"Over the past two centuries, technology has played a significant role in the understanding, diagnosis, and treatment of disease in Canada. Technology -- in the form of instruments, devices, machines, drugs, and systems -- has aided medical science, altered medical practice, and changed the illness experience of patients. Nineteenth-century medical technology consisted of predominantly surgical and diagnostic instruments used by individual practitioners. By the twentieth century, large, hospital–based technologies operated by teams emerged as powerful tools in the identification and management of disease [...] Our selection of diseases, research initiatives, and medical treatments highlights larger patterns in medicine, identifies Canadian contributions, and considers the impact of these innovations on Canadian society. In this fifty–year period, public health initiatives limited the spread of contagious diseases and addressed the problem of impure water and milk. Medical practitioners used X–rays to diagnose tuberculosis and to treat cancer. The discovery of insulin in Toronto in 1921–22 offered a management therapy for diabetes patients, who were otherwise facing certain death.