What was Lady Macbeth's reaction when Macbeth sees Banquo's ghost in Macbeth? What similar thing did she recall?

In Act 3, Scene 4, Macbeth is tortured by the appearance
of the ghost of Banquo, and Lady Macbeth attempts to preserve order and harmony by
reassuring guests that Macbeth's fit is fleeting:

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 Sit, worthy friends: my lord is often
thus,
 And hath been from his youth: pray you, keep seat;
 The fit
is momentary...

Her primary
intention is to pacify the potentially harmful effects brought on by Macbeth's outburst
and encourage Macbeth to let go of the vision he struggles with. She reminds him that
this vision is similar to the one which involved "a dagger of the mind," and she
convinces him that this is all a product of his imagination. She urges him to bury his
fear and demonstrate his sanity for the sake of the
guests:

 This
is the very painting of your fear:
 This is the air-drawn dagger which, you
said,
 Led you to
Duncan.

After this, Macbeth
seems to have come to his senses, but only briefly. The ghost reappears, and Macbeth's
descent into irrationality becomes clear again. This time, Lady Macbeth is unable to do
anything to mend the situation. Therefore, she is forced to tell the guests to leave,
stating that Macbeth is not well:

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He grows worse and worse;
Question
enrages him. At once, good night:
Stand not upon the order of your
going,
But go at once.