Answer:
much of action in the book is seen thru uttersons eyes so it is believable. he makes him a lawyer who is cold and serious and dry but mentions he is lovable. "when the wine was to his taste something eminently human beaconed from his eye"..meaning he likes a drink but he is strict with himself and doesn't even visit the theatre. he is tolerant of others but strict with himaelf. he is unique and he represents the victorian gentleman of the time. he is the opposite of jekkyl. he is tolerant of what goes on in the book and he needs to be serious so the story is believable if seen thru his eyes and tolerant enough to listen to the crazy stories of jekyll and still be able to hang around after hearing those experiences. he is trustworthy but doesn't distract from the other characters. he is not judgemental.
victorian era was an era with the advancement of science, economic growth and the awakening of socially repressed feelings/behavior. this book tapped directly into the anxieties of the times