FIGURE 1.1 The Yearly Rhythm of Rural Life and Death
The annual cycle of nature profoundly affected life in the traditional agricultural world. The death rate soared by 20 percent in February (from viruses) and September (from fly-borne dysentery). Summer was the healthiest season, with the fewest deaths and the most successful conceptions (as measured by births nine months later). A value of 100 indicates an equal number of deaths and conceptions.