"It was not easy to convince people of the importance of penicillin in the early days."

"The mould grew, and then I saw the clear space around it."

"It is the lone worker who makes the first advance in a subject; the details may be worked out by a team, but the prime idea is due to enterprise, thought, and perception of an individual."

"I did not invent penicillin. Nature did that. I only discovered it by accident."

"Penicillin sat on my bench for ten years while I was called a quack."