[MrYellowP]

It wasn't. "Stuff that kills bacteria" has been known for a long time, including times when nobody knew what bacteria were. Not every dirty wound was fatal, there's mixes of plants, applied to wounds, that do a good job.

Penicillin was the first highly effective AND mass producible antibiotic, though.

[Cthulhu_]

While true, actually applying it in practice took a long time. Imagine the shock and horror when male doctors were told by midwives that washing hands and keeping things clean reduced infant mortality.