The significance of Louis Pasteur, Robert Koch and Paul Elrich.
Before Louis Pasteur it was believed that miasma (bad air) caused disease and that spontaneous generation the process in which decaying matter creates living organisms such as maggots and other insect to be the way in which that decaying matter would end up with living organisms on it.
In 1861 Louis Pasteur discovered microbes after performing experiments for the alcohol industry to find out why the wines and beers where going bad he could not have done this with out the new technologies of the time such as the powerful electron micro scopes.
After Louis Pasteur discovered germs and published his works another scientist named Robert Koch began to look at weather there was a link between these tiny microorganisms and disease in humans so to start with he had to be able to differentiate between different microbes so in turn created “Bacteriology” this is the system in which tells one germ from another after doing this he was able to test drugs and other materials to find out what killed each bacteria.