"It has been said that I am a lucky man. I agree. I have been very lucky."

"A good gulp of hot whisky at bedtime—it's not very scientific, but it helps."

"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."

"I play with microbes. There are, of course, many rules to this play...but when you have acquired knowledge and experience it is very pleasant to break the rules and to be able to find something nobody…"

"The public will probably never understand the difficulties that beset the path of the original investigator."