Res apparentes à veris discernenti, quod remanebit, minimum quidem erit, sed optimum. Symb[olum]. In Te, Domine, speravi non confundar in aeternum! * Cum voto omnigenae felicitatis scrib[ebat] Georg Ernestus Stahl. Halis Magd[eburgicae] 23 Junij MDCCXIV.    * Ps 31:1.

p. 179. Halle, June 23, 1714

Stahl, Georg Ernst
(1660-1734), German natural scientist, physician, chemist

Georg Ernst Stahl was born in Ansbach on October 21, 1660. He received a deeply religious education. He studied in Jena, attending mostly the lectures of Georg Wolfgang Wedel (1645-1721). He graduated and taught here from 1783. At the age of 27 he was appointed court physician of Johann Ernest III (1664-1707), Prince of Saxon-Weimar. In 1693 Friedrich Hoffmann (1660-1742), his former fellow student and then professor of medicine at the recently founded university of Halle, invited him the second ordinary professor of medicine. These two excellent minds in a way distributed the disciples amongst themselves: Hoffmann specialised mostly in the practical branches of medicine, anatomy, surgery, physics and chemistry, while Stahl in physiology, pathology, pharmacology, dietetics and botany. In 1716 Stahl was invited to Berlin as court physician of the Prussian King; he beheld this office until his death. He was a reticent man with an orthodox mind, who could not suffer contrary opinions. He died in Berlin on May 14, 1734. Apart from practical medicine, he also pursued theoretical scholarship. In his Jena lectures, published by his students in 1720, he still professed the principles of alchemy. Later he gradually recognised that metals cannot be transformed into each other, and that the purpose of chemistry is not only gold-making and healing. According to his later definition, chemistry is the science – or art – of the analysis and creation of compound materials. He published his theory of phlogiston in 1697, but its real foundations were laid in the appendix to a work of Johann Joachim Becher (1635-1682) published in 1703. This theory, by admitting a hypothetical material called "phlogiston" (Greek phlogeos = burning) that flows from and into the materials in transformation, had the virtue of explaining on a uniform platform a large number of phenomena until then regarded as isolated, like combustion, processes of metallurgy, fermentation, rottening, respiration, as well as the innumerable independent experiences of alchemists. This first uniform theory of chemical transformations promoted the development of chemistry – interestingly, Carl Wilhelm Scheele (1742-1786), the discoverer of oxygen, also belonged to its believers –, and it was only substituted after a century by the modern theory of oxidation-reduction processes proposed by Antoine Laurent Lavoisier (1743-1794). In physiology Stahl occupied a middle position between earlier theories of chemiatry (jatrochemistry) and modern mechanistic ones with his "animist" thought: living organisms, which are typically composed of water, oil and earth, are saved from decomposing and rottening by an "anima" or "natura" as inner "principium movens", which, however, clearly differs from conscious and immortal soul. According to this theory, medicine has to activise these inner forces of organism. Stahl had some 240 various publications. Some of his principal works: Fundamenta chymiae dogmaticae & experimentalis. Nürnberg, 1723. – Zymotechnia fundamentalis sive fermentationis theoria generalis. Halle, 1697. – Joh. Joachimi Beccheri … Physica subterranea profundam subterraneorum genesin … ostendens … Specimen Becherianum … subjunxit Georg. Ernestus Stahl. Leipzig, 1703. – Experimenta, obsevationes, animadversiones … chymicae et physicae. Berlin, 1731. – Schriften von der Natur … des Salpeters, Frankfurt-Leipzig 1734. – De vera diversitate corporis mixti et vivi … demonstratio. Halle, 1707. – Theoria medica vera … Halle, 1708.

Georg Ernst Stahl wrote his memento in the album of Ferenc Páriz Pápai as a professor of Halle in 1714. Among his fellow professors it was Michael Alberti, and among his students Georg Sigmund Liebezeit of Sopron (Hungary) to write in the album (pp. 427, 351).

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