Frank Baxter
— Himself (as Dr. Frank C. Baxter)
Hadley Cantrell
— Himself - Princeton University Psychologist (as Professor Hadley Cantrell)
Edwin Max
— Bill
Wilder Penfield
— Himself - Director: Montreal Neurological Institute (as Dr. Wilder Penfield)
Peter Brown
— Aristotle's student (uncredited)
Karl Swenson
— Hal - the Cameraman (uncredited)