Before the availability of antibiotics minor infections could become life threatening. Nurses working in voluntary and public hospitals in Britain were exposed to such risks. This thesis uses both oral testimonies and published sources in order to examine their practices concerning the management of infection risks. The detail of nursing work in this period has been generally hidden in nursing histories of the 1930s and 1940s which have addressed mainly political, recruitment, educational, registration and status issues. Whilst these histories may comment about menial duties, and the culture and discipline in clinical areas, they lack detailed exploration of the day-to-day work of the nurse. This novel study contributes to redressing the balance by examining nursing practice between the discovery of penicillin in 1929 and its widespread availability in Britain in 1948. Data analysis, including the oral testimonies of nineteen former nurses who worked between 1929 and 1948, suggests that nursing practice during this period placed enormous emphasis on cleanliness and hygiene. It is argued that this was linked to sanitarianism which influenced nursing practice before its replacement by germ theory. Probationer nurses learnt their skills in managing infection risks to themselves and their patients in a disciplined and safe way. This was achieved through the exercise of strict routines and a hierarchy of tasks that provided a graduated exposure to the patient and infection risks. This thesis draws on debates in the literature about purity, vocation and status to explore, and add weight to this argument. The analysis also identifies that the introduction of sulphonamide drugs and antibiotics altered nursing practices in the management of both infection risks and patients with infection. Whilst the full effects of these changes are not examined in this thesis, it is argued that the significant impact of these drugs was such that the emphasis on cleaning and hygiene became diminished in importance and nursing had to redefine its role. It suggests that more prominence needs to be given to changes in clinical practice in the history of nursing.This study breaks new ground by suggesting the rigorous training of nurses in cleaning and hygiene tasks was needed in order to manage the infection risks faced by nurses before the availability of antibiotics.