What techniques are used in this quote: "Come to my woman's breasts,/ And take my milk for gall, you murdering ministers."

This scene begins with Lady Macbeth reading the letter written by her husband, a letter which acquaints her with the Weird Sisters' prophecies and the fact that he's recently been named Thane of Cawdor, bringing one of those prophecies to fruition. Immediately, Lady Macbeth seems to resolve on violence as a means of quickly achieving the remainder of the prophecy. She says, speaking of Macbeth,

Glamis thou art, and Cawdor, and shalt be
What thou art promised. Yet do I fear thy nature;
It is too full o' th' milk of human kindness
To catch the nearest way.  (1.5.15-18)

She vows that Macbeth will be everything the Sisters said he would, but she worries that Macbeth is too compassionate to take the quickest path to the throne: murdering the current king rather than waiting for him to die.

When Lady Macbeth finds out that Duncan is on his way to her castle, to stay the night, she sees this as their opportunity to get rid of him. In a soliloquy, she calls on any spirits that assist deadly thoughts to come and remove any feminine impulse she might have, an impulse like compassion, and fill her up with masculine cruelty. A soliloquy is a dramatic convention where a character who is alone on stage speaks her thoughts aloud; it is a way for the writer to reveal that character's innermost feelings to the audience. Shakespeare uses this technique here to show us just how ruthless Lady Macbeth is. Also, as part of this soliloquy, she says,

Come to my woman's breasts
And take my milk for gall, you murd'ring ministers,
Wherever in your sightless substances
You wait on nature's mischief.  (1.5.54-57)

Still speaking to those spirits that might help her to advance her deadly thoughts, she tells them to come to her breasts, take her milk and replace it with bitterness.  She wants to feel only the viciousness and heartlessness associated with men and none of the kindness and concern associated with women. In having her speak to someone or something that cannot respond, Shakespeare also employs apostrophe, a poetic technique, with this soliloquy.