Allusion

"'On the white wonder of dear Juliet's hand, may seize
And steal immortal blessing from her lips,'" Page 144

It is apparent that Huxley is a fan of Shakespeare. He intentionally put a book consisting of his works in the story. Additionally, he made a key character, John, speak as though from Shakespeare's time. He also uses it to show John's care for Lenina. Everyone knows the story of Romeo and Juliet. This is why Huxley had John recite a stanza from the play. In fact, John himself is a good symbol of a modern age (or age of Ford at least) Romeo.