While individuals experience health problems and require treatment when ill, many health matters are the result of wider social determinants—social, cultural, political, and economic factors that directly and indirectly influence individual and population health. Sociological perspectives on health and illness focus on social patterns, such as the differences in the health status of the rich and the poor, between women and men, or between Indigenous and non-Indigenous populations. The Public Health Act 1848 of England and Wales, which legislated for sanitary conditions, was ground-breaking public legislation. Scientific understanding of the causes of illness gained momentum by the mid-nineteenth century, with the growing acceptance of the biomedical model of health and illness. The power of the medical profession to control its own work and the work of others in the health system, and exert a major influence over health policy and the allocation of health resources.