The oracle of the dog

After a slightly disappointing introduction to the Father Brown series earlier this week, I decided to reverse the order: this time I started by watching the movie and read the story later on. It was a better experience; I am surprised, though, by the differences between movie and text.
In the movie, we see a quite classic detective story: a man makes his will and is murdered shortly afterwards. All the suspects and Father Brown himself have been around in the house, no-one seems to have been close to the murder scene when it happened. A detective collects the different testimonies; Father Brown solves the mystery.
The book has a somewhat different set-up: Father Brown is never present in the house of the murder, but only hears about the case from an eye-witness. This witness gives perceptive descriptions, though he also has some perceptions of his own. From the witness's story, Father Brown is able to reconstruct what happened. We are particularly impressed by his insight in the character of man and animal (the dog of the title).
The story did not have much direct action (it consists mainly of dialogue), which is one reason that the whole scene is changed in the movie. The surroundings are quite different too, and there are some differences in the characters (one nephew instead of two, a fidgeting or non-fidgeting lawyer).
Though I did like this movie, I still prefer the stories: the brilliant Chesterton-sentences are one of the chief delights of Father Brown's conversation, and these are not always easily adapted on the screen. His analysis of the behavior of the dog: "A dog is a devil of a ritualist. He is as particular about the precise routine of a game as a child about the precise repetition of a fairy-tale. In this case something had gone wrong with the game. He came back to complain seriously of the conduct of the stick. Never had such a thing happened before. Never had an eminent and distinguished dog been so treated by a rotten old walking-stick."