In Chapter 6, Bernard brings a piece of paper to the Director to be signed. This piece of paper has already been signed by Mustapha Mond, whose signature Huxley personifies as a means of demonstrating hierarchy or caste in action:
The Director glanced at him sourly. But the stamp of the World Controller’s Office was at the head of the paper and the signature of Mustapha Mond, bold and black, across the bottom. Everything was perfectly in order. The Director had no choice. He pencilled his initials—two small pale letters abject at the feet of Mustapha Mond.
In this passage, Mond's signature and the Director's initials are both personified, with one bowing to the other, prostrate as though praying to a religious figure. The mens' initials imitate their real-life behaviors and attitudes, in a manner of speaking.
Curiously, despite the fact that people in this totalitarian society are biochemically conditioned to accept their place in the caste system, it is clear in the above passage that the Director resents Mustapha Mond's power over him. The word "abject" does not communicate willing submission—clearly, if the Director were able to make the choice for himself, Bernard's paper would have no signatures whatsoever. In this sense, the description of the signatures suggests that higher one rises in the caste system of the World State, the more discontent one is with the caste system.