Paolo Mantegazza's science of emotions represents the dominant style of thinking that was fostered by the late nineteenth-century Italian scientific community, a pos- itivist school that believed that the dissemination of Darwin's evolutionary ideas would promote social progress in that country. Within this collective thought, Mantegazza was committed not only to studying the physiological experience of pain by means of vivisection but also to completing an anthropological study that examined the differ- ences between the expressions of suffering in primitive and civilized cultures. Thus, the meaning of pain appears throughout Mantegazza's research as a result of applying an ensemble of scientific practices integral to observation, experimentation, and the scien- tific self, which enabled its main physiological and psychological manifestations to be reproduced in the laboratory. Among these practices, photography allowed Mantegazza to mobilize pain as an emotion whose performativity shaped national identities, such as those that embodied the recently created Italian state.