Friday, 15 August 2008

More bad homeopathic water science

More from the new issue of comedy journal Homeopathy. Homeopaths continue to pursue research on 'high dilutions' (i.e. dilutions such that there is highly unlikely to be any of the original solute remaining) in search of a vaguely plausible mechanism for homeopathy to work. Since the evidence is that homeopathy doesn't work, this is unlikely to be a fruitful endeavour, but it does provide entertainment for connoiseurs of pseudoscience.

The latest offering is a paper by one R. Assumpção , entitled "Electrical impedance and HV plasma images of high dilutions of sodium chloride" and an acccompanying editorial by Cyril Smith. Two sets of observations are presented: a set of Kirlian photographs and a set of measurements of the impedance of various homeopathic dilutions of NaCl.

What is Kirlian photography? When an object resting on a photographic plate is connected to a source of high voltage, an image is formed on the plate. Semyon Kirlian, whom the technique is named after, thought that such images might be compared to a human 'aura'. You can see how this would be attractive to various kinds of energy medicine fruitcakes. In the paper, Assumpção provides Kirlian photographs of homeopathic dilutions of an NaCl solution (6c, 12c, 24c and 30c) and of succussed (shaken) water without dilution. The images are certainly pretty, but what do they show? Not a lot, as far as I can tell. It isn't clear how such images should be interpreted, and all Assumpção really concludes is that different dilutions look different. This, in itself, is not a particularly exciting finding, in the absence of any hypothesis as to why that is and what it might mean.

What of the impedance data? Assumpção finds that impedance of the samples increases with dilution, up to about 12c (which is the point where Avogadro's constant suggests that there is unlikely to be any of the original NaCl remaining), and then decreases again slightly with further dilution. "This phenomenon is inexplicable in terms of conventional chemical theory" concludes Assumpção, a statement that really should be followed by "OMG!!!!11!1!1!!1!!!!!1".

Well, I think I have a reasonable explanation for the results that causes no problems for conventional chemical theory. As expected, dilution of the NaCl solution causes an increase in impedance as ions are removed from the solution. But there is also a competing increase in the concentration of dissolved ions caused by the succussion (agitation) process, as atmospheric gases and other impurities are dissolved in the water. So the small decrease in impedance beyond 12c could result from this process. I'm more puzzled as to why the impedance of the distilled water increases when it is shaken, suggesting a decrease in the concentration of dissolved ions. However, I suspect that there is a conventional explanation, but Assumpção doesn't seem to be particularly curious about this. Is there a change in the ionic species in the water as it is shaken? Does shaking facilitate outgassing of the dissolved gases that remain in the distilled water? We don't know. This continues the homeopathic water research tradition of publishing things without any thought as to what factors (other than the magic of water) might have led to the results.

Of course, the other thing to note is that the paper only looks at one solute, NaCl. For homeopathy, what would be really interesting is if you could show that there was a difference between two different homeopathic substances at dilutions greater than 12c. Previous attempts to do this have ended in some embarassment, as Smith acknowledges in the accompanying editorial, when he states "in the light of the controversy which has attended previous claims in this field, caution, and independent repetition of these results is required". There seems to be little sign of any such caution so far.

Finally, in Figure 5 of the paper, Assumpção had omitted to label to the impedance curves, showing which curve belongs to which dilution. The solution? Simply write the labels in, with a pen, afterwards. It is truly amateur hour.

12 comments:

Paul Wilson said...

Just as a self-congratulatory aside, in Science Direct the first paper in the list of 'related articles' to Cyril Smith's editorial is my very own response to Martin Chaplin's memory of water piece last year...

Le Canard Noir said...

I have a nasty feeling that this paper might be comedy gold too. (I don't hae access at the moment.)

Homeopathic pathogenetic trials produce more specific than non-specific symptoms: results from two double-blind placebo controlled trials Walach H, Möllinger H, Sherr J, Schneider R. J Psychopharmacol. 2008 Jul;22(5):543-52.

Paul Wilson said...

Sample quote:

"Thus, placebo and homeopathic medications were undistinguishable by taste or by any conventional means of detection."

Heh...

Paul Wilson said...

I also like the conclusions:

1) In healthy volunteers, homeopathic remedies produce more symptoms typical for a remedy than non-typical symptoms, at least sometimes.

2) Volunteers taking homeopathic remedies are more likely to experience symptoms typical for that remedy than volunteers taking placebo, at least sometimes.

"At least sometimes", indeed...

HolfordWatch said...

Everybody's gotta learn at least sometimes - or not, in this case...(with apologies to Beck).

Can I ask how many symptoms are associated with a remedy? Are they to be confused with everyday itches, twitches and aches?

Mojo said...

"Can I ask how many symptoms are associated with a remedy?"

Loads. In the case of a proving of a remedy made from a shipwreck, and posted on the internet, the proving report included included the sinking of a Senegalese state-run ferry, The Queen's boat breaking down on a river in Winnipeg, an oil tanker sinking off Spain, and a diver from Quebec complaining about not being allowed to sell artifacts he'd found in an historic shipwreck.

HolfordWatch said...

A shipwreck - and those were symptoms? How would you ever stop? The whole of the geo-political system as nothing more than someone dosing up on dilutions of a devalued pound or dollar.

The more I hear about this, the less it seems like an eccentricity that is charming in parts and something that is floridly barking.

Paul Wilson said...

Crikey! If a homeopathic proving could actually cause a ferry to sink, that would rather suggest that homeopathy is not quite as harmless as it's cracked up to be.

Isabel deClaire said...

One could hope that a huge lump of entangled particles might land on your head and force you down into the depths of that desert, never to rear your supercilious smugness again.

Paul Wilson said...

Cheers!

Paul Wilson said...

"One could hope that a huge lump of entangled particles might land on your head..."

One could, but a huge lump of entangled particles is quite an unlikely phenomenon because, as shpalman points out, at room temperature "persistence of an entangled state of two of three particles for milli- or microsecond timescales (respectively) represents a breakthrough".

Paul Wilson said...

Regarding proving symptoms: there was a debate about provings a while ago, which I wrote about here. A group of homeopaths was arguing that provings should be done to higher scientific standards, i.e. actually have control groups and such like. This was criticised on the grounds that provings with better methodology tend to produce fewer symptoms: provings of hydrogen were mentioned, where a proving with improved methodology produced one fiftieth(!) of the symptoms of earlier provings with less robust methodology. The problem was that the improved methodology involved, I kid you not, "over rigorous filtering out of symptoms [and] left only a few common symptoms, resulting in an unusable proving".

So if you don't get a huge number of spurious symptoms, you're doing it wrong.