One event in the expert development of Jaap Goudsmit, which gradually takes us to the end of the second stage, is an affair that shocked many: the Buck-Goudsmit affair. 12 Early in 1990 Henk Buck, a professor of chemistry, wanted to check whether a DNA drug he had discovered could work on HIV. Goudsmit therefore ran tests with the substance, and mistakenly confirmed that it worked. A letter was sent to Science and Buck and Goudsmit held an official press conference. This was, after all, a discovery of great importance.