I can't find any big studio films that concern themselves with racism prior to 1949, and this film takes up the subject in a very raw way just the year after that.

Dr. Luther Brooks (Sidney Poitier) is a resident in a hospital. He is assigned to the prison ward when the Biddle brothers are brought in, both shot in the leg trying to get away from the police after the hold-up of a gas station. But one of the brothers, Johnny Biddle, is incoherent and feels nothing when a cigarette he is smoking falls and smoulders in his hand. Brooks suspects a brain tumor and performs a spinal tap, but Johnny dies during he procedure. His racist brother Ray Biddle (Richard Widmark) declares that the doctor killed him. The state this happens in does not force an autopsy under such circumstances unless allowed by the next of kin. But that would be Ray Biddle and he really enjoys accusing Dr. Brooks of murder without any pesky truth or confirmation.

The supervising physician assures Brooks that he may or may not have been correct in his assessment, but that he most certainly did not kill Johnny Biddle. Meanwhile this situation has the potential of blowing up into a full fledged race riot with Biddle fanning the flames from inside of his prison hospital room. Complications ensue.

Today, a film like this could not be made primarily because of the language used, which is the language used by racists then and now. And that's too bad, because Widmark's no holds barred portrayal of Ray Biddle paints a very ugly and stupid face on racism, one that rings true even today. Biddle holds fast to his racism because he needs to feel superior to somebody else, and the Brooks family climbing into the middle class while he is left behind in the slums completely upsets his world view.

Without getting into details, this film has a high level of suspense and tension that carries it through to the end. I'd highly recommend it, just realize it is not an easy thing to watch.