DAVINA: Lady Macbeth calls on evil spirits which can influence our mortal, or human, thoughts. 

RALPH: But mortal also means deadly; so a second meaning of this phrase is that she’s asking the spirits to instill in her murderous ideas.

DAVINA: She also calls on the spirits to "unsex" her.  

RALPH:  What could she possibly mean by that?

DAVINA:  She wants her traits of kindness and pity -- which she sees as natural to being a woman -- replaced with “direst cruelty”, which she sees as belonging naturally to a man.

RALPH: I see -- so ‘unsex’ means to ‘undo’ her feminine traits and become more masculine.

DAVINA: That’s right. 

RALPH: But is it really fair to divide those traits into feminine and masculine?  She seems to be coming up with cruel ideas all on her own, and she’s already said that her husband is full of human kindness.

DAVINA:  That’s a very good question, Ralph.