Andreas Vesalius - Medical Career and Mature Works

Medical Career and Mature Works

On graduation he was immediately offered the chair of Surgery and Anatomy (explicator chirurgiae) at Padua. He also guest lectured at Bologna and Pisa. Previously these topics had been taught primarily from reading classic texts, mainly Galen, followed by an animal dissection by a barber-surgeon whose work was directed by the lecturer. No attempt was made to actually check Galen's claims; these were considered unassailable. Vesalius, on the other hand, carried out dissection as the primary teaching tool, handling the actual work himself while his students clustered around the table. Hands-on direct observation was considered the only reliable resource, a huge break with medieval practice.

He kept meticulous drawings of his work for his students in the form of six large illustrated anatomical tables. When he found that some of these were being widely copied, he published them all in 1538 under the title Tabulae Anatomicae Sex. He followed this in 1539 with an updated version of Galen's anatomical handbook, Institutiones Anatomicae. When this reached Paris one of his former professors published an attack on this version.

In 1538 he also published a letter on venesection, or bloodletting. This was a popular treatment for almost any illness, but there was some debate about where to take the blood from. The classical Greek procedure, advocated by Galen, was to let blood from a site near the location of the illness. However, the Muslim and medieval practice was to draw a smaller amount blood from a distant location. Vesalius' pamphlet supported Galen's view, and supported his arguments through anatomical diagrams.

In 1539 a Paduan judge became interested in Vesalius' work, and made bodies of executed criminals available for dissection. He soon built up a wealth of detailed anatomical diagrams, the first accurate set to be produced. Many of these were produced by commissioned artists, and were therefore of much better quality than those produced previously.

In 1541, while in Bologna, Vesalius uncovered the fact that all of Galen's research had been based upon animal anatomy rather than the human; since dissection had been banned in ancient Rome, Galen had dissected Barbary Apes instead, and argued that they would be anatomically similar to humans. As a result, he published a correction of Galen's Opera omnia and began writing his own anatomical text. Until Vesalius pointed this out, it had gone unnoticed and had long been the basis of studying human anatomy. However, some people still chose to follow Galen and resented Vesalius for calling attention to such glaring mistakes.

Vesalius, undeterred, went on to stir up more controversy, this time disproving not just Galen but also Mondino de Liuzzi and even Aristotle; all three had made assumptions about the functions and structure of the heart that were clearly wrong. For instance, Vesalius noted that the heart had four chambers, the liver four lobes, and that the blood vessels originated in the heart, not the liver.

Galen assumed arteries carried the purest blood to higher organs such as the brain and lungs from the left ventricle of the heart, while veins carried blood to the lesser organs such as the stomach from the right ventricle. In order that this theory could be correct some sort of holes were needed to interconnect the ventricles, and so in the spirit of Galen's time, he claimed to have found them, adjusting the facts to suit his theory. So paramount was the authority of Galen that for the next 1400 years, a succession of anatomists claimed to find these holes until finally Vesalius declared he could not find them. However, while Vesalius dared to admit he could not find these holes, he did not dream of disputing Galen on the distribution of blood, and so imagined it distilled through the unbroken partition between the ventricles.

Other famous examples of Vesalius disproving Galen in particular was his discovery that the lower jaw was only one bone, not two (which Galen had assumed from animal dissection) and his proof that blood did not pass through the interatrial septum.

In 1543, Vesalius conducted a public dissection of the body of Jakob Karrer von Gebweiler, a notorious felon from the city of Basel, Switzerland. With the cooperation of the surgeon Franz Jeckelmann, he assembled the bones and finally donated the skeleton to the University of Basel. This preparation ("The Basel Skeleton") is Vesalius' only well-preserved skeletal preparation today, and is also the world's oldest anatomical preparation. It is still displayed at the Anatomical Museum of the University of Basel.

Later that year Vesalius asked Johannes Oporinus to help publish the seven-volume De humani corporis fabrica (On the fabric of the human body), a groundbreaking work of human anatomy he dedicated to Charles V. Most believe it was illustrated by Titian's pupil Jan Stephen van Calcar. A few weeks later he published an abridged edition for students, Andrea Vesalii suorum de humani corporis fabrica librorum epitome, and dedicated it to Philip II of Spain, son of the Emperor.

Though Vesalius' work was not the first such work based on actual autopsy, nor even the first work of this era, the production values, highly detailed and intricate plates, and the fact that the artists who produced it were clearly present at the dissections themselves made it into an instant classic. Pirated editions were available almost immediately, a fact Vesalius acknowledged would happen in a printer's note. Vesalius was 30 years old when the first edition of Fabrica was published.