“Maybe I should have thrown the data away”
Jacques Benveniste, 1935-2004
But being a scientist and believing in his data he could not.
Does water have memory?
The ‘memory of water’ is a popular phrase that is mostly associated with homeopathy and Jacques Benveniste following his and others’ allergy research work. These research teams reported that solutes subjected to sequential physical processing and dilution show biological effects different from those apparent using just the water employed for the dilutions. The subject has drawn a lot of controversy with many scientists simply rejecting it outright without studying the evidence. The topic has recently been the subject of a number of papers in the journal Homeopathy (July, 2007)c and has been reviewed. Although there is much support for water showing properties that depend on its prior processing (that is, water having a memory effect), the experimental evidence indicates that such changes are due primarily to solute and surface changes occurring during this processing. The experimentally corroborated memory phenomena cannot be taken as supporting the basic tenets of homeopathy, although they can explain some effects3.
Is water special?
The main evidence against water having a memory is that of the very short (~ps) lifetime of hydrogen bonds between the water molecules. Clearly in the absence of other materials or surfaces (see later), the specific hydrogen bonding pattern surrounding a solute does not persist when the solute is removed any more than would a cluster around any specified water molecule, or else water would not know which of its myriad past solutes took preference. Indeed the atoms that make up the water molecule only remain together for about a millisecond in liquid water due to proton exchange (see water ionization). A recent NMR study shows no stable (>1 ms, >5 ?M) water clusters are found in homeopathic preparations. It should, however, be noted that the lifetime of hydrogen bonds does not control the lifetime of clusters in the same way that a sea wave may cross an ocean, remaining as a wave and with dependence on its history, but with its molecular content continuously changing. Also, the equilibrium concentration of any clusters are governed by thermodynamics not kinetics.
An extraordinary paper authored by Nobel prize-winning Luc Montagnier has shown memory effects in aqueous DNA solutions that depend on interactions with the background electromagnetic field. These effects require the prior processing and dilution of the solutions and are explained as resonance phenomena with nanostructures derived from the DNA and water.
As applied to homeopathy, the ‘memory of water’ concept should also be extended to the memory of aqueous ethanol preparations, which are also used. Addition of ethanol to water adds an important further area of complexity. Ethanol forms solutions in water that are far from ideal and very slow to equilibrate. Although usually considered a single phase, such solutions may contain several distinct phases and more generally consist of a complex mixture dominated by water-water and ethanol-ethanol clusters, where hydrogen bonding is longer-lived than in water alone. They also favor nanobubble (that is, nanocavity) formation. Thus, the peculiar behavior of aqueous solutions (as mostly discussed on this page) is accentuated by the presence of ethanol.
Does the glassware matter?
The process of silica dissolution has been much studied, ever since it was proven by Lavoisier over 200 years ago and fits with this argument. This may explain why glass is preferred over polypropylene tubes. It should be noted that dissolved silica is capable of forming solid particles with complementary structures (that is, imprints) to dissolved solutes and macromolecules and such particles will ‘remember’ these complementary structures essentially forever.
Is gas important?
Water does store and transmit information, concerning solutes, by means of its hydrogen-bonded network. Changes to this clustering network brought about by solutes may take some time to re-equilibrate. Agitation (succussion) may also have an effect on the hydrogen bonded network (shear encouraging destructuring) and the gaseous solutes (with critical effect on structuring, and possible important production of structuring nanobubbles (nanocavities),, and such effects may well contribute to the altered heats of dilution with such materials. Such mechanically induced hydrogen bond breakage may also give rise to increased (but low) hydrogen peroxide formation [see equations] and such effects have been reported to last for weeks. It may be relevant to note that the presence of hydrogen peroxide can take part in and catalyze further reactions with other reactive species such as molecular oxygen and dissolved ozone18, (not often recognized but present in nanomolar amounts) which may well vary with the number of succussion steps and their sequence, which may offer an explanation for the changes in efficacy of homeopathic preparations with the number of dilutions. Also of note are the known effects of low concentrations of reactive oxygen species on physiological processes such as the immune response; with the recent discovery of the importance of low levels of hydrogen peroxide being particularly relevant.
Does dilution happen as predicted?
Dilution is never perfect, particularly at low concentrations where surface absorption may well be a major factor, so that dilution beyond the levels that can be analytically determined remains unproven. Remaining material may be responsible for perceived differences between preparations and activity. Of course the water used for dilution is not pure relative to the putative concentration of the ‘active’ ingredient; even the purest water should be considered grossly contaminated compared with the theoretical homeopathic dilution levels. This contamination may well have a major influence, and itself be influenced by the structuring in the water it encounters. Although it does, at first sight, seem unlikely that solutes in diluted ‘homeopathic’ water should be significantly different from a proper aqueous control, it has recently been cogently argued that the concentrations of impurities can change during the dilution process by reactions initiated by the original ‘active’ material, and this process has been mathematically modeled21.
A further consideration about ‘the memory of water’ is that the popular understanding concerning how homeopathic preparations may work not only requires this memory but also requires that this memory be amplified during the dilution; this amplification, necessitated by the increase in efficacy with extensive dilution, being even harder to explain. Samal and Geckeler have published an interesting, if controversial, paper concerning the effect of dilution on some molecules. They found that some molecules form larger clusters on dilution rather than the smaller clusters thermodynamically expected. Just the presence of one such large ?m-sized particle in the ‘diluted’ solution could give rise to the noticed biological action (of course, some such preparations may be totally without action, being without such clustered particles).a
However, it remains to explain this particular phenomenon, which appears to disobey the second law of thermodynamics. A possible explanation is that such biologically-active molecules can cooperatively form icosahedral expanded water networks (ES) to surround and screen them by the formation of face-linked icosahedra, similar to as expected in the minimal energy related poly-tetrahedral Dzugutov clusters. So long as such an icosahedral network structure requires the help of more than one neighboring such cluster to stabilize its formation then, in more concentrated solution, the molecules dissolve normally. However, as they are diluted (typically beyond about one clathrate-forming group per twelve icosahedral water clusters; 3,360 water molecules) no neighboring such clusters are available and the clusters coalesce to form larger clusters of biologically-active molecules within their own ES-related water network (so releasing some of the water). This tendency for particle formation is ultimately due to the hydrophobic effect and the tendency to form a small surface with the water. Overall the balance is expected to be rather fine between water cluster stabilization and particle cluster stabilization.
Solutions are more complex than expected
Water is not just H2O molecules. It contains a number of molecular species including ortho and para water molecules, water molecules with different isotopic compositions such as HDO and H218O, such water molecules as part of weakly-bound but partially-covalently linked molecular clusters containing one, two, three or four hydrogen bonds, and hydrogen ion and hydroxide ion species. Apart from such molecules there are always adventitious and self-created solutes in liquid water. Distilled and deionized water contain significant and varying quantities of contaminating ions. Often the criteria for ‘purity’ is the conductivity, but this will not show ionic contaminants at nanomolar, or even somewhat higher, concentrations due to the relatively high conductivity of the H+ and OH– ions naturally present. Other materials present will include previously dissolved solutes, dissolved gasses dependent on the laboratory atmosphere, gaseous nanobubbles, material dissolved or detached from the containing vessels12, solid particles and aerosols (also dependent on the laboratory history) entering from the gas phase, and redox materials produced from water molecules18 and other solutes produced on standing d and homeopathic processing 21. Liquid water is clearly a very complex system even before the further complexity of molecular clusters, gas-liquid and solid-liquid surfaces, reactions between these materials, the consequences of physical and electromagnetic processing and the addition of ethanol are considered. Any or a combination of these factors may cause ‘memory’ of past solutes and processing in water. Some of these solutions are capable of causing non-specific clinical effects whereas others may cause effects specifically linked to the solution’s (and laboratory) history, as outlined below3.