The early years of the scientific revolution, humanity’s first poke at addressing the real world sans our traditional superstitious blinders, were not nearly so wholly embraced with the urgency we might today expect. Seventeenth century medicine was still informed exclusively by the work of Galen, second century Greek polymath, whose interpolations and extrapolations of monkey anatomy were the source of his ideas on what goes on within the human body. Fifteen hundred years’ worth of medical doctors were taught by rote memorization our inner workings, and haughty defences of Galen over the new era of inquiry were proudly lauded by the entrenched medical establishment. They never bothered to – never believed they’d need to – examine actual human bodies.
This was a time when the hypothesis of the Four Humours reigned supreme. Our health was simply a matter of the balance between black bile, blood, phlegm, and yellow bile, and the solution to just about every ailment was either a bloodletting, or a purging by emetic or laxative. While the Four Humours were associated with different organs – spleen, heart, brain and liver– their presence was detectable through an observation of settled blood after draining. The dark colour of clotted blood formed the base, followed by a thin layer of red, unclotted blood, a thin layer of white blood cells, and finally the clear plasma on top.
Galen had hypothesized a source for blood, and his wisdom went unquestioned until the early seventeenth century. While today we accept that human bodies recirculate blood, and that it originates in our bones, Galen made the claim that ours is instead an open-ended system. Food goes in; we digest it in the stomach; it gets passed to the liver, where it is converted to blood; it passes next to the furnace of the heart; there, it is incinerated, and we breathe out the waste.
Although disreputable to locate and examine cadavers, it was still undertaken on occasion throughout medical history. The problem with blood research is that it requires a living person from start to finish. Blood clots very quickly, and the flow of blood has a tendency to cease altogether in the absence of a beating heart. The messy work of bloodletting, of trepanation or amputation almost never fell to the doctors, themselves. Poorly trained barber-surgeons were instead the prime practitioners of limb-cutting, which they performed in between clients waiting for simple hair trimmings.
Circulatory systems in animal species were well known, but it was thought that humans were far too impressive, far too close to our angelic ancestry, to be so poorly designed. It was not until 1627 that the English physician William Harvey announced the existence of the human circulatory system. This new knowledge, and the questions that now arose concerning the validity of Galen’s work, prompted medical researchers both official and amateur to consider the heretofore imponderable of blood transfusion. Could it be a miracle cure, even better than bloodletting itself?
The English were the first to explore transfusion, and concentrated on animal species as they worked, but the goal for all involved was to determine its beneficence as a medical procedure. The French academies of science and medicine, most especially the royally approved academy at the University of Paris, held out far longer than the English in questioning Galen, and were still reluctant to consider blood transfusions at all for nearly forty years.
These men were aware of the clotting problems of blood, but not about the existence of different blood groups, or their incompatibility even among the same species. The first tests involved animals, mostly the dogs and pigs that ran wild through pestilential city streets, and researchers were all too eager to experiment with cross-species tests in addition to single-species transfusions. Some tests proved successful. Others killed both patients. Among the many questions surrounding transfusions were not just its capacity to help one creature, but more philosophical questions like “Will the transfused patient now take on the characteristics of its supplier? Is it now a chimera? Will the dog turn into a chicken if it survives the procedure?” Important questions, to be sure, and not out of step with the credulous minds of even the most learned classes of seventeenth century.
“No matter”, thought the French doctor Jean-Baptiste Denis, “I want to be the first to perform a human transfusion. To be on the safe side, I’ll use the blood of a lamb.” Here is where Holly Tucker’s Blood Work: A Tale of Medicine and Murder in the Scientific Revolution really begins, and where it ends. The trial of Denis, enthusiastic provocateur and possible murderer, rang the death knell for transfusion experiments in France, and soon the rest of the world.
Too much was being done too soon, both for the technology itself, and the often rigidly dogmatic, superstitious society of the time. A cautionary tale, perhaps, and from both sides of the issue. While we certainly need to know as much as we can about a new medicine or procedure before we jump in with human trials, we also have to be willing to challenge our firmly held myths and legends, and put those to the test, too.