"The greatest tragedy is the misuse of a good thing."

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

"That's funny."

"It is not an exaggeration to say that the discovery of penicillin has saved millions of lives."

"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…"