In the book, there are discussions about abortion between Doctor Bull and Virginia Banning. These were dropped from the script after a complaint from the Hays Office. In the movie, there is just a vague notion she is pregnant. Also, the character of Larry Ward had a venereal disease in the book, but in the film he's just a hypochondriac.
Admiring Dr. Verney's laboratory instruments, Doctor Bull says, "You ought to take this to the Century of Progress!" He was referring to the 1933 Chicago World's Fair, with its theme "A Century of Progress" to commemorate Chicago's centenary since the city's incorporation in 1833, where the public was astounded by the latest technologies and scientific breakthroughs.