Jethro needs a health certificate to graduate from the fifth grade, so he goes to the only doctor the Clampetts know about - Mrs. Drysdale's psychiatrist. The psychiatrist may have bitten off more than he can chew when he starts treating Jethro. Dr. Twombly gets nowhere with Jethro, so Pearl comes and she thinks he is testing her virtue when he tries to lay her on his couch.
