Epidemics are usually conceived of as sudden, devastating events against which there is no defence. Other features common to all descriptions of epidemics include a sense of seclusion, loneliness and deprivation, an altered perception of the physical world and of its symbolic topography, changed attitudes to human relationships, relegation to oblivion of practices considered holy, such as the burial of the dead, the inability of scientists to find a remedy or a cause, the folly of those in public power and of their provisions, the invention and persecution of scapegoats, or of criminals supposed to spread the contagion, the moral degradation which accompanies the disease...