This is one of the rare films which, despite taking liberties from the book, gets the story's theme across successfully. For example, in the book the son's brother dies of consumption; in the movie it is in a coal mining accident. This is shown by a light rumble and a ripple on the waters of a lake, which, as TIME said in their review, creates a dramatic effect ten times more forceful than if the air had been filled with flying coal carts.
The theme successfully carried to the screen is that the Paul Morel character had love affairs, and his mother had him in a bind about it. The mother, played by Wendy Hiller, says at one point, "I feel like [your present girl friend] is trying to take you away from me." I don't recall this line from the book, but as I say, the movie's adaptation of the book's theme--the conflict of loyalties between a mother and one's girl friends--is carried across with nothing more to be desired.