On the Fabric of the Human Body is Vesalius’s greatest achievement. It is an anatomical text with illustrations of the human body believed to have been drawn by Jan Stephen van Calcar, but it is unlikely that a single artist created all 273 illustrations in such a short period of time. But it is clear that the artist(s) was present when the dissections were being done and were visualizing the bodies first hand, most likely drawing while they were looking at the cadaver. This level of detail and accuracy had never before been captured.
But this work was also centralized on the concept of empirical observation. Vesalius advocated that science could not be accurate and could not advance if things were taken to be true because someone of great knowledge and/or importance said that they were. He asked no one to believe his book to be true, but instead invited and challenged people to perform their own medical dissections to learn for themselves.
Discussion Topic: Why is empirical observation important? How does empirical observation effect science?
Digging Deeper: Do you think that we are falling into the “Galen Trap” today? Are we taking experts at face value and basing too much of our lives on what they tell us is true?
This work was met with great criticism and was attacked by the scholarly community. It was declared as inaccurate. Scholars stated that since Vesalius was challenging Galen’s ideas he was by default incorrect. Four years later (when the evidence in favor of Vesalius’s work was mounting) one of his main detractors and one-time professors, Jacobus Sylvius, published an article that claimed that the human body itself had changed since Galen had studied it.
Discussion Topic: Why was this book so heavily challenged? Why was it so hard for people to let go Galen’s ideas even when they were presented with clear and valid evidence that those ideas were incorrect?
Several motives underlay the composition and publication of the Fabrica. According to Vesalius medicine was properly composed of three parts; drugs, diet, and “the use of the hands,” by which last he referred to surgical practice and especially to its necessary preliminary, a knowledge of human anatomy that could be acquired only by dissecting human bodies with one’s own hands. Through disdain of anatomy, the most fundamental aspect of medicine, or, as Vesalius phrased it, by refusal to lay their hands on the patient’s body, physicians betray their profession and are physicians only in part.
Vesalius hoped that by his example in Padua and especially by his verbal and pictorial presentation in the Fabrica he might persuade the medical world to appreciate anatomy as fundamental to all other aspects of medicine and that, through the application of his principles of investigation, a genuine knowledge of human anatomy would be achieved by others, in contrast to the more restricted traditional outlook and the uncritical acceptance of Galenic anatomy. The very word “fabrica” could be interpreted as referring not only to the structure of the body but to the basic structure or foundation of the medical art as well.
The Fabrica also stressed the importance of dissection of multiple cadavers prior to coming to conclusions regarding what is “normal” for human anatomy. He reminded doctors that the reason that doctors are needed is that there are times that anatomy is abnormal. He also stated that it was important to be sure that differences in the cadavers was not the result of the technique. This was another reason that he felt it was important that each person perform their own dissections and document their findings.
One of the challenges that Vesalius faced when he began his work of creating a more comprehensive anatomy book was that of terminology. First, there were no names for some of the things that he was seeing. Second, there were several names for numerous common structures. There were several languages in use, but mostly Latin and Greek. There was no standard way of referencing the human body when talking about it’s structures. He had to develop an entire system for diagramming and talking about the human body. This diagramming system is still in use today.