"none the less natural to me because they were the expression, and bore the stamp, of lower elements in my soul."
Jekyll is pointing out that he is evil internally but Stevenson refuses to tell us what Hyde's face looks like to point out the physiognomy and how that is false and an unrealistic judgment
Victorian society is being questioned by Stevenson
it encourages people to shadow their true selves
"the large handsome face of Dr Jekyll grew pale to the very lips, and there came a blacknessabout his eyes" 1
the duality of man is openly presented here
the "blackness" is hinting that there is an evil side to him internally
he may look like this but underneath there is truth
this may appear to be a Christian novel however that’s what it looks like on the surface too but Stevenson aims at a sophisticated reader to interpret in in many different ways