By Allen Shotwell
In the sixteenth century life and death, health and disease, animals and humans mixed together in a number of interesting ways. In the pursuit of understanding human anatomy primarily in the service of medicine, anatomists dissected human cadavers and vivisected live animals, but their understanding of the differences between the two was complex and changing. Anatomical questions arising from mixing animals and humans were not always recognized as such, and even when one of the most famous anatomical texts of all time, noted the potential pitfalls of mixing animals and humans, the practice continued.
One of the major claims of Andreas Vesalius in his 1543 De humani corporis fabrica was that Galen, the Greek physician whose work was the primary source of anatomical knowledge for centuries, had never dissected humans, but only animals and had made a number of erroneous claims as a consequence. Although he was not immune from similar mistakes, Vesalius emphasized his own superiority in words and images, sometimes contrasting animal and human body parts in the same picture (Vesalius iv).
But animals still served an important role for Vesalius and other sixteenth-century anatomists. Time and again Vesalius described substituting an animal for a human body because it improved the visibility of one part or another (Vesalius 261). Animals were especially useful for vivisection since cutting open a living human was an obvious impracticability.
Early in the sixteenth-century, vivisection offered a chance to explore what properties of the body changed with death. In 1521, Berengario da Carpi investigated the fluids surrounding the heart and in the ventricles of the brain, dispelling the idea that in the living body they were actually gases by observing the still-beating heart in an animal (Shotwell 2012). Unlike Vesalius, when Berengario uncovered a discrepancy in Galen by observing the human umbilical cord was different than the umbilical cord of a dog, he attributed the problem to the differences in the development of the fetuses rather than the difference between animals and humans (Berengario 260r).
Vesalius employed vivisection to observe the pulse of the heart and the arteries, investigating a problem first described by Galen who also studied it through vivisection. Although in this case Vesalius agreed with Galen’s findings, other anatomists in the sixteenth-century, like Realdo Colombo, came to the opposite conclusion using the same procedures. Vesalius used a pig, Colombo a dog. Colombo ridiculed Vesalius for confusing the fetal anatomy of dogs with that of humans (Shotwell 2012).
All of these anatomists were focused on human bodies. They saw anatomy as primarily a medical subject, useful for diagnosis and treatment. Their various forays into animal dissection and vivisection were not designed for what we would now call comparative anatomy, a systematic attempt at understanding the differences among the bodies of all animals, humans included. Humans and their health was their goal.
By the late sixteenth-century, some anatomists did turn to studying a wide variety of animal bodies for comparative purposes, most notably Hieronymus Fabricius ab Aquapendente, but animal dissection and vivisection for the purposes of understanding how the human body worked continued throughout the seventeenth century and beyond.
Allen Shotwell is a professor in Liberal Arts at Ivy Tech Community and a PhD candidate in the History and Philosophy of Science at Indiana University.
Images: (1) A human skull balanced on the jaw bone of a dog from Andreas Vesalius’s Fabrica. (2)The Ventricles of the Brain from Berengario da Carpi’s Isagogae Breves. National Library of Medicine. “Historical Anatomies on the Web”. Web. 7 June 2012.
Berengario da Carpi, Jacopo. Commentaria cum amplissimis additionibus super anatomia Mundini una cum textu eiusdem in pristinum et verum nitorem redacto. Bologna, 1521.
Shotwell, R. Allen. “The Revival of Vivisection in the Sixteenth Century,” Journal of the History of Biology 45(3), 2012
Vesalius, Andreas. De humani corporis fabrica libri septem. Basel, 1543