How does the author use foreshadowing in Ethan Frome?

Just before Zeena leaves for her trip to the doctor, she finishes a bottle of medicine and pushes it toward Mattie: "It ain't done me a speck of good, but I guess I might as well use it up .. If you can get the taste out it'll do for pickles." This action might be interpreted as follows: after Zeena has exhausted the possibilities of her medicine for her "trouble," she turns to sex-but she passes on that alternative to Mattie. Mattie may use the Jar for pickles if she wishes. The action is a foreshadowing of Mattie's use of the pickle dish. In a sense, Zeena has urged her to that act, for she is abdicating the position of sexual initiative.