Many people were catching a deadly disease, small pox. However Edward Jenner found out that maids

who milked cows did not catch it.

Jenner found out that the reason why maids were not catching Smallpox is because they were catching Cowpox.

Cowpox makes one immune from Smallpox

To test this theory, Jenner picked a boy called James Phillips and deliberately gave him cowpox.

The cure for smallpox was finally found!!!Then, Jenner tried to give him Smallpox six weeks later, but he didn’t catch it.

He then was ill after a few days but soon became better.