When filth became dangerous: the miasmatic and contagionistic origins of nineteenth-century cleanliness practices among Swedish provincial doctors.

This investigation sheds light on the social history of pathogenic dirt and its significance for shaping medical practices during the nineteenth century. It consists of an analysis focusing on Swedish medicine, using 8800 yearly reports written 1820-1900 by Swedish provincial doctors for the National Board of Health in Stockholm. The main argument is that the provincial doctors' perceptions of the relationship between dirt and health during this century can be better understood by focusing on similarities in the handling of different kinds of pathological dirt over the course of many decades, rather than seeing interest in cleanliness as something mostly unprecedented. A novel cleanliness regime became dominant during the latter third of the century, meant to counter a new hybrid between everyday dirt - bodily emanations from healthy bodies - and matter believed to have caused miasmatic and contagionistic disease. New ideas about filth and its impact on health played a crucial role in the development of public health and sanitation movements, and were a precondition for everyday dirt becoming a central medical problem around the turn of the twentieth century, but as is shown, they built on old precedents. Thus, the miasmatic and contagionistic approach to disease shaped conceptions of hygiene and cleanliness.