Rat, Lice and History by Hans Zinsser 

I regularly check out the ones near me and any others I come across and I've made some great finds over the years.

Or they'd drink some of the water without boiling it first.

@@grumpyoldslan If I recall correctly, you can die from it just by swimming or bathing in it.

@@manfredconnor3194 Very possible -- the book did not go into the causes of it as it focused on typhus. I do know a lot of diseases got spread by consumption of bad water -- for a good example, see John Snow's maps of the cholera outbreak in London.

@@grumpyoldslan Ich kenne ihn. Er hat an der Mauer gedient im Norden.^^ Oink. = @ )