What does this quote mean: "Have pluckd my nipple from his boneless gums and dashd the brains out, had I so sworn as you have done to this."?I just...

Have the MacBeth's had children in the past? This quote indicates that Lady MacBeth has had a child in the past, perhaps the fact that their child has died has led the MacBeths to rely on each other a lot, feel depressed or even for Lady MacBeth to become unbalanced. Perhaps she looks to compensate for the loss of her child by ambition for her husband.

In the context of this speech she is showing MacBeth that in stepping back from what she considers he has to do - murder Duncan and become king - he is a coward and is letting her down badly. The image she gives here of the killing of a child is an appalling one, the idea of dashing out the brains of a child deliberately revolts us and turns us against Lady MacBeth. It also shows the sheer force of her character that leads to MacBeth following what she says.