On 9 May 1849 Hirschel was arrested in connection with the May Uprising and spent two and a half months in detention. Prescise details of his involvement are unclear, but there is reason to believe that he was not himself a participant in street fighting, but was arrested for applying his medical skills to treating wounded protesters. While he was in detention Hirschel wrote his "Prisoner's Diary" ("Tagebuch eines Gefangenen"), describing his incarceration as very depressing. He seems to have been ill at this time, and repeatedly stated his intention to withdraw from all political activities.