Chapter 1: A Moldy Surprise

Meet Alexander Fleming

Alexander Fleming wasn’t the kind of person who liked doing things just because everyone else did. If someone said, “That’s how it’s always been done,” he might raise an eyebrow and say, “But why?” He didn’t like rules that didn’t make sense, and he didn’t like giving up when he had a question bouncing around in his head. If something didn’t seem right, he had to figure out why. If something looked strange, he took a closer look. That was just how his brain worked.

As a kid, Alexander grew up on a farm in Scotland. He was surrounded by hills, sheep, and lots of mud. It wasn’t the kind of place where most scientists came from, but it was a place where you could explore. Out there, there were no textbooks telling you what to think. He could poke around in the grass, flip over rocks, and follow little streams just to see where they went. That kind of exploring stuck with him, even when he grew up and moved to London.

He didn’t always plan to be a scientist. At one point, he thought about being a doctor. At another, he worked in a shipping office. But none of those things felt quite right. It was science—real hands-on, messy, puzzling science—that got his brain excited. He liked the lab because it was full of questions no one had answered yet. It was like walking into a room with a hundred locked doors and being handed a big ring of keys. He never knew which one might fit, but he was always willing to try.

Fleming didn’t talk much. People said he was quiet, sometimes even shy. But inside his head, his thoughts were full of noise—ideas bumping into each other, questions zipping around like bees in a jar. When he did speak, it was usually something surprising or smart. His coworkers respected him, even if they sometimes didn’t know what to make of his odd habits. His lab bench was messy. Petri dishes piled up. Strange stains appeared on the tables. But Fleming didn’t mind the mess. To him, it was part of the process. He believed that staying curious mattered more than staying tidy.

One of the things that made Fleming different was the way he paid attention to small things other people ignored. While other scientists hurried to finish their tests and clean their stations, Fleming lingered. If something looked off—like a color that changed or a dish that grew something unexpected—he didn’t throw it away. He asked himself: “What’s going on here?” That’s how discoveries happen—not always with fireworks and shouts, but with quiet people asking strange questions.

He once found something interesting in his nose. That sounds gross, but wait! He had a cold and noticed that the mucus (yep, snot) killed some bacteria in his samples. Most people would’ve wiped their nose and moved on. Fleming, of course, tested it. That led to the discovery of an enzyme in the body that helps fight bacteria. He named it lysozyme. That one observation didn’t change the world, but it was a clue—a step along the path to something bigger.

Working in a lab wasn’t just about test tubes and microscopes. It was about being patient and willing to get things wrong, sometimes over and over. Fleming had spent years watching bacteria grow, studying how they moved and spread, and trying to figure out how to stop them. He didn’t have all the answers, but he was one of the few people asking the right questions.

And he didn’t like giving up. When something didn’t work, he didn’t throw up his hands and storm out. He would try again, or change one small thing to see if it made a difference. Over time, he became really good at spotting patterns—like when certain bacteria always died in the same weird way, or when a mold started growing where it shouldn’t. Most people would call that a mistake. Fleming called it interesting.

Outside of work, he enjoyed painting. Yep—painting, with actual paint and brushes. But not just any kind of paint. He made pictures using bacteria that grew in different colors. To most people, that sounds disgusting. To Fleming, it was fun. He mixed science and creativity in a way that most people never even thought about. That kind of thinking—the kind that sees art in germs—helped him think differently in the lab, too.

Not everyone understood what he was doing. There were times when his experiments seemed boring or weird. He didn’t mind. He wasn’t doing science to show off or to win prizes. He was doing it because he truly wanted to know more. He liked poking around in the unknown. If something looked like a puzzle, he wanted to solve it—even if the pieces didn’t make sense yet.

Even though he didn’t talk a lot, his notebooks were full of detailed observations. He didn’t just write down what happened—he wrote down what he thought might be happening, what confused him, and what made him curious. A lot of his discoveries started with a quick note about something odd. Later, those notes became clues. They helped him see connections that others missed.

And then came the mold. Not just any mold—this one showed up by accident, on a dish he forgot to clean. The dish had bacteria growing on it, but right around the mold, the bacteria were dead. That small clear circle looked strange. Someone else might have dumped it in the trash without thinking twice. But not Fleming. He looked closer.

That moment didn’t feel like a big discovery. No lightning. No loud music. Just a quiet man staring at a dish, wondering what he was seeing.