

A medical researcher is sent to a plague outbreak, where he has to decide priorities for the use of a vaccine.

Ronald Colman
Dr. Martin Arrowsmith

Helen Hayes
Leora Tozer Arrowsmith

Richard Bennett
Gustav Sondelius

A.E. Anson
Professor Max Gottlieb

Clarence Brooks
Dr. Oliver Marchand

Alec B. Francis
Twyford

Claude King
Dr. Tubbs

Bert Roach
Bert Tozer

Myrna Loy
Joyce Lanyon

Russell Hopton
Terry Wickett

David Landau
State Veterinarian

Lumsden Hare
Sir Robert Fairland

Erville Alderson
Pioneer (uncredited)

Ward Bond
Cop (uncredited)

Beulah Bondi
Mrs. Tozer (uncredited)

Florence Britton
Miss Twyford (uncredited)

Nora Cecil
Nurse (uncredited)

Sidney De Gray
Dr. Hesselink (uncredited)

Cyril Delevanti
Committee Member (uncredited)
Walter Downing
City Clerk (uncredited)
John Ford
Sidney Howard
Released