A director could have Macbeth look the doctor squarelyin the face, hand him money; the doctor smiles knowingly and give hima bottle and Macbeth then pours it into something on Lady Macbeth'snightstand from the sleepwalking scene.
Macbeth, for whom life is a painfulmeaningless enterprise, speaks of Duncan sleeping peacefully indeath "after life's fitful fever"; part ofMacbeth's own punishment is to be aninsomniac, and Lady Macbeth's is to sleepwalk.
Their son wasLulach the Simple (i.e., stupid;no, Lady Macbeth didn't brain him.) After Macbethkilled Gillacomgain, he took his widow Gruoch for his own wife,and raised Lulach astheir stepson.
This explainsthe appearance of the messenger to warn Lady Macduff just before she is killed --this episode does not contribute otherwise to the drama -- andafterwards, Lady Macbeth's repetitive writing during her sleepwalking.
There are silly urban legends about the boy actor whofirst played Lady Macbeth getting sick and Shakespearehaving to fill in, and Queen Anne closing the theatersafter people thought the deviltry of the play had caused a bad storm.
Lady Macbeth doesn't seem to thinkthat there's anything really unusual about the idea ofmurdering a guest, and she assumes it's occurred to her husbandas well.
They do not suffer fromfear of the afterlife (which Lady Macbeth b-tches out of her husband;he talks about giving up his "eternal jewel", i.e., his soul,to the devil simply as an accomplished fact).
Moore, who has taught the play for many yearsin high school and also shared the idea about Lennox and Lady Macduff, tells me that she invites class members toreproduce what Lacy Macbeth might have written.)There's a lot of talk about clothing -- clothes give youan identity and also conceal who you are.