may 12, 1854 - Germ Theory
Description:
Snow demonstrates that cholera bacteria is transmitted through contaminated drinking water. His "Grand Experiment" is when he compared two water companies supplying the same neighborhood. One water company moved to a fresh water site while the other remained in a polluted water site. He found out that the company with the polluted water site attained a lot more cholera deaths.(from https://www.ph.ucla.edu/epi/snow/grand_experiment.html)
Added to timeline:
Date:
may 12, 1854
Now
~ 171 years ago