With reference to language, structure and poetic devices.
The reader is shocked at the fact that she had kissed the head since the decapitation.
There is a sick inevitability and depravity about her; this is immediately evident from the gruesome crime she has committed.
'Grind away moisten and mash up thy paste, Pound at thy powder-I am not in haste.' The topic of the poem in My Last Duchess is infact a painting, had it been written in the 21st century it would have been far more likely to have been a photograph.
The theme of The Laboratory is one of the eternal love triangle.