"It is a happy accident that the mold grew on my plate, but it was not an accident that I recognized it."

"It is the common lot of discoverers to be misunderstood."

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

"It is not the man who first sees a thing who is the discoverer, but he who sees into a thing."

"I was not looking for penicillin when I discovered it. I was looking for a better antiseptic."