Delving into the history of understandings of the human body can be a disorienting experience. Not all of us spend time looking at the stars. Not all of us know the names of the plants that grow in our yards. But all of us “have” bodies. All of us have the experience of being sick or injured, of having bodies that don’t work. All of us have bodies that are marked by sex, race, ability or disability, and these bodies shape how we live and move and act in the world in ways we do not always think consciously about. It’s very easy for us to imagine that what we “know” about our bodies is simple or obvious. This makes it challenging to understand the views of people in the past, people who also “had” bodies, but who thought in very different ways about them.
Let’s take a simple example: imagine your response if a stranger sneezes on you. Some of you may feel a shudder of revulsion just thinking about coming into contact with the bodily fluids of another person, particularly one whose health status is completely unknown to you. All of you (I’m assuming) understand this as an encounter that could lead to your becoming ill. And I’m betting that every one of you would describe such an encounter as “disgusting” or “nasty” or “gross.” If I ask you why a stranger sneezing on you is so awful, you would tell me that this spreads germs and germs cause disease.
Your response to a sneezing stranger is probably both immediate and visceral. That is, you don’t stop to think, “sneezing spreads germs and germs spread disease, so that’s pretty nasty that this person just sneezed on me.” You just think, “YUCK!” and you may physically recoil from the person who sneezed on you. The fact that your response comes so fast and without any conscious thought may lead you to believe that it is an instinctive response, that it’s natural or obvious to believe that sneezing spreads disease. But your response is not instinctive; it is learned. Germ theory is only about 150 years old. Prior to the late nineteenth century, no one would have reacted to a stranger sneezing on them the way you do. Further, as anyone who has spent time around small children can attest, being grossed out by someone sneezing on you is most definitely learned behavior!
Try to bear this in mind as we explore earlier systems of understanding the body. You will encounter some ideas and beliefs that seem very familiar, and others that seem very strange. When you find yourself thinking, “how could they not know something so obvious?” try to reframe the question: Why do I think this is obvious? Why do you think it’s “obvious” that germs cause disease? The answer is that you’ve been taught to think this way. Your parents or teachers drilled into you that you should cover your mouth and nose when you cough or sneeze. When you got older you saw pictures of germs in biology or health textbooks and you learned about the immune system. So now, after years of indoctrination, you connect coming into contact with another person’s saliva and mucus with getting sick. But without those years of indoctrination, the connection between a stranger sneezing on you, and you becoming sick a day or two or three later would by no mean be obvious. You would see these as entirely unrelated events. (I’m not in any way trying to critique germ theory here. I fully believe in the reality of germs, the efficacy of antibiotics and the necessity of vaccinations. I’m just trying to point out that the idea that organisms too tiny to see might cause disease is in no way intuitive or obvious.)
The earliest Greek medical writings are the Hippocratic Corpus, associated with the Greek physician Hippocrates (ca. 460 – ca. 370 B.C.). Hippocrates lived and worked on the island of Kos in the Aegean Sea. He apparently had a “school,” or at least trained other physicians. The Hippocratic Corpus (“Corpus” is simply the Latin word for body, so the “Hippocratic corpus” is the body of work produced by the Hippocratic writers) contains about sixty Greek medical works attributed to Hippocrates, written mainly between 420 and 350 BC, and assembled at Alexandria in Egypt around 280 B.C. Up until the 19th century, these works were all thought to be by Hippocrates himself. Modern scholarship has demonstrated that they had a variety of authors and were composed at different dates. But when medieval and early modern physicians refer to “Hippocrates” they are assuming that he is the author of all of the Hippocratic texts. I will sometimes use “Hippocrates” as shorthand for “Hippocratic Corpus” or “Hippocratic writings.” Bear in mind that we don’t know which (if any!) of the extant texts Hippocrates wrote. The most famous of these texts today is the Hippocratic Oath. The Oath was written around 400 B.C. and, while it has long been attributed to Hippocrates, no one knows the actual author. The Oath is the earliest known document on medical ethics, or the proper professional behavior of doctors. The person swearing the Oath promises to teach the sons of his teachers for free, never to never give poison or drugs that cause abortions, to never perform surgery, to not reveal his patients’ secrets, and to not have sex with his patients’ relatives or slaves. A modernized version of the Oath is still used at some medical schools. You can find both the original and a modern version here.
Other texts in the Hippocratic Corpus focus on particular diseases, surgery, gynecology, on the influence of climate on health, and on general theories of disease. (For English translations of many of the Hippocratic writings, see the Internet Classics Archive.) The authors all have different viewpoints, different understandings of the body, and different approaches to healing. But there was enough commonality that all were attributed to Hippocrates or his associates. There are two important themes that run through the Hippocratic writings:
- Disease is purely naturalistic. Disease is not caused by supernatural entities (gods and goddesses) intervening in human life.
- Health and illness are forms of balance and imbalance. That is, the body is healthy when it is in balance, and diseased when it is imbalanced.
Let me illustrate these themes with two Hippocratic writings. The text On the Sacred Disease is about the disease we would today call epilepsy. This disease was frequently attributed to divine intervention, but the writer of On the Sacred Disease insists, “it appears to me to be nowise more divine nor more sacred than other diseases, but has a natural cause from the originates like other affections.” The insistence of Hippocratic physicians on naturalistic explanations of disease was closely related to the attempts of Greek natural philosophers (like Aristotle) to explain natural phenomena without reference to the gods. The writer of On the Sacred Disease asserts that the seizures characteristic of epilepsy are caused by phlegm blocking the movement of air around the body, which then agitated the body as it struggled to find a way round. This may strike you as the WRONG explanation, but it is an attempt to explain the observed symptoms and patterns of the disease with no reference to the supernatural. All the Hippocratic writers propose exclusively natural explanations for disease. This does not mean that all ancient Greeks accepted only naturalistic explanations for disease. Worship of the healing god Asclepius was very popular in ancient Greece, and continued to be popular in the Roman world. The tradition of Hippocratic or “rational” (that is, “naturalistic”) medicine developed alongside the cult of Asclepius, and naturalistic explanations of disease continued to coexist with religious views of disease (and indeed, this continues down to the present day).
Numerous treatises in the Hippocratic Corpus posit that health is a balance of the fluids in the body and ill health is an imbalance. (On the Sacred Disease posits that excess phlegm causes seizures, for example). The most important of these treatises is On the Nature of Man. This text gives the earliest complete description of the theory of the four humors, a theory that came to dominate medicine in ancient Greece and Rome, the Islamic world, and medieval and early modern Europe. That is, the theory of the four humors was the main theoretical framework for understanding health and disease for over two thousand years.
According to On the Nature of Man, the human body is made up of four humors. The word “humor” means “fluid” or “juice.” The Greek word denotes the juice of a fruit or the sap of a plant as well as bodily fluids. The four humors are blood, phlegm, black bile and yellow bile. Each humor is a combination of two of the four basic qualities: hot, cold, wet, dry.
The four humors are analogous to the four elements: earth, water, air and fire. The elements, like the humors, are combinations of the four basic qualities: hot, cold, wet and dry. Just as the elements exist in combination in the world around us, so the four humors exist in combination in the body. So the blood that you saw when you cut yourself was a mixture of humors, predominantly but not exclusively the humor blood. The humors were distributed throughout the body, but each humor had an organ it was most strongly associated with (its “home base”). Blood was associated with the heart, phlegm with the brain, yellow bile with the gall bladder, and black bile with the spleen. The notion that the body is made up of humors is not based on anatomical ignorance (the Hippocratic physicians did very few dissections, but later physicians DID, and they easily incorporated anatomical findings into the humoral system). Rather, it is based on the idea that the correct and healthy functioning of the body depends upon the quantity and quality of the fluids in the body, and the proper flow of these fluids around the body. Health was a correct balance or equilibrium of humors. Illness was an imbalance – the result of some disturbance in the natural balance of the humors. If you had too much of one humor, either all over your body or in one specific part, you would experience pain and loss of function. In other words, you would be sick. (In theory, one could have too little of one of the humors, but in practice humoral doctors almost always thought in terms of excess rather than depletion.)
To get a glimpse of how humoral theory worked in practice, let’s look at a rather lengthy excerpt from On the Sacred Disease, the book that deals with epilepsy.
[T]he patient loses his speech, and chokes, and foam issues by the mouth, the teeth are fixed, the hands are contracted, the eyes distorted, he becomes insensible, and in some cases the bowels are evacuated. And these symptoms occur sometimes on the left side, sometimes on the right, and sometimes in both. The cause of every one of these symptoms I will now explain. The man becomes speechless when the phlegm, suddenly descending into the veins, shuts out the air, and does not admit it either to the brain or to the vena cava, or to the ventricles, but interrupts the inspiration. For when a person draws in air by the mouth and nostrils, the breath goes first to the brain, then the greater part of it to the internal cavity, and part to the lungs, and part to the veins, and from them it is distributed to the other parts of the body along the veins; and whatever passes to the stomach cools, and does nothing more; and so also with regard to the lungs. But the air which enters the veins is of use (to the body) by entering the brain and its ventricles, and thus it imparts sensibility and motion to all the members, so that when the veins are excluded from the air by the phlegm and do not receive it, the man loses his speech and intellect, and the hands become powerless, and are contracted, the blood stopping and not being diffused, as it was wont; and the eyes are distorted owing to the veins being excluded from the air; and they palpitate; and froth from the lungs issues by the mouth. For when the breath does not find entrance to him, he foams and sputters like a dying person. . . . The patient kicks with his feet when the air is shut up in the lungs and cannot find an outlet, owing to the phlegm; and rushing by the blood upward and downward, it occasions convulsions and pain, and therefore he kicks with his feet. All these symptoms he endures when the cold phlegm passes into the warm blood, for it congeals and stops the blood. And if the defluxion be copious and thick, it immediately proves fatal to him, for by its cold it prevails over the blood and congeals it; or, if it be less, it in the first place obtains the mastery, and stops the respiration; and then in the course of time, when it is diffused along the veins and mixed with much warm blood, it is thus overpowered, the veins receive the air, and the patient recovers his senses.
The author of this treatise speaks of blood and phlegm and breath. The seizures of epilepsy are caused by an excess of phlegm. This phlegm blocks the passages through which air gets to the brain and the rest of the body. Lack of air renders the person insensible. The body struggles to rid itself of the excess phlegm in the veins by contorting violently, and this is the cause of the characteristic and uncontrollable seizures of the epileptic. The excess phlegm, which is cold and wet, overwhelms the blood, which is hot and wet, turning the blood cold, causing it to congeal, and thus hindering the proper flow of blood through the body. In some cases, this chilling of the blood is fatal. In others, the heat of the blood eventually warms the phlegm and disperses it, so the blood and air can flow properly through the body again.
According to Hippocratic physicians, EVERYONE has all four humors in their body. So EVERYONE has phlegm in their bodies, and yet epilepsy is a very rare disease. Why is this? The answer is that in the humoral system, the correct or normal balance of the humors varied from person to person. Everybody had a unique mixture of the humors, and generally one humor predominated. This unique mixture of the humors was called the “constitution” or the “temperament” and it was hereditary. Because different people had different constitutions, they were prone to different diseases. Epilepsy was a disease of people whose constitution was dominated by the humor phlegm. People dominated by the humor blood, for example, would be prone to different diseases.
Note that the author states that the SYMPTOMS of epilepsy are caused by excess phlegm. It would not be correct to say that epilepsy itself is CAUSED by excess phlegm. Rather, epilepsy IS an excess of phlegm. That is, in the humoral system, disease IS an imbalance of the humors. Particular imbalances cause the specific symptoms characteristic of each disease. So what causes the humors to become unbalanced? There are six broad categories of things that affect the balance of the humors. The technical term for these categories (which was invented by later writers, not the Hippocratics) is the NON-NATURALS. The six non-naturals are:
- food and drink
- evacuation of bodily residues
The first non-natural, food and drink, was arguably the most important, because the four humors were produced by the digestion of food. Certain foods tended to produce more of one humor than the other three. For example, red meat tended to produce more blood; milk tended to produce more phlegm. The second non-natural, environment, included the climate and weather of the place where you lived. People who lived in hot, dry places were prone to different diseases than those who lived in cold, wet locations. Changes in the weather could be healthy or unhealthy. The author of On the Sacred Disease says epileptic seizures are particularly likely to happen when a south wind blew, because this made brain moister, and created an excess of phlegm. The third and fourth non-naturals were sleep and exercise. The amount of rest a person got, and the amount and kind of exercise they performed affected the balance of the humors. Exercise included any kind of physical activity, not just sports, but also things like dancing and having sex. The fifth non-natural, evacuation of bodily residues, included all the various ways the body expelled substances: urine, feces, sweat, vomit, nosebleeds, sneezing, menstruation, etc. Finally, emotions, the sixth non-natural, played a powerful role in the humoral system. In humoral medicine, “lovesickness” is a real, physical disease, not a metaphor. Powerful negative emotions like anger, grief and jealousy could kill a person. Positive emotions like love and joy could heal.
None of the six non-naturals was in and of itself good or bad for the body. Each had impact on the humoral balance, but this could be for better or for worse, depending on the individual. So, for example, there were no types of food that were “healthy” or “unhealthy.” There were types of food that were unhealthy FOR CERTAIN PEOPLE WITH SPECIFIC TEMPERAMENTS. As you might imagine, for an epileptic, a person with a constitution dominated by the humor phlegm, drinking a lot of milk, which tended to produce even more phlegm, would be an unhealthy thing to do. But for someone with a different type of constitution, milk might be a perfectly healthy beverage. Similarly, there was no “right” amount of sleep or exercise. There were only right amounts FOR SPECIFIC INDIVIDUALS. The natural balance of health was precarious. It was subject to potentially harmful influences from diet, life style, and environment.
The six non-naturals were the things that threw a person’s humors out of balance. That is, these were the things that CAUSED disease. However, they were also the things that physicians could use to restore a patient’s humoral balance. They were the CURES for disease as well. In humoral medicine, therapy aimed to restore balance and rid the body of whatever humor or humors was in excess. When a person was sick, a physician would generally recommend a change in diet. They would recommend foods and drinks that would restore the person’s healthy humoral balance. For example, if a person had an excess of phlegm, they would be told NOT TO eat certain foods, like milk, that were cold and wet, and they would also be told TO eat foods that were hot and dry (because the qualities hot and dry are opposite those of phlegm. Diet was a major part of humoral medicine. Physicians might also recommend particular types of exercise, certain amounts of sleep, and sometimes a change in climate. As I mentioned before, disease was generally conceived as excess. Physicians thus frequently used the fifth non-natural, evacuation of bodily residues, as a way to rid the body of humors. They gave drugs (primarily herbal) to make people urinate, defecate, sweat, vomit or menstruate. They also used such techniques as bloodletting, cupping, and enemas.
A large part of humoral medicine was devoted to prophylaxis – to maintaining the proper balance of the humors. Physicians would try to understand their patients’ predispositions to certain diseases based on their constitutions and the season of the year or the climate, and then they would design regimens (recommendations about diet and lifestyle) to counteract these predispositions.
The other enormously important ancient medical writer is Galen of Pergamum (129 to ca. 216 A.D.). Galen, along with Hippocrates, shaped medical thinking in Europe and Islamic world for over 1500 years. Galen’s influence was actually greater than Hippocrates’ because Galen was a much more prolific and a much more systematic writer. Galen wrote over 350 texts, ranging in length from 30 to 500 pages. He covered a huge variety of topics: anatomy, pharmacy, surgery, and clinical practice (including case studies and diagnostic techniques). Galen had great respect for Hippocrates, and he built his own medical system on the foundations of Hippocratic medicine, including the notion of the four humors. It was largely through Galen’s writing that the humoral system took on its more elaborate and comprehensive form and became the cornerstone of medicine in both Europe and the Islamic world.
Vivian Nutton, Ancient Medicine
Shigehisa Kuriyama, “The Forgotten Fear of Excrement” Journal of Medieval and Early Modern Studies 38.3 (2008): 413-442.