"I am not a very good speaker, but I hope my work speaks for itself."

"My work was not a flash of genius, but a gradual unfolding of facts."

"The mold was a lucky accident, but the observation was not."

"The next time you are tempted to throw away a contaminated culture, remember the penicillin."

"I have been asked by many people how I came to discover penicillin. The answer is that I did not discover it. I just happened to notice it."