The phrase combines several different figures of speech. The first is apostrophe, or direct address, in which a person is addressing someone absent, or even herself, and "overheard" as it were by the intended audience of the reader. It is a "rhetorical question" which differs from a normal question in that it is intended for effect rather than being an address of one person to another intended to elicit information. In describing madness as "seizing", the phrase employs personification, treating an emotion as though it were an individual person or agent capable of action. This externalizes the emotion, making the reader sense the character being swept away by emotions descending from the outside, which the character is powerless to resist. This amplifies the effect of the reading situation, in which our emotions are engaged by the external voice of the author, an effect also created by the engagement of the reader directly by use of apostrophe and rhetorical question.