 Back at Princeton-Plainsboro, Foreman believes his patient has multiple sclerosis and begins the treatment of interferon, until Casey develops leg paralysis, due to Chris Taub and Amber putting her on steroids at the same time.Brennan strongly feels it is polio, but his suggestion is immediately turned down, until Brennan returns with positive test results for the condition.Brennan suggests a treatment of vitamin C, which he believes can destroy the polio virus and restore Casey's use of her legs.