What does White Dog represent?

This white dog is a symbol of the connection between the past and the present. For a short while, the author makes it appear as if the dog is perhaps a mirage. Sugar believes that she has gotten a glimpse of the dog but wonders if she might have seen something else that she interpreted as being the dog because she had just remembered the white dog that had to be killed when she was still a child. Colin also believes that he has seen this dog but cannot lure it to the house. The night that Heather tries to kill Merilee, the white dog leads Sugar to Merilee’s cottage, as if it is hoping that she will intervene to save Merilee’s life. It is only after Sugar saves Merilee that Colin is able to catch the dog.