Malcolm Stewart

as Dr. Louis Graber

as Joe Shaw

as Jim Holt

as Dr. Dean

as Leo

as Dr. Grewe (1 episode)

as Victor

as Kenneth Benson

as Lloyd Grayson

as Joe Shaw

as Roger Caldwell

as Joe

as Lawrence Hennessey

as Dr. Vedders

as Henry Tilton

as Lars Browing

as Freiderich Werthers (15 episodes), as Francis J. Dupont (11 episodes)

as Mr. Remora (3 episodes)

as Dennis Peck (7 episodes)

as Stan Hoffbrauer

as Joseph Mayfield

as Mr. Conceito

as Martin Strang

as Gray Ballantine

as Luke Reilly