Historical development of the concept of a pulmonary circulation.

Philosophical speculations and theories regarding the flow of blood through the lungs are reviewed from an historical standpoint. Michael Servetus (1511-1553) described the pulmonary circulation in his book 'Christianismi Restitutio', published in 1553. From manuscripts that were rediscovered and translated in 1924 we now know that Ibn al-Nafis (1210-1288) of Damascus had made the same observations three centuries earlier.