Bread and wine, and the seasonal changes that affect their production, were among the most familiar features of life in the Loire valley, in central France, in the sixteenth century. The appearance of the ‘plague’, although an infrequent event, was much more prominent in public consciousness. None of these realities was well understood. The range of grapes cultivated in this region was very extensive, and the wines produced were equally diverse. Growing grapes and producing wine relied on traditional techniques that had been passed on for generations. Those involved in viticulture could easily recognize a good season, with the right combination of spring rain and intense heat in midsummer, and they succeeded admirably without a scientific oenology. Likewise, the production of bread and other familiar foods did not presuppose biochemistry and any of its cognate sciences.

The plague, however, was a different story. In one province alone, in 1631, it killed 40,000 people. No one understood what it was, how it arrived in a town, or why it eventually abated, although they noticed that it tended to vary in intensity with the seasons, being worst in summer. They also knew that it was likely to cause a very large number of painful deaths and that the best defence was to flee, preferably before the plague arrived in a town.