This session, part of the National Library of Medicine's 1976 Colloquium on the Bicentennial of Medicine, features John Crayton Snyder, MD, Professor of Population and Public Health, Harvard University School of Public Health. Dr. Snyder presents an historical look at how devastating epidemics in the Middle Ages left a legacy of fear everywhere, causing citizens and authorities to take drastic, often unwarranted action to avoid such epidemics well into the 19th century. Because disease transmission was not well understood, precautions were often ineffective. As the science explaining communicable disease progressed, diseases such as yellow fever were brought under control and eradicated in some places. Dr. Snyder also discusses the evolution of medical specialties, health insurance, and publicly-funded health care such as the Medicare program.