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

"I have been accused of being untidy. I confess to being untidy, but I have never allowed my untidiness to interfere with my work."

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

"The discovery of penicillin was a stroke of luck, but it was also the result of many years of hard work."

"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…"