"I am sometimes asked what I think of the future of penicillin. I think it has a great future, but it must be used wisely."

"The mere fact that a substance has bactericidal powers does not mean that it can be used for the treatment of septic infections."

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

"The greatest joy of a scientist is to see his work used for the benefit of mankind."

"The story of penicillin is a lesson in serendipity and perseverance."