Unholy Fire: Discovering Michael Servetus' Contribution to Pulmonary Physiology Through Modern Historical Fiction

Abstract

Unholy Fire is a recent work of modern historical fiction by Don Stratton. Stratton's novel centers in part on the work of Michael Servetus (b. 1511) an anatomist, cartographer, and mathematician whose writings in his theological magnum opus Christianismi Restitutio put him at odds with the Catholic Church as well as John Calvin. Servetus was tried and found guilty for his anti‐Trinitarian views and was burned at the stake in 1553 in Geneva, Switzerland. Exactly who was Michael Servetus and how did his Christianismi Restitutio play an important role in the history of physiology? Despite the mainly theological nature of Servetus' Christianismi Restitutio, he is credited with the first accurate description, including key physiological and mechanical details, of the pulmonary circulation. First, in Christianismi Restitutio Servetus described how the spirit (blood) originates in the left ventricle and with the aid of the lungs is transported through the right ventricle and that this occurs through anastomoses within the lung and not through pores in the cardiac septum as previously postulated by Galen (129‐210 AD). Second, he said that it is in the lungs that the mixture of inspired air occurs and that this mixture contributes to the change in color of the blood. Third, Servetus hypothesized that based simply on the diameter of the arterial vein (pulmonary artery) it is too large in caliber to be for the sole purpose of supplying blood to the lungs. Because of his scholarly acumen, Servetus' placed himself among the first to shed new light on our understanding of the pulmonary circulation thereby loosening the dominance that Galen's teachings had held on medicine for nearly 14 centuries.