Catcher in the Rye- Allusion and Symbolism

The Catcher in the Rye
by J.D. Salinger
pgs 156-214

Earlier on in the novel, Holden hears a boy singing a little tune, and it gets stuck in his head and he keeps thinking about it.  Holden mentions it later to Phoebe when she asks him if he really likes anything a lot.  "'You know that song, 'If a body catch a body comin through the rye? ...What I have to do, I have to catch everybody if they start to go over the cliff...'" (Salinger, 173)
This quote alludes to a poem by Robert Burns, and it shows a lot about how Holden feels about himself and the affects of maturation on others.  I believe that the cliff Holden refers to is symbolic of the crossing over from youth into adulthood.  Holden as the catcher in the rye shows how Holden views himself as fitting in more with younger children, and also how he wants to save them from adulthood.  Holden is not having an easy time being grown up, and he wants to save other children from turning out like him- immature and confused in a very grown up and lonely world.  The cliff imagery is quite harsh- Holden views the transition from childhood to adulthood is a long and painful one.  And as Holden is still present in the rye, Holden himself has not truly grown up yet.
The rye is an innocent and cheerful place, with "all these kids playing some game" (Salinger, 173).  The cliff is the scary end to the rye, which is childhood.  What would make Holden the happiest is saving other children from the trauma he had to endure from growing old too fast and not fitting in in a mature world.
This points to the primary internal conflict of the story and indicates why the book is named after this poem: Holden grew up to fast and is still partly stuck in childhood; he is an immature boy forced into a mature world.