In an interview yesterday, Dr. Ricaurte said he realized his mistake when he could not reproduce his own results by giving the drug to monkeys orally. He then realized that two vials his laboratory bought the same day must have been mislabeled: one contained Ecstasy, the other d-methamphetamine.

Dr. Ricaurte's laboratory has received millions of dollars from the National Institute on Drug Abuse, and has produced several studies concluding that Ecstasy is dangerous. Other scientists accuse him of ignoring their studies showing that typical doses do no permanent damage.

At the time Dr. Ricaurte's study was published, it was strongly defended against those critics by Dr. Alan I. Leshner, the former head of the drug abuse institute, who had just become the chief executive officer of the American Academy for the Advancement of Science, which publishes Science.

Dr. Leshner had testified before Congress that Ecstasy was dangerous, and Dr. Ricaurte's critics accused him of rushing his results into print because a bill known as the Anti-Rave Act was before Congress. The act would punish club owners who knew that drugs like Ecstasy were being used at their dance gatherings. Dr. Ricaurte yesterday called that accusation "ludicrous."

Ricuarte now says he's a scientist, not a politician. When asked how the vials got mixed up, he says he's not a chemist and its not customary for him to check the substances. A spokesman for Johns Hopkins said Ricuarte is "still a faculty member in good standing whose research is solid and respected."

Update: Instapundit says the study was relied on by proponents of Joe Biden's dumb Rave Act.