Alexander Fleming

I have been accused of inventing penicillin. I never invented penicillin. I only discovered it by fortunate accident.

The possibility that the pathogenic bacteria might become resistant to penicillin after repeated sub-lethal doses was foreseen from the beginning.

My only merit is that I did not neglect the observation and that I pursued the subject as a bacteriologist.

The mould was there, producing the antibiotic, long before man appeared on earth.

It is strange how one can sometimes walk right past a truth without seeing it, until someone else points it out.

In the field of observation, chance favours only the prepared mind.

The discovery of penicillin was a joint effort of many minds, but the first step was a single observation.

One must be able to profit by a fortunate accident.

The lysozyme work was, in a way, a stepping stone to penicillin.

I have often been asked: 'Did you not realize the importance of your discovery when you first saw the inhibition of staphylococci?' The answer is: not in the least.

The use of penicillin is a two-edged sword. It can save a life, but it can also breed resistant strains.

I was just a humble bacteriologist following the path where it led.

The story of penicillin shows that fortune does indeed favour the prepared mind, but also the open mind.

There are thousands of different moulds, and there are thousands of different bacteria, and that mould happened to produce a substance which exactly fitted that particular bacterium.

Do not wait for fortune to smile upon you; prepare yourself so that you can recognize her when she passes by.

The laboratory was in a mess. That was the important thing.

I am not a chemist. I am a bacteriologist.

The discovery was made by a man who was not looking for it, but who was ready to see its significance.

Penicillin sat on my bench for months while I was working on other things.

The first rule of research is not to discard anything as trivial.