When I woke up just after dawn on September 28, 1928, I certainly didn’t plan to revolutionize all medicine by discovering the world’s first antibiotic, or bacteria killer, ... But I guess that was exactly what I did.

Penicillin has two chromosomes.

Differences in reaction to toxic substances vary considerably between species so that the value of these tests remains doubtful. Although thalidomide was extensively tested on animals in several countries, its terrible properties were not discovered. Conversely, penicillin, the greatest medical discovery of the century, was not extensively tested on animals before its miraculous therapeutic qualities were demonstrated in human patients. If it had been fully tested on animals its high toxicity for guinea pigs would have almost certainly prevented its clinical use.

If we want to make a discovery, we have to take a risk, since everything new was discovered by accident or by the fact that somebody took a chance and went ahead when there wasn't 100 percent safety for the solution.

Name the greatest of all inventors. Accident.

Somebody got lucky, but it was an accident.

Chance created the situation; genius made use of it.

It has been frequently said that many of the world’s greatest inventions were due to accident. In a sense this is true. But the accident was prepared for by previous hard thinking. It would never have occurred had not this thinking taken place.

I never did anything worth doing by accident, nor did any of my inventions come indirectly through accident, except the phonograph. No, when I have, fully decided that a result is worth getting, I go about it, and make trial after trial, until it comes.

How fortunate we didn't have these animal tests in the 1940s, for penicillin would probably not have been granted a licence, and possibly the whole field of antibiotics might never have been realised.

Great discoveries, Ganapathi, are often the result of making the wrong mistake at the right time. Ask Columbus.

Albert von Szent-Györgyi, the Hungarian Nobel Prize–winning physiologist who first discovered the benefits of vitamin C, was fond of saying, “Discovery lies in seeing what everyone sees, but thinking what no one else has thought.” That

That goes a step too far, I think. Leonardo did not invent the scientific method, nor did Aristotle or Alhazen or Galileo or any Bacon. But his uncanny abilities to engage in the dialogue between experience and theory made him a prime example of how acute observations, fanatic curiosity, experimental testing, a willingness to question dogma, and the ability to discern patterns across disciplines can lead to great leaps in human understanding.

The greatest chance is the birth of a great man. It is only by chance that two reproductive cells, of different sexes, met, each containing precisely those mysterious elements whose mutual reaction was to produce genius. We will agree that these elements must be rare and that their meeting is even rarer. That it would have taken little to deviate the spermatozoon that carried them from its course; it would have been enough to deviate it by a tenth of a millimeter and Napoleon would not have been born and the destiny of a continent would have been changed. No other example can better explain the true nature of chance.