Humorism
Humorism, the humoral theory, or humoralism, was a system of medicine detailing a supposed makeup and workings of the human body, adopted by Ancient Greek and Roman physicians and philosophers. Humorism began to fall out of favor in the 1850s with the advent of germ theory, which was able to show that many diseases previously thought to be humoral were in fact caused by microbes. Origin. The concept of "humors" (chemical systems regulating human behaviour) became more prominent from the writing of medical theorist Alcmaeon of Croton (c. 540–500 BC). His list of humors was longer and included fundamental  elements described by Empedocles, such as water, air, earth, fire, etc.. The concept of "humors" may have origins in Ancient Egyptian medicine, or Mesopotamia, though it was not systemized until ancient Greek thinkers. The word "humor" is a translation of Greek χυμός, "chymos" (literally juice or sap, metaphorically flavor). Ancient Indian Ayurveda medicine had developed a theory of three doshas (doṣas), which they linked with the five elements (pañca-bhūta): earth, water, fire, air, and space. Hippocrates is usually credited with applying this idea to medicine. In contrast to Alcmaeon, Hippocrates suggested that humors are the vital bodily fluids: blood , phlegm, yellow bile, and black bile. Alcmaeon and Hippocrates posited that an extreme excess or deficiency of any of the humors (bodily fluid) in a person can be a sign of illness. Hippocrates, and then Galen, suggested that a moderate imbalance in the mixture of these fluids produces behavioral patterns. One of the treatises attributed to Hippocrates, "On the Nature of Man", describes the theory as follows: The Human body contains blood, phlegm, yellow bile, and black bile. These are the things that make up its constitution and cause its pains and health. Health is primarily that state in which  these constituent substances are in the correct proportion to each other, both in strength and quantity, and are well mixed. Pain occurs when one of the substances presents either a deficiency or an excess, or is separated in the body and not mixed with others. Although the theory of the four humors does appear in some Hippocratic texts, other Hippocratic writers accepted the existence of only two humors, while some refrained from discussing the humoral theory at all. Humoralism, or the doctrine of the four temperaments, as a medical theory retained its popularity for centuries, largely through the influence of  the writings of Galen (129–201 AD). Hippocrates' theory of four humors was linked with the popular theory of the four elements (earth, fire, water, and air) proposed by Empedocles, but this link was not proposed by Hippocrates or Galen, who referred primarily to bodily fluids. While Galen thought that humors were formed in the body, rather than ingested, he believed that different foods had varying potential to act upon the body to produce different humors. Warm foods, for example, tended to produce yellow bile, while cold foods tended to produce phlegm. Seasons of the year, periods of life, geographic regions , and occupations also influenced the nature of the humors formed. As such, certain seasons and geographic areas were understood to cause imbalances in the humors, leading to varying types of disease across time and place. For example, cities exposed to hot winds were seen as having higher rates of digestive problems as a result of excess phlegm running down from the head, while cities exposed to cold winds were associated with diseases of the lungs, acute diseases, and "hardness of the bowels," as well as ophthalmies (issues of the eyes), and nosebleeds. Cities to the west, meanwhile, were believed to  produce weak, unhealthy, pale people that were subject to all manners of disease. In the treatise, "Airs, Waters, Places," a Hippocratic physician is described arriving to an unnamed city where they test various factors of nature including the wind, water, and soil to predict the direct influence on the diseases specific to the city based on the season and the individual. The imbalance of humors, or dyscrasia, was thought to be the direct cause of all diseases. Health was associated with a balance of humors, or eucrasia. The qualities of the humors, in turn, influenced the nature of the diseases  they caused. Yellow bile caused warm diseases and phlegm caused cold diseases. In "On the Temperaments", Galen further emphasized the importance of the qualities. An ideal temperament involved a proportionally balanced mixture of the four qualities. Galen identified four temperaments in which one of the qualities (warm, cold, moist, or dry) predominated, and four more in which a combination of two (warm and moist, warm and dry, cold and dry, or cold and moist) dominated. These last four, named for the humors with which they were associated—sanguine, choleric, melancholic and phlegmatic—eventually became better known than the others. While  the term "temperament" came to refer just to psychological dispositions, Galen used it to refer to bodily dispositions, which determined a person's susceptibility to particular diseases, as well as behavioral and emotional inclinations. Disease could also be the result of the "corruption" of one or more of the humors, which could be caused by environmental circumstances, dietary changes, or many other factors. These deficits were thought to be caused by vapors inhaled or absorbed by the body. Greeks and Romans, and the later Muslim and Western European medical establishments that adopted and adapted classical medical philosophy, believed that each  of these humors would wax and wane in the body, depending on diet and activity. When a patient was suffering from a surplus or imbalance of one of the four humors, then said patient's personality and/or physical health could be negatively affected. Four humors. Even though humorism theory had several models that used 2, 3, and 5 components, the most famous model consists of the four humors described by Hippocrates and developed further by Galen. The four humors of Hippocratic medicine are black bile (, '), yellow bile (, '), phlegm (, ""), and blood (, "haima"). Each corresponds to one of the traditional four temperaments . Based on Hippocratic medicine, it was believed that for a body to be healthy, the four humors should be balanced in amount and strength. The proper blending and balance of the four humors was known as "eukrasia". Humorism theory was improved by Galen, who incorporated his understanding of the humors into his interpretation of the human body. He believed the interactions of the humors within the body were the key to investigating the physical nature and function of the organ systems. Galen combined his interpretation of the humors with his collection of ideas concerning nature from past philosophers in order  to find conclusions about how the body works. For example, Galen maintained the idea of the presence of the Platonic tripartite soul, which consisted of “"thumos" (spiritedness), "epithumos" (directed spiritedness, i.e., desire), and "Sophia" (wisdom).” Through this, Galen found a connection between these three parts of the soul and the three major organs that were recognized at the time: the brain, the heart, and the liver. This idea of connecting vital parts of the soul to vital parts of the body was derived from Aristotle's sense of explaining physical observations, and Galen utilized it to build his view of  the human body. The organs (named "organa") had specific functions (called "chreiai") that contributed to the maintenance of the human body, and the expression of these functions is shown in characteristic activities (called "energeiai") of a person. While the correspondence of parts of the body to the soul was an influential concept, Galen decided that the interaction of the four humors with natural bodily mechanisms were responsible for human development and this connection inspired his understanding of the nature of the components of the body. Galen recalls the correspondence between humors and seasons in his "On the Doctrines of Hippocrates  and Plato," and says that, "As for ages and the seasons, the child (παῖς) corresponds to spring, the young man (νεανίσκος) to summer, the mature man (παρακµάζων) to autumn, and the old man (γέρων) to winter". He also related a correspondence between humors and seasons based on the properties of both. Blood, as a humor, was considered hot and wet. This gave it a correspondence to spring. Yellow bile was considered hot and dry, which related it to summer. Black bile was considered cold and dry, and thus related to autumn. Phlegm, cold and wet, was related to winter. Galen  also believed that the characteristics of the soul follow the mixtures of the body, but he did not apply this idea to the Hippocratic humors. He believed that phlegm did not influence character. In his "On Hippocrates The Nature of Man", Galen stated: "Sharpness and intelligence (ὀξὺ καὶ συνετόν) are caused by yellow bile in the soul, perseverance and consistency (ἑδραῖον καὶ βέβαιον) by the melancholic humor, and simplicity and naivety (ἁπλοῦν καὶ ἠλιθιώτερον) by blood. But the nature of phlegm has no effect on the character of the soul (τοῦ δὲ φλέγµατος ἡ φύσις εἰς µὲν ἠθοποιῗαν ἄχρηστος)." He  further said that blood is a mixture of the four elements: water, air, fire, and earth. These terms only partly correspond to modern medical terminology, in which there is no distinction between black and yellow bile, and phlegm has a very different meaning. It was believed that the humors were the basic substances from which all liquids in the body were made. Robin Fåhræus (1921), a Swedish physician who devised the erythrocyte sedimentation rate, suggested that the four humors were based upon the observation of blood clotting in a transparent container. When blood is drawn in a glass container and  left undisturbed for about an hour, four different layers can be seen: a dark clot forms at the bottom (the "black bile"); above the clot is a layer of red blood cells (the "blood"); above this is a whitish layer of white blood cells (the "phlegm"); the top layer is clear yellow serum (the "yellow bile"). Many Greek texts were written during the golden age of the theory of the four humors in Greek medicine after Galen. One of those texts was an anonymous treatise called "On the Constitution of the Universe and of Man", published in the mid-19th century  by J.L. Ideler. In this text, the author establishes the relationship between elements of the universe (air, water, earth, fire) and elements of the man (blood, yellow bile, black bile, phlegm). He said that: 17th century English playwright Ben Jonson wrote humor plays, where character types were based on their humoral complexion. Blood. The blood is clearly the product of food digestion. It was thought that the nutritional value of the blood was the source of energy for the body and the soul. Blood was believed to consist of small proportional amounts of the other three humors. This meant that  taking a blood sample would allow for determination of the balance of the four humors in the body. It was associated with a sanguine nature (enthusiastic, active, and social). The seasonal association of blood is the spring because the natural characteristics found in individuals was associated with being hot and wet. Yellow bile. Yellow bile was associated with a choleric nature (ambitious, decisive, aggressive, and short-tempered). It was thought to be fluid found within the gallbladder, however it could also be found in excretions such as vomit or feces. The associated qualities for yellow bile are hot and dry  with the natural association of summer and fire. It was believed that an excess of this humor in an individual would result in emotional irregularities such as increased anger or behaving irrationally. Black bile. Black bile was associated with a melancholy nature, the word "melancholy" itself deriving from the Greek for "black bile", μέλαινα χολή ("melaina kholé"). Depression was attributed to excess or unnatural black bile secreted by the spleen. Cancer was also attributed to an excess of black bile concentrated in a specific area. The seasonal association of black bile was to autumn as the cold and dry characteristics  of the season reflect the nature of man. Phlegm. Phlegm was associated with a phlegmatic nature, thought to be associated with reserved behavior. The phlegm of humorism is far from phlegm as it is defined today. Phlegm was used as a general term to describe white or colorless secretions such as pus, mucus, saliva, or sweat. Phlegm was also associated with the brain, possibly due to the color and consistency of brain tissue. The French physiologist and Nobel laureate Charles Richet, when describing humorism's "phlegm or pituitary secretion" in 1910, asked rhetorically, "this strange liquid, which is the cause  of tumours, of chlorosis, of rheumatism, and cacochymia – where is it? Who will ever see it? Who has ever ever seen it? What can we say of this fanciful classification of humors into four groups, of which two are absolutely imaginary?" The seasonal association of phlegm is winter due to the natural properties of being cold and wet. Humor production. Humors were believed to be produced via digestion as the final products of hepatic digestion. Digestion is a continuous process taking place in every animal, and it can be divided into four sequential stages. The gastric digestion stage, the hepatic  digestion stage, the vascular digestion stage, and the tissue digestion stage. Each stage digests food until it becomes suitable for use by the body. In gastric digestion, food is made into chylous, which is suitable for the liver to absorb and carry on digestion. Chylous is changed into chymous in the hepatic digestion stage. Chymous is composed of the four humors: blood, phlegm, yellow bile, and black bile. These four humors then circulate in the blood vessels. In the last stage of digestion, tissue digestion, food becomes similar to the organ tissue for which it is destined. If anything goes  wrong leading up to the production of humors, there will be an imbalance leading to disease. Proper organ functioning is necessary in the production of good humor. The stomach and liver also have to function normally for proper digestion. If there are any abnormalities in gastric digestion, the liver, blood vessels, and tissues cannot be provided with the raw chylous, which can cause abnormal humor and blood composition. A healthy functioning liver is not capable of converting abnormal chylous into normal chylous and normal humors. Humors are the end product of gastric digestion, but they are not the end  product of the digestion cycle, so an abnormal humor produced by hepatic digestion will affect other organs that are working towards the digestion of food in the digestion cycle. Unification of humorism with Empedocles model. Empedocles's theory suggested that there are four elements: earth, fire, water, and air, with the earth producing the natural systems. Since this theory was influential for centuries, later scholars paired qualities associated with each humor as described by Hippocrates/Galen with seasons and "basic elements" as described by Empedocles. The following table shows the four humors with their corresponding elements, seasons, sites of formation , and resulting temperaments: Influence and legacy. Islamic medicine. Medieval medical tradition in the Golden Age of Islam adopted the theory of humorism from Greco-Roman medicine, notably via the Persian polymath Avicenna's "The Canon of Medicine" (1025). Avicenna summarized the four humors and temperaments as follows: Perso-Arabic and Indian medicine. The Unani school of medicine, practiced in Perso-Arabic countries, India, and Pakistan, is based on Galenic and Avicennian medicine in its emphasis on the four humors as a fundamental part of the methodologic paradigm. Western medicine. The humoralist system of medicine was highly individualistic, for all patients  were said to have their own unique humoral composition. From Hippocrates onward, the humoral theory was adopted by Greek, Roman and Islamic physicians, and dominated the view of the human body among European physicians until at least 1543 when it was first seriously challenged by Andreas Vesalius. Vesalius mostly criticized Galen's theories of human anatomy and not the chemical hypothesis of behavioural regulation (temperament). However, some believe that theory of humors was cast into the underside of science in 1628 by the findings of William Harvey (also mostly criticizing the anatomy theory of Galen) and by Rudolf Virchow's  theories of cellular pathology in 1858. Typical 18th-century practices such as bleeding a sick person or applying hot cups to a person were based on the humoral theory of imbalances of fluids (blood and bile in those cases). Methods of treatment like bloodletting, emetics and purges were aimed at expelling a surplus of a humor. Other methods used herbs and foods associated with a particular humor to counter symptoms of disease, for instance: people who had a fever and were sweating were considered hot and wet and therefore given substances associated with cold and dry. Apocroustics were medications intended  to stop the flux of malignant humours to a diseased body part. 16th-century Swiss physician Paracelsus further developed the idea that beneficial medical substances could be found in herbs, minerals and various alchemical combinations thereof. These beliefs were the foundation of mainstream Western medicine well into the 17th century. Specific minerals or herbs were used to treat ailments simple to complex, from an uncomplicated upper respiratory infection to the plague. For example, chamomile was used to decrease heat, and lower excessive bile humor. Arsenic was used in a poultice bag to 'draw out' the excess humor(s) that led to  symptoms of the plague. Apophlegmatisms, in pre-modern medicine, were medications chewed in order to draw away phlegm and humors. Although advances in cellular pathology and chemistry criticized humoralism by the 17th century, the theory had dominated Western medical thinking for more than 2,000 years. Only in some instances did the theory of humoralism wane into obscurity. One such instance occurred in the sixth and seventh centuries in the Byzantine Empire when traditional secular Greek culture gave way to Christian influences. Though the use of humoralist medicine continued during this time, its influence was diminished in favor of religion. The  revival of Greek humoralism, owing in part to changing social and economic factors, did not begin until the early ninth century. Use of the practice in modern times is pseudoscience. Modern use. Modern medicine refers to humoral immunity or humoral regulation when describing substances such as hormones and antibodies, but this is not a remnant of the humor theory. It is merely a literal use of "humoral", i.e. pertaining to bodily fluids (such as blood and lymph). The concept of humorism was not definitively disproven until 1858. There were no studies performed to prove or disprove the impact of dysfunction  in known bodily organs producing named fluids (humors) on temperament traits simply because the list of temperament traits was not defined up until the end of the 20th century. Culture. Theophrastus and others developed a set of characters based on the humors. Those with too much blood were sanguine. Those with too much phlegm were phlegmatic. Those with too much yellow bile were choleric, and those with too much black bile were melancholic. The idea of human personality based on humors contributed to the character comedies of Menander and, later, Plautus. Through the neo-classical revival in Europe, the humor  theory dominated medical practice, and the theory of humoral types made periodic appearances in drama. The humors were an important and popular iconographic theme in European art, found in paintings, tapestries, and sets of prints. The humors can be found in Elizabethan works, such as in "Taming of the Shrew", in which the character Petruchio pretends to be irritable and angry to show Katherina what it is like being around a disagreeable person. He yells at the servants for serving mutton, a choleric food, to two people who are already choleric. Foods in Elizabethan times were believed to have an  affinity with one of these four humors. A person showing signs of phlegmatism might have been served wine (a choleric drink and the direct opposite humor to phlegmatic) to balance this.