"In the fields of observation, chance favours the prepared mind." - Louis Pasteur
The word "serendipity" was coined in 1754 by Horace Walpole, describing a story about "The Three Princes of Serendip", who "were always making discoveries, by accidents and sagacity, of things that they were not in quest of�." The term has crept into the language over the years and is often used to describe discoveries in science in which chance played a leading role.
One often hears politicians and opinion makers declare that funding for scientific research must justify itself in concrete terms, and provide a direct and obvious utilitarian benefit. One wonders if any leading politician would dare make such a demand of the arts which receive public money, and risk being dubbed philistines. Pat Rabitte, when he was Minister of State with responsibility for Science, all but demanded that science justify itself to industry and government. All this betrays ignorance of how science actually works.
The debate as to whether science is just as much a part of culture as theatre or literature, and as such deserves a certain degree of support anyway, is one for another article. Even if you believe that science must show hard, utilitarian benefits, any look at the history of science will show that it does not proceed in a strictly rational, textbook fashion from hypothesis to accepted fact or practical discovery.
Having said the above, serendipitous discoveries are not complete accidents. One doesn't go into the lab to find a cure for cancer and come out with a new theory of general relativity. As Pasteur's dictum put it, chance favours the prepared mind; all the cases here involved much hard work and confirmation of results, and a profound understanding of the topic. Serendipity is the variable you can't factor in predicting scientific progress.
One of the most vivid examples of serendipity comes from organic chemistry. In the nineteenth century, chemists were baffled by the unusual properties of benzene, a liquid which formed when gas was pressured for compression in tanks. For years chemists had debated the structure of benzene, the behaviour of which flouted the rules which applied to compounds of a similar composition. Friedrich Kekul� describes the process whereby he elucidated the structure of benzene as follows:
"I was sitting writing in my textbook, but the work did not progress; my thoughts were elsewhere. I turned my chair to the fire and dozed� the atoms were gambolling before my eyes�. My mental eye, rendered more acute by repeated visions of the kind, could now distinguish larger structures of manifold conformation: long rows sometimes more closely fitted together all twining and twisting in snake-like motion. But look! What was that? One of the snakes had seized hold of its own tail, and the form whirled mockingly before my eyes. As if by a flash of lightning I awoke; and this time also I spent the rest of the night in working out the consequences of the hypothesis."
This dream inspired the discovery of the six-carbon ring of benzene, a discovery which underpins the whole area of aromatic organic chemistry. Kekul� is often quoted as saying "Let us learn to dream, gentlemen, then perhaps we shall find the truth." But his next words are less often quoted: "But let us beware of publishing our dreams till they have been tested by the waking understanding."
In Medicine, numerous discoveries were made while looking for something quite different. For example, in 1889 in Strasbourg (then part of Germany), two researchers removed the pancreas from a dog while studying the digestive function of the organ. The next day a lab assistant happened to notice an unusual amount of flies swarming around the dog's urine. It was discovered that the urine was high in sugar - a characteristic sign of diabetes. This was the first step towards the discovery that diabetes is caused by insulin dysfunction, and the use of insulin therapy to treat a disease which previously had been invariably fatal.
The "Pap" smear to detect cervical cancer has saved the lives of countless women worldwide. Again, this was discovered in serendipitous circumstances. Dr George Papanicolaou was working in genetics at the time and in particular the role of chromosomes in the determination of sex. He produced a paper on the cellular changes in vaginal tissue during the menstrual cycle of a guinea pig. To learn if similar changes took place in the human female, Dr Pap (as he was universally known) worked on the cells of human vaginal fluid. One of the samples came from a woman suffering from uterine cancer. Dr Pap happened to notice the subtle differences in the cell biology that became the basis for the eponymous test.
The best-known example of medical serendipity is Sir Alexander Fleming's discovery of penicillin. In 1922 Fleming made a culture from his own nasal secretions while suffering from a cold. As he examined the culture dish, a tear fell from his eye into the dish filled with bacteria. The next day there was a clear space on the culture where the tear had fallen. He deduced that tears contain a substance causing rapid destruction (lysis) of the bacteria, but was harmless to human cells. This antibiotic enzyme in tears he named lysozyme - which turned out to be not terribly important practically, but an essential theoretical prelude to the discovery of penicillin.
In 1928 Fleming was carrying out research on influenza, and was routinely examining bacteria cultures when he noticed an unusual clear area in one dish. It became clear that an ordinary piece of mould had fallen into the dish, producing an antibiotic substance deadly to the bacteria in the dish. Fleming isolated the mould and identified it as belonging to the genus Penicillium, and hence named the antibiotic that was produced penicillin.
Vaccination has saved possibly more lives than any other medical advance and was discovered completely serendipitously. Edward Jenner, when a 19-year old medical student, was told by a former milkmaid that she could never develop smallpox since she had had cowpox. The idea fermented in his mind, and almost thirty years later he finally plucked up the courage to try it by inoculating an eight-year-old boy, James Phipps, with pus from the cowpox vesicles on a milkmaids hands, and exposing the boy to smallpox a couple of months later. This experiment would be regarded as unethical, to say the least, today - but was the basis for the smallpox vaccine and indeed all vaccination.
As smallpox was a terrifying disease, Jenner became a worldwide celebrity. For many years the anniversary of the vaccination of the boy Phipps was celebrated as a holiday in Germany. Napoleon released two English Prisoners of War on being told that Jenner had personally asked for their release, saying "Ah, we can refuse nothing to that name."
In many branches of science and industry, key discoveries and inventions were produced through serendipity. Cornflakes? Discovered by the Kellogg brothers when they left cooked wheat untended for over a day, and it came out flaked having been put through the rollers. Velcro? Discovered by George de Mestral after a country walk when his jacket was covered by cockleburs (burdock seed pods), and he was inspired to study the sticking mechanism more closely. Post-it notes? Art Fry was bored during a church service and realised an adhesive that was not strong enough to be permanent would be very useful as a page marker. Add Teflon, dynamite, the Dead Sea Scrolls, X rays, the cave paintings of Lascaux, Nylon, celluloid, Daguerre's photographic process - all owed something to serendipity.
But what comes through again and again in these stories of serendipity is not just accidental, apparently random circumstances which lead to great discoveries, but the sagacity (to use Walpole's term) of those who were astute enough to follow up their observations. Alertness and knowledge are vitally important in serendipitous discoveries. Science and scientific education must prepare minds ready to be favoured by chance.
