1Some of the greatest scientific breakthroughs in history have happened entirely by accident rather than by careful planning.
2The story of penicillin, the world's first antibiotic, began in a messy London laboratory in the autumn of nineteen twenty-eight.
3Alexander Fleming returned from his holiday to find that one of his bacteria dishes had been contaminated by a strange blue-green mould.
4Instead of simply throwing the spoiled dish away, he looked at it very carefully and noticed something truly remarkable indeed.
5All around the mould, the dangerous bacteria had been completely destroyed, leaving a clear ring on the surface of the dish.
6Fleming realised that the mould must be producing a substance that could kill harmful bacteria without harming human cells.
7He published his findings, but for more than a decade nobody could find a way to produce the drug in useful quantities.
8During the Second World War, a team of scientists finally developed practical methods to produce penicillin on a large industrial scale.
9The new drug saved the lives of countless wounded soldiers and completely transformed the way doctors treated deadly infections.
10Fleming later warned the world that careless use of antibiotics could allow bacteria to become resistant to their effects.
11Today, his warning has come true, and scientists are racing to discover new antibiotics before the old ones stop working.