In this quote from Wuthering Heights, the speaker personifies their own emotional state as being intense and fiery, contrasting it with the icy coldness of the other person's veins. It highlights a stark difference in feelings or attitudes, possibly reflecting emotional distance or coldness from one side and passionate, overwhelming feelings from the other.

This imagery emphasizes the inner turmoil and emotional conflict present in the characters, illustrating how contrasting their states of mind and feelings can be. The line captures a moment of tension, where the speaker perceives a harsh disparity between their own fiery emotions and another's icy detachment.