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)