The Scottish scientist Alexander Fleming recounted that the discovery of penicillin dates from September 28th, 1928. That was when he entered his laboratory in the basement of St Mary’s Hospital in London and found that one of the Petri dishes of Staphylococci that had been mistakenly left open had been contaminated by mould entering from an open window. It formed a visible blue-green growth, but around it was a ring of inhibited bacterial growth. Fleming concluded that something in the mould had killed the bacteria, and set about finding what it was.

The rest, as they say, is history. Fleming isolated it and grew a pure culture of it, naming it Penicillin chrysogenum. It became the first of a range of antibiotics that have saved millions of lives since that first discovery. Penicillin itself, once mass-produced, principally in America initially, saved many lives and limbs of injured soldiers in World War II.

Fleming’s laboratory is now part of Imperial College in London, and Fleming was awarded the 1945 Nobel Prize in Medicine, along with Howard Florey and Ernst Chain, who helped in the development of penicillin. Fleming was knighted in 1944, and in 1999 he featured in Time magazine’s list of the 100 most important people of the century.

It was not all down to the luck of that first discovery. While it was serendipitous that it happened, less skilled and less informed eyes might never have spotted the significance. As Popper says, there is an almost infinite number of things that our senses could focus our attention upon. We pick out those we regard as significant, perhaps those that reveal something new, or which do not fit in with our preconceived theories about what we expect. To Fleming, because of his intellect and his training, the sight of the Petri dish became an observation. He realized its significance and built upon it.

This is a very common feature in human progress, where something unexpected is recognized by trained or astute eyes as having a significance that merits investigation.

By coincidence, exactly 33 years before Fleming’s observation, Louis Pasteur had died on September 28th, 1895, after a lifetime of achievement in microbiology and chemistry. He had observed that environment mattered in the spread of diseases, and found that healthy silk-worms became ill when they nested in the bedding of those suffering from disease. He further observed that for wine to turn to vinegar, it must be open to the air, and concluded that microbes could be airborne and contaminate what they contacted.

From this he developed and researched the germ theory of disease, disproving the notion of the spontaneous generation of organisms that had previously prevailed.  It was the basis of massive advances in medicine, and in preserving foodstuffs. The word ‘Pasteurization’ honours his achievements.

Progress is more likely to be made when there are opportunities for research to be done that is somewhat outside the accepted paradigms of the time, and where observations of the unusual can be pursued, and where discoveries can gain a hearing. Competition for glory is part of what motivates researchers, so Royal Society accolades and Nobel Prizes play their part in advancing human knowledge and achievement, as do the cash rewards that often follow.