The first Homeopathic Materia Medica

Questions and research objective

Both the work with homeopathic pharmacopoeias in therapeutic practice and revision projects repeatedly raise questions about Hahnemann's concept of Materia Medica (see also Pharmacy & Pharmacology - Steps to the homeopathic Materia Medica). This concerns the methodology of the first systematic provings as well as the integration of practical experience. This gives rise to questions that are still relevant today:

• According to Hahnemann, why should people who are as healthy as possible take part in drug trials?
• How healthy were Hahnemann's test subjects really?
• How reliable are the observed reactions?
• How high is the proportion of observations not obtained from drug trials?
• How can it be clearly determined which effects are actually due to the substance taken when using very small doses?
• How can pharmacologically and therapeutically relevant knowledge be extracted from the wealth of observational data?

These questions form the starting point for the present research.

The need for modern terminology

The development of homeopathy gave rise to a specific terminology whose terms can only be understood in the context of this specialised discipline. Over the course of 220 years, specialised terms have become established and have become part of the language used in homeopathy. With the later development of modern pharmacology, other terms have evolved.

Originally, terms such as "proving", "provers" or "proving symptoms" were used in homeopathy to empirically experimentally record and lexically catalogue the effects of individual substances on participants in systematic drug trials. In current pharmacological terminology and practice, the term proving (German: Arzneiprüfung) is defined differently and represents not only a research element, but also an integral part of the quality guidelines (drug control), in particular the Good Manufacturing Process (GMP).

Significance for interdisciplinary exchange

This example makes it clear that homeopathic terminology must be unambiguous on the one hand, and on the other hand terms must be adapted to the scientific language used today. Clear definitions that are compatible with current research enable a more precise description of concepts and promote further scientific development.

Between tradition and contemporary terminology

The decision between historically evolved terms and modern technical terms is more complex than it seems at first glance. It concerns not only the language itself, but also the underlying thinking styles based on certain models, views and contexts of reasoning. Modern terminology not only contributes to a more precise description of current findings, but also opens up new perspectives on scientific contexts. It forms the basis for underpinning scientific progress with current concepts and continuing historical developments in a reflective manner. Careful analysis and consideration are therefore essential in order to shape linguistic and conceptual change in a well-founded manner.

Adaptation of terminology

In current pharmacological research, historically evolved, homeopathy-specific terms are replaced - where possible - by more precise and contemporary terms:

• Drug proving (German: Arzneiprüfung) → Drug trial
• Drug prover (German: Arzneiprüfer) → (Study) Participant / Test Subject
• Proving protocol (German: Prüfprotokoll) → Test Protocol / Drug documentation
• Proving symptom (German: Prüfsymptom) → Drug Effect (Drug reaction^[1], Drug symptom^[2])

However, complete terminological consistency cannot always be guaranteed in a transitional phase, especially if original quotations from historical sources contain the original terms.

As a pioneer of experimental pharmacology, Samuel Hahnemann coined key terms such as Arzneimittelprüfung and Arzneiprüfung. His methodology was innovative for his time and these terms are still important in homeopathy. For this reason, the term homeopathic drug proving (HDP) (German: Homöopathische Arzneimittelprüfung - HAMP) has been retained. The suffix H in HDP and HAMP clearly distinguishes the specific specialist terminology within homeopathy from general pharmacological terms.

Just as subject-specific terminology currently requires adaptation, today's readers can more easily understand original text passages and quotations if they follow the currently valid rules in terms of spelling, grammar and linguistic style. For this reason, most of the quotations in the following text have been glossed. The references make it possible to find the passages in the original wording.

Hahnemann's pharmaceutical research - history and methodology

While the concept of the simile principle was maturing in Hahnemann, he was looking for a clear and applicable pharmacotherapeutic method.

In July 1808, Hahnemann explained in a Brief an einen Arzt von hohem Range that appeared in the Allgemeine Anzeiger der Deutschen that he had already been deviating from the usual approach to medicine for 18 years (Hahnemann, 2001). He addressed this declaration not only to his friend, the "doctor of high rank", but deliberately to the public.

It is noteworthy that Hahnemann felt compelled to break new ground in medicine for ethical reasons. In addition to his moral concerns - he felt that the unconventional approach of medicine at the time was a "piaculum", i.e. comparable to a ritual of atonement to the gods - his personal experience as a young father also played a decisive role.

"But I had children, several children, and then gradually serious illnesses set in, which, because they tormented my children - my flesh and blood - and put them in danger, made me feel guilty that I couldn't help them with any reliability.

But where can we get help, certain, sure help, with our doctrine of the powers of medicines based merely on vague observations, often merely on conjectural opinions, and with the innumerable number of arbitrary views of disease in our pathologies?" (cf.: Hahnemann, 2001g, p. 491 f.; author’s transl.)

Between 1783 and 1806, he and his wife had eleven children, nine of whom survived. The financial and medical care of such a large family was an immense challenge. It is obvious that these experiences had a formative influence on his research as a doctor. So he reflected:

"How could you now" (- I began to find my way -) "find out from the remedies for which disease states they are created? [...]

"You must," I thought, "observe the remedies as they affect the human body when it is in the calm waters of health. The changes that the medicines cause in the healthy body do not exist for nothing, they must mean something" (cf: Extract from a letter to a physician of high rank (1808) in: Hahnemann, 2001g, p. 493, author’s transl.) .

It is not surprising that Hahnemann, as a young father and doctor, was initially particularly interested in treatment options for the epidemic paediatric disease scarlet fever.

Pharmacological research using the example of scarlet fever

As early as 1788, when he was still practising in Dresden, he wrote an essay on how complications could be prevented after a scarlet fever epidemic. (Verhütung der Geschwulst nach dem Scharlachfieber (1788 ) in: Hahnemann, 2001a, p. 77 ff.)

In 1801, Hahnemann published a more comprehensive treatise on the disease (Heilung und Verhütung des Scharlach-Fiebers in: Hahnemann, 2001c, pp. 299-311)

He was referring here to the scarlet fever epidemic that came to Königslutter at the beginning of 1799 and then spread there in the middle of the year.

"Scarlet fever, as in all other epidemics, was the most transmissible and infectious of all childhood plagues. If a single child was afflicted with it, neither siblings nor other children who came too close to the sick or to things contaminated with their vapours were spared." (cf.: Hahnemann, 2001c, p. 300; author’s transl.)

At the very beginning of his pharmacological research, Hahnemann devoted himself to the effects of belladonna (Atropa belladonna), which proved helpful in the treatment of scarlet fever.

Because how else could a doctor know about a medicine?

"which sensory organs belladonna inhibits in their function, which it influences in other ways, which nerves it mainly anaesthetises or excites, which changes it causes in the blood circulation and digestive system, how it influences the mind and the spirit, what effect it has on certain excretions, what effect it has on the musculature, how long its effect lasts - and by what means it can finally be reversed [...]"? ( cf: Über die Kraft kleiner Gaben der Arzneien generell und der Belladonna insbesondre (1801) in: Hahnemann, 2001d, p. 349; author’s transl.).

Apothekerlexikon (Pharmacists' encyclopaedia) - A comprehensive literature search

In the preceding years, Hahnemann had already collected pharmacological, toxicological and clinical findings from both the specialist literature and the traditional knowledge of lay healers. This extensive research found expression in the Apothekerlexikon, the four parts of which were published between 1793 and 1799. As a critic of medicinal mixtures, he wanted to create a solid basis for sound pharmacotherapy with the detailed information on the homeopathic drug substances commonly used at the time. The respective substances include information on their origin, production, suitable dosage as well as his own experiences with simple medicines.

The path to systematic drug trials

As a doctor at this time, Hahnemann prescribed medicines in quantities of a few granules^[3] . In his essay Versuch über ein neues Prinzip zur Auffindung der Heilkräfte der Arzneisubstanzen published in the Hufeland Journal in 1796, he mentioned self-experiments for the first time. He wrote that taking a gram of Aethusa helped him to regain his mental concentration after severe exhaustion. (Hahnemann, 2001b, p. 227) He had also trialled other substances at this time.

After he did not notice any lasting harmful effects on himself, he extended the scope of his drug trials to family members. He published the results of this initial experimental research in Latin in 1805 under the title Fragmenta de viribus medicamentorum : positivis sive in sano corpore humano observatis (Hahnemann, 1805). In this work, he summarised the effects of remedies that he had obtained from his literature research and initial systematic experiments. He carried out these experiments with tinctures made from powdered plant parts or thickened pressed plant juices as well as with substances dissolved in alcohol or water. (Schmidt, 2007; Wettemann, 2000)

As his experience grew, Hahnemann's conviction that the entire healing power of a remedy lies in its ability to change the human condition became more firmly established. This state-altering effect, which can be perceived after ingestion, should therefore be structured and researched for as many substances as possible. Hahnemann used this as the basis for his appeal to students and colleagues to carry out systematic drug trials themselves - starting with self-experiments.

Research into drug effects

Precursor of Hahnemann

Paracelsus (1493-1541) already recognised that the boundary between the poisonous and healing effects of a substance is often blurred. References to the principle of similarity and its individual application can be found throughout his work. However, Paracelsus did not systematically elaborate on these approaches.

In the preface to his Pharmacopea Helvetica (1771), Albrecht von Haller (1708-1777) called for drug trials on healthy people. Hahnemann refers to Haller in the footnote to the Organon § 108 (6th edition) and reproduces his demand in the following words:

"Of course, the medicine must first be tried in a healthy body, without any foreign mixture; and after having investigated its odour and taste, one should take a small dose of it and observe all the affects that come in contact with it, which pulsate, which heat, which respiration, which excretions. From there to the course of the phenomena observed in the healthy body, on to the experiments on the diseased body, etc." (Hahnemann, 1996 ; translation from Latin by linguatools.net; cf. Tischner, 1998, p. 93; Tischner points out that this is not a literal quote from Haller, but only one that has been reproduced analogously)

This approach, which was extremely innovative for its time, seems like an early anticipation of modern pharmacology, as it demands that a medicine is first tested on volunteers before it is used on patients. From today's ethical perspective, this principle corresponds to the principle of Primum non nocere - "first do no harm". In this sense, homeopaths were ahead of their time.

Another important impulse came from Anton von Störck (1731-1803), an important representative of the First Viennese School. In the second half of the 18th century, he carried out experiments on himself to investigate the dose-effect relationships of medicines. Hahnemann mentions that he was inspired by the "marvellous efforts of Baron Anton von Störk" in his essay Was sind Gifte? Was sind Arzneien? (1806) (in: Hahnemann, 2001f, p. 457)

In addition to Störck, he also refers to Conrad Gesner (1516 - 1565), William Cullen (1710 - 1790), William Alexander (? - 1783), François Coste (1741 - 1819) and Rémi Willemet (1762 - 1790), who already used "simple remedies alone and without mixing in certain diseases or in the healthy body". ( Aeskulap auf der Wagschale (1805) in: Hahnemann, 2001e, p. 382; author’s transl.)

Hahnemann's sources on pharmacology

Hahnemann used three sources to research the effects of medicines:

1. (Systematic) drug trials on volunteers (Homeopathic Drug Provings - HDP)
2. Toxicological case reports and information from clinical publications,
3. Observations and insights gained in the treatment of chronically ill patients.

Source 1: Drug trials on healthy people

Hahnemann explained at various points how he carried out his homeopathic drug provings (HDP), what was important to him, what experiences he made and how he dealt with the drug documentation:

We find statements on this as early as 1805 in the preface to the Fragmenta (Schmidt, 1995), in the preface (vol. 1) and in the preliminary reminiscence (vol. 2) of the work Reine Arzneimittellehre (Hahnemann, 1995; reprint of the 3rd edition of 1830) and in the newspaper article Wie Sam. Hahnemann seine Arzneyprüfungen angestellt habe? The latter appeared in the Allgemeine Anzeiger of 13 July 1839 (Hahnemann, 1839).

Hahnemann provided a detailed methodological overview and instructions for systematic drug provings on healthy volunteers (HDP) in the Organon of Medicine (6th edition) in §§ 105 to 145. In the course of the various Organon editions, he made additions and slight modifications in some cases.

In order to ensure as far as possible that the reactions caused by the remedies were not the result of other influences and were not mixed or falsified with individual symptoms of the test subjects, Hahnemann attached great importance to consistent test conditions and imposed the condition that none of his participants were acutely ill:

"In my own experiments as well as those of my students, attention was paid to all those circumstances that could contribute to the greatest possible purity of the results - so that the true potency of each medicinal substance could be shown as clearly as possible in the perceptible reactions. The experiments were carried out on persons as healthy as possible and under largely equal and moderate external conditions." (cf.: Hahnemann, 1995, Preface p. 5, author’s transl.)

But could these conditions really be met? Up to what point was a subject considered "as healthy as possible" and when was he or she no longer eligible for participation? It was not only Hahnemann and his colleagues at the time who were very concerned about this. Critics raised justified objections regarding the reliability of the procedure and consequently the data collected in this way.

Irrespective of this, treatment successes have already been recorded in the practical application of the knowledge gained about drug effects.

The section on “Source 3” discusses in more detail how the ostensible contradiction was dealt with, namely that the test subjects should be as healthy as possible and at the same time Hahnemann also collected data from people who were obviously chronically ill, as they could obviously also make valuable contributions to the knowledge of medicines.

Source 2: Clinical publications

"At the end of each medicine I have added what the writers of medicine have noted of the positive powers of the medicines - by dealing with something else, so to speak." (Fragmenta, Hahnemann, 1805; quoted from: Schmidt, 1995, p. 97; author’s transl.)

What some of these medical writers dealt with were stories of poisoning, from which Hahnemann knew how to draw information:

"I also saw that the pathological effects which writers before me had described after the ingestion of medicinal substances which had entered the stomach of healthy persons in large quantities by mistake, with the intention of killing them or under other circumstances, corresponded in many respects with my own observations in experiments with the same substances on myself and other healthy persons. [...]

None of these observers, however, suspected that the symptoms they presented merely as evidence of harmfulness or poisonous action contained certain indications of the potential of these substances to cure complaints similar to them and that these disease-like manifestations were already indications of their homeopathic efficacy." (see: Organon § 110, Hahnemann, 1995; author’s transl.)

He also analysed well-documented treatment trials with individual substances:

"Among the strange observations included here are some that were recorded on sick persons. But as they were chronic sufferers with known symptoms of disease, which were not mixed with the new effects of the experimental remedy, to which Greding apparently paid careful attention, these observations serve in some places as confirmation when similar or the same symptoms appear in pure provings on healthy persons." (cf.: Hahnemann, 1995, Preface p. 4 f.; reprint of the 3rd edition of 1830; author’s transl.)

Clinical observations from medical literature

For the remedy Stramonium, Hahnemann took 191 drug reactions from Johann Ernst Greding's work Sämtliche medizinische Schriften (Greding, 1790). In the chapter Observations on the power and effect of the extract from the datura (Datura Stramonium Linn.) in curing melancholic and dropsy diseases, Greding describes his sometimes unsuccessful treatment attempts with a Stramonium preparation. He carried out these experiments on people "who had long been afflicted with frenzy and at the same time with six others of this kind, who could by no means be brought to their former perfection of mind by the henbane" (cf.: Greding, 1790, pp. 37-102; author’s transl.).

This is not an exception, but makes it clear that the observations taken from the medical literature do not only include clinical healing experiences or symptoms of poisoning, but that Hahnemann also specifically incorporated information from (treatment) experiments on sick people into the evaluation and integrated it into the pharmacopoeia.

Table 1) uses selected homeopathic remedies to illustrate the proportion of observations from other sources in the total number of documented drug reactions.^[4] As this is a random selection, no generally valid statements can be derived from it. Nevertheless, it is already clear from this how strongly the proportion of other sources varies depending on the remedy. This underscores the importance of such sources for Hahnemann's Materia Medica, as they—just as he mentions in Organon § 110—confirmed his own observations.

Table 1 - Proportion of clinical observations from the medical literature in the total number of remedies - own calculation (PMM = Pure Materia Medica, CD = Chronic diseases)

	Total number of drug effects PMM Aufl.3 (S.H., 1830)	Total number of drug effects CD, ed. 2 (S.H.m 1837)	Observations Hahnemann	Observations of test subjects	Data taken from other sources
					Quantity	in %
Belladonna	1440		394	525	521	36
Cannabis sativa	330		60	222	48	14,5
Cina	301		54	235	12	4
Dulcamara		409	58	258	93	22,3
Jodum		704	109	223	372	52,8
Opium	662		116	24	522	78

Source 3: Observations from medical treatments

With increasing practical experience, Hahnemann used the realisation that not only healthy people but also chronically ill people could make valuable contributions to the Materia Medica - especially through unintentional drug reactions that occurred when prescribing drugs that were not optimally suited - and noted this in Organon § 142 (cf.: Hahnemann, 1996, p. 205; author’s transl.):

"But how to determine even in diseases, especially in the mostly constant chronic ones, in addition to the symptoms of the original disease, also some symptoms* of the simple remedy administered for treatment, is very demanding and can only be left to masters in observation.

*FN: i.e. symptoms that were either only noticed a long time ago or have never been noticed in the entire history of the disease and are therefore new to the remedy"

Chronically ill patients react more sensitively to medicines that are only partially suitable

As early as 1801, in his text Über die Kraft kleiner Gaben der Arzneien generell und der Belladonna insbesondre, he pointed out the special sensitivity of sick people to inaccurately chosen remedies. He also addressed doubts about the efficacy of high dilutions and argued that a small amount of belladonna usually had no effect on a "robust, completely healthy countryman".

"It by no means follows from this, however, that one gran of this thick juice would be an adequate or even too weak a dose for this or a similarly robust man, if he were ill and his illness were of a kind not suited to Belladonna." (cf: Über die Kraft kleiner Gaben der Arzneien überhaupt und der Belladonna insbesondre (Hahnemann, 1801 in: Hahnemann, 2001d, p. 349; author’s transl.)

Even stronger reactions are to be expected in patients if the medicine has been preserved, diluted and shaken with alcohol.

"Will we at last realise how small - indeed, how infinitely small - the doses of medicines may be in cases of disease, in order nevertheless to affect the body markedly?
Yes, they affect it strongly if the remedy is wrongly chosen: New, violent symptoms appear, and it is customary to say - whether rightly or wrongly, it remains to be seen - that the disease has worsened.

The remedy has an equally strong effect if it is chosen correctly: even the most serious illnesses often disappear within a few hours." (cf: Über die Kraft kleiner Gaben der Arzneien überhaupt und der Belladonna insbesondre (Hahnemann, 1801) in: Hahnemann, 2001d, p. 350; author’s transl.)

Partially suitable medicines provoke new reactions

In the Organon, Hahnemann explains this fact (Org. §175-182) to the effect that the "outlines of the form of the disease" (§175), i.e. the symptom pattern, are not clearly recognisable in every patient from the beginning .

In such cases, only the most suitable homeopathic remedy can initially be selected on the basis of the few symptoms identified.

"Now the remedy, chosen as well as possible, but [...] only imperfectly homœopathic, will, in its action against the disease only partially analogous to it, [...] excite secondary complaints, and interfere with the patient's condition by several accidents from its own series of symptoms [...]" (Hahnemann, 1996, § 180, p. 223 f. ; author’s transl.)

"[...] but they are always only such symptoms as this disease was already capable of manifesting in this body, and which were merely drawn out and induced to appear by the medicine used [...]." (Hahnemann, 1996, § 181, p. 224; author’s transl.)

While a healthy organism usually tolerates and compensates for homeopathic druc stimuli better, chronically ill patients often react more sensitively and subtly. This can provoke clear drug effects in individual cases, which, however, still need to be further tested for their evidence - a procedure that Hahnemann practised very specifically.

The "NB" labelling

From the D3 journal (1802) onwards, Hahnemann labelled newly appearing changes in a patient's condition that were previously unknown and only appeared after the administration of a remedy as drug symptoms with the abbreviation NB (Papsch, 1998). This abbreviation is interpreted both as nota bene ("well noted") and as a secondary complaint. Exactly which term Hahnemann meant by NB is of secondary importance - what is decisive is its meaning. Hahnemann used the abbreviation NB in his medical journals to indicate newly occurring symptoms that were assigned to the last remedy administered.

"Hahnemann crossed out the 'NB' signs in the journal text as soon as the symptoms labelled with them could be regarded as confirmed and adopted the statements marked in this way in the 'Fragmenta' and later in the Pure Pharmacopoeia. Journal N.5 contains 81 cancelled 'NB' symptoms." (Varady, 1987, p. 284; author’s transl.)

In the medical journal D16 (1817 - 1818), for example, 43 Thuja, 11 Cicuta and 10 Staphysagria signs were identified, which occurred as an effect during treatment with the remedy and were integrated into the pharmacopoeia (Schuricht, 2004, p. 147). The case history of Antonie Volkmann contributed 46 Sepia-, 17 Nit-ac-and 16 Phosphorus remedy effects. (Hahnemann, 2007, ed. Lucae & Wischner, p. 6f.)

How Hahnemann used this working abbreviation was investigated by the authors in the transcriptions and analyses of various medical journals. (Varady, 1987; Seiler, 1988; Schuricht, 2004; Fischbach-Sabel, 20). As they were able to prove, the abbreviation was primarily used to:

1. Labelling of new symptoms in the medical journals:
   • If a patient showed new symptoms after taking a homeopathic remedy, Hahnemann labelled them with the abbreviation NB
   • He considered these newly occurring drug reactions to be potentially caused by the last administered and not optimally suitable drug. He therefore considered attributing this observation to this drug
2. Cancellation of the NB abbreviation:
   • As soon as Hahnemann regarded the new drug reactions as confirmed drug-specific effects or wanted to include them in his Materia Medica (pharmacopoeia), he crossed out the NB abbreviation.
   • This meant that this drug reaction was now considered tested and documented.
   • Not all observations labelled with NB can be found in later new editions of his pharmacopoeias. This indicates that Hahnemann linked their adoption to certain verification criteria - without, however, explicitly naming them.
3. Significance for the drug trials:
   • The NB abbreviation was part of his systematic approach to homeopathic drug proving (HDP). It helped him to analyse and document the effect of certain substances on the organism.

This practice shows how Hahnemann incorporated his observations into the development of homeopathy in a structured and systematic way.

After the transcriptions of some patients' journals, however, a debate arose as to whether these "NB symptoms" in the pharmacopoeia should be equated with the "genuine" drug reactions observed in trials on healthy people (Mortsch, 2005). Hahnemann apparently did so and also justified this in Org. § 156:

"It is not uncommon that even an apparently suitably chosen homeopathic remedy, especially when given in too small a dose in very irritable and sensitive patients, provokes at least a small, unusual complaint or a small, new symptom during its period of action. For it is almost impossible for a remedy and a disease to coincide in their symptoms as exactly as two congruent triangles. But this - in a favourable case - insignificant deviation is easily compensated for by the living organism's own self-regulation and is not even noticed by relatively insensitive patients; the regeneration nevertheless continues to progress towards the goal of recovery, if it is not disturbed by foreign medicinal influences on the patient, by errors in the order of life, or by mental and psychological obstacles to healing." (cf.: Organon § 156, Hahnemann, 1995; author’s transl.)

Hahnemann's Materia Medica - Work-in Progress

Hahnemann was aware of the incompleteness and provisional nature of his collections of signs from the very beginning.

"As far as it is given me to observe [these drug effects], I have devoted myself most scrupulously and conscientiously to the truth. Let us use them, however they may be; no one knows better than I how defective and weak they are." (Fragmenta, Hahnemann, 1805; quoted from: Schmidt, 1995, p. 97; author’s transl.)

Verification of drug reactions

From the very beginning, Hahnemann endeavoured to systematically verify the observed drug reactions by marking reliable, repeatedly confirmed observations. He also clearly labelled the still uncertain data.

"I have observed a symptom printed in capital letters more frequently, but one printed in small letters less frequently. I publish those in brackets ( ) with reservations, as they have only been observed by me once, in a case that was not sufficiently clear and free from doubt. Sometimes the insufficiently tested truthfulness of a person added these brackets, or when a person was a little slow of mind or had made some dietary mistake." (Fragmenta, Hahnemann, 1805; quoted from: Schmidt, 1995, p. 96; author’s transl.)

Findings from medical journals and version comparisons of the pharmacopoeia

The analysis of Hahnemann's medical journal no. 5 (1803 - 1806) is an example of how systematically and continuously he used his practical experience to verify and supplement the collected drug effects (Hahnemann calls them symptom series of the remedies in the Organon). In the compilation Fragmenta, which he presented to the professional world in 1805, he already incorporated findings (NB symptoms) that can be found in the first third of the medical journal. He later made handwritten notes in his personal copy of the Fragmenta, which he then logically incorporated into the Reine Arzneimittellehre. (Varady, 1987)

Other studies (Kritzenberger, 2010, 2015) investigate the labelling, i.e. highlighting and time indications, of drug reactions that Hahnemann changed in new editions. The author was able to prove that there were comprehensible reasons for the upgrading and downgrading of observations in the respective new edition. An essential criterion for the highlighting (upgrading) was apparently the "frequent observation of a symptom in the same way" (Kritzenberger, 2010, p.177). The withdrawal of emphasisations (downgrading) is probably due to the fact that the reliability of certain protocol recordings was re-evaluated by test subjects after a certain time interval and with a greater horizon of experience (Kritzenberger, 2010).

Hahnemann probably did not always strictly adhere to the theoretically ideal sequence: drug trial - drug effect - drug application - verification in practice. Thanks to his many years of experience and trained patterns of thought and perception, he was able to efficiently shorten certain steps. Sometimes the process was even reversed: Hahnemann used a remedy successfully before the corresponding results from drug trials had been documented. He tried to obtain these retrospectively by sending the remedy, including instructions for taking it, to friendly colleagues for further verification. Statements from letters to v. Gersdorff at least suggest this.

"They [the proving symptoms of Carbo vegetabilis] are exact and correspond very well with others that I already had in stock; for I have been using charcoal (from birch trees) for half a year as an indispensable remedy."

".... and wish .... to make experiments with one of these substances [sepia or ambergris], which I already know from the best side as a remedy." (Letter of 9 February 1824, quoted from: Kritzenberger, 2015, p. 16; author’s transl.)

The pharmacopoeias were adapted to new findings

Hahnemann used the recorded observations to revise and expand his medication documentation. This evolved in a continuous process of comparison and comparison with new findings and was subject to ongoing validation of individual entries.

As with the Organon, which Hahnemann worked on until the 6th edition, the pharmacopoeia also went through several cycles of revision:

• Fragmenta (1805)
• Pure pharmacopoeia edition 1 (1811-1821)
• Pure pharmacopoeia edition 2 (1822-1827)
• Pure pharmacopoeia edition 3 (1830-1833)
• The Chronic Diseases Edition 1 (1828-1830)
• The Chronic Diseases Edition 2 (1835-1839)

Source-orientated studies of Hahnemann's Theory of Medicines have shown that the volumes of the second edition of the Chronic Diseases in particular differ from the previous publications. Not only were new additions made, but the arrangement and order of the text was also reorganised. Hahnemann made slight changes to the wording in some places, he shortened, summarised or split up complex descriptions of individual passages in the remedy documentation. He not only changed the emphasis, but also partially cancelled the obligatory dates of the observations at the beginning.

When integrating new observations from others, he made sure that several similar observations from one subject did not draw a supposed centre of gravity. If possible, he wanted to ensure a more balanced picture of the pure mean effect by using observations from several different participants. (see also Kritzenberger, 2015)

The analyses show that Hahnemann proceeded systematically in his revisions, but also that he did not transparently disclose his editing guidelines.

The "Leipziger Prüfergesellschaft"

The doctors and students were among Hahnemann's first supporters in his homeopathic medicine experiments (Cf. Hartmann, 1850):

F. Hartmann (1796 - 1853)	J.C.D. Teuthorn (1795-?)
C.G.K. Hornburg (1793-1834)	C.T. Herrmann (1796-?)
G.W. Gross (1794-1847)	C.F. Langhammer (1786-184?)
C.G. Franz (1795-1835)	J.E. Stapf (1788-1860)
E.F. Rückert (1795-1843)	S. Gutmann (1789-1852) Zahnarzt.
W.E. Wislicenus (1797-1864)

They were guided and supervised directly by Hahnemann. With their support, Hahnemann's six-volume "Pure Pharmacopoeia" was written between 1811 and 1821.

Franz Hartmann, who is quoted here as a student and contemporary witness, came to Leipzig at the age of 18 and was soon introduced to Hahnemann by his friend Hornburg. Many years later, as co-editor of the Allgemeine Homöopathische Zeitung (AHZ), he recognised the value of his memoirs for future generations.

In a series of articles about Hahnemann's life and his own first experiences with homeopathy, he shared personal insights that had not yet been published.
(Hartmann, 1850, AHZ No. 20, 38th vol.) Here we learn details about the course of the remedy trials:

Logging the symptoms

Each subject first had to practise documenting the remedy trials and recorded numerous symptoms, which he learnt to specify under Hahnemann's guidance:

"He [Hahnemann] never accepted the symptoms we gave him in good faith, but always went over them again with us to be sure that we had used the right expressions and terms, and had neither said too much nor too little. In the beginning there were often inaccuracies, which became less and less frequent after each new examination and finally disappeared completely, at least for those who realised the importance of the matter and who were therefore really serious about these provings [...]." (Hartmann, 1850, AHZ No. 20, 38th vol., p. 307; author’s transl.)

The tendency to certain complaints

The complaints and illnesses to which a test person was prone influenced his or her reaction:

"If it [the remedy] did not produce any considerable changes after three repetitions, Hahnemann assumed that the organism was not receptive to this remedy and therefore did not have the subject try it again, but had the same person try another remedy after several days." (Hartmann, 1850, AHZ No. 20, 38th vol., p. 306; author’s transl.)

Hahnemann writes in § 116 and 117 of the Organon that some people, "although otherwise healthy, nevertheless have a tendency to be put into a more or less morbid state by certain things which seem to make no impression or change at all on many other people".

All of Hahnemann's fellow campaigners had certain tendencies towards illness. The general health that he demanded of the subjects could, realistically speaking, only be relative.

Accurate observation and precise description

The exact observation and precise description of drug reactions are demanding activities.

When treating their patients, Hahnemann's students did not rely on all observations equally, but relied in particular on their own experience and that of individual esteemed colleagues. Hartmann, for example, considered Gross to be particularly reliable:

"Gross was one of the most skilful provers of medicines among us and the symptoms observed by him are of great practical value, indeed I put his, Franz's and Stapf's on a par with Hahnemann's." (Hartmann, 1850, AHZ No. 20 38th vol., p. 311; author’s transl.)

Hartmann's judgement was also based on practical experience, as he saw

"the deficiencies of the drug reactions become more and more vivid with the acquisition of each new patient" (Hartmann, 1850, AHZ No. 20 38th vol., p. 308; author’s transl.).

The health of individual participants

Hartmann's descriptions of his colleagues at the time not only provide insights into their personalities, but also allow conclusions to be drawn about their state of health.

Gustav Wilhelm Gross

Gross was unassuming, modest and seriously reserved, but was considered extremely reliable. When they first met, Hartmann immediately noticed the yellowish-grey colour of his face, which is why he initially mistook him for a patient. Despite his sickly appearance, Gross never complained of any physical complaints. Hahnemann had no qualms about allowing him to take part in drug trials and favoured remedies that he hoped would have an effect on his apparently ailing internal organs and pale appearance.

Carl Gottlob Franz

Franz came to Leipzig to study theology in poor health. It is reported that he had "lost his health due to a botched skin rash" and searched for a cure for a long time without success. It was only after successful treatment by Hahnemann that he switched to medicine and eventually became his "right-hand man".

Christian Friedrich Langhammer

Langhammer was probably the most controversial figure within the Leipzig group. Hartmann thought little of him, but mentioned him because his name appeared several times in the pharmacopoeia. He describes Langhammer as a small, frail man, about ten years older than his fellow students, of a timid, shy and suspicious nature. As puny as he appeared on the outside, Hartmann had little faith in his mental abilities, diligence or energy. In addition, Langhammer is said to have been in a difficult financial situation and repeatedly lost himself in unfruitful thoughts.

Hartmann doubted the value of Langhammer's test results as, in his opinion, they merely reflected the expression of his idle lifestyle and bad habits. His mental and emotional symptoms in particular always appeared in a similar way in different tests, which is why Hartmann attached little importance to them.

G.W. Gross essentially shared Hartmann's assessment:

"It is quite possible that here and there an observation has also been made by other test subjects which, like Langhammer's, was not a real result of the medicinal power. I myself may have encountered such things. Their worthlessness will become apparent in time at the bedside. In any case, Hahnemann's own observations are more important than all others. One can even see this outwardly, but the practice in particular bears witness to this." (Stapf & Gross, 1843, Vol. XX, H1, p.76; author’s transl.)

In fact, time showed that Langhammer's observations, which were consistent with a depressive, anxious and hypochondriacal state, were extremely differentiated in this respect. This realisation was one that was still unclear at the beginning of the series of experiments.

With an increased susceptibility to a drug stimuli, a person will always produce changes in condition that are associated with individual constitutional or disease-prone centres of gravity. C. Hering in particular drew more comprehensive conclusions in this regard, also on the basis of his own extensive drug trials.

Constantin Hering's practical findings

Constantin Hering always maintained an independent and critical attitude in his dialogue with Hahnemann - a quality that Hahnemann greatly appreciated. They maintained a constructive correspondence over many years. Hering gained profound insights through his own numerous drug trials and his intensive examination of methodological issues, which significantly advanced both the theoretical understanding and practical application of homeopathy.

Constantin Hering about Langhammer

Hering expressed the view that Gross spoke critically of Langhammer primarily because the homeopathic theory of medicine was already being heavily criticised. Gross, who was himself a convinced "Hahnemannian", probably wanted to show that even Hahnemann's followers recognised and reflected on the weaknesses of the theory of medicine.

After comparing Langhammer's observations with other drug trials, Hering came to completely different conclusions from Hartmann and Gross:

"So he not only imagined that he had symptoms, but was, as hypochondriacs usually are, all too accurate! Hypochondriacs, like hysterics, are very often extraordinarily subtle observers, and to the agony of physicians they do not miss even the smallest symptoms; it is only their conclusions from these symptoms in which they are mistaken." (Langhammer and no end (1864) in: Hering, 1988b, p. 1375 f. ; author’s transl.)

Today, C. Langhammer would probably be categorised as depressive. His symptoms may appear similar with different drugs, but on closer inspection they are not. Hardly any other subject reacted in such a differentiated way with a wide range of depressive drug reactions to different drugs. Langhammer possessed a tendency to illness that enabled him to show different facets of illness-like drug reactions with different remedies in homeopathic provings. These differentiating drug reactions are therefore extremely valuable for practical work today.

In his article Langhammer und kein Ende from 1864 (Hering, 1988b), Hering intensively with the criticism of Langhammer's remedy experiments, in particular that of the homeopathic remedy Euphrasia. After careful analysis and from his own practical experience, he came to the conclusion that Langhammer's observations were actually the best. Not only did they reveal physiological and pathological correlations, but they were also almost universally confirmed by other participants and found multiple confirmation in clinical application.

"We have Langhammer to thank for the characteristic sign of Euphrasia: Sputum throughout the day, after which the sick have often and repeatedly been cured." (Hering, 1988b, p. 1387; author’s transl.)

"Some critics say that Langhammer was not suitable for medical examinations because he was an easily mobile person! On the other hand, it could be argued that this is precisely why he was particularly suited to it! [...] in proving medicines we need the easily mobile as well as the severely mobile; a medicine can only be recognised if its effects on the largest possible number of the most diverse people are seen." (Hering, 1988b, p. 1393; author’s transl.)

In the course of his active life, Hering repeatedly criticised Hahnemann and his theory of medicine. Some homeopathic physicians of the time rejected Hahnemann's revisions and innovations, in particular the use of high potencies both in treatment and in provings. They felt committed to a strictly "scientific" homeopathy and demanded precise, standardised retests or retrials. They attempted to explain the results on the basis of pathophysiological correlations.

Hering's own experiences with self-experiments - The American Drug Trials (1857)

Like Hahnemann, Constantin Hering valued the empirical-experimental approach, supplemented by a comprehensive collection of pharmacological sources. As early as 1828, he introduced an important remedy homeopathic use with his series of experiments on the remedy Lachesis. Together with several colleagues, he researched further new substances until 1857 and published the results under the title Amerikanische Arzneiprüfungen: Preliminaries to Pharmacology as a Natural Science. After almost 30 years of experience, he met criticism of his work with composure:

"Incidentally, all drivel about such experiments should be rejected, as if they had to be carried out on healthy people alone, on sick people alone, or only on humans or only on animals. However different the value may be, they all have equal rights to be heard." (Hering, 1857, p. IV)

While Hering was rather undogmatic in his practical approach, he attached great importance to comprehensive and accurate documentation of his research. He rejected rigid rules regarding potency and dosage in drug trials. The optimum dosage should be determined by the trial subjects themselves through gradual trial and error. In addition to the test protocols, all reliable sources should be included in a medicine database – these include case reports, folk usage, effects of ingestion, treatment courses, poisoning reports, as well as the effects of animal bites and insect stings (Apis). This wealth of detail enabled a far more comprehensive understanding of the drug effects:

"Only through such clear summaries of all effects can one learn to distinguish the general properties from the specific ones. Proving these must be left to subsequent diagnostic work." (Hering, 1857, p. VI; author’s transl.)

In his article published in 1861, Where is the evidence for these symptoms? (Hering, 1988a) published in 1861, Hering once again set out in detail his experiences on the subject of homeopathic drug provings (HDP):

• Drug trials are an art that has to be learnt.
• The series of tests on healthy volunteers are only the first step towards understanding the medicine - the results from the applications on patients provide more reliable findings.
• All documented test results are initially to be regarded as actual perceptions that may have been caused by the drug.
• Not all phenomena observed during a series of experiments are actually drug reactions.

"All the signs of every tester in every proving consist solely of perceptions of his own bodily state, which only become noticeable through the influence of the remedy. Even with the sick it is quite the same influence." (Hering, 1988a, p. 1196; author’s transl.)

Hering's "purification stages"

In the same essay, Hering explains how the reliable observations are filtered out of the raw data collection in a step-by-step process and how a materia medica suitable for practical use finally matures. (Hering, 1988a, p. 1205 f.)

He calls this process of evaluation "purification stages” (German: Läuterungsstufen^[5]):

1. Systematic drug trials

The data collection initially requires as many drug trials as possible from as many different people as possible with the same drug. The first revision of the raw data comprises the following steps:

→ Comparisons of different tests of the same subject with the same agent

→ Comparisons of the drug reactions of the participants with each other

→ Comparisons between all of them - but this requires a symptom register

2. Verification in practice

This level of purification is achieved through healing reports

→ Comparison of the cured symptoms with the drug reactions

3. Synchronisation and data analysis

The third stage is achieved by combining the results of the two previous stages

→ Comparison of the means used and

→ Comparison of cured cases among themselves

"We arrive at the third stage by combining the results of the two previous ones, comparing the remedies used on the basis of them, and comparing the cured cases among themselves. Here signs are added which can neither be made nor cured by remedies, and we obtain in this way: Characteristic pictures; with which also the first step towards science is shown to be a possible one." (Hering, 1988a, p.1206; author’s transl.)

Constantin Hering was open to the constant further development and refinement of materia medica. He called for a continuous comparison with all findings that contribute to a comprehensive understanding and serve to work out the characteristics of the remedy pictures more precisely.

Summary

According to Hahnemann's conceptual considerations, medicinal therapy according to the simile principle requires the most comprehensive knowledge possible about the effects of pure medicinal substances. This work illuminates the beginnings of his data collections for the first homeopathic Materia Medica as well as the methodology of his systematic remedy provings.

Three closely interlinked questions were at the centre of the investigation: What was the state of health of the subjects of Hahnemann's remedy experiments? What proportion of his first Materia Medica was made up of observations from non-experimental sources? And why did Hahnemann deviate - at least in part - from his original strictly methodical approach? These aspects give rise to a central consideration: How can the knowledge that is pharmacologically and therapeutically relevant for homeopathic therapy be reliably extracted from a heterogeneous multitude of observations?

The study essentially shows that in addition to Hahnemann's clear methodological approach, pragmatic implementation also proved its worth. Increasing experience and further development allowed him to expand the narrow methodological framework without abandoning the principle of consistent and continuous verification - to supplement, falsify and verify his data.

• Methodological approach: Hahnemann began with self-trials and extended his investigations to other subjects, whereby he favoured exclusively healthy people in order to document unadulterated drug reactions. In retrospect, biographical information about Hahnemann's colleagues makes it clear that they could only have been relatively healthy individuals. It was impossible to rule out previous illnesses or tendencies to certain complaints in the subjects. This later turned out to be rather useful because it made different manifestations and colourations of the drug reactions more clearly visible.
• Pragmatic implementation: Despite the theoretical requirement to base his knowledge of remedies on experiments on healthy people, he also included literature sources in his data collections that described observations on patients. With the help of his precise and detailed treatment documentation (patient journals), Hahnemann was able to extract specific drug reactions that he observed in his own patients. He justified this with the increased sensitivity of chronically ill patients, who (due to impaired self-regulation) reacted more sensitively to very specific stimuli.
• Ongoing revisions and new editions: Hahnemann's working method is characterised by a continuous process of collecting, comparing, verifying and falsifying data. Although his methodological principles were never set down in writing, his dynamic approach forms the foundation of the homeopathic Materia Medica.

The study emphasises that Hahnemann's first homeopathic Materia Medica is a tried and tested instrument despite methodological inaccuracies. For further scientific research in homeopathy and work on the Materia Medica, what Constantin Hering described as a gradual "purification process" of the data originally collected as comprehensively and impartially as possible should apply - an iterative process of collecting, comparing, verifying and falsifying in dealing with:

a) results from new drug trials,
b) historical case histories and
c) contemporary case documentation and practical experience.

For therapeutic practice, this means that drug prescriptions must not be based on quantitative considerations - i.e. not on how often certain observations are recorded in the pharmacopoeia - but on the specific qualitative comparison between the pattern of the drug reaction and the pattern of the disease process.

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[1] In connection with the active phases of remedies, Hahnemann often used the term Hahnemann often used the term “reaction” in the sense of a reaction of the vital force - i.e. as a counteraction, primary or secondary effects to a remedy stimulus. Since his use of the term changed slightly in the course of his work and he did not fixed definitions, the term can also be used to generally describe the entire response of the organism to a medicinal stimulus of a remedy.

[2] While a drug reaction includes any kind of response of an organism to a substance (i.e. positive or negative), the term drug symptom refers to perceptible phenomena, signs, sensations or complaints that represent a deviation from the healthy state

[3] Gran (gr.) was the smallest German pharmacist's weight (Latin granum = grain). It weighed approx. 65 mg, (Wikipedia) The weight of a peppercorn served as a reference (Hahnemann, S. Apothekerlexikon: Apothekergewicht). Since 1872, the granum has been replaced by the gram weight in Germany.

[4] Examples with a high proportion of clinical observations from medical publications were selected to illustrate the facts. The basis was a tabular overview of all remedies published in Hahnemann's pharmacopoeias (Hahnemann et al., 2007, pp. 2018-2024). This already shows the total number of observations ("symptoms") for each remedy as well as the number contributed by Hahnemann. Subtracting the observations of the individual subjects labelled with their names gives the number of observations from other sources. (Link to PDF with detailed description)

[5] The term "Läuterung" describes a process in which a product or substance is improved through several stages of purification or refinement.

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Auth.: smi | Rev.: bsx, glt | Ed.: pz | last modified June 29, 2023