There is a gap that almost nobody thinks about, and this episode is about the gap.
It is the distance between somebody working out how a thing could be done, and there being enough of that thing to matter.
It is usually years. It usually involves people whose names nobody remembers, doing work that is not clever in the way the original idea was clever, and it is almost always the part that decides whether the idea does any good.
Two of the most important objects of this war sat in that gap for a long time. One of them was a mould. The other was a wing.
In September nineteen twenty eight, Alexander Fleming came back from holiday to an untidy laboratory in London and found that one of his culture dishes had gone mouldy.
Around the mould, the bacteria he had been growing had died back in a clear ring.
He worked out what was happening, identified the mould, called the substance penicillin, and published a paper in nineteen twenty nine.
And then, essentially, nothing happened for eleven years.
It was not laziness. Fleming was a bacteriologist, not a chemist, and the substance turned out to be extremely difficult to extract in any quantity and extremely unstable once you had it. He tried, could not do it, and moved on to other work. His paper attracted very little attention.
So the cure for most bacterial infection sat in a journal on a shelf for over a decade while people died of scratches.
In nineteen thirty eight, a team at Oxford went looking through the literature for antibacterial substances worth investigating, and found Fleming's paper.
The team was led by Howard Florey, an Australian pathologist, with Ernst Chain, a biochemist who had left Germany in nineteen thirty three. And a third man, Norman Heatley, solved the problem that had defeated everybody, which was not discovering anything but making some.
By nineteen forty they had enough purified penicillin to try on eight mice. Four infected mice were given it and four were not. The four that were not died overnight. The four that were treated lived.
Scaling that up to a human being turned out to require an amount of liquid mould culture that nobody had any equipment for. Britain was under bombing, the chemical industry was fully occupied, and there was no money.
So Heatley improvised, and the improvisation is the famous part. They grew the mould in whatever wide flat containers could be found: biscuit tins, milk churns, pie dishes, and above all hospital bedpans, which turned out to be almost the ideal shape. Eventually a ceramics firm made vessels to Heatley's design, which were bedpans in all but name.
The department became a factory. A team of six young women, known in Oxford as the penicillin girls, were employed to tend the cultures. Heatley built the extraction apparatus out of bookshelves, milk churns, a doorbell, copper tubing and a bath.
In February nineteen forty one they had enough to try on a person.
The patient was Albert Alexander, a policeman in his forties with an infection that had spread through his whole body from a small wound to his face. He was dying, and there was nothing anybody could do about it.
They gave him penicillin, and within a day he was visibly improving. Within four days he was sitting up and eating.
Then the penicillin ran out.
The team had been collecting his urine and re-extracting the drug from it, because they could not make it fast enough, and even that was not enough. The supply failed, the infection returned, and he died a month later.
It is a terrible outcome and it proved the point completely. The substance worked. The problem was entirely one of quantity.
Florey concluded that wartime Britain could not scale this up, and in the summer of nineteen forty one he and Heatley flew to the United States with samples of the mould packed in their coats.
They were sent to a government agricultural laboratory in Peoria, Illinois, which existed to find uses for farm surpluses, and which therefore knew more about growing things in vats than anybody in the world.
Two things happened there. The first was corn steep liquor, a waste product of maize processing that the laboratory had in enormous quantities and had been looking for a use for. Adding it to the culture medium increased the yield roughly tenfold.
The second is one of the great pieces of luck in the history of medicine. The laboratory asked people to bring in mouldy things, and a laboratory assistant, Mary Hunt, brought in a cantaloupe melon from a local market that had a golden mould on it. That strain produced far more penicillin than Fleming's original, and after further work almost all the penicillin made in the world for decades descended from that melon.
American pharmaceutical companies then did the thing that only American industry in nineteen forty two could do. In nineteen forty three there was enough for a few hundred cases. By D-Day in June nineteen forty four there was enough for every Allied casualty who needed it, and over two million doses were ready.
The other half of this episode is a wing, and it is the same story in a different shape.
Reginald Mitchell designed the Spitfire for a very specific reason. He needed a wing thin enough to be fast, and thick enough at the root to hold guns, ammunition and a retracting undercarriage.
The shape he arrived at was an ellipse, which happens also to be the shape that produces the least drag from lift. It is why a Spitfire is beautiful, and everybody who has ever seen one has noticed.
It was also close to a nightmare to manufacture. An elliptical wing has compound curves and no two ribs are the same size, which means that almost every part is different from every other part and a great deal of it has to be shaped by hand.
The Hurricane, designed at the same time to the same specification, used old-fashioned methods and a straightforward wing, and could be built and repaired far faster. There were more Hurricanes in the Battle of Britain than Spitfires, and Hurricanes shot down more aircraft, and this is why.
Britain then made a serious mess of Spitfire production. An enormous new factory was built at Castle Bromwich to build them and produced, for a considerable period, none at all, until the management was removed and the aircraft company was put in charge of it.
Mitchell never saw any of this. He died of cancer in nineteen thirty seven, at forty-two, a year after the prototype first flew.
Fleming, Florey and Chain shared the Nobel Prize in nineteen forty five. Norman Heatley, whose bedpans and bookshelf apparatus made the whole thing physically possible, was not included, because the prize goes to at most three people.
Oxford eventually gave Heatley an honorary doctorate of medicine in nineteen ninety, which the university had never awarded to anybody in its entire eight hundred year history. He was reportedly rather pleased and mostly embarrassed.
Fleming himself said repeatedly that he had not invented penicillin, that nature did that, and that he had only noticed it. He also gave a warning in his Nobel lecture that reads uncomfortably today: that it was easy to give someone too little of the drug, that the bacteria that survived would be the resistant ones, and that this would eventually cause serious trouble. That was in nineteen forty five.
Here is something to think about tonight. The idea that changed medicine sat in a journal for eleven years, and what unlocked it was a waste product from a corn factory and a melon from a market in Illinois. How many good ideas do you think are sitting on a shelf right now, waiting for somebody to solve the boring part?