Nor do the pains she is at to ’screw his courage to the sticking-place’, the reproach to him, not to be ‘lost so poorly in himself’, the assurance that ‘a little water clears them of this deed’, show anything but her greater consistency in depravity.  Her strong-nerved ambition furnishes ribs of steel to ‘the sides of his intent’; and she is herself wound up to the execution of her baneful project with the same unshrinking fortitude in crime, that in other circumstances she would probably have shown patience in suffering.  The deliberate sacrifice of all other considerations to the gaining ’for their future days and nights sole sovereign sway and masterdom’, by the murder of Duncan, is gorgeously expressed in her invocation on hearing of ‘his fatal entrance under her battlements’: 

          —­Come all you spirits
     That tend on mortal thoughts, unsex me here: 
     And fill me, from the crown to th’ toe, top-full
     Of direst cruelty; make thick my blood,
     Stop up the access and passage of remorse,
     That no compunctious visitings of nature
     Shake my fell purpose, nor keep peace between
     The effect and it.  Come to my woman’s breasts,
     And take my milk for gall, you murthering ministers,
     Wherever in your sightless substances
     You wait on nature’s mischief.  Come, thick night! 
     And pall thee in the dunnest smoke of hell,
     That my keen knife see not the wound it makes,
     Nor heav’n peep through the blanket of the dark,
     To cry, hold, hold!—­

When she first hears that ‘Duncan comes there to sleep’ she is so overcome by the news, which is beyond her utmost expectations, that she answers the messenger, ‘Thou’rt mad to say it’:  and on receiving her husband’s account of the predictions of the Witches, conscious of his instability of purpose, and that her presence is necessary to goad him on to the consummation of his promised greatness, she exclaims: 

         —­Hie thee hither,
     That I may pour my spirits in thine ear,
     And chastise with me valour of my tongue
     All that impedes thee from the golden round,
     Which fate and metaphysical aid doth seem
     To have thee crowned withal.

This swelling exultation and keen spirit of triumph, this uncontrollable eagerness of anticipation, which seems to dilate her form and take possession of all her faculties, this solid, substantial flesh-and-blood display of passion, exhibit a striking contrast to the cold, abstracted, gratuitous, servile malignity of the Witches, who are equally instrumental in urging Macbeth to his fate for the mere love of mischief, and from a disinterested delight in deformity and cruelty.  They are hags of mischief, obscene panders to iniquity, malicious from their impotence of enjoyment, enamoured of destruction, because they are themselves unreal, abortive, half-existences, and who become sublime from their exemption from all human sympathies