'The Prisoner of Shark Island' is based on an actual historical event and makes a pleasing contrast to the last film I watched that concerned 19th-century American history (Young Mr Lincoln, 1939). That is not to say it is correct about every detail. However, total historical accuracy is obviously impossible to achieve in any case (Kurosawa's 'Rashomon', 1950, explains the reason why), and besides, 'The Prisoner' avoids the fawning and sycophantic tone that annoyed me when I watched the film about Mr Lincoln's days as a young lawyer. 'The Prisoner' is about one Dr Mudd who treated the broken leg of the assassin of President Lincolns without realising who his patient was. He is jailed, and because the government needs a scapegoat to calm a mob baying for blood, is imprisoned for life on the Dry Tortugas where normal US law does not apply (something like a 19th-century Guantanamo Bay, as other reviewers noted). On the whole I think this is a well-acted film. I liked Warner Baxter as Dr Mudd and Claude Gillingwater as the doctor's father in law and comic relief. The pacing is somewhat uneven, though. There is quite a long exposition, whereas the military kangaroo court that tries Mudd is handled excellently. Most of the prison scenes are alright, though the Yellow Fever epidemic could have been used to better effect - after all, it is why Mudd was eventually rehabilitated. What is seriously jarring is the way black former slaves and black soldiers are shown. This is racial stereotyping of the worst kind, and this despite one of the black actors (Ernest Whitman) playing an important and almost heroic role. All in all I'd say this is not a bad film, but one that could clearly have been much better. It is obvious why it failed to become a classic.
