Why are the carrousel ride at the end of the book and the Museum of Natural History so important to Holden?

The
visit to the Museum of Natural History is brief and of no special importance toexcept possibly
to remind him that he is no longer a child and no longer frightened or impressed by the mummies
and other ancient artifacts. He is just killing time. The carousel is a different matter. He
doesnt ride on it himself because he realizes he is too old to get much...