My great grandfather Jonathon, departing from the family tradition, left the land and became a soldier. At the age of 21 he fought in the Crimean War (1854-1856), and he returned to marry my great grandmother, Georgina Wells. A gravestone in a London cemetery records the sad fate of their first five children (Figure 1). The first two, George and Ernest, died in 1866. The two youngest, Laura and Arthur, survived only to be smitten, together with their younger sister Lily, in 1870. The timing of the deaths almost certainly means that they died in the course of one of the periodic epidemics of cholera or diphtheria. Early death from infectious disease was one of the harsh facts of life in nineteenth century England, as it is still in the third world today. The psychological trauma inflicted upon the young couple can hardly be imagined. However, life went on and they eventually produced four healthy boys, all of whom lived long lives.
In the western world various public health measures, such as keeping the water supply clean, and immunization, have largely
*This chapter is based on lectures given in 1988 at Harvard and Queen's Universities.