WRITERS, D.H. Lawrence once pointed out, should be scrupulously ignored when they stop making their art and start talking about it. "The artist is a damned liar," he wrote adding, "Never trust the artist. Trust the tale." Lawrence, of course, was right. When a Dick Cavett coaxes a writer in front of the camera for a half-hour of high gossip, the writer often turns into a sly little prevaricator. Or when a Herbert Mitgang lets an author expatriate about his oeuvre in balanced prose you know no one speaks in... Writers should not be invited to "ideal" dinner parties. They ought to stay home and write.

Of course, there are a few writers who merited dispensations allowing them to appear in public. One was S.J. Perelman, the sort of writer one would want to spend not an hour or two but a few days with. The point of meeting Perelman would, however, not be to find out whether that redoubtable wit could drop a line or two over breakfast like those he penned for the Marx Brothers, nor to determine if he poured forth in conversation the astonishing, almost Nabokovian, word-play that runs through his myriad of New Yorker stories. Perelman would certainly have proven disappointing on these counts--no one could do off the cuff what he so meticulously crafted. Instead, one would meet Perelman to find out one thing--How much of that literary schmendrick persona that appears over and over again in his stories was him?

And it is quite a persona. Whether the name is Kluckhorn, Perlmutter, or Ginsberg, the same character resurfaces. He is a semi-suave ectomorph who will chase any nubile starlet, whether it requires a descent into a sea of polyester leisure suits at the Americana Hotel or a lengthy sojourn in a Ukrainian cafeteria in the east twenties. Though craven in the utmost, he dashes off to Djibouti or Jakarta at a moments notice, spewing out words along the way like "henbane," "anchor," "parlous," "jardiniere" as well as an occasional "zounds" or "sweet-patootie". A cultural sponge that oozes erudition and arcana, he recalls Yeats in the same breath that he expounds on an ancient tooth powder advertisement. No matter what guise he shows up in, Perelman's persona is a curious mixture of gallic pride, English cynicism, and mostly, Yiddish fatalism. He is a foil who ventures quixotically into the world and then returns, each time, to testify that it is far more looney than he is.

Perelman died two years ago, so until some biographer turns him into academic chopped liver, it is going to be hard to tell how much of the Perelman persona was Perelman himself. Until then, the only thing to go on is the 45-page autobiographical fragment "The Hindsight Saga," in the posthumous opus The Last Laugh which Perelman's publisher and executor have just produced. Concentrating on Perelman's early years in Hollywood, where he worked on the screenplays for the Marx Brother's Monkey Business and Horse Feathers and on a number of other comedies, it reveals a Perelman considerably less impulsive and a bit more socially adept than his fictional alter ego. Beyond this however, The Hindsight Saga offers little. Perelman relates his experiences with a number of the celebrities of the day, but, with the exception of a terrific anecdote about Dashiell Hammett, these are lackluster. Most of the characters don't even have the fresh madness of Perelman's fictional figures.

As for the rest of The Last Laugh, it is, unfortunately, low grade Perelman. For the last few years of his life, his writing lacked much of the snap that distinguished such earlier collections as Crazy Like a Fox and The Road to Miltdown. The writing in the last volume he published while alive, Eastward Ha! was somehow less densely funny, less wildly allusive than it had been before. The pieces in The Last Laugh, all of which originally appeared in The New Yorker, represent more of the same. In these last stories Perelman drifts more and more into a cosmic nostalgia which he fails to connect to anything relevant to non-octagenarian readers, Stories like And Then the Whining Schoolboy With His Satchel, in which the 15-year-old Perelmanesque character finds himself accused for plagiarizing Cooper, Kipling, Stevenson. The Riders of the Purple Sage and half a dozen other works in an autobiographical essay for a tenth grade class, makes it pretty far across the historical gulf. The scenario is ticklish and one need not have a turn-of-the-century birth certificate to appreciate it. Another, Wanted--Short or Long Respite by Former Cineaste, a meandering through some silent film memories, just doesn't make the leap, though. And, unfortunately, there are several others which fall in like manner.

GREAT LINES still abound, of course. Anyone who could construct the following commentary on Proust obviously had not lost it all. "In Steinberg's judgement--and he buttresses it with a formidable array of interior evidence from the work--Proust's Madeleine was in reality a matzo ball, and the past unfolded itself to the Master as he sat hunched over a bowl of chicken soup in Flambaum's, the famous kosher restaurant in Paris..." And, almost invariably, the Perelman opening moves are as fine as always. For example, the beginning of "All Precincts Beware--Pater Tigress Loose" is a vintage piece--" Saturnine, Tweedy Gabe Hammerschlag, head of N.Y.P.D.'s Confidence Detail, struck a match on his desk top and, sucking the flame into the bowl of his pipe, eyed me meditatively. Gabe and I had known each other ever since 1953, when I had helped him straighten out a rather nasty copyright mess among the Kachins of Northern Burma, and I knew that when Hammerschlag sucked flame meditatively into his bowl the unexpected could be expected."

Yet somehow, things loosen up along the way. The jokes flow less smoothly and one's attention wanes as the story progresses. In his best work, Perelman's words crowd together on the page and jab at you continually. Here they seem to spread out and sit more complacently. It is a shame that in our last glimpse of this fine writer, he is not at his best.