I didn't get this joke ? please help

A young man is sentenced to fifteen years
in prison. The warden
takes a liking to him and puts him in a cell
with a kindly oldtimer
so that he can be shown the ropes and not
get himself in trouble.

So the oldtimer teachs the youngster the
rules of the prison, what
to do, what not to do, stuff like that. One
of the rules he learns
is that there is no talking allowed during
meals.

A curious thing happens during meals
though and the young prisoner
is a bit confused. In the large mess hall,
once everyone is seated,
one of the prisoners stands up and loudly
says, "47." Everyone
in the hall laughs hysterically. A few
minutes later, another
prisoner stands up and loudly says, "19."
Again, a torrent of
laughter from everyone. This goes on
throughout the meal.

Later, when the youngster and the
oldtimer get back to their cell,
the young man asks, "What was going in
the mess hall tonight? I
thought you said there was no talking
allowed."
"Ah, yes, the mess hall. Well years ago,
the warden eased up on
that rule a bit, the one that disallows
talking at meals. You see,
all of us inmates have memorized a long
list of jokes and stories
by the number, so that all one of us has to
do is call out its
number, and, because we have all of the
stories memorized, it's
like someone told the whole funny story."
The young inmate nods understandingly
and falls off to sleep.

After a few weeks of this mealtime
behavior, the young man gets
up a bit of nerve and decides to tell a
story.

So, one evening at the dinner meal, he
stands up and loudly says,
"26." No one laughs. Not even a twitter.
So he tries again, "26."
Still nothing. He sits down sheepishly and
embarrassed.

Later, he pleads with the oldtimer to
explain what happened.
"That is such a good story, number 26, how
come no one laughed."
The old man turned to him and explained,
"It's the way you told it."