    • Jeremy M. Norman (HistoryofInformation.com), Who Discovered the Pulmonary Circulation? Servetus, Valverde or Colombo?. n.d.. Link · Archive secondary
    • Museo Galileo, Florence, Realdo Colombo (biography). n.d.. Link · Archive scholarly

  4. Fabricius described the valves of the veins in 1603 but believed they slowed blood flowing away from the heart; his student William Harvey reinterpreted them as evidence that venous blood flows towards the heart, and argued in De motu cordis (1628) that the blood circulates.

    • Hieronymus Fabricius ab Aquapendente, De venarum ostiolis. 1603. Padua. primary
    • William Harvey, Exercitatio anatomica de motu cordis et sanguinis in animalibus. 1628. William Fitzer, Frankfurt. Link · Archive primary
    • University of Missouri Digital Library (record), De Venarum Ostiolis. n.d.. Link · Archive scholarly
    • Jeremy M. Norman (HistoryofMedicine.com, Garrison-Morton), Fabricius, De venarum ostiolis. n.d.. Link · Archive secondary

  5. Harvey inferred but never saw the connection between arteries and veins; in 1661 Malpighi, with Carlo Fracassati, observed blood in minute vessels of the frog lung.

    • Marcello Malpighi, De pulmonibus observationes anatomicae (two letters to Borelli). 1661. Bologna. primary
    • Luca Tonetti, Frogs' lungs and Malpighi's discovery of pulmonary capillaries. 2015. Acta Phlebologica 16(1):41–51. Link · Archive scholarly
    • University of Bologna (Scienza Giovane), Malpighi (continued). n.d.. Link · Archive scholarly