Realdo Colombo Biography (c. 1516-1559)


Realdo Colombo was one of the first anatomists in the Western world to describe pulmonary circulation, observing that blood travels between the right andleft ventricles of the heart by way of the lungs. Previously, it was believedthat blood traveled through a hidden passage (or passages) connecting the ventricles.

Although two other Europeans wrote about this phenomenon around the same time, it was Colombo's book, The 15 Books Written Concerning Anatomy, thatdirectly influenced seventeenth-century anatomist William Harvey's concept of the heart as a pump circulating blood throughout the body.

Son of a pharmacist based in Cremona, Italy, Colombo initially followed his father's trade before undertaking studies in Milan, Venice and then in Padua.Colombo earned his M.D. degree in 1544. At the University of Padua, he studied medicine under another famed anatomist, Andreas Vesalius, eventually becoming his assistant. In 1544, he succeeded Vesalius as lecturer on anatomy and surgery. From 1545 to 1559, Colombo taught in Pisa and at the Sapienza in Rome. Additionally, in 1550 he was appointed a surgeon to the Pope. Throughout Colombo's career as a lecturer, many distinguished persons, including ambassadors, cardinals, and archbishops, attended his lectures.

The phenomenon of pulmonary circulation, also known as the lesser circulation, was first reported in the thriteenth century by the Syrian doctor Ibn al-Nafis. Some of Ibn al-Nafis' writings were translated into Latin during the Renaissance, but his observations about blood circulation were apparently neverread by Colombo or his European counterparts, who subscribed to the ancient Roman belief that a passage existed through the septum, a thick muscular partition separating the ventricles of the heart. Anyone questioning this conceptof the heart risked being accused of heresy by religious leaders who considered the organ to have spiritual properties. However, Vesalius wrote in 1543 that the septum appeared to contain no passages, prompting Colombo to wonder how blood actually traveled between the ventricles, if not through the septum.

Much of Colombo's knowledge of anatomy was obtained by the now controversialpractice of vivisection: he dissected live animals, paying particular attention to the movements of their lungs and heart. He also dissected as many as 14human cadavers a year.

Through these experiments, Colombo determined that blood traveled between thetwo sections of the heart through the lungs. Colombo wrote, "Between the ventricles there is a dividing wall . . . Almost everyone assumes that the bloodpasses from the right ventricle into the left across this wall....But they are completely wrong. For the blood is conducted to the lungs by the pulmonaryartery, where it is diluted and together with air is led from the left ventricle by the pulmonary veins, which no one has noticed until now, nor described in writing, although everyone should take particular notice of this fact."

Colombo's dissections allowed him to make other important observations. The Greek scientist Aristotle had taught that the left ventricle contained cold blood, whereas the right ventricle contained warm blood. Contradicting this, Colombo observed: "In the left ventricle you can feel for yourself that the heat is so intense that the hand cannot possibly endure it." He also noticed that the active phase of the heart was in systole (contraction), not in diastole(dilation) as was previously believed. These discoveries were crucial to Harvey, who credited Colombo's work in his landmark book, On the Motion of the Heart and Blood in Animals.

However, whether Colombo was actually the first Western anatomist to observethe pulmonary circulation is subject to controversy. Juan Valverde, a formerstudent of Colombo, accurately described pulmonary circulation in a 300-pagebook published in 1556, three years before Colombo's book. However, it is known that Valverde had attended lectures in Padua between 1544 and 1546 at which Colombo revealed his discovery. Valverde is also accused of heavily plagiarizing Vesalius.

Less easily dismissed is an incidental but quite accurate reference to the lesser circulation in a theological work published by the Spanish theologian and physician Miguel Serveto in 1553. That book, The Restoration of Christianity, had actually been written much earlier, as Servetus had sent a manuscript copy to the religious reformer John Calvin in 1546. It is known, however, that Servetus and Vesalius had studied together in Paris during the previous decade.

In any case, Colombo's concept of the pulmonary circulation is considered thefullest and most authoritative of his day.

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