Othello Questions Act III Scene IV: What is the story of the handkerchief

What is the story of the handkerchief?

What does Emilia mean when she says, “’Tis not a year or two shows us a man.

They are all but stomachs, and we all but food;

To eat us hungerly, and when they are full,

They belch us.”

Why does Desdemona say that now is not a good time to talk to Othello about Cassio (p. 112-3)?

What do we learn about Cassio and Bianca?