Again, depending on just how the theme of eugenics is to be developed, there are a range of classic films. If it is taken as not just "purifying" but "improving" the race (or "human stock"), then one theme that fits in is robots. That is, in Capek's "RUR" (1924) artificial workers are created so humans don't have to do this kind of labor (and since they are machines, eliminating all sorts of social problems--poverty, drunkeness, unwanted children [and the need for birth control], etc.). There is probably a strong air of it in all robot/genetic engineering films/stories--manual labor is brutish, and the humans doing this are kinds of/closer to brutes/mere animals. Getting rid of them improves the race, and human life. This, along with some notion of "Brave New Worldish" strata of social organization, may well underlie such films as "Metropolis" [c.1926] and probably "Frankenstein". Charles Laughton's Moreau in "The Island of Lost Souls" (1933--one of the first Wells's adaptations, and still probably the best) is a chilling figure. ---- Online resources for film/TV studies may be found at ScreenSite http://www.ScreenSite.org