A series of experiments, performed on plant models with
ultra high dilutions (UHD) of arsenic trioxide at 45th decimal
potency has been reviewed with a particular focus
on variability. The working variables considered are: the
number of germinated seeds out of a fixed set of 33, the
stem length of wheat seedlings and the number of
necrotic lesions in tobacco leaf disks inoculated with tobacco
mosaic virus (TMV). A thorough comparison between
treatment and control group has been proposed,
considering the two main sources of variability in each
series of experiments: variability within and between experiments.
In treated groups, a systematic decrease in
variability between-experiments, as well as a general decrease,
with very few exceptions, in variability within experiments
has been observed with respect to control.
Variability is traditionally considered as control parameter
of model systems. Our hypothesis, based on experimental
evidences, proposes a new role of variability as a
target of UHD action. This hypothesis may help interpret
unanswered questions that keep rising in basic and clinical
research in homeopathy.