Why is the old man afraid of cats and what extreme measures has he taken to keep them at bay?

He has an irrational fear of cats, for when he was a child a freed slave had warned him about "wampus cats" that prowled invisibly around the mountains. They could not be seen by normal people, but she put some drops on his tongue which, she said, would make them visible for him. He was always afraid that he would see a cat outside his window at night, and sometimes he did. Once he even blasted his window and wall with a shotgun because he thought a cat was sneaking up on him. After that, he decided to no longer keep the shotgun by his bed.