Come Friday next, it will be the 50th anniversary of the day that President John F. Kennedy was assassinated. Half a century. That's what we've had to get accustomed to this idea. And so much has been written, so much thought given to the event and the consequences that one would think that everything there is to say has been said.

But after all this time, after all the "Where were you whens?" and "What I was doing when I heards," we need to remember that there are two generations who have no such memories, only questions. Those questions reflect an essential lesson of history, which is — in Shakespeare's words — "What's past is prologue."

Some of what we have become as a society and a nation began that morning in Dallas. We remember. We listen to those who remember. And we learn.

If you are John Purroy, your memories are typed in purple ink on scraps of yellow paper that your wife, Teresa de la O, found in a manila folder that had spent several years in a storage unit.

John, a retired reporter and editor for The Press Democrat, was working the wire desk that morning. His mementoes are a few of the scores of teletypes received from the wire services that day. The most dramatic among them has just three words:

" — — FLASH


Beside it, written in pencil, in an editor's scrawl, the letter B — for bulletin, the "hold-everything" term that set the bells ringing on the Teletype machines.

Diane Morgan, then a young reporter, remembers Purroy's ashen look. She also recalls that the news editor, Dick Torkelson, took the paper from his hand and said, "Bulletin, hell! We've gotta hold the press!"

It was just the first of many press stoppages that day. The PD was an afternoon paper then and the front page already was in type when the first "SHOTS FIRED" message came through. It was replated many times before the day was done.

These were "hot lead" times. Purroy's bulletin would be handed to a Linotype machine operator who would produce lines of type to be placed by hand in a page frame that was still two full steps from the press.<NO1><NO>

As the terrible news came in small servings, and the photos — of Jackie cradling her wounded husband's head, of the Secret Service agent climbing on the back of the car, of the blood-stained pink dress, of Oswald's arrest, of the grim swearing-in ceremony aboard the plane — the PD staff, like journalists everywhere, struggled to get the next "EXTRA" on the street.

Hearing the stories today, in this age of Twitter and tweets, they sound almost medieval.<NO1><NO> It's not only the way today's news is broadcast, but in other, subtler ways, which young people can't comprehend and even some older ones have forgotten — the clack of typewriters, that persistent bell in the wire room that announced the next news flash, the astonishingly primitive methods. One example is found in a memoir Sheri Graves has written about that day. Sheri, a reporter for the PD who retired in 2004, was a 19-year-old "copy boy" whose assigned task, when the first bulletins appeared, was to go next door to Montgomery Wards (where the parking lot is today just south of The Press Democrat)<NO1><NO> to watch television and use the furniture department telephone to call the newsroom and tell the editors what she saw. There were no TVs in newsrooms. It had never occurred to anyone that it was necessary.

Finally, Diane Morgan and Graves were sent into the streets to interview people, bringing the first word to many in the lunch-hour crowd. "People were numb. It was like it was some kind of a nightmare," Morgan said.

In San Francisco, a Chronicle reporter named Keith Power, now a Healdsburg resident, also was on the street. As a rookie, he was the Chron's "Question Man," and he had started his day with one of those titillating inquiries for the-man-on-the-street that the Chronicle specialized in those days.

"I think it was something like "What part of the pajamas do you wear, top or bottom?" Power recalls. "When I heard the news, I changed the question."

One man he asked for reaction, a ship scheduler from Hunters Point, said: "This is something you don't get over." He was right.

Patrick Rattigan was at my house that afternoon. Pat, who was 5, and his brother Tim, who was 3, had come to help our daughter Suzanne, who was 2 that day, eat her birthday cake and teach her the proper way to ride her new tricycle.

Pat doesn't remember that, although he does have faint recollections of watching the funeral procession on a black-and-white television with his family sitting around.

I remember that birthday party all too well. Pat's mother and I sat in near silence. We had said it all at the start, now we waited for the party to end, to get back in front of the television and share in the national grief. I certainly remember being stopped in my tracks several hours earlier by the "We interrupt this program" in the middle of Suzi's Mickey Mouse Club.

There is a word that jumps out at you in the old news stories, in the quotes from the street, and in the memories of those sad days. The word is "disbelief." A repeated theme is disbelief. How many times has the phrase "We couldn't believe it?" been repeated since. Or "We didn't think it could happen here."

Why were we so shocked and surprised? Three other presidents had been assassinated. And there had been attempts on four others earlier, including FDR and Truman. But remember, we were in "Camelot," a favored place.

In a column I wrote at the time, I pondered the term "nation," wondering if it can mean "175 million people reacting as one, crying out in one voice?" What I wonder now is: can we still react with one voice?

Is there anything that would be greeted with such disbelief today? So much has happened since — Bobby Kennedy, Martin Luther King, Oklahoma City, the World Trade Center, airplanes blown out of the sky, mass shootings. What would it take, in our world of interplanetary warfare and zombies, to shock us the way JFK's assassination did?

Was that day in 1963 the day we began to change as a society and a nation? I think it was Pat Rattigan, in our conversation this week, who said that the event "tore the door off our innocence."

So why do we need to remember? Because "What's past is prologue."