OBM Integrative and Complementary Medicine Homeopathy in Epidemics: Birth and Evolution of Hahnemann’s Thought (Part 1)

The 19th century saw an explosion of serious epidemic diseases, such as smallpox and scarlet fever, which led to the development of a new medical system called homeopathy. Under this system, S. Hahnemann developed a rigorous methodology based on repeated observations on the field, leading to successful results. The aim of this work is to depict the birth and evolution of his thought. The correct understanding and application of this methodology became the reference model for subsequent generations of homeopaths, who successfully treated some epidemics, such as cholera and Spanish flu. Although these results were well-documented, they were not recognized by the academic community; however, they gave a great impulse to the worldwide spread of homeopathy.


Introduction: Aim of the Work
The rapid spread of homeopathy worldwide in the nineteenth century can be credited to the extraordinary success achieved in the treatment of various epidemic diseases. It is enough to recall the six waves of cholera that hit Europe and the rest of the world hard at the time. However, during the whole eighteenth century, smallpox raged, which caused over 40,000 deaths in England alone [1], (3,000 in London alone), 20,000 in Paris (in 1753), 60,000 in Naples (in 1768), 1077 in Berlin (in 1766), and 2000 in Amsterdam (in 1784). Greenland in 1733 lost three-quarters of its population because of smallpox [2]-a real plague that was resolved thanks to the introduction of the Jennerian vaccination. It is interesting to note how the history of smallpox is closely intertwined with that of homeopathy itself-both, in fact, share curious analogies not only at a chronological level but also, above all, at a methodological level: • Hahnemann's "Essay on a new principle", for example, dates back to 1796, while Jenner's first publication on vaccination in English is from 1798 (the German one is from 1799). Hahnemann himself speaks in positive terms of vaccination practice since the first edition of the Organon (1810). • Hahnemann noted that some diseases, such as smallpox, were able to block and even heal other diseases (measles, orchitis, conjunctivitis, mumps, etc.) with similar manifestations "homeopathically." In fact, as reported in the Organon, "A weak dynamic affection is permanently canceled in the living organism by a stronger affection if this, differing in quality, is very similar in manifestation" [3].
Hahnemann preferred to resort to "similar" remedies rather than the mechanical introduction of pathogenic material-which could have awakened similar long-standing diseases-as they were "more dangerous means of healing than the evils themselves" [4]. Carol Ann Galego, a researcher from the Bosch Foundation, rightly writes, "the application of the principle of similars is based mainly on the observation of the processes induced by remedies capable of producing similar symptoms, rather than in the mechanical insertion of the disease itself" [5].
Nonetheless, Hahnemann recognized vaccination as a form of "homeopathic healing" and considered it to be irrefutable proof of Vis Medicatrix Naturae [6]: "The human smallpox that arrives at the vaccine truncates it completely (homeopathically) both for its greater strength and for its great affinity and not he lets it continue until the end." This is why "… human smallpox… due to the great similarity it is greatly attenuated and made more benign." As a confirmation of this, in footnote 3, he writes that "this seems to be the reason for the beneficial and wonderful phenomenon of Jenner's vaccination, for, which smallpox has no longer appeared epidemically so malignant" [6].
The purpose of this work is to depict the gradual evolution of the Hahnemannian methodologya methodology that subsequent generations of homeopaths have taken as a reference model in the management of several epidemic diseases.

Hahnemann: The Epidemiologist-Smallpox
Hahnemann's first epidemiological observations date back to 1782 when he published a work on the disease "bluetongue" (observed from August 1780 to February 1781) [7]. Subsequently, in 1794-95, as a health officer, he was able to study various epidemic diseases and deepen the concept of prevention. He compiled all the observations and experiences gained between 1792 and 1795 in "The friend of health" [8]. In the first part of this text, Hahnemann recommends the general precautions to be taken while visiting a patient. It also advises taking all precautions with the utmost gradualness to maintain a certain psychophysical balance. He believed that nature does nothing without adequate and careful preparation, so everything must be done gradually. In other words, simplicity and gradualness are the choices made by nature to ensure spontaneous rebalancing. Hahnemann always focused on individuals of the community as he believed that helping the individual means helping everyone. It is a romantic vision-the multitude becomes unique even if the individuality of the answers must be respected in order to avoid undesired side effects. As he wrote in the Organon: "We only get sick when our body has the disposition" [9].
However, Hahnemann's thoughts were not static, in fact, they underwent a significant evolution in subsequent editions of the Organon. In the II (1819), III (1821), and IV (1829) editions, he thinks that vaccination can provide a permanent immunization, whereas, in the V (1833) edition, he omits this consideration [10] and then confirms it again in the VI edition. In the second part of the text, he invites communities and administrators to take a series of preventive measures, such as: − attention to prisoners whose gathering could cause epidemic outbreaks. − social distancing in environmental conditions of closure or constraint (prisons, hospitals, religious communities, and schools), and he suggested prison sentences in case of disobedience.
− the displacement of polluting factories outside the cities. − the disposable clothes must be washed with boiled water. − the ventilation of the houses and the hygiene of the floors must be maintained. − avoid drinking water whose origin is unknown. − avoid the common use of furnishings, metal, or paper coins because they can be a source of contagion. In particular, metal coins must be boiled and fumigated with sulfur.
Finally, he suggests observing a healthy lifestyle and, from a dietary point of view, avoiding excesses. However, the most interesting aspect is the clinical methodology followed by Hahnemann in the symptomatologic study of epidemics. He suggests that a doctor must not be influenced by "some similar case that appeared earlier in the world under this or that name" [11]. On the contrary, "... the pure picture of every dominant disease at the moment must be premised as new and unknown" since "every epidemic has a particular expression that upon careful examination is found very different from all previous epidemics" [11].
Another important aspect of Hahnemann's methodology is the rigorous research of the clinical peculiarities of each epidemic. This is based on the observation that only the accurate collection of the symptoms of many similar cases will allow us to have the complete and characteristic picture of the epidemic. In fact, in footnote 1 of §102, Hahnemann affirms that only on the basis of the totality of symptoms will it be possible to choose the most suitable homeopathic medicine.
From the above-mentioned observations and recommendations, it is clear that Hahnemann's methodology is based on a modern approach, as they are the same measures adopted nowadays. We must not forget, however, that in his day the epidemiological culture was in its beginning stage. Although the origin of the major epidemics could not be determined, compared to previous centuries, an important understanding was settling in among doctors, scientists, and rulers that began to look at Hippocratic medicine with renewed interest. According to Hippocrates, in fact, certain climatic or geographical conditions can be the origin of certain diseases [12].
The Age of Enlightenment, therefore, favored the adoption of prophylactic measures, albeit in an embryonic and empirical manner. Since Hahnemann carried out most of his work at this time, he was inspired by the rational criteria already enunciated by Galileo. Therefore, he chose to base his methodology on the rigor of live observations and on the necessary verification of the same at a qualitative and quantitative level. In other words, he laid the foundation of what he himself would have defined in the following years "The Medicine of Experience" [13]. For him, empirical and rational knowledge are by no means incompatible; on the contrary, they represent different aspects and moments of reality. From a cultural point of view, experience often tends to precede and guide scientific investigations, which, in turn, are appointed to confirm or deny the empirical observation.

Hahnemann and Scarlet Fever
Nowadays, scarlet fever is present in an endemic form in almost all parts of the world, with possible epidemic exacerbations, especially among the infant population. Although there is no specific vaccine, prophylaxis is based on avoiding contact with infected subjects. Currently, it is curable thanks to antibiotic therapies; however, in the past, especially in the 18 th century, there was a world pandemic of scarlet fever, and several severe pandemics occurred in Europe and North America.
During this period, Hahnemann knew that this disease was one of the major health emergencies in Germany. Therefore, from the year 1788, he began to take an interest, especially from a prophylactic point of view [14]. In 1800, he published a series of works [15][16][17] that culminated in the 1801 publication [18], in which he described the preparation and use of Belladonna 30 CH both as a therapy and as a prophylactic medicine. The dilutions used were inconceivable and shocking for the scientific community of the time, just like the initial administration frequency-every 72 hfollowed by long intervals, as confirmed in subsequent works [19,20]. In 1808, Hahnemann summarized the results achieved [21], and in 1810, on the occasion of the first edition of the Organon, he explained the rationale behind the choice of Belladonna: "All the patients of a dominant epidemic have indeed a disease coming from the same cause and therefore the same disease, but the whole complex of an epidemic disease and the totality of its symptoms cannot be observed on a single patient but must be obtained and detected in a totalitarian way from the sufferings of several patients of different constitution" [22]. Also, since all those affected by the epidemic have the same symptoms, it is as if that group behaved as a single individual: "And since the cases of the disease are of similar origin, their manifestations are similar too" [23].
Therefore, according to Hahnemann, while in chronic diseases the homeopathic prescription must be strictly personalized, in epidemics the medicine must take into account the epidemic symptoms as a whole. Also, in epidemics, the doctor's experience is fundamental, as he writes in the Organon "Before 1801, scarlet fever from time-to-time reigned epidemic… I was able to ascertain in Königslutter that those children who had taken, at the right time, a very small dose of Belladonna remained immune" [24].

Conclusions
Epidemic diseases have always been the most challenging health emergencies for humanity. Thanks to the formidable progress made at the diagnostic, prophylactic, and therapeutic levels, today, most of these diseases have been eradicated successfully. However, in the pre-antibiotic era, medical science was almost impotent because of a lack of knowledge and tools to cope with such situations. On the contrary, homeopathic medicine, since its inception, could boast a precise methodology and an efficient therapeutic arsenal, thereby being able to minimize the impact of epidemics. The strategies developed by Hahnemann were not based on empty theoretical ruminations but on the scientific and impartial rigor of his observations, or rather on the experience gained on the field. Thus, it can be concluded that the model he developed represents the reliable and sure point of reference for subsequent generations of homeopaths.

Author Contributions
Dr. F. Negro contributed to Conceptualization and historical research; Dr. Marino contributed to text writing and proofreading.