"Out of the nursery, into the college, and then back into the nursery". What does this quote from Fahrenheit 451 mean??

This is a quote spoken by Beatty toward the end of the first part of the book.  He says this when he is talking to Montag on the day that Montag decided to stay home from work because he was sick.  Beatty knows that Montag's belief in the system is wavering and he is trying to let Montag see the logic behind their current society's ways.  The specific quote is part of his explanation of how people are educated in their society.  He means that people are given such small bits of true literature and education and they are passed through the educational system quickly and efficiently with no real emphasis or concern about whether or not the students are learning anything of value.  Once through with college, the students aren't really any smarter, more aware, or enlightened than they were when they started out in nursery school.  Furthermore, the government has taken over the job of deciding what is to be taught and parents are essentially out of the loop.