Motifs are recurring structures, contrasts or literary devices used in a novel.  Several motifs are introduced in the first two chapters of Dr. Jekyll and Mr. Hyde.  One of the most striking is the motif of silence.  English society at the time places a value on reserve.  Utterson and Enfield are so reserved that they can walk together for some time without speaking.  When they witness evil, they cannot even seem to articulate their fear about what they have seen as if talking about it will make it more real.  The characters can sense Hyde's evil yet they cannot describe it.  They go so far as to agree to never speak of the incident again.  This motif adds to the sense of dread that permeates the novel.

 A second motif that is introduced is that of hidden crimes that lurk below the surface of urban London.  Stevenson introduces this motif in Utterson's dream in chapter two.  In this dream he sees Hyde lurking through the darkness in London leaving a child screaming on every corner.  This feeling that Hyde has committed more crimes than we know that are hidden in the labyrinth of London streets will be carried further as the story continues but it begins here.  Here the motif allows Stevenson to highlight the evil of the charater without retelling many specific events.