Harvey and the Blood Circulation

William Harvey s discovery of the blood circulation and the function of the heart shook the foundations of a medical doctrine that went back all the way to Hippocrates and Aristotle. It was believed that blood was formed in the liver and then transported in the Vena Cava to the heart. The main function of this organ was to act as the source of body heat. Furthermore, the activity of the 

William Harvey (1578-1657) came from a rather wealthy English family and could afford to study at the most famous of all medical schools, that in Padua. Here he must have heard Fabricius ab Aquapendente lecture about his great discovery, the valves that he had found in the veins. Fabricius completely misunderstood their function (like everyone else he thought that the blood of the veins flowed from the heart towards the periphery), but maybe his young English student already at that time had realized the true explanation. The movement of the blood in the veins is from the periphery towards the heart and the valves are there to prevent it from flowing in the opposite direction. 

In any case, when he returned to England and became a lecturer at the Royal College of Physicians, Harvey s lecture notes reveal that at least in 1616 he had worked out the main features of the blood circulation. However, it was only after having performed innumerable experiments on all kinds of animals that in 1628 he published his short book Excercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus ( An Anatomical Investigation of the Movements of the Heart and the Blood in Animals ). 

Harvey had thought that his heretic ideas would cause a lot of hostile criticism, but on the whole they were fairly well received. The great French philosopher Rene Descartes, with his view of the living organism as a very complicated machine, was supportive and considered that Harvey s blood circulation fitted quite nicely into Descartes own thinking. When the Italian anatomist Marcello Malpighi in 1661 could demonstrate a system of fine tubes (capillaries) through which the blood could be seen to flow from the arteries to the veins, Harvey s model of the blood circulation was complete. It is not unreasonable to claim that this discovery is the most revolutionary in the history of medicine. 

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