I've started reading another "medical history" book - "The Ghost Map" by Steven Hunter. It's about the Cholera epidemic of 1854 in London, and the people who tried to track down the source of the illness. I haven't gotten very far into the book yet, but this gave me pause:

Imagine if every time you experienced a slight upset stomach you knew that there was an entirely reasonable chance you'd be dead in forty-eight hours. Remember, too, that the diet and sanitary conditions of the day - no refrigeration; impure water supplies; excessive consumption of beer, spirits, and coffee - created a breeding ground for digestive ailments, even when they didn't lead to cholera. Imagine living with that sword of Damocles hovering above your head - every stomach pain or watery stool a potential harbinger of imminent doom.