"The power of observation is crucial in scientific research."

"My only merit is that I did not discard the cultures at an early stage."

"The accidental contamination of my cultures by a mold was not an unusual event in a bacteriological laboratory. What was unusual was my decision to investigate the mold."

"I can only warn. It is up to others to heed the warning."

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