Theory of the four humors

Illustration of the centuryXVI of the four humors: Flegmat (flema), Sanguin (sangre), Coleric (yellow skill) and Melanc (black skills)

The theory of the four humors, also called humorism, humoralism or humoral theory, is a system archaic medicine adopted by ancient Greek and Roman physicians and philosophers that detailed the supposed composition and functioning of the human body based on the interaction between the supposed 4 basic humors: phlegm, blood, black bile, and yellow bile.

Humor began to lose prominence in the 1850s with the advent of the germ theory, which showed that many diseases previously thought to be due to "humoral imbalances" they were actually caused by microorganisms.

History and origins

The concept of "moods" (chemical systems that regulate human behavior) became more prominent beginning with the writings of the medical theorist Alcmaeon of Crotona (c. 540-500 BCE). His list of humors was longer and included the fundamental elements described by Empedocles, such as water, air, earth, fire, etc. The concept of "moods" It seems to have origins in ancient Egyptian medicine, or in Mesopotamia, although it was not systematized until ancient Greek thinkers. The word humor is a translation of the Greek χυμός, chymos (literally juice or sap, metaphorically flavor). The ancient traditional Indian medicine Ayurveda had developed a similar theory of three doshas (doṣas), which were linked to the five elements: earth, water, fire, air and ether.

Hippocrates is generally credited with applying this idea to medicine. Unlike Alcmaeon, Hippocrates suggested that the humors are the vital bodily fluids: blood, phlegm, yellow bile, and black bile. Alcmaeon and Hippocrates postulated that an extreme excess or deficiency of any one of the humors (body fluids) in a person can be a sign of disease. Hippocrates, and later Galen, suggested that a moderate imbalance in the mixture of these fluids produces certain behavior patterns. One of the treatises attributed to Hippocrates, "On the Nature of Man", describes the theory as follows:

The human body contains blood, flem, yellow bile and black bile. These are the things that make up your constitution and cause your pain and health. Health is mainly that state in which these constituent substances are in the correct proportion between themselves, both in strength and in quantity, and are well mixed. Pain occurs when one of the substances has deficiency or excess, or is separated into the body and is not mixed with others.

Although the theory of the four humors appears in some Hippocratic texts, other Hippocratic writers accepted the existence of only two humors, while others refrained from discussing the humoral theory altogether.

Humoralism, or the doctrine of the four temperaments, as a medical theory remained popular for centuries, largely thanks to the influence of the writings of Galen (129-201 CE). Hippocrates' theory of the four humors was linked to 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 were primarily concerned with bodily fluids.. Although Galen believed that humors were formed in the body, rather than ingested, he also claimed that different foods had a variable potential to act on the body to produce different humors. Hot 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 that were created. In this way, it was understood that certain seasons and geographical areas could cause imbalances in the humors, which caused different types of diseases at those times and places. For example, cities exposed to hot winds were thought to have higher rates of digestive problems as a result of excess phlegm coming down from the head, while cities exposed to cold winds were associated with lung disease, acute illness, and "hard intestines", as well as ophthalmia (eye problems) and nosebleeds. Meanwhile, the cities of the west were believed to produce weak, sickly, and pale people who were subject to all manner of diseases.

In the treatise "Aires, Waters, Places", a Hippocratic physician is described as arriving in an unnamed city where he tests various factors of nature, including the wind, water and soil, to predict the direct influence on city-specific diseases depending on the season and individuals.

The theory of humor was enhanced by Galen, who incorporated his interpretation of the humors into his conception of the human body. He believed that the interactions of the humors within the body were the key to investigating the physical nature and function of organ systems. Galen combined his interpretation of the humors with his collection of ideas about nature from philosophers of the past to come up with conclusions about how the body works. For example, Galen maintained the idea of the presence of the Platonic tripartite soul, which consisted of " thumos (vibration), epithumos (directed vibrancy, i.e. desire) and Sophia (wisdom)".

Through this, Galen proposed a connection between these three parts of the soul and the three main organs that were recognized at the time: the brain, the heart and the liver. This idea of connecting vital parts of the soul with parts vitals of the body was derived from the Aristotelian way of explaining physical observations, and Galen used it to build his vision of the human body. Organs (called organa) had specific functions (called chreiai) that contributed to the maintenance of the human body, and the expression of these functions was manifested in characteristic activities (called energeiai) of a person. Although the correspondence of the parts of the body with the soul was an influential concept, Galen decided that the interaction of the four humors with the natural bodily mechanisms were responsible for human development, and this connection inspired his understanding of the nature of the components of the body. body.

Galen takes up the correspondence between the humors and the seasons in his text "On the doctrines of Hippocrates and Plato", and says that, "Regarding the ages and seasons, the child (παῖς) corresponds to spring, the youth (νεανίσκος) to summer, the mature man (παρακµάζων) to autumn, and the old man (γέρων) to winter". He also related a correspondence between moods and seasons based on the properties of both. Blood, like humor, was considered hot and wet. This gave him a correspondence with spring. Yellow bile was considered hot and dry, which linked it to summer. Black bile was considered cold and dry and therefore associated with autumn. And the 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 humours. He believed that phlegm did not influence character. In his On the Nature of Man by Hippocrates, Galen stated: ' The acuity and intelligence (ὀ καὶ συνετόν) are caused by yellow bile in the soul, perseverance and constancy (ἑδραῖον καὶ βέβαιον) by melancholic humor, and simplicity and ingenuity (ἁπν) καὶ) by blood. But the nature of the phlegm has no effect on the character of the soul (τοῦ δὲ φλέγµατος ἡ φύσις εἰς µὲν ἠθοποιῗαν ἄχρηστος)." He further claimed that blood was a mixture of the four elements: water, air, fire and earth.

Humour imbalance, or dyscrasia, was thought to be the direct cause of all disease. Health was associated with a balance of the humors, or eucrasia. The qualities of the humors, in turn, influenced the nature of the diseases they caused. Yellow bile caused heat illness and phlegm caused cold illness. In On Temperaments, Galen further emphasized the importance of qualities. An ideal temperament implied a proportionately balanced mix of all four qualities. Galen identified four temperaments in which one of the qualities predominated (warm, cold, humid or dry), and four more in which a combination of two dominated (warm and humid, warm and dry, cold and dry or cold and humid).. These last four, named for the humors with which they were associated (sanguineous, choleric, melancholic, and phlegmatic), eventually became better known than the others. Although the term temperament would refer only to psychological dispositions, Galen used it also to refer to bodily dispositions, which determined a person's susceptibility to particular diseases, as well as emotional and behavioral inclinations..

Illness could also be the result of "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 into the body. The Greeks and Romans, and later Western European and Muslim medical establishments who adopted and adapted this classical medical philosophy, believed that the proportion of each of these humors would rise and fall in the body depending on diet and activities performed. When a patient suffered from an excess or imbalance of one of the four humors, then the patient's personality and/or physical health could be negatively affected.

The four humors

The four temperaments represented in a wood engraving of the centuryXVIII: phlematic, colic, blood and melancholic.

Although humor theory had several models using 2, 3, and 5 components, the most famous model consists of the four humors described by Hippocrates and developed by Galen. The four humors of Hippocratic medicine are black bile (Greek: μέλαινα χολή, melaina chole), yellow bile (Greek: ξανθη χολή, xanthe chole), phlegm (Greek: φλέγμα, phlegma) and blood (Greek: αἷμα, jaima). Each corresponds to one of the four traditional temperaments. Based on Hippocratic medicine, it was believed that for a body to be healthy, the four humors must be balanced in quantity and strength. The proper combination and state of balance of the four humors was called "eucrasia&#34.;.

These terms correspond only in part to modern medical terminology, in which there is no distinction between black and yellow bile, and in which phlegm has a very different meaning. The humors were believed to be the basic substances from which all the fluids in the body were made. Robin Fåhræus (1921), the Swedish physician who developed the erythrocyte sedimentation rate, suggested that the four humors may have been based on the observation of blood clotting in a transparent container. When blood is drawn into a glass container and allowed to sit for about an hour, four different layers can be seen: a dark clot forms at the bottom (the 'black bile'); on top of the clot is a layer of red blood cells (the "blood"); on top is a whitish layer of white blood cells (the "phlegm"); the top layer is light yellow serum (the "yellow bile").

Many Greek texts were written during the golden age of the theory of the four humors in post-Galenian Greek medicine. One such text was an anonymous treatise called "On the Constitution of the Universe and of Man", published in the mid-century XIX by JL Ideler. In this text, the author establishes the relationship between the elements of the universe (air, water, earth, fire) and the elements of man (blood, yellow bile, black bile, phlegm). Affirming:

• People with red blood are friendly. They joke and laugh at their bodies, and they are pink, slightly red and have a pretty skin.
• People who have yellow bile are bitter, of bad genius and daring. They look green and have yellow skin.
• People composed of black bile are lazy, fearful and sick. They have black hair and black eyes.
• Those who have flem are discouraged, forgotten and have white hair.

Blood

Blood is clearly the product of the digestion of food. The nutritional value of blood was thought to be the source of energy for body and soul. It was also believed that the blood consisted of small proportional amounts of the other three humors. This meant that taking a blood sample would allow the balance of the four humors in the body to be determined. It was associated with a 'sanguineous' nature; (enthusiastic, active and social).

The seasonal association of the blood was spring because the natural characteristics found in individuals were associated with heat and humidity.

Yellow bile

Yellow bile was associated with a choleric nature (ambitious, decisive, aggressive, and short-tempered). It was thought to be a fluid found within the gallbladder, however it could also be found in excretions such as vomit or feces.

The qualities associated with yellow bile were heat and dryness with the natural association of summer and fire. It was believed that an excess of this humor in an individual would lead to emotional irregularities such as increased anger or irrational behavior.

Black bile

Black bile was associated with a melancholic nature, (the word "melancholy" derives from the Greek term for "black bile", μέλαινα χολή melaina kholé). Depression was attributed to an unnatural excess of black bile secreted by the spleen. Cancer was also attributed to excess black bile concentrated in a specific area.

The seasonal association of black bile was with autumn, as the cold and dry characteristics of the season reflect the nature of man.

Phlegm

The phlegm was associated with a phlegmatic nature, described as a reserved behavior. The phlegm of humor is far from the phlegm as it is defined today. Phlegm was used as a general term to describe white or colorless discharges such as pus, mucus, saliva, or sweat. Phlegm was also associated with the brain, possibly due to the color and consistency of brain tissue.

French physiologist and Nobel laureate Charles Richet, when describing "phlegm or pituitary secretion" of humor in 1910, he rhetorically asked, "this strange liquid, which is the cause of tumors, chlorosis, rheumatism and cacochemy, where is it? Who will ever see it? Who has ever seen it? What can we say about this fanciful classification of the humors into four groups, two of which are absolutely imaginary?"

The seasonal association of phlegm is winter due to its natural properties of being cold and wet.

Unification of humor with the model of Empedocles

Empedocles' theory suggested that there are four elements: earth, fire, water, and air, and that earth produces natural systems. Since this theory was influential for centuries, later scholars combined the qualities associated with each mood as described by Hippocrates and Galen with the seasons and the 'basic elements' of the mood. 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

The medieval Islamic medical tradition in the Golden Age of Islam adopted the theory of humor from Greco-Roman medicine, particularly through Persian scholar Avicenna's The Canon of Medicine (1025). Avicenna summarized the four humors and temperaments as follows:

Western Medicine

Typical practices of the 18th century such as bleeding a sick person or applying hot cupping to a person were based on humoral theory of fluid imbalances (blood and bile in those cases). Treatment methods such as bloodletting, emetics, and purges were aimed at expelling an excess of humor. Other methods used herbs and foods associated with a particular humor to counteract the symptoms of illness, for example: people who had a fever and sweating were considered hot and humid and were therefore administered substances associated with cold and dryness. The apocrustics were medicines intended to stop the flow of noxious humors into a diseased part of the body.

The 16th century Swiss physician Paracelsus further developed the idea that beneficial medicinal substances can 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 simple to complex ailments, from an uncomplicated upper respiratory infection to the plague. For example, chamomile was used to reduce heat and reduce excess bile humor. The arsenic was used in a poultice bag to 'pull out' the blood. the excess of humor that was believed to lead to the symptoms of the plague. Apphlegmatisms, in premodern medicine, were medicines that were chewed to eliminate phlegm and humors.

Although advances in cellular and chemical pathology critiqued humoralism in the 17th century, the theory had dominated medical thought. Western for more than 2,000 years and was not definitively refuted until 1858. During this long period, only in a few cases did the theory of humoralism lose pre-eminence in favor of other conceptions. One such case occurred in the 6th and 7th centuries in the Byzantine Empire when traditional secular Greek culture gave way to Christian influences. Although the use of humoral medicine continued during this time, its influence waned in favor of religion. In this case the revival of Greek humor did not begin until the turn of the century IX, due in part to changing social and economic factors.

Modern Usage

The use or practice of humor is considered pseudoscience in modern times. And the concept of humor was definitively refuted in 1858.

When modern medicine refers to humoral immunity or humoral regulation when describing substances such as hormones and antibodies. This is not a holdover from the theory of the humors, but simply a literal use of the term humoral, i.e. relative to bodily fluids (such as blood and lymph).