Step-by-step explanation:
This excerpt appears to be a piece of dialogue from a play or screenplay, as it includes stage directions and character names. It also provides insight into the characters' personalities and their relationships.
The character speaking is Walter, who is dancing with Ruth. Walter's comments reveal that he is critical of his sister's activism and feels that she is overly focused on racial issues. He implies that she is brainwashing herself by constantly harping on the subject of race, and he mocks her for being too extreme in her views.
The way that Walter speaks to Ruth and the content of his remarks also suggest that he is somewhat aggressive and confrontational. He imagines her as a surgeon who interrogates her patients about their political beliefs before operating on them, which implies that he sees her as someone who is willing to use her power to force her views on others.
Overall, this excerpt helps to characterize Walter as someone who is skeptical of his sister's activism and willing to speak his mind, even if it means being confrontational or abrasive. It also hints at tensions between him and Ruth, which could become important later in the story.