Memory of water

Template:TOC-right Memory of water is a phrase used by homeopaths to explain how aqueous ("watery") solutions used as remedies might effectuate the results that they claim to see in their patients. Because homeopathic remedies purposefully use extremely high dilutions it is unlikely that the solutions contain even a single molecule of substance other than pure water. This has led homeopaths to speculate that a possible explanation for the observed responses is "memory of water". Many widely differing explanations have been proposed to explain how water can supposedly remember the biologically active molecules that it had once been in contact with and that have now been removed altogether from the solution by repeated dilution.

The first laboratory observation—and still the most famous—that a homeopathic treatment (succussion and dilution) might have an effect on water as well as on ethanol and propanol was embodied in research by Jacques Benveniste and his colleagues, published in the prestigious English journal Nature in June of 1998. Benveniste purportedly discovered that diluted water might retain some qualities of various materials that had once been dissolved in it. The French newspaper Le Monde popularized the phrase that same day in a front-page article and touted its ramifications for the foundations of physics. The original research could not be replicated under the scrutiny of a committee sent by Nature and its conclusions remain extremely controversial. In the two decades since the first article, most molecular physicists and physical chemists working in the laboratory have not accepted any explanations of the "memory of water" as plausible.

The Nature article

In their Nature article, Benveniste et al. reported that particular solutions of biologically active compounds subjected to sequential physical processing (shaking) and progressive dilutions appeared to have some biological effects that were different from the "control" effects of the water used as a solvent, even though the solution was diluted so much that the chance that a single molecule of the biologically active solute was left in it was completely negligible. In their original paper Benveniste et al. state that their results remain unexplained, but suggest that it is somehow related to the molecular organization of water. Later Benveniste et al. hypothesized that water somehow "remembers" the active compounds (together with their biological properties) that it contained before dilution. The work resulted in considerable controversy, as most other laboratories stated they were unable to reproduce the reported effects, while, on the other hand, an international collaboration led by Professor Madeleine Ennis of Queen's University of Belfast reported confirmation. Following Benveniste and coworkers, Ennis et al. studied the effects of homeopathically treated solutions on human basophils. In their paper Ennis and coworkers state emphatically and repeatedly that they cannot explain their findings.

An overview of the issues surrounding the memory of water and its relationship to homeopathic medicine was the subject of a special issue of the leading journal on homeopathy. The articles in this issue propose widely varying mechanisms for water memory, such as: electromagnetic exchange of information between molecules, breaking of temporal symmetry, thermoluminescence, entanglement described by a new quantum theory, formation of hydrogen peroxide, clathrate formation, etc. without any mechanism singularly standing out as the definitive explanation. Some of the proposed mechanisms require revolutionary new physical laws.

The consensus of mainstream science is that liquid water exists as a continuously rearranging hydrogen-bonded network with motions on the picosecond (10⁻¹² s) scale.. A picture of a quickly rearranging network is very difficult to reconcile with liquid water structures that are sustained for more than a few picoseconds. Accordingly there is no room for a water "memory" in the modern scientific view on the liquid. If work other than effects on human basophils would become available that would support the notion of water memory, and if this work would stand scientific scrutiny, then much of the existing experimental and theoretical data on liquid water would have to be reinterpreted or even rejected. Before this happens, most water researchers do not find it useful to speculate in what way liquid water could store long-lived information.

The Benveniste studies

Human basophils are a rare granulocyte cell type accounting for 0.1–1% of white blood cells; these cells contain large numbers of "granules" which store inflammatory mediators, including in particular histamine. These cells can be cultured readily and studied in vitro. In these cells, exposure to anti-human-IgE antibodies triggers a "degranulation" process in which the granules fuse with the plasma membrane to release their contents, including histamine, into the extracellular fluid. At high concentrations (>10⁻⁶ M) histamine binds to H2 receptors on the surface of the basophils, and regulates the basophil degranulation by feedback inhibition.

Basophil activation can be measured in several different ways. First, degranulated cells can be stained and then counted; this is a subjective measurement and is prone to variable outcomes depending on the observer. Second, histamine release into the culture medium can be measured using fluorimetric assays. Third, the fusion of cytoplasmatic granules leads to the expression of the marker CD63 on the surface of the basophils; the percentage of basophils that express CD63 can be determined with flow-cytometry, and correlates well with histamine release.

As mentioned above, the discussion about water memory started when in 1988 Jacques Benveniste (1935-2004) a distinguished French immunologist published a controversial paper in Nature reporting on the action of very high dilutions of anti-immunoglobulin E on the degranulation of human basophils. At the high dilutions used, the solutions should have contained only molecules of water, and no molecules of (anti-IgE) at all. Benveniste concluded that the configuration of molecules in water was biologically active.

Nature published the article with two unprecedented conditions: first, that the results must first be confirmed by other laboratories; second, that a team selected by Nature be allowed to investigate his laboratory following publication. Benveniste accepted these conditions; the results were replicated in Milan, Italy; in Toronto, Canada; in Tel-Aviv, Israel and in Marseille, France, and the article was accompanied by an editorial titled "When to believe the unbelievable." After publication, the follow-up investigation was conducted by a team including the editor of Nature, Dr John Maddox, American scientific fraud investigator and chemist Walter Stewart, and "professional pseudoscience debunker" James Randi. With the cooperation of Benveniste's team, under double-blind conditions, they failed to replicate the results. Benveniste refused to withdraw his claims, and the team published in the July 1988 a detailed critique of Benveniste’s study. They claimed that the experiments were badly controlled statistically, that measurements that conflicted with the claim had been excluded, that there was insufficient avoidance of contamination, and that there were questions of undisclosed conflict of interest, as the salaries of two coauthors of the published article were paid for under a contract with the French company Boiron et Cie.

In the same issue of Nature (and subsequently) Benveniste vigorously attacked the Nature team’s "mockery of scientific inquiry." Subsequent attempts by other labs to reproduce Beneviste's results have failed to reproduce the effects . However other studies have looked at the effects of very low concentrations of histamine on degranulation induced by anti-immunoglobulin E (IgE) antibodies, and again reported effects at very low concentrations. As degranulation itself produces relatively high concentrations of histamine in the medium, one would only expect an effect with very high concentrations of added histamine—and indeed the most recent study reported significant effects only at 10⁻² M histamine. These experiments generally involved dilutions of histamine to concentrations of as low as 10⁻³⁸ M, and the dilutions were performed conventionally not according to the protocols used in homeopathy.

So how is it possible that adding vanishingly low concentrations of histamine to a preparation that is already secreting high concentrations might have any effect? What could possibly explain the extraordinary results reported by Beneviste and others? One difficulty with the basophil preparation is that, in these cells, degranulation can be triggered by many different stimuli, including slight mechanical disturbances and environmental variations in temperature, and is sensitive to small differences in incubation time, making adequate controls very difficult. For example, in the experiments of Guggisberg et al. the authors found no significant effects of low dilutions of histamine, but did find significant effects for row numbers of the microtiter plates—i.e., there was a significant effect simply of the order in which the samples were assayed. They concluded that seemingly, trivial differences in the experimental set up can lead to significant differences of the results.

Benveniste never retracted his claims. On the contrary, in 1997, he declared that the memory could be transmitted across a digital telephone link, suggesting that the memory involved electromagnetic signals.