What is Holden's fascination with the Museum of Natural History?

Holden's fascination with the museum is that everything always stays the same, except the people that visit. Proof of his fascination is Holden saying "The best thing, though, in that museum was that everything always stayed right were it was. Nobody'd move. You could go there a hundred thousand times, and that Eskimo would still be just finished catching those two fish, the birds would still be on their way south, the deers would still be drinking out of that water hole, with their pretty antlers and their pretty, skinny legs, and that squaw with the naked bosom would still be weaving the same blanket. Nobody'd be different. The only thing that would be different would be you." The purpose of this quote is to emphasize on the point that you would always see the same old museum with the same old stuff in it every time. The statement is important from it being one of the very few things that Holden really enjoys. Since Holden is usually negative and is always complaining about the things around him, the reader gets to experience some joy in him and realize he is not just a negative person. There are very few parts in the book that aren't negative thoughts by Holden, so these parts must be highlighting something important to the reader.