Memory of water

Memory of water is a phrase used by homeopaths to explain how the aqueous (water) solutions they use as remedies might produce the results that they claim to see in their patients. Homeopathic remedies deliberately use extremely high dilutions, so it is unlikely that a therapeutic dose contains even a single molecule of the substance being diluted. This has led homeopaths to speculate that a possible explanation for the observed responses is "memory of water"; the water somehow "remembers" the biologically active molecules that it has once been in contact with, and that "memory" produces therapeutic effects.

Chemists and physicists generally see this notion as nonsense. The consensus of scientists working in the field is that liquid water exists as a continuously rearranging hydrogen-bonded network with motions on the picosecond (10⁻¹² s) time 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 current scientific view on the liquid.

The Benveniste study

In 1988, a French immunologist, Jacques Benveniste, and a group of colleagues published a paper in the prestigious English journal Nature. Their data indicated that diluted water, ethanol or propanol might retain some qualities of various materials that had once been dissolved in it. In particular, they claimed to have measured effects on human immune response.

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.

Benveniste and his colleagues found evidence that very high dilutions of anti-immunoglobulin E had an effect on the degranulation of human basophils. At the 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.

The French newspaper Le Monde covered this, referring to "la mémoire de la matière" (the memory of matter) and le souvenir de molécules biologiquement actives (recollection [by water] of biologically active molecules). In English, however, the phrase that became widespread was "memory of water". Le Monde considered the paper important, making it a front page story, and correctly pointing out that if this work were correct, it would overthrow many of the foundations of physics.

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..

Subsequent attempts by other labs to reproduce Benveniste's results have failed to reproduce the effects.

Benveniste has never retracted his claims. In the same issue of Nature that carried the critique, Benveniste vigorously attacked the Nature team’s "mockery of scientific inquiry." . He has maintained his position in later publications as well.

Homeopathic coverage

The notion of "memory of water" is taken quite seriously among homeopaths. For them, it provides an explanation of why some of their remedies work, and raises some very interesting questions — how does one explain the phenomenon, and what will the explanations tell us about more general issues of the structure of liquids, or indeed of matter? It is clear that we will need some new physics to explain it.

To a more orthodox scientist, it is also clear that explaining the phenomenon would require some new physics. What is not clear is that there is anything that needs explaining; the only evidence is the flawed Benveniste work, and that is not nearly enough to contemplate fundamental changes in physics.

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 principles overthrowing much of 20th century physics. Remarkably, all explanations concentrate on water and its alleged special properties, the fact that—according to Benveniste et al.—ethanol and propanol also have memory is completely ignored.

Digital biology

Benveniste never retracted his claims. On the contrary, later he turned to working on what he called "Digital Biology", which is based on the assumption that molecules emit electromagnetic radiation in the frequency range 20 Hz to 20 KHz, the same range as sound waves audible by humans. He argued that electromagnetic vibrations are "signals exchanged among molecules" that are used by living things to convey information. By means of an amplifier, electromagnetic coils and a PC sound card Benveniste claimed that he was able to digitize and store the molecular signals. The digital information (possibly after sending it over the Internet) could be replayed to a biological system making it believe that it is in the presence of its "favorite molecule".

To most scientists, these notions are obviously utterly implausible. In the first place, the wavelength of electromagnetic waves at these frequencies is several kilometers, far too long to interact with microscopic molecules. The usual theories of physics give no reason to expect molecular EM waves in this region of extremely low frequencies and no-one else has observed them. Benveniste's description of his experiments is too vague to even begin thinking about trying to reproduce them. His theory is in complete contradiction to the well-established principles of molecular spectroscopy, and is nowhere near either well enough developed or sufficiently supported by experiment to be taken seriously as a challenge to established theories.