This paper examines Johann Ulrich Bilguer’s 1761 dissertation on the inutility of amputation practices, examining reasons for its influence despite its nonconformance to genre expectations. I argue that Bilguer’s narratives of patient suffering, his rhetorical likening of surgeons to soldiers, and his attention to the horrific experiences of war surgeons all contribute to the dissertation’s wide impact. Ultimately, the dissertation offers an example of affective rhetorics employed during the Enlightenment, demonstrating how bodies and environments—those ambient rhetorics made visible in a text—can contribute to an analysis of genre deviations and widen the scope of genre studies.