I was thinking about how far medicine has come in the last 200 years. That the discovery of the title items have led to a medical revolution, in the way we fight/deal with disease and injuries.
The discovery of germs\bacteria has totally changed how we handle surgery, operations or treatment. Proper hygiene techniques have saved potentially billions of lives since it's discovery.
It got me thinking about what massive changes could have taken place in Human history, if prior to something like the Black Death, we knew how the disease spread? Or that doctors should wash their hands prior to childbirth. That in turn made me start to wonder how early a date would the discovery of these items be possible?