JUNIOR EDITION for Ages 6+
Medicine: From Discovery to Everyone · Book 2

Microbes: The Tiny World Nobody Saw

What is hiding in clear water — and why did it take so long to see it?

In this book, you will find out…

When you grow up, you could…

Who is in the story

AgastyaAgastyaCurious. Loves counting things.
CharlieCharlieAsks one good question — then lets Agastya find out.
WarrenWarrenTurns up late. Thinks about a hundred years from now.

Today’s mystery

What is hiding in clear water — and why did it take so long to see it?

Look for the clues. Try to guess the answer before Agastya does!

Chapter 1

One Drop

🔍 What is inside a drop of clear water?
In a museum case sat a tiny brass plate. Smaller than a matchbox.
In a museum case sat a tiny brass plate. Smaller than a matchbox.
Two brass sheets. One glass bead. Three screws. That was the whole microscope!
Two brass sheets. One glass bead. Three screws. That was the whole microscope!
Beside it stood a jar of pond water. Perfectly clear.
Beside it stood a jar of pond water. Perfectly clear.
Agastya had a job. On Friday, he had to show his class what was in clean water.
Agastya had a job. On Friday, he had to show his class what was in clean water.
He borrowed the school microscope. One drop from the jar.
He borrowed the school microscope. One drop from the jar.
Nothing in that jar? It was full of tiny living things!
Nothing in that jar? It was full of tiny living things!
Agastya stared.
Agastya stared.
AgastyaIt's crowded. It's completely crowded!
About fifty of the smallest ones could fit across one hair.
About fifty of the smallest ones could fit across one hair.
He tested six ponds. Every jar looked clear. Every drop was crowded.
He tested six ponds. Every jar looked clear. Every drop was crowded.
🔎 Clue found!
Clear water can be full of tiny living things.
Charlie came to look.
Charlie came to look.
AgastyaThe water is full of animals!
CharlieAnd then what?
Agastya wrote a new question. Who saw these first?
Agastya wrote a new question. Who saw these first?
Chapter 2

The Cloth Seller

🔍 Who saw the tiny things first?
He found the answer in a library book. A town of brick and canals, long ago.
He found the answer in a library book. A town of brick and canals, long ago.
Agastya guessed a famous professor. He was wrong. It was a cloth shop!
Agastya guessed a famous professor. He was wrong. It was a cloth shop!
Cloth sellers used little lenses to count the threads in their cloth.
Cloth sellers used little lenses to count the threads in their cloth.
One cloth seller made his own lenses at night. Tiny beads of glass in brass.
One cloth seller made his own lenses at night. Tiny beads of glass in brass.
One day, he filled a little bottle with lake water.
One day, he filled a little bottle with lake water.
Little animals, he wrote. Alive! Swimming in water that looked like nothing.
Little animals, he wrote. Alive! Swimming in water that looked like nothing.
He wrote letters about it to scientists far away.
He wrote letters about it to scientists far away.
They read his letters. But they did not believe him!
They read his letters. But they did not believe him!
So another man built the same tool and tried the same test.
So another man built the same tool and tried the same test.
He waited for days. Then he looked.
He waited for days. Then he looked.
He saw them too! Now two people had seen the tiny animals.
He saw them too! Now two people had seen the tiny animals.
🔎 Clue found!
A new idea gets trusted when other people check it.
Printers printed the letters. Now strangers could read them too.
Printers printed the letters. Now strangers could read them too.
What did the cloth seller look at next? Agastya made a guess.
What did the cloth seller look at next? Agastya made a guess.
Chapter 3

The Mouth Test

🔍 Are there tiny living things inside us too?
Agastya guessed the cloth seller looked at his own teeth. He was right!
Agastya guessed the cloth seller looked at his own teeth. He was right!
A little wooden pick. A glass dish. The cheapest test in this book.
A little wooden pick. A glass dish. The cheapest test in this book.
Rods. Balls. One long spiral. All alive!
Rods. Balls. One long spiral. All alive!
Agastya tried it too.
Agastya tried it too.
AgastyaThere are animals living in my mouth?
The cloth seller drew them carefully. He did not know what they were.
The cloth seller drew them carefully. He did not know what they were.
Charlie asked one thing.
Charlie asked one thing.
AgastyaWhy did nobody use this?
CharlieUse it for what, exactly?
Nobody knew yet that some tiny things make us sick.
Nobody knew yet that some tiny things make us sick.
So the drawings went onto a shelf. For a very long time.
So the drawings went onto a shelf. For a very long time.
Agastya counted. Two hundred years! Then he had a strange thought. Are they all bad?
Agastya counted. Two hundred years! Then he had a strange thought. Are they all bad?
Chapter 4

Helpers Everywhere

🔍 Are all tiny living things our enemies?
Back at home, Agastya looked again. Now he saw different kinds.
Back at home, Agastya looked again. Now he saw different kinds.
This one is a single cell, hunting its food.
This one is a single cell, hunting its food.
These round ones help bread rise. People used them for thousands of years!
These round ones help bread rise. People used them for thousands of years!
Bread puffs up because yeast eats sugar and breathes out gas.
Bread puffs up because yeast eats sugar and breathes out gas.
Cheese is made with the help of good tiny living things.
Cheese is made with the help of good tiny living things.
And some live on bean roots, helping the plants grow.
And some live on bean roots, helping the plants grow.
Charlie smiled.
Charlie smiled.
AgastyaThey're not all enemies!
CharlieWhat would the world be like if they were?
🔎 Clue found!
Most tiny living things are helpers. Only a few make us sick.
Our skin is like a wall. Very little gets through it.
Our skin is like a wall. Very little gets through it.
Tears and tummy juices help keep the bad ones out.
Tears and tummy juices help keep the bad ones out.
So how do you tell the bad ones from the good ones? You need a better tool.
So how do you tell the bad ones from the good ones? You need a better tool.
Chapter 5

Better Glass

🔍 Why was it so hard to see them clearly?
For a long time, microscopes made pictures blurry, with rainbow edges.
For a long time, microscopes made pictures blurry, with rainbow edges.
Glass bends each colour a tiny bit differently. That made the blur.
Glass bends each colour a tiny bit differently. That made the blur.
Agastya worked it out first.
Agastya worked it out first.
AgastyaGlass bends each colour by a different amount!
Then people paired two kinds of glass. The blur went away!
Then people paired two kinds of glass. The blur went away!
Workshops made lenses by hand, one at a time.
Workshops made lenses by hand, one at a time.
Later, a workshop worked out each lens on paper first.
Later, a workshop worked out each lens on paper first.
Most of the new glass came out wrong. They tried again and again.
Most of the new glass came out wrong. They tried again and again.
At last, rows of good microscopes, all the same, all year round.
At last, rows of good microscopes, all the same, all year round.
🔎 Clue found!
Better glass and careful workshops made sharp microscopes.
But the tiny things were see-through. Hard to spot, even with good glass!
But the tiny things were see-through. Hard to spot, even with good glass!
Chapter 6

Colours From Coal

🔍 How do you make see-through things easy to see?
The answer came from a surprising place. A factory that made colours from coal!
The answer came from a surprising place. A factory that made colours from coal!
It made bright purple and red dyes for clothes.
It made bright purple and red dyes for clothes.
Agastya could not believe it.
Agastya could not believe it.
AgastyaThe dye for a shirt colours germs?
Yes! Coloured, the tiny things jumped right out. Different kinds took different colours.
Yes! Coloured, the tiny things jumped right out. Different kinds took different colours.
Then people put a camera on the microscope.
Then people put a camera on the microscope.
Books full of photos meant anyone could check anyone else.
Books full of photos meant anyone could check anyone else.
Agastya’s notebook
Glass + dye + camera = everyone can check.
Now every lab could look. But who actually had a lab?
Now every lab could look. But who actually had a lab?
Chapter 7

Looking for Everyone

🔍 How does looking reach everyone?
One big city decided looking should be a free public service.
One big city decided looking should be a free public service.
Tubes. Swabs. Racks. A collection round every day.
Tubes. Swabs. Racks. A collection round every day.
Boxes on street corners, emptied every evening.
Boxes on street corners, emptied every evening.
The answer went quickly back to the doctor.
The answer went quickly back to the doctor.
Warren arrived.
Warren arrived.
AgastyaEvery hospital could have one!
WarrenCould. How many actually did?
A microscope only helps if someone is trained to read it.
A microscope only helps if someone is trained to read it.
Today, trained people still look, in thousands of clinics, every morning.
Today, trained people still look, in thousands of clinics, every morning.
🔎 Clue found!
Finding something and getting it to everyone are two different jobs.
Chapter 8

Friday

🔍 What did the tiny-world hunt really change?
On Friday, Agastya set up the school microscope.
On Friday, Agastya set up the school microscope.
Microscopes like his stand on benches all over the world.
Microscopes like his stand on benches all over the world.
He showed his class one drop of clear water. They gasped!
He showed his class one drop of clear water. They gasped!
Charlie came too.
Charlie came too.
CharlieSeeing them didn't save anybody.
AgastyaNo. But now people could check!
Agastya thought of the tiny brass plate. It started everything.
Agastya thought of the tiny brass plate. It started everything.
One question was left. If they are everywhere, how do bad ones get in?
One question was left. If they are everywhere, how do bad ones get in?

All the clues

  1. Clear water can be full of tiny living things.
  2. A new idea gets trusted when other people check it.
  3. Most tiny living things are helpers. Only a few make us sick.
  4. Better glass and careful workshops made sharp microscopes.
  5. Finding something and getting it to everyone are two different jobs.

So… What is hiding in clear water — and why did it take so long to see it?

Tiny living things too small for our eyes. Most are helpers, a few make us sick. It took better glass, careful workshops, coloured dyes and trained people before everyone could see — and check.

OmahaIndia Junior · a simpler version of Book 1 for readers aged 6-8