He was appointed as an assistant at Halle but he did not have the opportunity to work there for long since, in 1933, he was forced to leave Germany because of the Nazi policies.
Siya ay hihirangin bilang isang assistant at Halle ngunit siya ay hindi magkaroon ng pagkakataon na magtrabaho doon para sa mahabang dahil, sa 1933, siya ay sapilitang umalis sa Germany dahil sa ang Nasi patakaran.