Line 13 seems to be the takeaway point of all the weird stuff we've just seen. The librarian just doesn't get any of it.
But here's a question: what's the significance of the "outside" party being represented by a librarian? Yes, the speaker is eating poetry, so he's presumably in a library with librarians, but is there something else going on here?
Maybe besides being an outsider, the librarian is also symbol of the types of bookish people who study things, but who don't really get the lived experience of the real world that's around them. Likewise, they don't get the weird people that live in the real world. (Check out "Symbols, Imagery, and Wordplay" for more.)
And again, when we think of anyone's personal experience of joy, darkness, or anything else, we understand that those outside parties will never fully grasp that individual's experience.
So the only thing left to say is "she does not understand." Period.
When I get on my knees and lick her hand, she screams.
Hmm—we get some more weird stuff here. Is the speaker suddenly one of the burning dogs? Did all that eating of poetry transform him into some kind of mutant dog-man?
It's possible—remember that this is Poetry Land. But one thing we can say for sure is that a transformation has occurred in conjunction with the shifting mood we just saw.
So the speaker is licking the librarian's hand like a dog and, of course, the librarian doesn't get that either. So she screams. That seems natural, right?
On top of not understanding, the librarian is also a little frightened of the poetry eating and now our dog-man speaker.
And we think she's got good reason to be frightened.
But what's really going on here? There are a number of things to consider. First, let's take into consideration the fact that joy and darkness are being portrayed here in a constant state of flux with one transitioning into the other.
And those who aren't part of the immediate experience, like the librarian, are unable to understand and also a little frightened by what they see from an outsider's perspective.
Alternatively, if we think more specifically about the experience of reading poetry, we understand that readers will have different experiences and reactions to particular poems. There's no static way of reading anything.
For our purposes, the poetry eating dog-man speaker may represent the transformations that can occur for the individual reading poetry. Only here the effect is magnified in the matter-of-fact, physical, doggy transformation that we see. Good boy, speaker. Sit.