What new information does Poole furnish in regard to Dr. Jekyll and Mr. Hyde’s relationship, and how does Utterson react to it?

In Chapter 8, Poole tells Mr. Utterson that he saw a figure digging at some crates in Jekyll's room. When the figure looked at him, he cried out and ran upstairs. Poole says that the figure was wearing a mask. As a result, Mr. Utterson comes to the conclusion that Jekyll must be wearing a mask because of an illness.... some malady that caused a physical deformation. In a way, Jekyll has been living a life in which he wears two masks--one, a mask of respectability, and the other, a mask of depravity. When he is no longer able to change "masks" at will, he is forced to wear a mask..... in order to disguise his "mask."