Keywords droplet evaporation method - pattern formation - combination remedies - basic research - low dilution range
Introduction
Basic homeopathic research concentrates mainly on investigating the effects of potencies produced from single substances and in dilutions beyond the Avogadro limit. In contrast, low dilutions or combination remedies are rarely studied. Nevertheless, combination remedies have a tradition spanning over a hundred years. Most of these remedies were developed based on the empirical therapeutic results accumulated by generations of practitioners.[1 ]
[2 ] Subsequently, manufacturers adapted this knowledge and used it to further develop therapeutic approaches. Although clinical studies investigating the effectiveness of combination remedies have been conducted, theoretical and basic research targeting the interactions between the remedy components remains rare.
The literature on combination remedies frequently references the work of the Swiss pharmacologist Prof. Emil Bürgi (1872–1947). Based on his research results on the effects of combined pharmacological substances, Bürgi established a hypothesis: when two substances produce the same functional change or alleviate the same disease symptoms, their effects are additive if they share the same target. If they operate through different targets, their effects can be multiplied.[3 ] Despite the frequent referencing of this hypothesis, we do not know of any experimental study that has investigated its applicability to the interactions between the constituents of homeopathic combination remedies.
Research on multi-component fluids is challenging because classical fluid mechanics cannot fully describe these fluids' complexity and internal structure.[4 ]
[5 ]
[6 ] Typically, standard composites with well-known ingredients are used to study the mechanics of complex fluids.[7 ]
[8 ] However, for complex fluids used in medicine, such as medicinal plant extracts, research mainly focuses on their therapeutic properties, including active ingredient analysis and treatment effects through interventional studies. Apart from the clinical interest, the physical characteristics and compositions of natural multi-component liquids are seldom an object of investigation.
In a series of studies, the droplet evaporation method (DEM) was applied to analyze plant extracts at low potency levels.[2 ]
[9 ]
[10 ]
[11 ] These studies demonstrated that the patterns formed as the droplets dried on glass substrates were substance-specific, enabling differentiation between different plant extracts even at dilutions up to 10−5 . Additionally, the fractal and textural parameters of DEM patterns from differently prepared potencies of the same extracts were sensitive to mixing procedures (e.g., vertical vigorous strokes, laminar flow, diffusion-based mixing) and the number of vertical strokes applied during the potentization process.[9 ]
[10 ]
[11 ] One study investigated a homeopathic complex, Luffa 4x – Mercurius bijodatus 9x.[2 ] In that preliminary study, it was possible to demonstrate that an interaction between the two compounds took place and that both had an influence on the final pattern.
Moreover, studies using the copper chloride crystallization method were able to identify specific effects of Stannum metallicum 30x on extracts from seedlings of Lepidium sativum ,[12 ] and analysis of dried body fluid droplets showed potential in distinguishing between patients with different diseases.[13 ]
Analyzing structuring properties have proven to be well-suited for studying complex fluids, considering their composition and physical properties (e.g., viscosity, surface tension). Various methodological approaches based on phase transition-induced pattern formation have been described and classified. These methods fall into two categories: those where pattern formation occurs spontaneously without added reagents (e.g., DEM) and those where pattern formation is induced by adding a reagent, typically a salt (e.g., copper chloride crystallization).[14 ]
The pilot study presented here aimed to deepen our understanding of combined potentized substances and the patterns they form during evaporation compared with their single components. Based on earlier investigations,[2 ] we anticipated that the combination of the two potentized preparations would exert some degree of influence on one another. This may manifest as a dominant individual compound, a combination of the patterns of the components or the emergence of novel patterns.
To realize that aim, experiments were conducted using a matrix approach, combining substances of mineral and plant origin at potency levels 2x or 3x. The resulting patterns were systematically analyzed using DEM. The study sought to determine (1) whether the combination patterns of potentized salt solutions and plant extracts can be differentiated based on their individual components, (2) whether the salt or plant components dominate the patterns of the combinations, and (3) if the combination patterns result from an additive effect of the patterns of the single solutions or (4) if they contain new, emergent, forms that are distinct from those of the individual plant extract or salt solution.
Materials and Methods
Workflow
Plant extracts and salt solutions were analyzed with the DEM in 2x and 3x potencies as single substances and as combinations. To this end, we diluted and potentized the single substances and prepared their combinations. The evaporation patterns of 2.3-µL droplets were photographed under a dark-field light microscope at 25-fold and 100-fold magnification. Acquired images were analyzed by visual inspection and computerized analysis ([Fig. 1 ]).
Fig. 1 Flowchart of the experimental process and analysis design.
Plant Extracts
Five plant extracts ([Table 1 ]) were provided as mother tinctures in ethanol 70% by Hevert-Arzneimittel GmbH & Co. KG, Nussbaum, Germany. The mother tinctures were diluted and succussed to a 1x potency by a 1:9 dilution in double-distilled water in a total volume of 8 mL followed by 10 manual strokes (shakes). This procedure was repeated until reaching a potency level of 2x and 3x. The mother tinctures of two other plant extracts, Equisetum and Urtica (also provided by Hevert-Arzneimittel GmbH & Co. KG, Nussbaum, Germany), with 50% EtOH were potentized to 1x in 7% EtOH to achieve a comparable ethanol content in all samples.
Table 1
Used plant extracts and salt solutions
Plant extracts
Manufacturer
Lot number
EtOH starting concentration
Baptisia
Hevert
5256/214/00305
70%; mother tincture
Cimicifuga
Hevert
5260/2014/0034
70%; mother tincture
Cypripedium
Hevert
5030/36361
70%; mother tincture
Echinacea
Hevert
5085/37615
70%; mother tincture
Equisetum
Hevert
00006649
50%[a ]; mother tincture
Passiflora
Hevert
5477/2015/00630
70%; mother tincture
Urtica
Hevert
00007772
50%[a ]; mother tincture
Salt solutions
CuCl2 ∙ 2H2 O
Merck
K29785133 217
7%; 1x potency
CuSO4 ∙ 5H2 O
Merck
1146582
7%; 1x potency
KNO3
Fluka
326636/1 793
7%; 1x potency
Na2 SO4
Hevert
00007728
7%; 1x potency
NaCl
Merck
K31900304 314
7%; 1x potency
a Potentized to 1x with a concentration of EtOH 7% to achieve comparable ethanol contents in all samples.
For the DEM investigation of the single plant extracts, the 2x and 3x samples were mixed with the equivalent volume of 2x and 3x ethanol (0.7 and 0.07%) respectively.
Salt Solutions
Five salts ([Table 1 ]) were separately dissolved in ethanol 7% followed by 10 manual strokes (shakes) to a 1x potency and then further processed to 2x and 3x.
For the DEM investigation of the single salt solutions, the 2x and 3x samples were mixed with the equivalent volume of ethanol 0.7 and 0.07% respectively.
Combinations
For the combinations, equal volumes of 2x or 3x salt potencies were mixed with 2x or 3x plant potencies, respectively, by gentle up and down pipetting and then used for DEM.
Droplet Evaporation Method
DEM (described in detail elsewhere[9 ]
[10 ]) was used to analyze seven plant extracts, five salt solutions, and 35 combinations of plant extracts and salt solutions at potentization level 2x and 3x (giving a total of 94 samples). On two manually cleaned microscopic glass slides (76 × 26 mm, supplier pre-cleaned, cut edges; Thermo Scientific, Gerhard Menzel B.V. & Co. KG, Braunschweig, Germany), 12 to 16 droplets were pipetted with a volume of 2.3 µL of either a plant extract, a salt solution, or a combination of the two. The liquid was evaporated at 44% relative humidity and 26°C in a climate chamber (KBF 720, cooled incubator with controlled humidity system, WTB Binder Labortechnik GmbH, Tuttlingen, Germany) for a minimum of 1 hour and no longer than 3 hours. The experiments were performed on different days, analyzing several substances or combinations per day. The glass slides were organized in a quasi-randomized set-up in the climate chamber.
Image Acquisition
The dried droplets were photographed under a dark-field optical microscope (Zeiss, Axio LabA1) at 25- and 100-fold magnification using a Moticam 5 camera (5.0 mega pixels, Motic, Hong Kong). At 25-fold magnification, roughly the whole area of the evaporated droplet was captured, whilst at 100-fold magnification only sections of the crystals could be photographed. A total of 2,629 and 2,935 images were acquired at 25- and 100-fold magnification respectively. The set of images in 100-fold magnification comprised sections of patterns of the drops. In some cases, more than one section of a drop was photographed. Images were saved as .jpeg files.
Image Pattern Characterization
By describing and summarizing the characteristics of each set of images, we tried to provide an overview on the characterization of the different structures emerging from the aforementioned plant extracts, salt solutions and combinations of the two. A total of 19 descriptors were defined to describe and categorize the various features of the patterns. We then applied up to four descriptors per potency pattern, allowing for grouping into specific and general potency patterns. For some characteristics of the patterns, metaphors were used.
Computerized Image Evaluation and Statistics
By means of software imageJ[15 ]
[16 ] (v1.53t), the images were transformed to 8-bit and background subtracted. These images were transformed into binary images. The “GLCM texture” plug-ins and “Batch GLCM Measure” macro were employed to measure the GLCM parameters Entropy and Contrast of the 8-bit images. By means of the particle analysis tool, the binary images were utilized to determine the degree of Solidity and Circularity . The F-values were calculated for these four parameters using one-way analysis of variance (ANOVA) (CoStat v6.541, www.cohortsoftware.com ) with “plant extract” or “salt solution” as factor. A comprehensive overview of the image characteristics is provided for both the 25- and 100-fold magnified images in [Figs. 2 ], [3 ] and [Supplementary files 1 ] and [2 ] (available in online version only). For each set of images, the image displayed in these matrices was selected by choosing the image that was closest to the mean value of Entropy and Circularity , respectively, for all 25- and 100-fold images. Tables and figures were prepared using Excel and RStudio (Posit Software, PBC, v2023.06.1+524, with software R v4.3.1).[17 ]
Fig. 2 Matrix of images of dried droplets of 2x potentized salt solutions and plant extracts and their combinations at 25-fold magnification. The images were selected on the basis of their proximity to the mean value of the texture analysis variable Entropy for each solution.
Fig. 3 Matrix of images of dried droplets of 2x potentized salt solutions and plant extracts and their combinations at 25-fold magnification. The images were selected on the basis of their proximity to the mean value of the texture analysis variable Circularity for each solution.
Results
Pattern Characterization
We described and summarized the characteristics of each set of images, to provide an overview of the different structures emerging in dried droplets of single potencies of plant and mineral origin and their combinations. A total of 19 form descriptors were defined based on the entire image database from the present study. Up to four descriptors were used for the characterization of all the plant and salt potencies, as well as all possible combinations thereof ([Supplementary file 3 ] [available in online version only]; example patterns of the descriptors are presented in [Supplementary file 4 ] [available in online version only]). By means of this procedure, we could identify the general and specific elements of the patterns. Further, quantitative results can be found in [Supplementary files 5 ] and [6 ] (available in online version only).
As illustrated in [Figs. 2 ], [3 ], the crystallized structures exhibited a diverse range of characteristics, from small dots to highly dense crystals that covered portions or the entirety of the original surface of the droplet. In most cases, the patterns of combinations were larger and more differentiated than those of the individual compounds. In some cases, the salt component appeared to exert a significant influence on these patterns. For example, 2x potency combinations of KNO3 with Baptisia , Cimicifuga and Cypripedium as well as 3x with Baptisia , “straight lines” appeared in the patterns, that were typical for KNO3 and resemble the macroscopic needles formed by this salt ([Fig. 4 ]). KNO3 uniquely formed “rhombus-like” and “bowed” crystals in combination with various plant potencies ([Supplementary file 4 ] [available in online version only]). In contrast, combinations of NaCl 2x potencies were characterized by the presence of “arrowheads”, “rectangles” and “cracks” ([Supplementary file 4 ] [available in online version only]). Only in rare cases, the patterns seemed to be dominated by the salt component: e.g., in 2x Echinacea combinations, Echinacea seemed to be suppressed.
Fig. 4 Examples of the descriptor “Straight lines” specific for KNO3 in combination with Baptisia 2x (A , 25-fold magnification), Cimicifuga 2x (B , 25-fold magnification), Cypripedium 2x (C , 25-fold magnification) and Baptisia 3x (D , 100-fold magnification).
In the 2x potency combinations of Baptisia , Cimicifuga and Cypripedium ([Fig. 2 ]), a greater number of structures were observed, frequently covering the entire droplet area. This was in contrast to the combinations of Equisetum , Passiflora and Urtica , where relatively fewer structures were noted. The lowest number of structures were identified in combinations containing Echinacea or CuSO4 . In combinations of 3x potencies ([Fig. 3 ]), the samples with CuCl2 showed the most pronounced patterns, followed by NaCl and Na2 SO4 , and then CuSO4 with the least pronounced patterns. Additionally, the combinations with Equisetum showed only a few structures. Interestingly, the combinations with Echinacea 3x showed more structures than those with Echinacea in 2x.
Patterns of Single Plant Potencies
At potency level 2x the patterns of the single plant extracts were mainly characterized by a central crystal (Baptisia , Cypripedium , Echinacea , Equisetum , Passiflora and Urtica ) and small dots, except for Cypripedium and Passiflora . The outline of the dried droplet was only visible in Baptisia , Cimicifuga and Echinacea . In 3x, a border of the droplet was barely visible. The whole area of all 3x plant potencies was covered with small dots. A detailed description of the patterns of plant extracts is given in [Supplementary file 7 ] (available in online version only).
Patterns of Single Salt Potencies
In the 2x single salt potencies, a central crystal structure was always visible. Dots were visible in CuSO4 , Na2 SO4 and NaCl. No other structure was detected. In 3x salt potencies, small dots were visible in all salts. A central crystal was found only in KNO3 and Na2 SO4 . In NaCl, there were some larger crystals visible. A detailed description of the patterns of structures derived from salt solutions is given in [Supplementary file 7 ] (available in online version only).
Patterns of Combined Plant Extracts and Salt Solution in 2x Potency
In a matrix of the combinations of 2x potentized plant extract and salt solution images in 25-fold magnification ([Fig. 2 ]), the patterns frequently covered the whole area of the dried droplet. The patterns were much more structured, complex and more detailed than those of their single ingredients. In general, combinations containing Baptisia , Cimicifuga and Cypripedium showed the greatest crystallized structures, whereas CuSO4 combined with the plant extract potencies showed fewer patterns and structures than the other plant–salt combinations. The patterns of Echinacea combinations primarily exhibited the characteristics of the individual salt potencies. Urtica in combination with the salt potencies of CuSO4 , KNO3 , Na2 SO4 and NaCl was characterized by fewer structures than the other plant–salt combinations, except for Echinacea .
In 2x potencies, the most general descriptors were “border of droplet visible”, “scattered dots”, “central crystal”, and “slightly bowed lines” (see examples of the descriptors in [Supplementary file 1 ] [available in online version only]). Five descriptors (“bowed form”, “foggy/cloudy”, “circular crystal”, “rhombus”, and “straight lines”) were exclusively found in KNO3 combinations and the salt potency itself. The descriptors “rectangle”, “arrowheads” and “cracks” within a flat crystal were exclusively found in NaCl combinations. “Air bubbles” appeared only in copper-containing combinations (CuCl2 and CuSO4 ) ([Supplementary file 3 ] and [4 ] [available in online version only]).
As shown in the 100-fold magnified images of 2x potency combinations ([Supplementary file 1 ], available in online version only), the small-scale structures of the crystals also differed between the single salt and plant potencies and their combinations. However, similarities of the patterns between the different combinations could be identified for instance in NaCl combined with Baptisia or Cypripedium , as well as in CuCl2 combined with Baptisia , Cimicifuga or Cypripedium . At closer view, the combinations of KNO3 with Echinacea or Urtica appeared to be closely related to the patterns appearing for the single salt. A comparable situation was found for Na2 SO4 combined with Echinacea , Equisetum or Urtica .
Patterns of Combined Plant Extracts and Salt Solutions in 3x Potency
In general, the dried droplets of the 3x potencies exhibited fewer patterns than those of the 2x potencies. However, also in the case of 3x potencies, the combined potencies showed larger patterns and more structures than the single salt and plant potencies.
The pattern characteristics typical for single CuSO4 3x potency appeared also in the combinations of this salt with Echinacea , Equisetum , Passiflora and Urtica , but not with Baptisia , Cimicifuga and Cypripedium . In a few cases (e.g., CuCl2 combined with Baptisia , Cimicifuga , Cypripedium or Echinacea ) a “scattered dots” structure seemed to appear even outside of the evaporated droplet. Using the 100-fold magnification revealed that the patterns of KNO3 in all combinations except with Baptisia were comparable to the single KNO3 pattern. The same relative dominance of the salt pattern was also observed for Na2 SO4 combined with Cimicifuga and Cypripedium , and CuSO4 combined with Echinacea , Equisetum and Passiflora . Comparable patterns were found between the combinations of NaCl with Cimicifuga , Cypripedium , Echinacea and Equisetum .
In 3x potencies, the categories “border of droplet visible” and “scattered dots” were the most abundant descriptors. All other descriptors appeared at most six times, except for the descriptor “diverse” that contains several, only rarely appearing patterns. “Bowed form”, “rhombus” and “straight lines” appeared only in KNO3 . As in the 2x potencies, the descriptors “rectangle”, “arrowheads” and “cracks” were found exclusively in NaCl combinations. In the 3x potencies the appearance of “slightly bowed lines” and “central crystal” had dropped notably from 12 to 2 and 15 to 9 respectively; whereas “scattered dots” almost doubled its occurrence in the 3x potencies compared with the 2x potencies ([Supplementary file 3 ] [available in online version only]). The “cross” descriptor did not appear in the 3x potencies. The analysis revealed that images of 2x potencies and 2x potency combinations exhibited a greater number of patterns and a higher diversity of patterns compared with those of 3x potencies and potency combinations.
Visual Homogeneity of Replicates
From a visual point of view, the replicates within one series of droplets of one substance or one combination were mostly homogeneous (examples in [Supplementary file 8 ] [available in online version only]).
Emergence of Novel Patterns in Combinations
In the majority of cases, the combinations of potencies exhibited novel structural features that were not evident in the patterns of single substances. This was particularly evident in the case of Cypripedium and KNO3 , where the potency combination exhibited markedly disparate patterns ([Fig. 4 ]) from the single compounds. The single extract of Cypripedium in 2x showed only little structure and sometimes a central crystal. KNO3 as single salt in potency 2x formed strong, sharp crystals, forming a ring. However, the combination of both substances yielded three structures to which different descriptors were assigned (descriptors: (1) “bowed form”, (2) a “field of straight lines” and (3) a more or less wide zone free of any crystals). Similarly, the combination of Baptisia –NaCl and Equisetum –CuCl2 exhibited disparate structural and patterning characteristics when compared with their individual constituents. However, new emerging patterns were not found always, as for example in Echinacea combined with CuCl2 ([Fig. 5 ]) no novel pattern characteristics developed.
Fig. 5 Examples of plant and salt 2x potencies and their combinations, demonstrating richer patterns in the combinations. This holds true for all combinations, except Echinacea combined with CuCl2 . Images 25-fold magnified.
Likewise, the images of the 3x potencies revealed only minimal crystal pattern formations in the single plant extracts and salt solutions, whereas the combinations exhibited a greater degree of diversity. For example, in the combination of Passiflora with Na2 SO4 , the individual potencies exhibited only faint crystal structures, whereas in combination, more pronounced structures were observed ([Fig. 6 ]). Emergent patterns of this kind were also found in Baptisia –NaCl and, interestingly, in Echinacea –KNO3 . However, combinations of Cimicifuga and CuSO4 exhibited the same crystal formation characterized by a ring-like structure surrounding the droplet, as observed with the individual substances.
Fig. 6 Examples of plant and salt 3x potencies and their combinations, demonstrating richer patterns in the combination. This holds true for all presented combinations except Cimicifuga combined with CuSO4 . Images 25-fold magnified.
Discussion
In this phenomenological pilot study, we observed that patterns formed in drying droplets of combinations of low potencies of plant extracts and salt solutions often exhibit novel morphologies compared with their constituents.
The patterns of single salt potencies appeared to demonstrate de-wetting phenomena (see rightmost column in [Fig. 5 ]). De-wetting, or the rupture of a thin liquid film and the formation of islands or droplets, has been described for many salts, including CuCl2
[18 ] and NaCl.[19 ]
[20 ] The frequently observed peripheral rings of dried deposits ([Figs. 5 ], [6 ]) indicate that the droplet's evaporation rate is highest near its periphery, causing contact-line pinning.[21 ] This results in a thin liquid film that nucleates and de-wets or, in the absence of nucleating particles, eventually undergoes spinodal de-wetting.[20 ] The shapes of the structures formed are predominantly due to intra-molecular forces leading to the formation of solid salt-specific crystals.[10 ]
The patterns of single plant potencies seem to result from diffusion-limited aggregation, a pattern formation process typical for large-size molecules causing the formation of branched, fractal-like structures located in the droplet center and leaving the rest of the droplet structure free.[10 ]
In contrast to patterns of single potencies, several potency combination patterns covered the entire droplet area (combinations of the 2x potencies of CuCl2 , KNO3 , Na2 SO4 and NaCl with 2x potencies of Baptisia , Cimicifuga , Cypripedium and partially Equisetum, Passiflora and Urtica ; [Fig. 2 ]). This phenomenon appears to be triggered by changes in the wettability of the microscope glass surface, induced by different combinations of salt–plant extracts. This has been previously demonstrated for CuCl2 by adding ≥ 3 theoretical monolayers of bovine serum albumin.[18 ]
[22 ]
[23 ] The complex, extract-specific patterns appear to be dictated by the salt, extract and the receding liquid boundary.[24 ]
The formation of a novel structure-type in combination remedies suggests that the pattern formation is not a simple additive process, but leads to the appearance of new emergent structures, though sometimes containing elements typical for both ingredients. Analogous to Bürgi's hypothesis[3 ] stating that the biological action of two substances administered in parallel may result from the multiplication of their individual actions, if they use different pathways, we observed that a related phenomenon occurs (i.e., emergence of new patterns) during pattern formation using a physical model. Furthermore, different pathways of biological action in Bürgi's hypothesis might be seen as analogy to the different ways that pattern formation occurs (e.g., the above-described diffusion-limited aggregation and crystallization triggered by intra-molecular forces). Follow-up studies should investigate if combining two components using the same pattern formation mechanisms (“pathways”) would result in simple structure addition rather than the emergence of a new structure type, and if new structure emergence is enhanced when different pattern-formation pathways are involved.
In this pilot study, we limited the investigation to a 1:1 combination ratio of the samples, and to potency levels of 2x and 3x, as these potency ranges show the most differentiated patterns.[10 ] Furthermore, the experiments were not replicated. Due to these limitations, the present study is exploratory and purely phenomenological. Our main focus was on the comparison of single substances and the combination of these substances at two potency levels. The pattern evaluation was based mainly on visual assessment, with a computerized evaluation of some structure parameters used solely for calculating F-values as an indicator of the discrimination potential, but not for typical inferential statistics, as the experiments were not replicated.
Because of the high differentiation of patterns obtained, we could not use a uniform method of pattern acquisition for all patterns. We photographed all patterns at two magnifications: 25-fold, encompassing the whole droplet, and 100-fold, showing a close-up of specific features. For each substance, we adjusted the light intensity to optimize the visibility of the structures in the photographs. Consequently, the F-values obtained are only indicative, and no further statistical evaluation was possible. The problem of performing uniform pattern acquisition should be considered when selecting substances and combinations for follow-up studies.
In our opinion, a study design with substances chosen based on the results of the present study might enable a uniform pattern acquisition technique throughout the whole pattern range and serve the performance of repeated experiments. The acquired image database might serve to study the pattern properties of single and combined potencies more deeply and would be suitable for computerized and deep-learning-based pattern evaluation techniques, providing insights into the methods' discrimination potential and potentially leading to the development of new analytical tools based on pattern formation in droplets.
Conclusions
The data presented in this study demonstrated the formation of patterns in drying droplets of 2x and 3x potentized substances. The 2x potentized substances generated more patterns than the 3x potentized substances. The combination of a plant extract and a salt solution at a 2x and 3x potentization resulted in the emergence of novel patterns in several instances (e.g., in Baptisia –KNO3 ). The impact of plant extracts on pattern formation when combined with different potentized salts was sometimes only discernible at one of the two potentization levels. In some cases, such as in the combinations of Echinacea 2x, the salts seemed to dominate the developing patterns. In contrast, Echinacea 3x did not seem to be dominated by the salt components.
Since we tested only a limited set of plant extracts and salt solutions as single components and in combination, further studies could take into account additional substances as well as plant–plant or salt–salt combinations. Additionally, different ratios of the plant and salt potencies should be evaluated. Since a huge range of experiments could follow the present study, future studies should take into account a more stringent image acquisition regimen that allows for statistical evaluation, deep-learning or even artificial intelligence-based pattern evaluation techniques, potentially providing insights into the pattern formation process.
Highlights
The droplet evaporation method (DEM) revealed more patterns and structures in 2x compared with 3x potencies.
The replication of DEM on single substances and combinations led to homogeneous patterns.
Combinations of plant and salt potencies formed patterns with a higher number of varying structures.
In several instances new patterns emerged in combinations compared with their single components.
In combinations, some plant potencies were dominated by the salt component in 2x but not in 3x potency.
The compound (plant or salt) with the greater impact on the pattern was found to vary between 2x and 3x combinations.
