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De humani corporis fabrica Exercitatio Anatomica de Motu Cordis et Sanguinis in
Animalibus credit: Courtesy of Philip Smith, Bookseller, Berkeley
In 16th and 17th century Europe the heart became an object of renewed scientific attention. In the 1530s, Belgian anatomist Andreas Vesalius (1514–1564) translated into Latin many Greek texts by Galen (ca. 129– 216), whose descriptions of human anatomy had remained unchallenged in the West throughout the Middle Ages. To test Galen’s conclusions, Vesalius was one of the first to dissect human cadavers. In 1543 Vesalius published the fruits research in his most famous work, De humani corporis fabrica, of which two pages from the first edition are shown, top, with drawings and descriptions of the human heart. Versalius’ observations not only of the heart but also many other organs were more accurate than Galen’s. He continued, however, to regard the heart as a two valve organ in which arterial blood originated and the liver as the source of venous blood, with blood from these two organs flowing to all part of the body where it was consumed. William Harvey (1578–1657) is generally credited with discovering the actual course of circulation. In 1628 Harvey published Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus in which he demonstrated blood was pumped around the body by a four-valve heart before returning to it in a closed system. Two pages from the first edition of this seminal science book are reproduced here. Even so, Harvey only theorized on how blood was transferred from arteries to veins. It wasn’t until 30 years later that in 1661 Marcello Malpighi (1628–1694) identified the capillaries, providing the missing link. In 1553, anticipating Harvey by 75 years, Michael Servetus (1511–1553) in his Christianismi Restitutio had accurately described the circulation of blood. His discovery went unnoticed in good part because after being declared a heretic by both Protestant and Catholic authorities for his anti-Trinitarian views all but three copies of this book were burned as was he at the stake in Geneva on orders of John Calvin (1509–1564). Predating all these Western scientists by 300 years, the Islamic polymath Ibn al-Nafis (1213–1288) in 1242, at the age of 29, published Commentary on Anatomy in Avicenna's Canon in which he accurately described the circulatory system, including the capillaries. In this monumental work, he concluded the brain, not the heart, was the source of cognition, sensation, imagination, and animal locomotion and the soul nothing other than what a human indicates by saying “I.” In this he anticipated René Descartes (1596–1650), who famously proclaimed, “Cogito ergo sum,” authorized dissections on live animals because unlike humans he claimed they had no soul and thus could feel no pain, and divided the world into mind and matter. Reflecting the spirit of the times, Nicolas Steno (1638–1686), best known for his contributions to paleontology and geology, wrote in his Anatomical Observations (1662), “The heart has been regarded as…the throne of the soul, yes, even as the soul itself…while, if you observe more closely, you will find nothing in it but a muscle.” Steno converted to Catholicism and was consecrated a bishop, but the mind-body dichotomy haunts us to this day.
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