Dick Arrowsmith
Layons
Samuel Wolfe
Engineer Nikitin
Sazonov
Bill Steer
Rector (uncredited)
Comrade Olga
Gostev
Bistayev
Gaydar
Garreth
Rakitin
Ethel
Professor (uncredited)
Felice (uncredited)
John's wife
Laboratory worker (uncredited)
Arrowsmith's guest
