Several prominent French doctors cautioned that the results would have to be confirmed and warned of possible side effects. The French health minister deemed the trial promising but called for more testing. Raoult had already begun assembling data for a larger study, but he dismissed the need for anything particularly vast or lengthy. Like other critics of the R.C.T., he likes to point out that a number of self-evidently useful developments in the realm of human health have never been validated by such rigorous tests. This observation has come to be known as the parachute paradigm: We tend to accept the claim that parachutes reduce injury among people who leap from airplanes, but this effect has never been proved in a randomized study that compares an experimental parachute group to an unlucky parachuteless control. “It’s like Didier says,” Drancourt told me. “If you don’t have something that’s visible in 10 patients, or 30, it’s useless. It’s not of any consequence.” An effective treatment for a potentially lethal infectious disease will be visible to the naked eye.