Let’s introduce a coincident scientific discovery.

Fleming, who was a medical doctor, searched for substances with effective bactericidal action on a regular basis. He found that blue mold grows on one of the petri dishes where he cultured bacteria. It was a summer day.

He thought that it would be moved to trash. “Wait!” He found something and stopped throwing it away.

He looked at the petri dish carefully, and found that the part breeding blue mold made the bacteria disappeared. The colony was Staphylococcus aureus.

This was a moment of discovery of penicillin, which was a bactericidal substance secreted by the blue mold.

In fact, Fleming was too busy to close the lid of the petri dish, but this incidence saved millions of lives later on.

The picture: N_53_16_700 Production of Penicillin Copied 1944