In The Wind in the Willows, Kenneth Grahame's magisterial work, the first half of the book is mostly given over to the adventures of Mole and Ratty (although we are introduced to Badger and Mr. Toad). It ends quietly in chapter 5 (Dulce Domum), with Mole (accompanied by Ratty) finding his old and long-neglected home.
The second half of the book, quite rightly, deals with the amazing (and I suspect highly embellished) adventures of Mr. Toad, of which I am sure you are entirely familiar. However, embedded in these stories are two highly reflective chapters, The Piper at the Gates of Dawn and Wayfarers All.
Chapter 7 (The Piper at the Gates of Dawn) deals with Mole and Ratty's frantic search for Otter's missing son, Portly. They eventually find him on an island, sleeping at the feet of the demigod, Pan, who Grahame personifies as the protector of animals, and they give him due worship. This indicates that the animals follow a far more ancient religion than the Christianity hinted at in chapter 5 (Dulce Domum). Ratty is thoroughly taken up with the experience, so Mole rows him and Portly back home.
Chapter 9 (Wayfarers All), deals with Ratty's restlessness, and his desire to expand his horizons, and explore a world of which he has little knowledge. He chances on another rat (a true rat, rather than a water vole), and they strike up a conversation. The rat is actually a sailor who has decided to give up the sea and settle down, but he regales Ratty with tales of far-off lands, and Ratty decides that this is the very life for him, and tries to abandon his home (and his friend) and take to the sea. Fortunately, Mole realises that something is wrong and manages to rescue him from his mania.
Now, what are these chapters for? Why did Grahame write them? Are they just intermezzi in a three-act comic opera about Toad, or is there some other significance? As a child, I found The Piper at the Gates of Dawn utterly enchanting, but Wayfarers All bored me, and I usually skipped it. Now that I am well into my middle-age, I can see the relevance of it, and I wish that I had been more adventurous in my youth, but when I was a child, its meaning was lost on me, so what is it doing in a book intended for children?
A related (and perhaps more important) question is: are there any parallels in adult fiction, preferably (but not necessarily) pre-dating this book (first published in 1908)? If so, what purpose do they serve, apart from providing a counterpoint to more exciting chapters?