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Friedrich Hoffmann Edit Profile

chemist , physician

Friedrich Hoffmann was a German physician and chemist. He was a leading medical systmatist of the first half of the eighteenth century.


Friedrich Hoffmann was born on 19 February 1660 in Halle.


In 1678 the younger Hoffmann went to Jena, where he studied medicine for two years under the direction of Wedel.

His interest in chemistry lured him for a short period to Erfurt, where he attended the chemistry lectures of Cramer.

In 1681 he received his M. D. from the University of Jena and was allowed to teach there.

But the subsequent success of Hoffmann’s chemistry lectures reportedly provoked the jealously of Jena’s senior faculty, and the young physician soon left for the city of Minden, where his brother-in-law provided him with an official, salaried position.

Given the privilege of selecting a second professor of medicine, he brought to the university in 1694 a former fellow student at Jena, Georg Stahl, originator of the phlogiston theory.

In 1709 Hoffmann was called to Berlin by Frederick I to become the ruler’s personal physician.

In 1734 Hoffmann was again summoned to the Prussian court, owing to the recommendation of Boerhaave; as physician he served Frederick William I for about eight months and then returned to Halle.


Haffmann was charged with the organization of the medical school, and his success in the new institution was immediate.

He remained only three years at the court, which was oppressively beset with petty intriguing.

After extricating himself from this situation, Hoffmann returned to Halle to resume teaching and medical practice.

From the time of Hippocrates, physicians had sought to discover and establish the fundamental laws governing the phenomena of health and sickness.

It was long believed that medicine would become a truly scientific endeavor, rather than a purely empirical craft, only through the apprehension of rational causes and an understanding of the mechanisms producing disease.

This outlook led in time to formulation of an elaborate paradigm of so-called balanced and corruptible humors.

The animal spirits, for example, were visualized by Hoffmann as volatile, ethereal corpuscles of matter flowing through the nervous system.

To explain the functions of the body, Hoffmann relied heavily on the Cartesian hydrodynamic schemes.

According to these, the various humors flowed through the body’s vessels at different rates, depending upon the diameter of the vessels.

In these activities the ethereal spirits were directed by an anima, or sensitive soul, which Hoffmann conceived of as a subtle, hypothetical form of matter on which God himself had directly impressed motion.

Responsible, in an Aristotelian sense, for the form of the body, this soul, or “nature, ” possessed mechanical powers, or virtues, responsible for the purposeful and apparently goal-directed activities of the organism; moreover, it constituted the material link with the immaterial and rational human mind created by God.

Accordingly, Sprengel tried to interpret Hoffmann’s ethereal spirits as veritable aggregates of monads which directed and coordinated their own activities according to a general plan.

Tone in the fibers could also be influenced by the animal spirits, he held, rather than being dependent solely on immanent physical cohesiveness.

To Hoffmann, the prerequisite for good health was proper circulation of the humors, attributable to normal tension or tonus in all the fibers.

Disease, on the other hand, was the result of distorted vital actions arising from impaired humoral motions and resultant changes in the solid parts of the body.

Many of these disturbances were caused by abnormal motions of the ethereal animal spirits.

These spirits increased the tone of certain fibers, producing vascular and intestinal spasms or a diminished fiber tension called atony.

According to Hoffmann, local humoral stagnations led in turn to a series of chemical changes responsible for many local lesions.

He followed closely the corpuscular views of contemporary physics and chemistry and tried to interpret physiology and pathogenesis strictly in terms of matter and motion.

His formulations of a series of general principles for understanding the human organism, as well as the formulations of other eighteenth-century systematists, led to the more precise investigations that laid the theoretical foundations of modern medicine.

Hoffmann maintained a lifelong interest in chemistry.

His primary contributions here were in the investigation of mineral waters, specifically in improving contemporary analytical methods and distinguishing essential components.

Hoffmann studied spiritus mineralis (carbon dioxide) in water, which he characterized as a weak acid intermixed with various salts.

He also discerned the presence of sulfates in certain waters and clearly separated magnesia from lime.

The hot springs of Carlsbad especially interested Hoffmann, who explained that the high temperatures of the waters were caused by a chemical reaction involving sulfur, iron, and oils.

Another of his studies, having clear medical implications, was his description of carbon-monoxide poisoning from the fumes of burning charcoal (1716).

While taking substantial issue with Stahl’s medical theory, Hoffmann accepted many of his chemical ideas, one exception being that of the existence of phlogiston in metals.


  • In 1693, shortly after the establishment of the University of Halle, he was appointed primary professor of medicine and natural philosophy.

    During his career there, he held the position of rector three times. With the exception of four years (1708–1712), which he passed at Berlin in the capacity of royal physician, Hoffmann spent the rest of his life at Halle in instruction, practice and study, interrupted now and again by visits to different courts of Germany, where his services procured him honours and rewards.

    His fame became European. He was enrolled a member of many learned societies in different foreign countries (including being elected Fellow of the Royal Society in 1720), while in his own he became privy councillor.



Hoffmann was a fellow of the Royal Society of London and a member of the Berlin Academy of Sciences, and in 1735 was elected to the Imperial Russian Academy of Sciences in St. Petersburg.


Kurt Sprengel