Barthélemy St. Hilaire of Paris (1805-1895) in one of his writings says: "I am convinced that the central idea in Stahl's physiology was suggested to him by the reading of Aristotle's 'De anima,' in which this great philosopher states that the soul nourishes the body, and also that nutrition is one of the four ways in which the soul manifests itself."
Speaking of the effect of Stahl's doctrines upon the actual practice of medicine as a whole, Cullen says that it was of a controlling character, leading physicians to propose the "art of curing by expectation"; the natural result of which was that they advocated for the most part the employment of only very inert and frivolous remedies. On the other hand, they zealously opposed the use of some of the most efficacious drugs, such as opium and the Peruvian bark, and resorted to bleeding and to the administration of emetics only in exceptional cases. Cullen adds that:—
The Stahlian system has often had a very baneful influence on
the practice of physic, as either leading physicians into, or continuing
them in, a weak and feeble practice, and at the same time
superseding or discouraging all the attempts of art. . . . The
opposition to chemical medicines in the sixteenth and seventeenth
centuries, and the noted condemnation of antimony by the Medical
Faculty of Paris, are to be attributed chiefly to those prejudices
which the physicians of France did not entirely get the better of
for near a hundred years after. We may take notice of the reserve
it produced in Boerhaave with respect to the use of the Peruvian
bark.
Stahl, after taking up his residence in Berlin, devoted
himself energetically to the increase and spread of the
knowledge of chemistry. The thing which brought him the
greatest celebrity, both in his own lifetime and also during
the years following his death, was his propounding of the
"phlogiston" theory. This theory was to the effect that
all combustible materials or substances contain (as he
assumed) an element to which he gave the name of
phlogiston. He was not able, however, to demonstrate the
actual existence of this element; he simply assumed that
