I never saw this movie "For the love of Rusty" (1947), but it will be playing on TCM on Sat. 7/4/09 at 7:15 am. (Check your local listings if U.R. not in Eastern Time) It's about a boy and his dog.
I wonder if Rusty used this title to write the song "For the love of Mary".
BTW-There are 2 other "Rusty" movies the following Saturday, 7/11/09: At 6:00 am there's the Son of Rusty (1947), about a town that learns from Rusty's devotion to another dog, and at 7:15 am, Rusty leads the Way (1948), about how Rusty and his boy help a little blind girl.
I watch a lot of old movies, but these don't have anyone famous in'em. I set my TiVo to record all of'em. I love puppies!