Realdo Matteo Colombo

1515-1559

Italian Anatomist, Physician, and Professor

Realdo Colombo was one of the first European scientists to clearly describe the pulmonary circulation, or passage of blood between the heart and the lungs. Columbo, the son of an apothecary, was born in Cremona, Italy. He served as an apprentice to a surgeon for seven years before be began his studies of medicine and anatomy at the University of Padua in 1540 with Andreas Vesalius (1514-1564), the founder of modern anatomy. When Vesalius left the university in 1543, Colombo became professor of surgery. Colombo was an excellent anatomist, as well as an influential scientist and teacher. Colombo carried out many systematic dissections on both living animals and human cadavers. However, he seems to have exaggerated the number of dissections that he performed and he was quite critical of the work of others, including Vesalius. Indeed, Columbo was one of the most vociferous critics of the Vesalius's great treatise On the Fabric of the Human Body (1543). Surprisingly, Colombo and Vesalius seem to have had a cordial collegial relationship before Colombo assumed his professorship. In response to Colombo's criticism, Vesalius called his former student a scoundrel, an ignoramus, and an "uncultivated smattering" whose general education was as deficient as his mastery of Latin. Later the anatomist Gabriele Fallopio (1523-1562) accused Colombo of plagiarizing the discoveries of other anatomists. In 1546 Colombo became the first professor of anatomy at the University of Pisa. Two years later he was appointed professor of anatomy at the Sapienza, or Papal University, in Rome. He also served as surgeon to Pope Julius III.

When he first became a professor, Colombo spoke of plans for the publication of a major illustrated anatomical treatise that would detail the errors made by Vesalius and others, but this ambitious enterprise never materialized. Colombo's only major anatomical treatise, De re anatomica (On Anatomy, 1559), was published posthumously by his heirs. Although the book is not illustrated, it was clearly written and organized and included several important original observations. Colombo carefully described the organs within the thoracic cavity, the membrane surrounding the lungs, and the membrane surrounding the abdominal organs. His most important contribution was his description of general heart action, which included his observations and experiments concerning the minor, or pulmonary circulation of the blood. However, Columbo may have been demonstrating the pulmonary circulation as early as 1545. Calling upon the reader to confirm his observations by dissection and vivisection, Columbo boasted that he alone had discovered the way in which the lungs serve in the preparation and generation of the vital spirits. Unlike Michael Servetus (c. 1511-1553) and Ibn an Nafis, Colombo made it clear that his ideas on the pulmonary circulation were based on clinical observations, dissections, and experiments on animals. He described the anatomy of the heart in detail and corrected many ancient errors. Colombo explained that blood entered the ventricles of the heart during diastole (the relaxation phase of heart action), and is expelled from the ventricles during systole (the contraction of the heart muscle). Colombo clearly followed the movement of venous blood from the right ventricle, through the pulmonary artery to the lungs. He noted that blood was bright red when it left the lungs where it was mixed with a "spirit" present in the air. The blood then returned to the left ventricle through the pulmonary vein. In other words, air was received by the lungs where it mixed with blood brought in by the pulmonary artery from the right ventricle of the heart. Blood and air were taken up by the branches of the pulmonary vein and carried to the left ventricle of the heart to be distributed to all parts of the body.

Although pulmonary circulation had been described during the thirteenth century by the Egyptian physician Ibn an Nafis and by Servetus, these accounts were generally unknown. Therefore, sixteenth- and seventeenth-century scientists generally recognized Colombo as the discoverer of the pulmonary circulation. However, Colombo's claim to priority has been questioned on several accounts. Even if he begun his study of the pulmonary circulation as early as 1545, his ideas might have been stimulated or confirmed by learning about the speculations of Servetus. Despite his professions of originality and daring, Colombo was actually rather conservative concerning other aspects of the functions of the heart, blood, and respiration. Therefore, although Colombo's work proved that it was not necessary to invoke invisible Galenic pores in the septum of the heart in order to get blood from the right side to the left side, it did not explain the major, or systemic circulation of the blood.

LOIS N. MAGNER