I play with microbes. There are, of course, many rules to this play...but when you have acquired knowledge and experience it is very pleasant to break the rules and to be able to find something nobody has thought of.
(The discovery of penicillin) was a triumph of accident, a fortunate occurrence which happened while I was working on a purely academic bacteriological problem.
It was astonishing that for some considerable distance around the mould growth the staphococcal colonies were undergoing lysis. What had formerly been a well-grown colony was now a faint shadow of its former self...I was sufficiently interested to pursue the subject.
In my first publication I might have claimed that I had come to the conclusion, as a result of serious study of the literature and deep thought, that valuable antibacterial substances were made by moulds and that I set out to investigate the problem. That would have been untrue and I preferred to tell the truth that penicillin started as a chance observation. My only merit is that I did not neglect the observation and that I pursued the subject as a bacteriologist. My publication in 1929 was the starting-point of the work of others who developed penicillin especially in the chemical field.