"A good many people think that I deserve some credit for the discovery of penicillin. They are wrong. It was discovered by nature."

"I have been asked to say a few words about the discovery of penicillin. I must confess that I have been asked to do this so often that I am beginning to be a little tired of it."

"I hope that my work will inspire others to pursue scientific discovery."

"It is not difficult to make microbes resistant to penicillin in the laboratory by exposing them to concentrations not sufficient to kill them."

"The time may come when penicillin can be bought by anyone in the shops. Then there is the danger that the ignorant man may easily underdose himself and by exposing his microbes to non-lethal quantitie…"