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THERE ARE enough Americans living in exile nowadays that one more won't make much difference, I suppose. But S. J. Perelman's recently announced move to England should be a real cause for distress, if only for what it says about America's sense of humor. It's not just the violence, he says, it's the way the violence fills up the newspapers and doesn't leave any room for his stock in trade: the bizarre, the eccentric, and the unusual. England, he thinks, will be better. I hope he's right. I doubt it.

For more than forty years S. J. Perelman has been writing some of the funniest things in English. He was a scriptwriter in Hollywood in the early thirties, and was responsible for some of the Marx Brothers' best films. In 1956 he won the N. Y. Film Critics' Award for the script of Around the World in 80 Days. Meanwhile he had found his niche in the New Yorker, writing the short, uncategorizable comic pieces which gave him his reputation, and thirty-two of which constitute Baby, it's Cold Inside. These pieces rely not so much on characters or situations but on the comic possibilities of words themselves. Perelman is a master of a bewildering array of trite and overused literary styles, and has a vocabulary the size of Webster's Unabridged. Above all, he knows precisely when to use the obscure word, the foreign phrase, or the outlandish simile for maximum effect.

Baby, it's Cold Inside is good but not great Perelman. Some of the pieces are hugely funny, but many seem a trifle flat, lacking the sudden explosion of unexpected phrases that makes much of his prose so spectacular. Perhaps America was getting him down as he wrote these pieces, dampening his usually exuberant imagination with a little too much harsh reality.

When his style is working, though, Perelman can be so funny it's almost awe-inspiring. What can one say about the words he sprinkles through the book, always in impeccably proper context: words like dyspnea, archimandrite, steatopygous, and eisteddfod? And what would Dickens have given to use this description of a bellhop at an old Hollywood hotel: "a stoop-shouldered, overworked wraith with an air of patient resignation like that of Zasu Pitts." Perelman is making a pass at a beautiful colleen (all his women are beautiful but for lips or nostrils that are a trifle too sensuous, a figure a shade too voluptuous) and: "I was just about to propose that we hie ourselves to a tumbledown shack in Athlone when a behemoth the size of Brian Boru, a great loogan with ropes around his corduroys, clumped into the snug." Her fiance, Rory McClobber.

PERELMAN'S subjects range from reminiscences of the Marx Brothers to an encounter with a singing lady dentist who plants a radio transmitter in his incisor and calls him up when she hears him eating a forbidden bagel ("Lock Lips-Monkey-shines in the Bridgework"). Very rarely does he have any real satiric intentions. In one piece, though, "Let a Snarl Be Your Umbrella," there is a hint of very good-natured satire. Perelman finds himself ignored, insulted, and humiliated by a series of British clerks, in what appears to be a conspiracy to make the customer suffer. He discovers by accident that it is all the work of a company called "Creative Humiliation Associates, Ltd.," which teaches clerks how to "protect" themselves from the customers. "Well, we teach em the dynamics," the manager explains, "woolgathering, disdain, the snub direct and implied, Schadenfreude, the mechanics of sniggering, simple and compound exacerbation-the lot." But all is not lost-they're planning a course for customers as well.

In a piece entitled "Anna Trivia Pluralized," Perelman, on a trip to Ireland, is beset on all sides by people trying to sell him the same anecdote about a "prosaic old codger" who wonders whatever happened to old John Joyce's son Jim-the one that went to the Jesuit College at Clongowes. Perelman is able to resist this fabulous literary nugget, but he overhears a professor smugly telling his wife Chlorine that it was worth the hundred dollars he had paid for it: "It throws Joyce's youth into a wholly new perspective, crystallizing in a phrase, as it does, the denigration of his coevals."

The masterpiece of the book is an eight-page epic called "Thunder Under the Kalahari" or, Aliquid Novi ex Botswana? Prefaced by an item in the London Times about the discovery of truffles in the Kalahari desert and the possible resulting boost to the economy of Botswana (the former Bechuanaland), it's a tale of intrigue, adventure, and romance. Perelman is ensconced in the Mushmouth Arms, Bexhill-on-Sea, knowing that it is at this type of dreary seaside resort that one runs into an eccentric fellow guest who imparts some remarkable tale. Sure enough, he finds a strange old man there named Monk Hesseltine who quivers at the mention of Bechuanaland and turns white at the sight of a truffle. When Hesseltine is murdered by a poisoned arrow, Perelman becomes involved in his mysterious past at the behest of Hesseltine's beauteous neice, Cosima. Needless to say, Perelman solves the mystery, which involves vengeful Bushmen and blackmail of the French truffle industry, and gets the beautiful Cosima.

Not all of Baby, it's Cold Inside is of that quality. But in a country of Bob Hope and Lucille Ball and Alan King, S. J. Perelman is a humorist worth keeping.