This movie has already been given an excellent review for IMDb. I agree that this is Boris Karloff's finest screen performance as an actor, not to take anything away from his classic Frankenstein's monster portrayal. And it is tragic that Bela Lugosi's character is almost a cameo since this was the last time Karloff and Lugosi appeared together on the screen. I also agree that Henry Daniell is one of the few actors of the period who could shine in a role opposite Karloff without Karloff running away with the show. I would, however, like to add that the relationship between Karloff and Daniell is a key to the entire movie and Val Lewton knowingly focuses on this part of Robert Louis Stevenson's nightmare tale. There are many stages of our lives that we would like to forget and we don't like living reminders haunting us about those stages. The strange relationship between the doctor and the murderer points clearly that there is a fine line between good and evil and it is very easy to cross that line when we are tempted to do so for fame, fortune, or any other vainglorious desire. The final scene in "Body Snatcher" is one of the scariest scenes ever captured on film. I won't give it away for those who have not seen the movie. Just get ready to have the coach ride of your life.
Review of The Body Snatcher
