"I have always been interested in the fight against disease."

"I had no idea that I would be involved in such a great discovery. It was purely accidental."

"The story of penicillin is a lesson in serendipity and perseverance."

"Some people have been very enthusiastic about penicillin, others less so."

"It is a remarkable fact that this substance, which is so potent against bacteria, is almost harmless to animal tissues."