Reproducibility of the effects of homeopathically potentised Argentum nitricum on the growth of Lemna gibba L. in a randomised and blinded bioassay.

BACKGROUND: A previous study reported a significant statistical interaction between experiment date and treatment effect of Argentum nitricum 14x-30x on the growth rate of duckweed (Lemna gibba L.). The aim of the present study was to investigate the stability of the test system and intra-laboratory reproducibility of the effects found. METHODS: Duckweed was treated with A. nitricum potencies (14x-30x) as well as succussed and unsuccussed water controls. The outcome parameter area-related growth rate for day 0-7 was determined by a computerised image analysis system in two series of independent randomised and blinded experiments. Systematic negative control (SNC) experiments were carried out to investigate test system stability. Statistical analysis was performed with full two-way analysis of variance (ANOVA) and protected Fisher's Least Significant Difference (LSD) test. RESULTS: In the first repetition series we found a significant treatment effect (p = 0.016), while in the second series no effect was observed. The negative control experiments showed that the experimental system was stable. An a posteriori subgroup analysis concerning gibbosity revealed the importance of this growth state of L. gibba for successful reproduction of the statistically significant interaction in the original study; flat: no interaction (p = 0.762); slight gibbosity: no interaction (p = 0.356); medium gibbosity: significant interaction (p = 0.031), high gibbosity: highly significant interaction (p = 0.005). CONCLUSIONS: With the original study design (disregarding gibbosity status of L. gibba) results of the original study could not be reproduced sensu stricto. We conclude that the growth state gibbosity is crucial for successful reproduction of the original study. Different physiological states of the test organisms used for bioassays for homeopathic basic research must carefully be considered.

Wheat and ultra high diluted silver nitrate--further experiments and re-analysis of data.

BACKGROUND: Since 1926, an influence of a dilution of silver nitrate (24x) on the growth of coleoptiles of wheat seedlings was described. The aim of the study discussed here is the critical proof of the reliability of a test system which has been quoted as a basic model for the research on homoeopathy for decades. METHODS: Grains of winter wheat (Triticum aestivum) were observed under the influence of extremely diluted silver nitrate (10(-23)) prepared by stepwise dilution and agitation according to a protocol derived from homeopathy ('24x'). Analogously prepared water and/or inert water was used for control. Thirty experiments including 5000+5000 grains were performed by 5 researchers. RESULTS: Stalk lengths clearly indicate that development is enhanced by the probe silver nitrate 24x as compared to control. When the experiments 1989-1995 were pooled, means and SD for silver nitrate 24x-groups were 42.3±26.9 mm and for water control groups 34.7±22.2 mm. Verum stalk length was 21.9% bigger than control (100%) (p<0.01; d=0.31, i.e. small). For the experiments 1998-2014, means and SD were 73.7±21.7 mm and 60.5±20.9 mm. Verum stalk length was 21.7% bigger than control (100%) (p<0.01; d=0.62, i.e. medium). From the results one may hypothesize that the result is more marked in experiments showing an average mean of stalk length between ca. 50 and 90 mm in contrast to smaller or bigger mean lengths. CONCLUSION: The previous findings were confirmed by the results.