ABSTRACT
Recall that Chapter 2 covered historical perspectives of epidemiology. The time period before the mid-nineteenth century can be considered the first era of epidemiology. It was largely a time of replacing mystical and natural notions about disease with epidemiological reasoning. As the nineteenth century approached, several persons were responsible for establishing the scientific notion of disease. Rather than inferring cause from the coincidence of two events, the epidemiological reasoner observed closely and took into account all possible factors in the physical, social, and biological environments that might influence disease events.
