William Dieterle Director Edward G. Robinson Dr. Paul Ehrlich Actor Ruth Gordon Mrs. Ehrlich Actor Otto Kruger Dr. Emil Von Behring Actor Donald Crisp Minister Althoff Actor Maria Ouspenskaya Franziska Speyer Actor Montagu Love Professor Hartmann Actor Sig Ruman Dr. Hans Wolfert Actor Donald Meek Mittelmeyer Actor Henry O'Neill Dr. Lentz Actor Albert Basserman Dr. Robert Koch Actor Edward Norris Dr. Morgenroth Actor Harry Davenport Judge Actor Louis Calhern Dr. Brockdorf Actor Louis Jean Heydt Dr. Kunze Actor Charles Halton Sensenbrenner Actor Irving Bacon Becker Actor Douglas Wood Speidler Actor Theodore von Eltz Dr. Kraus Actor Hermine Sterler Miss Marquardt Actor John Hamilton Hirsch Actor Paul Harvey Defense Attorney Actor Frank Reicher Old Man Actor Torben Meyer Kadereit Actor Louis Arco Dr. Bertheim Actor Wilfred Hari Dr. Hata Actor John Henrick Dr. Bucher Actor Ann Todd Marianne Actor Polly Stewart Steffi Actor Egon Brecher Martl Actor Robert Strange Koerner Actor Jack L. Warner Producer Hal B. Wallis Producer