What is frequently spoken of as the power of nature—the “vis conservatrix et medicatrix naturae”—resides entirely in the rational soul. Stahl supposes that upon many occasions the soul acts independently of the body, and that, without any physical necessity arising from that state, the soul, purely in consequence of its intelligence, perceiving the tendency of noxious powers threatening, or of disorders any ways arising in the system, immediately excites such motions in the body as are suited to obviate the hurtful or pernicious consequences which might otherwise take place.
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 it existed. At the same time the fact should here be stated that the terms “oxidation” and “reduction,” which came into use during the following century, developed out of this theory of phlogiston.
Friedrich Hoffmann.—Friedrich Hoffmann was born at Halle, Prussian Saxony, February 19, 1660, and received his medical education in his native city, largely under the direction of his father, who was himself a physician. In 1678 he attended lectures at the University of Jena, and in the following year visited Erfurt in order to benefit from the instruction of Caspar Cramer, who was at that time a distinguished authority in chemistry. At the end of two years he returned to Jena, took his degree of Doctor of Medicine, and acquired the right to deliver public lectures. Then, during the following three years, he visited Holland and England, and, upon his return in 1685, settled at Minden, Westphalia, as a general practitioner of medicine. In 1686 he was appointed District Physician of the Principality of Minden and also Court Physician of the Prince Elector; and two years later he accepted the position of District Physician at Halberstadt. After the inauguration of the new university at Halle, July 12, 1694, Hoffmann appears as one of the earliest professors chosen to serve the institution. In 1701, when Frederick the Third, Electoral Prince of Prussia, assumed the crown under the title of Frederick the First, King of Prussia, he extended to Hoffmann an invitation to come to Berlin and accept the position of Private Physician to His Majesty. Hoffmann was not at first willing to accept the invitation, but in 1708, when the King, who had then become seriously ill, renewed his request, Hoffmann accepted, on condition that he might retain his professorship. In 1712 he returned to Halle and remained there until he died in 1742.
Before Hoffmann’s time very little was known concerning the nature of carbonous (or carbonic) oxide and concerning the fatal effects which may be produced by inhalation of this gas. It was a common belief, for example, that the gas was given off by freshly plastered walls; and—as an even worse error—the theological authorities showed an inclination, in many of the fatal instances which probably were due to inhalation of carbonous oxide, but in which no recognizable cause of death had been discovered, to explain the event as due to the malign interference of the Devil. In our time it is well understood in the community that the fumes of carbonous oxide constitute the most dangerous gas that one is liable to encounter, but in Hoffmann’s day the people appear to have been less well informed concerning this danger than they were in ancient times. In the treatise on this subject which Hoffmann published in 1716,[81] several of the earliest known instances of such poisoning are narrated, the first one being that mentioned very briefly by Aristotle (384–322 B. C.). Then follow two very short references to this subject in the “De rerum natura” of the Roman poet Titus Lucretius Carus (95–52 B. C.). They read as follows: (1) “The fumes of burning charcoal easily affect the brain if thou hast not first taken a drink of water.” (Book VI., verse 803.) (1) “If the fumes of the night lamp,[82] after it has been extinguished, are inhaled rather deeply the effect experienced will be the same as if one had been struck down by a blow on the head.” (Book VI., verse 792.) The idea that the previous drinking of water is competent to prevent the effects of poisoning by charcoal fumes is declared by Neuburger, the translator of Hoffmann’s treatise, to be erroneous.
The earliest really satisfactory description of an instance of non-fatal poisoning by the fumes of burning charcoal is credited by Hoffmann to the Roman Emperor, Julian the Apostate, who reigned from 361 A. D. to 363 A. D. Before he was made Emperor, Julian was intrusted by Constantius II., in 355 A. D., with the government of the Province of Gaul, and in 357 he won a great battle against the Alamanni at Strassburg; after which he took up his residence in the little city of Lutetia, the present Paris. It was undoubtedly soon after this event that he wrote the Greek satire which bears the title “Misopogon,” and from which Hoffmann quotes the following account of Julian’s narrow escape from death through the poisonous effects of carbonous oxide:—
The little city which the Celts call Lutetia is built upon a small island in the midst of a river, and access to it from both sides is gained by means of wooden bridges. Ordinarily the winter climate in this region is mild, owing—as the people of the place claim—to the proximity of the Ocean. Good wine is produced there, and even fig-trees flourish provided care be taken to wrap them well in wheat straw or some similar protective material during the winter season. But my visit happened to have been made during an exceptionally severe winter, and as a result things which looked like slabs of Phrygian marble, closely packed together, were constantly floating down the river with the current, and, soon becoming jammed, they formed a sort of natural bridge. Although most of the houses—the one I occupied among the number—were provided with fireplaces and chimney-flues, and might therefore readily be heated, I was not willing that a fire should be kindled in my bedroom. I was very little sensitive to cold, and, in addition, I was desirous of becoming more and more hardened to its influence.... As the severity of the weather, however, showed no signs of letting up, I permitted the attendants to bring into the room a few glowing coals, just enough to render the air of the chamber less chilly. But, notwithstanding the very small degree of heat which these few burning coals supplied, it proved to be sufficient to draw out from the damp walls exhalations that caused my head to feel as if it were tightly held in a vice and also produced a sensation as if I were choking. I was immediately removed from the room, and the physicians who were promptly summoned administered an emetic which enabled me to get rid of the food which I had eaten a short time before. Soon afterward I had a refreshing sleep and was able on the following day to resume my work as usual. [Translated from the German version printed in Neuburger’s monograph.]
As will be seen from the reports which I have just quoted, there existed among the Germans, early in the eighteenth century, no fixed belief as to the real cause of death in many of these unexplained fatal cases; and it was therefore no small public service which Hoffmann rendered when he, in whose judgment about such matters the people at large placed the greatest confidence, published such a clear and simple explanation of the real cause of these deaths as that which is given in this interesting monograph.