This groundbreaking study analyses the development of veterinary science in South Africa during the first half of the twentieth century. It focuses on the activities of the Onderstepoort Veterinary Institute, which was founded by Arnold Theiler during Milner's reconstruction of the Transvaal following the South African War (1899-1902), and rose to international prominence by the 1920s. While delineating Onderstepoort's relationship with the state and its economic and social imperatives, the study examines more closely the development of knowledge and methods of disease prevention. A series of innovative chapters on protozoology, vaccines, plant poisoning and veterinary entomology enables an analysis of scientific thinking on the relationship between disease and environment. In turn, this led to the development of preventive technololgies and to social interventions. Onderstepoort's relationship with the wider world of western veterinary science is also examined. This book will berelevant to those interested in the history of empire, southern Africa, science, medicine and environment.