GEORG STAHL: BIOGRAPHY, PHLOGISTON THEORY, VITALISM - ARTE - 2024

Georg Stahl (1659-1734) was a German-born physician, chemist, and theorist who became well known for being the founder of the phlogiston theory of combustion. In addition, he had great relevance in the scientific world because he was the author of vitalist ideas within the area of ​​medicine.

The phlogistic theory, already refuted, was the most relevant contribution he had throughout his career. This theory, which had to do with combustion, became one of the most remarkable principles that served to unify the chemistry of the 18th century.

Source:], via Wikimedia Commons. In his theory of phlogiston, Stahl assured that the different substances that were burned contained a fuel that received the name of phlogiston (which means "flammable or flame" according to Greek philologists), which was released during the combustion process.

Biography

The first years of Georg Stahl's life were spent in a parish of St. John in Ansbach, in Brandenburg, Germany. There he was born in 1659.

Georg Ernst Stahl was the son of Johann Lorentz Stahl, who served in different positions of great importance. For example, he was secretary of the Ansbach court council and also served as clerk of the Anhalt-Brandenburg church session.

He was married three times and, unfortunately, his first two wives died of puerperal fever. This is a disease that affects women after childbirth, due to an infection that occurs from the wounds generated by pregnancy.

Pietism was a fundamental part of his life. This was a religious doctrine that was part of the Lutheran movement and that, although it began in the seventeenth century, its greatest peak occurred during the eighteenth century, a time that the German doctor lived.

Stahl acquired his first knowledge in his hometown, where he showed great interest in chemistry thanks to the influence exerted on him by his professor of medicine Jacob Barner, as well as the chemist Johann Kunckel.

By 1679 Stahl enrolled at the University of Jena with the goal of studying medicine. This faculty was one of the most recognized at the time for its focus on chemical medicine, deepening the application of chemistry in medical processes or phenomena.

Jobs

Stahl graduated in 1684 and began working as a teacher, albeit without pay. This stage lasted three years, until he became the personal physician of Prince Johann Ernst of Saxe-Weimar.

Years later, in 1694, Stahl held the position of professor of medicine at the University of Prussia in Halle, which had only been in business for a very short time. Then, in 1716, Stahl resigned from his teaching duties to dedicate himself fully to being the personal physician to King Frederick I of Prussia, a role he held until his death in 1734.

Phlogiston theory

Georg Stahl's most important theory was that of phlogiston. For its development it was based on the ideas of the German physicist Johann Joachim Becher, who raised the basic principles of the theory, but did not go into the experimental part. Phlogiston was born then as a principle of flammability. The word in Greek meant "to burn."

Stahl was responsible for experimenting with the phlogiston theory and that it could be applied in chemistry. His work was based on showing that the phlogiston separated from the elements when the combustion process was applied to them.

Stahl stated that phlogiston could be released by burning sulfurous minerals (which were those formed by sulfur and metallic elements). Phlogiston was also released by burning plant substances that were in the process of fermentation or in pieces of animals that were in the rotting phase.

The phlogiston theory mutated over time and became the oxidation theory, principles proposed by the French chemist Antoine-Laurent Lavoisier. Despite this change, Stahl's theory of phlogiston was seen as the step from alchemy to chemistry, the merit of the German chemist being respected even though his theory had been disproved.

Vitalism

Vitalism emerged in the 18th century thanks to the thoughts put forward by Georg Stahl in his studies. One of the theses of the chemist, who sustained this new trend, was in which he spoke of the difference that existed between different living organisms and bodies that were inorganic.

Stahl pointed out that organic bodies had a decomposition process that was very fast once their life ended, while he claimed that inorganic bodies rather had a much more stable chemical permanence.

After these statements he was able to conclude that the rapid decomposition of organic bodies must be a direct consequence of their material nature, which is the same as their chemical composition.

Anima

Stahl named this analysis as the beginning of life. He also gave it the name 'natura' (which originates from nature) and at other times he used the term 'anima' (which refers to the soul). In this case, the anima functioned as a natural reason.

This natural reason that Stahl spoke of when referring to the anima was considered the source that gave the organism self-healing powers. When natural reason was confused with logical or critical reasoning, as is the case with emotions, it led to the birth of diseases.

This dual characteristic of Stahl's life principle laid the foundations for physiology and pathology. He established that the work of doctors should be focused on working to restore healing power through careful observation.

Opposition to the mechanical

Stahl never agreed with the proposals and ideas of mechanical physicians, better known as iatromechanics. These doctors did not have the role of the anima, but the vital, physiological or pathological phenomenon on which they were based were mechanical principles.

For Stahl this was a mistake. The German argued that machines would never be able to respond with the speed, accuracy and naturalness with which the body itself responded to any threat or need.

In spite of everything, Stahl did not completely reject any mechanical element in the vital function, recognizing the importance of the tonic movement. This referred to a contractive and relaxing movement in parts of the body (or tissues) that played a relevant role for metabolism. Although, for Stahl, it was the anima that directed these movements.

Although with the passage of time the vitalists were discarding the ideas about the anima, some highlighted Stahl's thesis where he differentiated between living organisms and machines without lives.

Other contributions

Stahl's contributions to the scientific world could be observed thanks to the large number of experiments he carried out at the chemical level on oils, salts, acids and metals. His publications were often devoted to topics that had to do with practical chemistry.

Among other research, he dealt with topics such as brewing, the dyeing process, the production of saltpeter and the processing of minerals.

His work was also focused on defending the contribution made by science and the chemical industries to other areas, especially the benefit it generated for the economy at the national level.

Stahl was a faithful believer in the existence of the alchemical transmutation of metals when he began his career. This thought was changing with the passage of time and finally he was a skeptic of alchemy.

As a teacher he had a lot of influence on those who sought his knowledge. Some of his students had a prominent presence in German academic institutions, as well as in government positions.

His fame as a medical thinker did not reach higher peaks due to the presence of Hermann Boerhaave and Albrecht von Haller, from Leiden State University in the Netherlands and the University of Göttingen in Germany, respectively. The ideas of these doctors had a great impact in Europe and became mainstream, something that overshadowed the figure of Stahl.

The phlogiston theory proposed by Stahl was categorically accepted in Europe, but was soon displaced by the chemical revolution, which began in the 1980s, at the hands of the French chemist Antoine-Laurent Lavoisier.

Plays

Among the most relevant works carried out by Georg Stahl during his career are five publications made between 1697 and 1730.

In 1702, he published Specimen becqueriano which was a work where Stahl established a favorable position on the theory put forward by Becher in relation to combustion. It was here that Stahl captured his ideas on the phlogiston theory.

Despite its significance, his story has not been widely publicized, in fact, there are no relevant studies on Stahl's life in English. Only authors such as John Stillma and James Partington spoke about their contributions to the area of ​​chemistry in some of their works.

References

1. Chambers, R. (1856). Modern History. Edinburg: W. & R. Chambers.
2. Martini, A. (2014). The renaissance of science. Florida: Abbott Communication Group.
3. Porter, R. (2008). The Cambridge history of science. Cambridge: Cambridge University Press.
4. Thompson, C. (2012). Alchemy and alchemists. Mineola, NY: Dover Publications.
5. Zumdahl, S., & DeCoste, D. (2013). Chemical principles. California: Brooks / Cole.