Memory of water

The memory of water is a phrase mostly associated with homeopathy and the controversial research of Jacques Benveniste and his colleagues. This team reported that particular solutes subjected to sequential physical processing and dilution appeared to have some biological effects that were different from the "control" effects of the water used for the dilutions.

Water is not simply a collection of molecules of H2O, it contains several molecular species including ortho and para water molecules, and water molecules with different isotopic compositions such as HDO and H218O. These 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. In addition, there are always adventitious solutes in liquid water. Even double-distilled and deionized water always contains significant and variable trace amounts of contaminating ions, and different samples will differ in the contaminants that they contain.

There is some support for the notion that water can have properties that depend on how it has previously been processed (that is, water has, in some sense, a kind of "memory"). The experimental evidence indicates that the "memory" are due primarily to solute and surface changes occurring during this processing. In particular, water, as a result of repeated vigorous shaking, might include Redox molecules produced from water, dissolved atmospheric gases and airborne contaminants, Silicates - tiny glass "chips", nanobubbles and their material surfaces, dissolved ions, including from the glassware. It may be contaminated by material that adheres to the surfaces of glassware, for example by bacterial material. There might also be some effects of successive shaking on water structure - "clustering" of water molecules.

These mechanisms are not mechanisms of memory in any cognitiove sense; the term memory here is used as a metaphor, implying only that the past history has a discernible influence on the present properties.

Water in living organisms

Water is essential for functional macromolecular folding, stabilization and activity, transport, membrane formation and protein insertion into membranes; it the intracellular matrix in which biological molecules interact. Understanding exactly how water diffuses when confined in proximity to complex macromolecules inside a cell is therefore an important challenge. The diffusion coefficient of water in biological tissues has been measured using nuclear magnetic resonance, and these have shown that, within a cell, water diffuses much more slowly than pure water in aqueous media. This is at least partly explained by tortuosity effects, macromolecular crowding and confinement effects, but some (but not all) have suggested that the interaction with macromolecules might cause "clustering" of water molecules -that it might change the structure of the intracellular water.

In contrast with this post-hoc analysis of water behavior in cells (proteins may cause water to arrange in clusters - or not), Patterson proposes, in an invited paper for Chaplin's Water structure and science resource, "the cluster-domain model (which) depicts the cytoplasmic space as a densely packed world: not as a fluid solution, and not as protein molecules in empty space". Further, it postulates a "protein-water network (...) an energized gel whose units, protein domains and water clusters, manipulate pressure and tension to perform mechanical steps." This model is intended "to explain (...) the mechanical and energetic events of the cell (because) the traditional view (statistical mechanical principles) cannot explain (how these events) proceed without failure (...)". According to this model, the interaction of water with macromolecules does not cause "clustering" of water molecules, it is a cluster: a “pressure pixel”.

The cell can be seen, from a somewhat extreme structuralist point of view, as organized water. There is an incipient order in liquid water, which is given long-range coherence and permanence by the protein framework. In the words of A. Szent-Gyorgyi, “Life is water dancing to the tune of solids”.

Enzyme function: random events or coherent action? (2004) JG Watterson in Pr. Chaplin's Water structure and science online resource.

As we have seen, the materials science of liquid water, in a similar fashion, is abandoning the random network model of liquid water. The physics and the biophysics of water could be united in a synthesis that may accomodate homeopathy.