History of Medicine
Spurned by his creator, Mary Shelley's monster kills for revenge. The movie monster, on the other hand, kills because he's been given the brain of a criminal. Early in the twentieth century, "biological determinism" was in the air; heredity, more than environment or education, the idea went, caused social problems. Proponents of eugenics wanted to improve the human species through compulsory sterilization of criminals, the mentally retarded, and others deemed social misfits. Some two-thirds of Americans were said to support such measures.
Do you see the "sex pervert" in brain no. 590? Such overly neat links between biology and destiny were intellectually fashionable in the 1920s, in the period just before Universal Studios released Frankenstein.