What type of film is Alex shown? What is his reaction?

Alex is shown films about terrible things, the type of things that he used to do to people before he was arrested. He is shown an old man being beaten, a woman being gang-raped, a human face being mutilated, a shopkeeper being burned alive, and soldiers being tortured by the Japanese during World War II. All of this makes Alex feel sick, although he cannot throw up. He begs the doctors to stop the film, but they just laugh at him.