Alexander Fleming inventor of penicillin

World War I, northern France. Life expectancy on the front line, six weeks. In World War I, eight and a half million people died. But a third of those deaths are not from man-made weapons. They're from disease. But from the worst of times comes the best of mankind. Alexander Fleming, a Scottish army doctor, commended for bravery. Neither surgeon nor medic, but a new kind of doctor. A bacteriologist. On a quest to treat not the symptoms of a disease, but its root cause. It was through his absolutely obsessive need to understand what was happening in his laboratory that he wandered into the greatest advance ever among human scientists. Fleming sees thousands die needlessly. Not from bullets and shrapnel, but from wounds infected by bacteria. There's an age-old tussle between microbes and man. This war has been an invisible war. We don't see them. They're too small. But collectively, they're quite intelligent and quite crafty. 100 trillion bacteria inhabit the human body. 10 times the number of human cells. Microorganisms that feed on living tissue. Most are harmless. But a few species release toxins. They cripple the immune system and spread disease. Bacteria have killed more people than all the wars in history combined. Now one man wages war on bacteria. At stake, millions of lives. By World War I, doctors realized there's a link between bacteria and disease. But can't stop infection spreading. The tried and tested cure? Cut away tissue. Douse it in an antiseptic. Carbolic acid. A deadly trade-off. The acid disinfects wounds, but also attacks white blood cells. The body's natural defense against bacteria. Imagine being at the side of a soldier with a small flesh wound, easily treatable, yet watching the gangrene climb up the leg. Most did not survive very survivable wounds because of the resulting infections. Fleming, face to face with the enemy. He knows bacteria are killing millions. Now he begins a 10-year battle to stop them. I was consumed by a desire to discover, after all this struggling, something which will kill those microbes. London, 1928. The war is over and Fleming is a civilian doctor. Working in a hospital laboratory, testing samples of infected tissue. And after so many dead ends, the ultimate chance discovery. A sample, left open for two weeks, is contaminated. Inside, a fungus is growing, producing a substance which stops bacteria in their tracks. Instead of multiplying, microbes rupture and die. That substance, penicillin. When I woke up, just after dawn, I didn't plan to revolutionize all medicine. But I suppose that's exactly what I've done. Within 15 years, penicillin saves one million lives a year. A miracle drug. The world's first antibiotic. Today, we make 45,000 tons of it every year. Imagine a world before antibiotics, before Fleming's invention. A world where moms feared for their child's lives because so many were lost. One out of every three people who could hear my voice right now and see my face would be dead if it wasn't for the antibiotics that Fleming first invented. Medicine for millions, in a world shaped by mass production.