"The future of chemotherapy lies in the intelligent use of these new antibacterial agents."

"I had no idea that I had stumbled on to a subject that would prove to be of such immense importance."

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

"The mold was a lucky accident, but the observation was not."

"I have been working for many years on the problem of finding substances which would destroy microbes in the body without injuring the cells of the body."