Sperm, urine, blood… In the eighteenth century, scientists started to look differently at the functions of these 'body fluids'. Historian Ruben Verwaal discovered the reason during his PhD research.
The Dutch eighteenth century has long been called the century of decline. It would contrast sharply with the progressive and rich seventeenth century full of famous artists and scientists. This century is also a neglected child within the history of medicine. Little exciting happened between the invention of the microscope and the rise of anatomy in the seventeenth century and the beginning of modern medicine in the nineteenth century.
Historian Ruben Verwaal (University of Groningen) has conducted research into the development of medicine in this century and specifically into the handling of human 'juices'. “It really is nonsense that nothing happened in this century. Okay, the number of students decreased, but that gave the professors at universities room to experiment and they did that to the fullest. This century appears to be a tipping point and the new insights from that time form the basis of modern medicine.”
Out of balance
Until the seventeenth century, the cause of diseases lay in the imbalance of the four "moods" (blood, phlegm, black bile and yellow bile, invented by Hippocrates, who lived between 460-370 BC). To get better you had to get the balance back. Doctors mainly used leech phlebotomy to drain excess blood. In the seventeenth century doctors started experimenting more and more. New instruments such as the microscope were developed, nerves and sperm cells were discovered and anatomy was introduced.
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Anatomy is great for learning how a body is put together, but you can't do much with it for examining fluids. Verwaal:“From 1700 we see a turnaround and scientists start looking at the body fluids again. They were necessary for reproduction, digestion, circulation, perspiration and urination, but how exactly did it work?”
The advance of chemistry
New research methods had to be developed to study the bodily fluids. Chemistry played a major role in this, according to Verwaal's research. “Chemistry was used in new experiments with bodily fluids to explain symptoms of disease. For this, instruments had to be developed such as the thermometer, hydrometers to weigh water. Chemical labs were established to distill, ferment and mix the liquids. All this together has led to new insights into the functioning of the living body.”
A good example is pee-watching. For centuries, the doctor looked at, sniffed and listened to his patient's urine in order to make a diagnosis. But experimenting with urine in the lab to explain a disease was new. “To discover where bladder stones came from, doctors started distilling urine. Their research showed that the urine of sick and healthy people consisted of the same components, but in different amounts. The bladder stone patient had more salt in his urine and this imbalance would cause the bladder stones.”
Followers of Boerhaave
The students of Leiden professor Herman Boerhaave (1668-1738) turned out to be an important movement for the spread of chemistry within medicine. Their teacher, who is seen as the final piece of the medical revolution of the seventeenth century, was just at the beginning of a new period, according to Verwaal. He has examined this group as a whole for the first time.
“The group of scientists who followed in his footsteps became professors themselves and spread his ideas internationally. They gave chemistry a place within the university and with that they developed a new medical system. This is the prelude to modern medicine at the beginning of the nineteenth century.”
The logs from the eighteenth century of the university experiments with bodily fluids in the lab have been preserved. “Except for the sperm studies, because that was a bit of a taboo subject. Only the final results are recorded in books.” For his research, Verwaal took up the old lecture notes about separating white and red blood cells and started working with his own blood. “The notes were very correct, I could repeat it exactly. We heated my blood so that people knew that it consisted of white and red blood cells.”
No shame
As an extension of his research, Verwaal has created an exhibition. Here he shows how topical the researchers from the eighteenth century were. They already investigated how you could live a healthy life and translated their research into advice about a good lifestyle. For example, by balancing your body fluids, breastfeeding and not masturbating because that caused gonorrhea.
It also shows how cramped we deal with our body fluids these days. We find it embarrassing to hear about going to the toilet or seeing sweat stains. According to Verwaal, this has to do with the blocking of our body fluids, for example due to the construction of the sewage system in the nineteenth century.
“In the eighteenth century, our bodily fluids flowed much more freely. We think urine is dirty, but then it was used as a cleaning agent, as a moisturizer, as an ingredient in medicines or to wash your eyes. Women breastfed each other's babies, men wept in tears. It was all much more present in everyday and public life.” This reminds me of my grandmother, who also saw morning urine as the solution to all kinds of ailments. Maybe there was more to it than I always thought…