What History Teaches Us About Blood, Stem Cells, and Fear

Some medical debates are as old as the Scientific Revolution. An interview with Holly Tucker, the author of Blood Work.

An animal and a human arm on a table, with the tubular attachments necessary for connecting the two. Johann Sigismund Eisholtz, 1667. National Library of Medicine

Blood and the process of removing it from people are objects of enduring cultural fascination, as the glut of teenage vampire novels can attest. It was not much different in 17th-century Europe at the dawn of the Scientific Revolution, when a band of natural philosophers armed with knives and goose-quill tubes began to investigate the idea of transferring blood from one person or animal to another. Their story, as told in a new book by Vanderbilt University historian Holly Tucker, is vivid, strange, and reveals much about modern medicine.

In Blood Work: A Tale of Medicine and Murder in the Scientific Revolution (W.W. Norton, March 21, $25.95), Tucker follows the exploits of Jean-Baptiste Denis, an ambitious young physician who decided to make a name for himself by experimenting with the dangerous new idea of transfusion. His gory experiments transferring blood between dogs led him to attempt the first human transfusion—creating a scandal that would be his downfall and would cause transfusion to be banned for more than 200 years. In a time when health was thought to depend on the body's four humors—blood, black bile, red bile, and phlegm—the best medical schools believed blood was produced by the liver and might even be the seat of the soul. Blood transfusion was thus an abomination, broaching deep fears about the pollution of the human species.

Today, of course, transfusion is one of the miracles of modern medicine and has saved millions of lives. I asked Tucker about how medical science interacts with our cultural preconceptions and what we can learn from the past.

In the book, you draw detailed character sketches of the men exploring early blood science, so they seem as familiar as modern scientists. What about medical science today is similar to medical science during the Scientific Revolution?

In writing Blood Work, I was continually struck by similarities between the 17th-century blood transfusion debate and our own genomic era. Then, as now, natural philosophers (as scientists were called then) had a clear sense that they were at the forefront of something big. They weren't sure what it meant and how it would turn out. But they knew it was potentially game-changing in regard to medicine.

The story of early blood transfusion reminds us that there are predictable ways that society tries to classify researchers who are trying to push the boundaries of science in any moment of biomedical innovation. Depending on your viewpoint, scientists can take on hero status for their seemingly dispassionate pursuit of the truth. They can be vilified as power-hungry renegades interested only in celebrity. Or even monster-like characters who are so possessed by their work that they would sacrifice humanity for their singular cause.

Still, I feel very confident that there are few, if any, Dr. Frankensteins and Dr. Moreaus out there. In fact, science is rarely as dramatic as what we read about in works of science fiction. In the end, we all want the same thing from medical science: to live healthier and fuller lives.

What precepts from this early era of medical science have persisted to the present day?

How much time do I have? The list would be endless. The Scientific Revolution of the 17th and 18th centuries has a lasting legacy involving everything we do, especially how we do it. In the 1630s, the philosopher René Descartes ("I think, therefore I am") was one of the first to articulate what we would later call the Scientific Method.

What interests me, though, is also how Descartes's most contested philosophy—mind/body dualism—also permeates modern medical science and how we're still questioning whether it is the best approach to the body.

Descartes held that animals and humans were similar in that their bodies functioned something like clocks. What distinguished humans from animals was, according to Descartes, that they had souls that were not part of the body itself. This theory opened the doors to vivisection and other animal experimentation. It also paved the way for a separation of mind and body that has long characterized medical practice.

You began to write the book after hearing a speech in which George W. Bush urged on a ban on research that might result in "human-animal hybrids." This fear of adulteration is what originally kept transfusion from being studied further; clearly, it's still present in our attitudes toward medical science. What does that say about modern areas of study that seem to some people to cross dangerous lines, like stem cell research and cloning?

After that speech, I was struck, dumbfounded actually, how the arguments and reactions on the Internet and in the media mirrored those that I was seeing in the early blood transfusion trials, where the donors were animals.

Traditionally, historians have said that transfusion was banned after the events chronicled in Blood Work because it was too dangerous. But I wasn't convinced. After all, surgeons were performing skull drilling, caesarian sections, and removing bladder stones through the penis—all without anesthesia and antisepsis. I knew there had to be another reason.

It turns out there was. After several years of archival work, I discovered that transfusion was stopped because of intense fear that physicians now held the secret for creating new species. Some men, like the illustrious chemist Robert Boyle, felt pretty certain that this was not possible. But still, he stressed that science could not prove the point without experiment. And then there were still others for whom interspecies transfusion was not a mere scientific curiosity. Science was toying with God's intentions and needed to be stopped immediately.

In recent years, scientists have explored possibilities of using animals to incubate human organs or blood, and bioethicists have discussed whether interspecies neurological trials should be permitted. What would be the eventual moral status of an animal with human brain cells in society? Huge and even strange questions, but they have to be asked before launching into any experiment of this nature.

Stem cell research (especially human embryological stem cell research) may seem to be different because it involves the question of when human life itself begins, rather than the issue of engineering new creatures. But I would say that there are also important overlaps with early debates on blood transfusion.

In the end, it is all about how we understand what it means to be human and when "humanness" begins and ends. Every society in every time period has to come to terms with how those definitions change in the wake of new scientific discoveries.

Do you think we will ever get past this fear of adulteration, if the stakes are high enough?

In 1666, Robert Boyle asked "whether by frequently transfusing...the blood of some animal into one of another species, something further and more tending to some degrees of a change of species" may be effected. He didn't think it would. But he said it would be "worthwhile for satisfaction and curiosity to determine the point by experiments."

It's hard to imagine modern medicine today without the benefits of transfusion. And I wonder whether one day we'll say the same of stem cell and other genetic therapies.

But, in the end, we can't prove the point without experiments. The question is: are we willing to see this happen? Or, as was the case in the 17th century, do the social concerns that these new technologies bring up outweigh the scientific benefits that they could provide?

We always have to keep in mind is that history will be judging us eventually too. I just hope that the future will be kind.

Book cover: W. W. Norton & Company