"I appeared rather like one doomed by slavery to toil in the mined" (68)
This quote contributes to the theme because he looks differently than something he does.
"I did not remark how ill you appear; so thin & pale; like you had been watching for several nights." (73)
This contributes to the theme as well because he appears different than normal because of his level of stress.
"His yellow skin scarcely covered the work of muscles & arteries breath." (69)
This contributes to the theme because he looks scary even though he has a normal untouched soul.
"Let me go, monster! Ugly wretch!" (179)
He looks threatening because he is very ugly which is why this contributes to the theme as well.