In many ways, Dracula is more than just a thriller. It explores, among other themes, issues of sexual repression and the conflict between the old and new. Stoker presents Mina as the model Victorian female: she is dutiful to her husband, pure and chaste, and sympathetic. Furthermore, she exemplifies the Victorian ideals of progress, technological advancement and rationality. As such, she is key to the conflict between old and new (the irrational and the rational), and between repressed sexuality and "voluptuous wantonness". Her protection becomes vital to the protection of Victorian society as a whole, lest it crumble into superstition and lust. Mina is also central to the novels ability to thrill. In the earlier stages of the book, Stoker uses her ignorance to create irony and tension, and in the later stages of the book he uses her vulnerability to create tension and suspense
One of Mina's traits as the model Victorian woman is the duty she feels to her husband, and to her friends.
The strength of Mina's sense of duty to her husband is evinced by her willingness to travel all the way to Transylvania to care for him. Furthermore, she had been "working very hard" so as to keep up with Jonathon's studies, feeling that she would "like to be useful" to him. Her commitment to her husband even extends to learning the train time-table off by heart so that she can inform him if necessary.
Another attribute of the Victorian idealised woman is purity. Although it is perhaps not emphasised to the extent it is with Lucy, Mina does possess this quality. We see her purity and chastity in the scene described shortly after her marriage to Jonathon. She is "solemn" instead of excited; there is mention of sexuality ("he kissed me"), but for Mina...