A blue litmus paper turns red with acid is a school fact most people are familiar with. And why does this happen? Again, a school child would tell us that the acid molecules react with the molecules of the substance litmus is made of, resulting in the color change. An obvious answer. But inherent in it is the understanding that for the reaction to take place, molecules of both the substances must be present. Let us extend this school experiment a bit further. Suppose we started with 10 ml of acid and we now dilute it with 90 ml of water. The resulting acid solution shall be 10 times more dilute than the original. By repeating the procedure, we can keep on getting more and more dilute solutions, meaning solutions with lesser acid molecules. Now, there is known to be a number, called the Avogadro number, that tells us that number of molecules in a gram-molecule of material is roughly 6.023×10 raised to 23. If we keep this in mind, then it can easily be deduced that after dilutions of the type described above, the chances, are that the solution contains about one acid molecule. That any acid molecule would be left in the solution after 30 dilutions is virtually impossible. Suppose we carry on this experiment till 120 similar dilutions, that is, till the final solution is 10 raised to 120 times more dilute than the original, and test the solution after each dilution with litmus. Common sense tells us that after just a few dilutions, there should be no reaction, certainly not after 23 or 30 dilutions. But suppose someone was to inform us that the reaction persists till 120 dilutions, and that too in a fluctuating manner, i.e., it appears and disappears with increasing dilutions, how should we react? With utter disbelief, calling into question the sanity of the informer! But if the experimenter is not a casual friend but a group of scientists from reputed laboratories, and the results are published in a reputed journal, what does one say? The mind boggles. Amazingly, that is what happened in 1988 when under the title "Human basophil degranulation triggered by very dilute antiserum against IgE" a paper appeared in Nature. Dr. Jacques Benveniste and his colleagues, at the University of Paris started with a liquid containing not an ordinary acid, but antibodies, which make a type of white blood cell (called basophils) give off molecules called histamines. They then mixed one part of antibody solution with nine parts of antibody-free liquid, and repeated the process 120 times. Incredibly, as reported, the basophil cells kept responding to the liquid, even though according to existing knowledge, it no longer contained antibodies. Even more perplexing, the response came and went. When exposed to the 52nd dilution, the cells reacted strongly, but showed no response to the 55th. The 58th dilution again produced a response, and so on till the 120th. According to all physical laws, this is impossible. If there are no molecules, there can be no reaction. The essence of the result is that an aqueous solution of an antibody retains its ability to evolve a biological response even when diluted to such an extent that there is negligible chance of there being a single molecule in the sample. As it turns out, the article had been first submitted for publication three years ago. The editors of Nature had insisted that more laboratories engaged in related work should be involved in the experiment. Accordingly, the Paris laboratory collaborated with scientists in laboratories in Israel, Italy, and Canada, and the published paper was in fact a joint publication of all these laboratories. Nature finally published it along with an editorial titled "When to Believe the Unbelievable", adding, "An article in the week's issue describes observations for which there is no present physical basis. There are good and particular reasons why prudent people should, for the time being, suspend judgment". Giving reasons for publishing the article, the editors hoped 'that vigilant members of the scientific community, with a flair for picking holes in other people's work may be able to suggest further tests for the validity of the conclusion'. The article, of course, questions not a small area of biological domain, but strikes at the very roots of two centuries of observation and rationalization of physical phenomena. Amongst others, it questions the Law of Mass Action, of which Avogadro's number is a part. The editors conclude by asserting that 'the principle of restraint which applies is simply that, when an unexpected observation requires that a substantial part of our intellectual heritage should be thrown away, it is prudent to ask more carefully than usual whether the observation may be incorrect'. Nature had accepted the article in spite of incredulity expressed by many referees, and had made a pre-condition that independent investigators would observe a repetition of the experiment. Swiftly one of the earlier referees, Henry Metzger, of the National Institutes of Health, fired the first salvo in a letter to Nature demanding that publication of irreproducible data as distinct from speculative opinion requires more exacting editorial standards. Otherwise, the process of science, he said, would be confused, even lent a 'circus atmosphere'. The editors contended that it is rare that some such claim should come from a government-supported laboratory that its principal author should urge publication in the face of common sense, and should complain that failure to publish will be tantamount to suppression of truth. As it turns out, the importance of the article goes beyond the questions of pure science, since wider socio-economic interests seem to be involved. The conclusions of the article tend to support the basic premise of homeopathic medicine, which has been seeking a verification of the theory of biological activity at extreme dilutions from its very inception. It seems the results of the paper had leaked to the popular press of France a long time before appearing in Nature, much to the glee of homeopathic practitioners there, who constitute one-fourth of the total medical doctors in France. It is clear that an acceptance of the claims of the paper would put homeopathy on a scientific pedestal generally denied to it, increasing its avenues of profitability and respectability. The Nature investigating team did visit the laboratory for five days. The team consisted of the editor John Maddox, a physicist by profession, Walter T. Stewart, reputed for his ability to sniff out errors in other's work but also widely criticized, and James (Amazing) Randi, a hero for rationalists, but being a professional magician, distrusted by many. They watched the experiments and proclaimed them below standard. More important, they pointed out statistical errors. From laboratory notebooks they found that the experiments often failed to work for no apparent reason, and that the failures had been ignored. The investigators reported that the atmosphere in the laboratory was not conducive to scientific objectivity and that the experimenters saw only the results they wanted. The team scathingly concluded that Dr. Benveniste's laboratory had 'fostered and cherished a delusion'. In his reply in the same issue of Nature, an angry Benveniste charged that it was outrageous to dismiss years of work on the basis of three experiments conducted 'blind', i.e., without the experimenters knowing what to expect, which failed to show any effects. He accused the investigators of astounding incompetence. Dr. Stewart, he says, had to be 'restrained from screaming at people' and 'Randi kept playing tricks'. More damaging was the revelation by the investigating team that the salaries of two members of the research team of Benveniste were paid through a contract by a French company supplying homeopathic medicines, and the same company, Boiron et Cie, paid the hotel bills of the investigating team. After a few months of fierce and lively correspondence that had few precedents, Nature finally closed correspondence on the issue. No laboratory had reported a reproduction of the claims of the original article. First of all, there is the question of the viability peer review and investigation which is linked with the role of a science journal of repute. Can one discount a scientific result merely because it questions the existing fundamental notions? Successive scientific revolutions have done just that―Relativity was unpalatable to so many, as was Quantum Mechanics to the creator of Relativity. Having 'regretfully' arrived at the conclusion that energy is quantized, Max Planck thought that Einstein's concept of light quanta, photons, was excusable nonsense. One can go on and on. If, therefore, challenging existing fundamentals is in fact an inherent attribute of the scientific process, who or how is the challenge to be evaluated? Then there is the question, as one may put it, of the political economy of science. It has persuasively been argued in recent years that even though some results of science may seem to be untainted by particular sociological or ideological considerations, the path of organized science are controlled by similar socio-political forces as any other branch of inquiry, thereby questioning the notion of 'neutrality' of science. Thus, the nature and source of research funding in science is an important consideration in determining the kind of results likely to be found. That the world is threatened by a technological catastrophe is seen by many as a consequence of the very high defense funding for science during and after the Second World War. Similarly, there are many instances where scientific research has been funded in order to elevate or justify a particular interest, ideological or material. But, as one commentator puts it, 'the investigation report of Benveniste's claim may end up being all things to all men. It gives those who doubted the original article in the first place reasons for doing so, and allows heretics to scream of persecution. But, perhaps, not a lot will change. Homeopaths will continue to sell their medicine, orthodox scientists will continue to say that there is, quite literally, nothing in it, and some patients will be convinced it has made them better.'