A less serious threat is the visit to the Academy of a Nazi "expert" in "racial science", who claims particular skill in detecting Jews. The Nazi selects "Jupp" as his subject for a demonstration and carefully measures his head and face. He then calculates "Jupp"'s anthropometric indices and pronounces him mixed but "pure Aryan stock", to Jupp's relieved surprise. Soon after, while working in a factory for the war effort, Jupp and his classmates learn that the German 6th Army has been defeated at the Battle of Stalingrad.