Dilution debate
Martin Robbins reports on a demonstration where over 300 activists “overdosed” by taking a whole bottle of a homeopathic remedy based on arsenic (30 January, p 22). They aimed to show that arsenicum album homeopathic pills contain no arsenic, as you might expect given the dilution.
About two years ago I analysed arsenicum album homoeopathic tablets and found traces of arsenic. I had previously analysed other homeopathic tablets and had always found traces of the material they were said to contain. Thus, I would suggest that you cannot rely on the mathematics of dilution.
In terms of the value to people, the pills may work via the placebo effect, which is enhanced by a label and a trace of something thought to be good and relevant. Remember that it has been shown that coffee tastes better when drunk from your favourite cup.
From Alan Calverd
Samuel Hahnemann’s original experiments in homeopathy investigated the possibility that the body’s immune systems might be stimulated by toxins, prompting a natural healing process 鈥� an extrapolation from the principles of vaccination and acquired immunity.
The mysticism that now surrounds some homeopathic practice makes it easy forget that very dilute solutions can still have an effect: a lethal dose of botulinum toxin 鈥� the most poisonous substance we know 鈥� in primates is 1 part in 109 of body weight when taken orally ().
That’s a fair bit stronger than the 1 in 1023 dilution the 10:23 protesters were demonstrating against, but is not inconsistent with inducing a response at the “eighth potency” 鈥� 1 in 108 dilution, as I recall Hahnemann reported for some toxins.
Bishops Stortford, Hertfordshire, UK
From John de Rivaz
The reason homeopathic treatment appears effective is that the practitioner spends a lot of time with the patient in calm, serene surroundings. In comparison, conventional medicine closely resembles a production line with patients spending hours on the road visiting various different health centres miles apart in space, and weeks apart in time.
If evidence-based medicine was presented to patients in a serene, ordered and unchaotic manner it would then be a fair test, and the public would vote with their feet. Until such a thing happens, treatments such as homeopathy will flourish.
Truro, Cornwall, UK
From John Poynton
Before we rush to follow Martin Robbins in rejecting homeopathy, there are still questions raised in the literature that should be investigated.
W. E. Boyd published a paper in the British Homoeopathic Journal (DOI: ) reporting on the action of micro-doses of mercuric chloride on the hydrolysis of starch with malt diastase. While standard dilutions of mercuric chloride deactivate enzymes, a series of carefully controlled and double-blind procedures showed that as the mercuric chloride was progressively diluted, accompanied by mechanical shock, the rate of hydrolysis was increased. The final dilutions would not have contained any molecules of the original mercuric chloride, yet they were the most effective.
Standard clinical trials are almost designed not to detect whether homeopathic treatments are effective, since treatment has to take into account a patient’s individual state and requirements on each occasion for any success to be anticipated. Mass dosing is therefore bound to be ineffective.
London, UK
From Julien Glazer
If homeopathic products work on believers that’s fine. However, I do think that there should be a government health warning on all packets, stating: “This medication is not suitable for sceptics”.
Westcliff-on-Sea, Essex, UK
Consumer emissions
In his article on UK carbon emissions (6 February, p 11), Phil McKenna misinterprets our findings. The article implies that the UK’s Department for Environment, Food and Rural Affairs (DEFRA) is deferring the publication of a report that shows UK emissions “rose by 13.5 per cent between 1992 and 2004”.
However, this is not a new result. In 2008, in a report entitled , DEFRA published the finding that carbon dioxide emissions from producing goods in the UK had decreased between 1992 and 2004 as CO2 emissions from the consumption of goods and services kept growing. Rather than reiterate these findings, what we did in our research was quantify the relative importance of various drivers behind the increase in consumer emissions in the UK.
The 217-megatonne rise in carbon emissions mentioned in the article, which McKenna attributes incorrectly to “emissions from imported goods”, arises from a changes in consumer choice and rising levels of consumer demand for goods and services manufactured in the UK and abroad. In fact, the rise in emissions from the production of imported goods and services was roughly 84 megatonnes.
In our view, instead of asking why a report on consumer emissions in the UK commissioned by DEFRA has not yet been published, it might be more interesting to think about why so few other governments in industrialised countries have analysed the complex origins of their emissions.
Hot rocks, hot topic
Nick Lane’s article on the origins of oxygen on Earth misses key points when discussing the fossil record (6 February, p 36).
The article mentions 3.5-billion-year-old stromatolites in the Apex chert of Western Australia, and questions whether they are biological. The stromatolites come from only one of 12 known stromatolitic units older than 3 billion years. These stromatolites are of many types, found in diverse settings, including conical forms that, like their modern analogues, require the presence of a layer of mobile microorganisms at the time of rock formation (DOI: ).
Fossils from the Apex chert in Western Australia have been shown to be cellular and have organic walls (DOI: ). In support of this, Bradley De Gregorio and co-workers concluded that the chemistry of the Apex organic matter implies “that the Apex microbe-like features represent authentic biogenic organic matter” ().
Moreover, those authors who report that temperatures during formation of the Apex rocks would have been too high to support life, state that their study “cannot be extended directly to the microfossil of the Apex chert” ().
We have never found non-biological organic matter in the geological record, and thousands of carbon isotopic analyses are consistent with the presence of autotrophs, which synthesise organic matter from inorganic constituents, dating back to 3.5 billion years ago.
Additionally, the hydrocarbon biomarkers in 2.7-billion-year-old Australian shales mentioned in the article were present in the rocks when they formed (DOI: ) as are biomarkers in rocks of similar age from South Africa (DOI: ). Given all this evidence, it seems clear to us that a thriving microbial biota was in existence 3.5 billion years ago.
Out of data
In speculating that we might lose vital knowledge if civilisation were to collapse, your authors missed the very real threat that it might happen in the near future (30 January, p 36).
Most software is updated every few months, and is frequently completely rewritten, which can result in errors in reading the old programs. This can be a real problem for the engineering systems in planes and ships, for example, where accurate information is needed to maintain and repair them decades after they are built.
And what about the computer models that prove systems are safe? In years to come, the models showing that the Large Hadron Collider is safe may no longer be trustworthy after several generations of upgrades to the software.
Printing out the relevant information or stockpiling old computers will not help, since people in the future will not only need the data, they will have to understand it. Aside from the software side of the problem, there is an even more difficult question: do we know how to train people to understand the old models?
My own work in the development of a standard for the long-term archiving and retrieval of aircraft product data suggests that these problems are not as rare as the article suggests.
Genes swap
Mark Buchanan suggests that there might have been a stage between the emergence of a universal genetic code and full-blown Darwinian evolution (23 January, p 34) where genomes capable of heredity and mutation first united in single organisms.
Understanding this “prevolution” is important: it is a process that has not stopped just because evolution proper has started. The horizontal transfer of genetic information between organic organisms happens all the time, including in human beings, where it surely has enormous repercussions.
Given our current ignorance of horizontal gene transfer, we should treat our experiments in this area with great care.
No scratch, do sniff
Clare Wilson mentions the large volume of research dedicated to the suppression of armpit odour (19 December 2009, p 54).
I have been wiping my armpits with methylated spirits ever since I discovered the odour has a bacterial source: a simple and cheap solution to the problem. The smell stays away for days in sweaty summers and my armpits are no longer irritated by daily applications of deodorants.
For the record
鈥� In our discussion of packaging overkill, it the was packaging-to-goods ratio of the empty box Geoff Robinson received that was infinite, not the goods-to-packaging ratio as we said (Feedback, 6 February) 鈥� a description that would have applied only if Geoff’s present had arrived unwrapped.
鈥� In our article on rock varnish (13 February 2010, p 40) we said the ExoMars mission would return rock samples from Mars to Earth. In fact, this is part of the separate Mars Sample Return mission, pencilled in for launch 2020 to 2022.