German chemist Kurt Geckeler and his colleague Shashadhar Samal stumbled on the effect while investigating fullerenes at their lab in the Kwangju Institute of Science and Technology in South Korea. They found that the football-shaped buckyball molecules kept forming untidy aggregates in solution, and Geckler asked Samal to look for ways to control how these clumps formed. What he discovered was a phenomenon new to chemistry. "When he diluted the solution, the size of the fullerene particles increased," says Geckeler. "It was completely counterintuitive," he says. Further work showed it was no fluke. To make the otherwise insoluble buckyball dissolve in water, the chemists had mixed it with a circular sugar-like molecule called a cyclodextrin. When they did the same experiments with just cyclodextrin molecules, they found they behaved the same way. So did the organic molecule sodium guanosine monophosphate, DNA and plain old sodium chloride.--Fred Pearce of University College London, who tried to repeat Benveniste's experiments, agrees. But it could offer some clues as to why other less dilute homeopathic remedies work, he says. Large clusters and aggregates might interact more easily with biological tissue.Chemist Jan Enberts of the University of Groningen in the Netherlands is more cautious. "It's still a totally open question," he says. "To say the phenomenon has biological significance is pure speculation." But he has no doubt Samal and Geckeler have discovered something new. "It's surprising and worrying," he says.The two chemists were at pains to double-check their astonishing results. Initially they had used the scattering of a laser to reveal the size and distribution of the dissolved particles. To check, they used a scanning electron microscope to photograph films of the solutions spread over slides. This, too, showed that dissolved substances cluster together as dilution increased. --"It doesn't prove homeopathy, but it's congruent with what we think and is very encouraging," says Peter Fisher, director of medical research at the Royal London Homeopathic Hospital.