Little Gemellus had a persistent cough. It seemed to irritate Caligula. "We really must do something about that," he sighs.

halfway through episode nine of "I Claudius," a faithful servant brings Caligula the head of Gemellus. Caligula mutters offhandedly to Claudius, "I cured his cough" . . .

And I turn to look at my children who are staring in horrified glee.

Ah yes, I remember it well, that reckless Sunday several weeks ago, when I said something like, "Come, children, it's time for your weekly hostory lesson via the Public Broadcasting System, compliment s of the BBC.

At time, it was, of course, the proverbial parental kiss of death as I, a masterpiece Theater junkie, tried to introduce two children, age 11 and 13, to "I Claudius."

Groans greeted the first episode's attempts to sort out that hopelessly entwined cast of Romans. But after a few Sundays, my children learned that "I Claudius" could be subtitled, "The Family that slays together, stays together."

There was more gore in one hour in this series than I had allowed in a whole year of TV viewing. Now, asit gets progressively more X-rated, I'm considering banishing them to watch something tame, like " - The Godfather." But this is over fierce protests from my 13-year old who, taking his cue form Alistair Cooke, says it's all historical truth that should not be skirted. I, myself, am hooked, of course, along with a growing band of "I Claudius" freaks who deplore violence - unless, of course, it's tinged with PBS historical significance.

John Hurt, as Caligula, that deranged and deabauched monster, is brilliantly, mincingly, mad. Emperor at 25, he has a long history of frolicsome boyhood - he killed his daddy at 8 and began sleeping with sister Drusilla at 11.

But the more recent onstage gore has me longing for Livia, Claudius' grandmother, who merely did in a dozen or so of her intimates (including two husbands) via poison.

Whenever faced with a plate of something she doesn't like, my 11-year-old has taken to repeating one of Livia's exit lines to Tiberius. After poisoning Emperor Augustus with his favorite fruit Livia said, "by the way, don't touch the figs."

another favorite line to act out is Livia's narrow-eyed rejoinder to stuttering Claudius, "if you don't stop that head from twitching. I'll have it cut off and put on a stick."

Sian Phillips as Livia, was superbly chilling as hse moved from young beauty to old hag, surviving all who tasted her cooking. Derek jacobi as Claudius, limps, stumbles, stutters and twitches so admirably that one Washington politico - watching in awe - said, "I've been recultivating my stutter."

Today, cliques of Claudius followers greet one another at parties, as if giving a secret handshake, jerking the head to one side and using Livia's nickname "Cl-Cl-Clau-Clau." And a 12-year-old daughter of a friend of mine now runs around the house saying, "oh, Zeusie! Oh, Zeusie!" - the pet name for Caligula, who thinks he's Zeus, used by his sister-lover.

The machinations - murders, rape, incest, orgies, untrammeled power plays, you name it - of PBS's Roman EIM.

The 13-part series is fairly faithful to Robert Graves' novel, "I Claudius," give or take some lively embellishments. Livia's diabolical excesses stem from Graves' imagination, scholars feel, but much of "I Claudius" is based on Suetonius' death Suetonius is dismissed by some classicists as an early Leornard Lyons, overly given to recounting court gossip and scandal. But who cares? it plays.