Alexander Fleming

The time may come when penicillin can be bought by anyone in the shops. Then there is the danger that the ignorant man may easily underdose himself and by exposing his microbes to non-lethal quantities of the drug make them resistant.

It is not difficult to make microbes resistant to penicillin in the laboratory by exposing them to concentrations not sufficient to kill them.

The thoughtless person playing with penicillin treatment is morally responsible for the death of the man who succumbs to infection with the penicillin-resistant organism.

I did not invent penicillin. Nature did. I just found it.

I have been asked to say a few words about the discovery of penicillin. I must confess that I have been asked to do this so often that I am beginning to be a little tired of it.

A good many people think that I deserve some credit for the discovery of penicillin. They are wrong. It was discovered by nature.

The mould was very interesting. I cultured it and found it produced a powerful antibacterial substance. It was very effective against staphylococci and other Gram-positive pathogenic bacteria.

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.

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.

Many difficulties were encountered in the early attempts to isolate and purify penicillin.

The story of penicillin has been told so often that it is almost a cliché.

It is a popular misconception that I was a brilliant chemist, but I was not. I was a bacteriologist.

I had no idea that I would be involved in such a great discovery. It was purely accidental.

The public will not understand the dangers of using penicillin indiscriminately.

It is not wise to use penicillin as a prophylactic against every little infection.

My own work was really quite simple. I just observed what was happening.

The greatest discovery of my life was not penicillin, but the fact that I was wrong about something.

It is a remarkable fact that this substance, which is so potent against bacteria, is almost harmless to animal tissues.

I have been very lucky in my scientific career. I have stumbled on things by accident.