Harry’s been sneezing for a week, and thinks he has the flu. But since Harry has no fever or headache, Dr. Larry suspects otherwise. For the rest of the day he asks Harry to keep a record of how often he sneezes in a minute each time he arrives at a new locations. When they analyze Harry’s data, they see that Harry sneezed most when he visited his friend Inga and her cat Daisy May. Since this suggests Harry may be have a cat allergy, Dr. Larry predicts that if Harry visits a nearby vet’s office, he’ll do a lot of sneezing. Because the clerk is holding a cat, what Dr. Larry predicted would happen does happen: Harry sneezes a lot. It turns out, the reason he sneezed even when he was not around cats was due to wearing a jacket with fur from Daisy May. The treatment is to clean his jacket and apartment, and never cat-sit again.