Five years later, Arthur Eichengrün published a paper in Pharmazie in 1949, where he explained that he had instructed Hoffmann to synthesise acetylsalicylic acid and that the latter had done so without knowing the purpose of the work. The paper elucidated how he planned and directed the synthesis of aspirin along with the synthesis of several related compounds, describing these events in detail. He also claimed to be responsible for aspirin's initial surreptitious clinical testing. Finally, he explained that Hoffmann's role was restricted to the initial lab synthesis using his (Eichengrün's) process and nothing more.