In the 1870s a debate over the spontaneous generation of microorganisms took place in Britain. Much opposition to the doctrine of spontaneous generation came from the Victorian scientific naturalists, especially John Tyndall, Professor of Natural Philosophy at the Royal Institution, London. This thesis provides an understanding of and explanations for the beliefs surrounding the spontaneous generation debate, particularly with regard to Victorian scientific naturalism and its relationship to medicine. Spontaneous generation threatened some of the fundamental tenets of naturalism. Furthermore, Tyndall clearly related his opposition to spontaneous generation to his support for the germ theory which he used as a vehicle for advocating a scientific approach to medicine. The thesis concludes that Tyndall's campaign for scientific medicine was part of the scientific naturalists' campaign to spread the naturalistic world-view and to gain cultural leadership. The spontaneous generation debate is examined in detail. The shift in experimental paradigm away from physical conditions towards a bacteriological approach is described. Chapter 5 examines the threats an acceptance of spontaneous generation posed to naturalism in terms of evolution, protoplasm and naturalistic explanations of disease. The effects of Tyndall's campaign for the germ theory on the medical profession are described. In order to understand how scientific knowledge was introduced into medicine, Chapter 6 examines the work of key medical scientists in the field of pathology with reference to their involvement in the spontaneous generation debate and in particular the reasons for their acceptance or rejection of the germ theory. Chapter 7 shows how the spontaneous generation debate impacted the domain of public health from the 1870s-1890s by means of a detailed examination of handbooks of sanitation and hygiene. The gradual introduction of results from the spontaneous generation debate into these works demonstrates the importance of the spontaneous generation debate in forming a bridge from the medical knowledge of the 1860s to the new bacteriology of the 1880s.