Boris Livanov

Dick Arrowsmith

N. Golitsyna

Ethel

Maksim Shtraukh

Samuel Wolfe

Boris Svetlov

Layons

Sergey Tikhonravov

Garreth

Viktor Stanitsyn

Bill Steer

Andrei Abrikosov

Engineer Nikitin

Sergei Tsenin

Sazonov

Aleksey Dolinin

Gaydar

Dmitriy Kara-Dmitriev

Bistayev

Vera Maretskaya

Comrade Olga

Vladimir Uralskiy

Gostev

Leonid Kulakov

Rakitin

Oswald Glazunov

Rector (uncredited)

Ivan Lavrov

Professor (uncredited)

Lyudmila Glazova

Felice (uncredited)

Marta Aleschenko

John's wife

Timofey Remizov

Laboratory worker (uncredited)

Eva Milyutina

Arrowsmith's guest

Ivan Chuvelyov

Arrowsmith's guest

Leonid Obolensky

The reporter (uncredited)

Weyland Rodd

The worker (uncredited)

Eduard Gunn

The provocator (uncredited)