The Ghost Map
Over the Thanksgiving break, I read the Ghost Map The Story of London's Most Terrifying Epidemic--and How It Changed Science, Cities, and the Modern World by
Stephen Johnson. This is the story how John Snow convinced
the London health authorities that the Cholera epidemic was not caused
by bad air (miasma), but was caused by contaminated drinking
water. Johnson does an excellent job describing what life
was like in London during the middle of the 19th century. Imagine a
city of 2 million with no sewers - in fact much human waste would end
up in the cellars of the poorer housing (and from the cellars, the waste
could make its way to the public well.) There was a
scavenger class of night soil men, toshers, shoremen, pure collectors
and others that made their living dealing with waste. Despite the
fact that Londoner's were surrounded by all of waste, it was not obvious
that this was related to the spread of disease. John Snow was
convinced that all of this waste was polluting the drinking water.
His challenge was to collect enough evidence in order to convince the
establishment that this was the case. Snow used his familiarity
with the Broad Street neighborhood, plenty of shoeleather, and
(eventually) visualizations (the ghost map) to make his case, and the
authorities removed the handle from the Broad Street pump. All in
all, a good read, highly recommended.
The book has a website with a number of good resources including a high resolution copy of the ghost map.