What imagery is used in the section where Faith visits her father's study after being forbidden to do so?

The overall scene in the study when Faith tries to interrupt her father includes descriptions meant to convey the idea that something is terribly wrong there, and Faith's observations affect the tone. Erasmus is writing, but Faith can see that this scrawl is nothing like his normal handwriting. His eyes are yellow with tiny pupils. The color yellow is often associated with cowardice, but is also associated with deceit, which leads back to the Mendacity, Tree, also called the Lie Tree. When she calls out to get his attention, Erasmus answers with a whispered command to leave, but Faith senses “more venom” than she had ever heard from him. She also notices a smell, which is later revealed to be the smell given off by the Mendacity Tree. However, in her inexperience she fears that he might have turned to opium to salve his battered pride.