I spent eight years as a research biochemist. Throughout that time I lived with Sam, a large, ginger neutered tom cat. He had moved in with no fur on his belly and back legs – apparently as a result of fleas – and a medicine cabinet of powerful and expensive steroids. I decided that if fleas were causing Sam’s baldness then I would deal with them rather than spend my meagre funds on cat steroids. So I bought him a flea collar and dusted him down with flea powder. Before long his fur had grown back