"The thought that I might have discovered something which would be of value in treating disease was, of course, uppermost in my mind."

"The therapeutic value of penicillin is enormous, but its indiscriminate use could lead to disaster."

"The story of penicillin has been told so often that it is almost a cliché."

"It is not wise to be too dogmatic in science. One must always be prepared to change one's mind."

"The mold was there, I just saw it."