How does Lady Macbeth respond to Macbeth's outburst in Act III, scene 4?
In Act Three, Scene 4, Macbeth holds a banquet and invites the Scottish lords to dine with him. During the banquet, Macbeth begins to hallucinate and sees Banquo's bloody ghost. Macbeth then speaks to the ghost, which disturbs and confuses the Scottish lords. In hopes of calming the strange situation, Lady Macbeth excuses her husband's odd behavior by telling their guests that Macbeth has suffered from similar strange attacks as a youth.
When Macbeth continues to speak to Banquo's ghost, Lady Macbeth chastises him for being afraid and losing his mind. She also encourages her husband to focus on entertaining their guests and urges him to forget about the hallucination. When Macbeth commands the ghost to get out of his sight, Lady Macbeth tells their guests,
"Think of this, good peers, But as a thing of custom. 'Tis no other; Only it spoils the pleasure of the time." (Shakespeare, 3.4.102-105)
Macbeth then begins to ask his guests whether or not they also see the ghost, and Lady Macbeth quickly intervenes. Before the situation can get any worse, Lady Macbeth tells the Scottish lords to leave the banquet because their presence is making Macbeth's condition worse. Lady Macbeth is clearly upset at her husband's behavior and lack of self-control at the banquet. She is also worried that his strange behavior will make the Scottish lords suspicious. After their guests leave, Lady Macbeth tells her husband to get some sleep.
In this scene Macbeth sees the ghost of Banquo during the banquet at his castle just after receiving confirmations that the murderer's he had hired had actually killed Banquo. First Macbeth speaks to the ghost that no one else could see. Lady Macbeth responds to this first scene of apparent madness by explaining to his guests that Macbeth has had such spells and visions since childhood and telling them to ignore him. Taking Macbeth aside, she then tries to snap him out of his spell. Macbeth makes a brief recovery until the ghost appears again. Now Macbeth appears increasingly mad and Lady Macbeth is afraid that in this state he will actually confess his crime. Thus she hurries the guests out of the hall explaining that his illness is growing worse. At this point, Lady Macbeth herself is not really sure what is going on in Macbeth's mind. She did not see the ghost herself. As the guests leave, the ghost leaves also and Macbeth seems to come back to himself somewhat worrying about Macduff's absence from the banquet. At this point Lady Macbeth urges Macbeth to get some sleep.
Lady Macbeth responds to her husband's outburst in Act III, Scene IV with a question: "Are you a man?", she asks him. Again calling into question his masculinity just as she did when he told her he did not want to kill King Duncan.
She then exclaims, sarcastically to him that he is imagining something, just like he thought he saw the dagger floating in the air before he killed Duncan. She continues to chide him about his fear and that he looks ridiculous and reminds her of a woman telling scary stories. He is spoiling the party with his nonsense.
In this scene, while entertaining guests at a banquet, Lady Macbeth responds to her husband who is seeing a vision of the ghost of Banquo.
Lady Macbeth first responds to their guests and tries to minimize Macbeth's behavior by acting as if this always happens. She asks them to pay no attention to him as this might make his "fit" even worse.
Her second response is to her husband, and it is to question his masculinity. She turns aside to him and asks,"Are you a man?" (line 59). He is in the midst of giving a feast as king, and he is acting much less than that. She says, "Oh, these flaws and starts, / Impostors to true fear, would well become / A woman's story at a winter's fire" (lines 63-65). Lady Macbeth then tries to convince him that his vision is not real. He is not seeing the ghost of Banquo, only an empty seat.
In the end, she rebukes him. He is ruining the party and ultimately his image of kingly strength. Her final response to him, before asking their guests to leave to avoid further embarrassment, is laced with disappointment and sarcasm. Macbeth has "displaced the mirth, broke the good meeting / With most admired disorder" (110-111).
Lady Macbeth's response is both an attempt to save face with the lords at the banquet and to stabilize Macbeth and bring him back to his kingly senses.