IF THE violence that movie screenwriters have done to popular books sometimes hints of sadism, then Terry Southern is currently playing out a textbook case of masochism. For reasons known only to himself. Joe McGrath, and Peter Sellers (his two collaborators on the screenplay), Southern has reduced his stingingly satirical novelette, The Magic Christian, to a cinematic monument of horedom and banality.

The pointless liberties that Southern takes with his own book make the movie adaptation as unrecognizable as it is unbearable. The book's humor generated from its non-hero, a round little gnome named Guy Grand who indulged in marginal lunacies to relieve the boredom of his billionaire empire. Southern wryly drew the bead on the linearity and arid dullness that typify the lives of everyday Americans by dropping a rich nut in their midst.

Any similarity between the middle-aged child of the book and the Sir Guy Grand that Southern brings to the screen is purely coincidental. Sir Guy, an erudite industrial magnate with Oxford diction and an aristocrat's locked jaw, gets his slightly malicious kicks by showing, over and over again, that men chase money. In one of the very first scenes, Sir Guy gives a traffic bobby 500 pounds for eating the parking ticket so that he can smugly pronounce that "every man has his price." The rest of the movie consists of various anecdotal restatements of that same theme until we finally get to watch prim London businessmen wallowing in an immense vat of shit, blood, and piss that Grand has built and stocked with 100 pound notes. Just for the sake of chaos, these didactic little vignettes are interspersed with anomalous sight-gags that, like Grand's hobby, are never worth the pains it takes to set them up. Grand hunts ducks, for example, with tank artillery, and-funny, impetuous man!-roasts them where they drop with army flame-throwers.

Without its plush outdoor landscapes, the movie would be almost indistinguishable from a particularly disastrous Laugh-In. The choppiness of the action could be excused as it precludes a continuous plot-line, which is also absent in the book. But the minimal transitions that are attempted lack the barest suggestion of originality. It just so happens, for instance, that Grand is an avid TV-watcher, and his propensity to change channels lets Southern smuggle in random bits about a disguised puma that eats its competition at a silk-stocking New York dog show and two gnarled heavyweight contenders who prance to the center of the ring, embrace, and writhe down to the canvas moaning passionately. And the cruise aboard the Magic Christian pleasure liner inexplicably disintegrates into a freak orgy that gives werewolves, midgets, body-cultists, and gorillas the opportunity to mug out a few giggles from the bored audience.

DIRECTOR Joe McGrath's cast represents a careless compromise between faulty characterization and movie-mag exploitation. The choice of Peter Sellers as Sir Guy is bad enough without making him as much like David Niven as was humanly possible. One suspects that Niven wasn't cast only because Sellers has more experience delivering inane lines. Sellers tries to invest his practical jokes with a little humor by varying his voice, letting it range all the way from aristocratic nasality to extreme aristocratic nasality.

And while we are on the subject of nasality, let it be said that the use of Ringo Start is a barren promotional gimmick. His role (Youngman Grand, Sir Guy's adopted son) was contrived expressly for the movie version and is superfluous from beginning to end. The same puppy-dog non-acting that complements flashiness so well in Hard Day's Night and Help is sheer stupidity (which is not inappropriate) in Magic Christian. The only thing cheaper than Ringo's name on the theatre marquee is Raquel Weich's above it. Her lucrative, careermaking breasts quivered expressively throughout her fifteen-second role as an Amazon whip-mistress. The role, needless to say, also has no relation to Southern's original satire.

The Magic Christian's promoters have topped their competition in substituting flesh (whether on Raquel's chest or Ringo's face) for substance. But if you'd like to get what the movie has to offer before it comes to TV (no more than a year), just drop a dime into a public urinal and watch someone dig it out.