1. The story of smallpox

2. In the 18th century, smallpox was a deadly disease...
The story of smallpox
In the 18th century, smallpox was a deadly disease...
Milkmaids catch cowpox but they never catch smallpox.
Dr. Jenner ( )

3. Why do milkmaids catch cowpox but not smallpox?
The story of smallpox
Why do milkmaids catch cowpox but not smallpox?

4. The story of smallpox
Perhaps milkmaids do not catch smallpox because they have caught cowpox before.

5. Dr. Jenner first put cowpox pus onto a boy’s arm.
The story of smallpox
Dr. Jenner first put cowpox pus onto a boy’s arm.
After a few days, he put smallpox pus onto the boy’s arm.
The boy did not fall ill.

6. I‘m right! If we have caught cowpox before, we won’t catch smallpox!
The story of smallpox
I‘m right! If we have caught cowpox before, we won’t catch smallpox!