Jo lives--that is to say, Jo has not yet died--in a ruinous place known to the like of him by the name of Tom-all-Alone's. [...] It must be a strange state to be like Jo! To shuffle through the streets, unfamiliar with the shapes, and in utter darkness as to the meaning, of those mysterious symbols, so abundant over the shops, and at the corners of streets, and on the doors, and in the windows! To see people read, and to see people write, and to see the postmen deliver letters, and not to have the least idea of all that language--to be, to every scrap of it, stone blind and dumb! It must be very puzzling to see the good company going to the churches on Sundays, with their books in their hands, and to think (for perhaps Jo does think at odd times) what does it all mean, and if it means anything to anybody, how comes it that it means nothing to me? To be hustled, and jostled, and moved on; and really to feel that it would appear to be perfectly true that I have no business here, or there, or anywhere; and yet to be perplexed by the consideration that I am here somehow, too, and everybody overlooked me until I became the creature that I am! It must be a strange state, not merely to be told that I am scarcely human (as in the case of my offering myself for a witness), but to feel it of my own knowledge all my life! To see the horses, dogs, and cattle go by me and to know that in ignorance I belong to them and not to the superior beings in my shape, whose delicacy I offend! Jo's ideas of a criminal trial, or a judge, or a bishop, or a government, or that inestimable jewel to him (if he only knew it) the Constitution, should be strange! His whole material and immaterial life is wonderfully strange; his death, the strangest thing of all. (16.8-12)
This is kind of an amazing passage. For one brief paragraph, Jo suddenly gets to be the narrator of the novel. Notice how the text switches from talking about Jo in the third person ("Jo lives," "it must be strange to be like Jo") to trying to imagine his inner monologue in the first person ("I have no business here," "I am here somehow"). This isn't really in character, since Jo doesn't really know half these words, but it's pretty startling to suddenly get a glimpse inside Jo's head as he wonders what the point of his life is and thinks about how he's like a dog.