Louis Pasteur (in France) and Robert
Koch (in Germany) came along with
their germ theories of disease, people
thought that infection was caused
by various kinds of bad air.
The new theories (introduced around
1870) proposed that infection was
caused by tiny invisible living organisms
(germs). To many this
seemed hard to believe (Tiny
invisible invaders in my body? Right.
And my granny's the Queen of England.)
Even when the theory was accepted,
it wasn't clear how it related to
surgical practices. Over thirty years,
surgeons gradually figured out that
the first step in reducing the inflammation,
pus, rotting flesh, and death after
a surgery was making sure the surgical
area was clean and germ-free.