MORE DIE OF HEARTBREAK By Saul Bellow Morrow. 335 pp. $17.95

IT USED to be said you could find every sort of person in American fiction except one: the intellectual. The generalization was never quite true -- what of Poe, Hawthorne, Melville, Henry James? In any case, half a dozen Saul Bellow tales, going as far back as his first novel, Dangling Man (1944), and certainly including The Adventures of Augie March (1953), Herzog (1964) and Humboldt's Gift (1975), might in themselves be cited as refutation of the theory.

Indeed the two main characters in Bellow's newest novel, More Die of Heartbreak, are conspicuously "intellectual" in our usual understanding of that word. Benn Crader is a distinguished botanist. His nephew-confidant Kenneth Trachtenberg, who himself does a good deal of confiding, is a Russian literature scholar. He and Uncle Benn, whose story he narrates, start joking, pondering and haranguing right away. Within the first 50 pages we hear from them, for instance, about a Charles Addams cartoon, Hitchcock movies, Sigmund Freud, plant morphology, Julius Caesar, the pianist Sviatoslav Richter, the natives of Ubangi, Carl Sagan on TV, Bruce Springsteen, Poe's reference to "hyacinth hair," Admiral Byrd's account of Antarctic isolation, Chaplin's Gold Rush, Stalin's labor camps, Kenneth's parents as Paris expatriates, the actor John Carradine, the Russian writers Solzhenitsyn and Sinyavsky, Coleridge's albatross, the acuteness of Balzac, the mysticism of Swedenborg, and so on and so on.

As the list suggests, they do not spend all their time in lab or library. Though based on a midwestern metropolis that is presumably Bellow's own Chicago, they are often on the move -- to Florida, California, Tokyo. Sometimes this motion is a matter of being on the run. Their flights of fancy can turn literal. Both men, in common with several other Bellow characters, have trouble with women. Professor Crader suffers from alluring creatures, rich and beautiful and aggressive, who want to marry him. Nephew Kenneth pines for a woman who has borne him a child but refuses matrimony. Uncle Benn tries to avoid each rendezvous with wedded destiny, Kenneth to set one up.

The two have other worries. In particular they feel victimized by another family member, a real estate tycoon who has done them out of a fair share in the sale of a piece of valuable property. Vilitzer, a vilely indomitable old crook, is a splendid creation. We pay attention to him in part because he too is a vehement talker. It is not only the eggheads in Bellow who have a way with words. Even the family failures, such as Vilitzer's son Fishl, a black sheep vainly striving to be a wolf, are remarkably articulate, and often perceptive. Fishl confesses to feeling that Benn is superior to himself: "He didn't invest his whole life in a struggle with his parents. I meet people of eighty who are still furious over their toilet training, or because their dad wouldn't take them to the ball game. Imagine such an infantile life! . . . A whole life of caca-pipi! . . . I'm typical, still pursuing my father at the age of fifty, hating and loving and begging him to let the prodigal come back. Now I've tried a dozen prodigal careers, each more sensational than the last. Benn had it better. Without thinking twice he stepped out at a higher level."

The quantity of opinionated talkativeness puts you in mind of a typical Bernard Shaw play. But that idea has already occurred to the Speedy Mr. Bellow, who remarks of Benn's father-in-law, Dr. Layamon: "He had a thin, gabby mouth, and when he wasn't speaking he sometimes wore a look of violent primness, like an actor in a Shaw play, forced briefly to listen to the other guy but thinking how he would rip into him in a minute. 'His thing is to punch the fat out of you,' said Benn."

BELLOW DOES however distinguish between the scholars and the wised-up. Benn Crader's absorption in plant life has conferred upon him a serenity that Fishl wistfully envies. His out-of-this-world contemplativeness endows him with an intuitive authority that his nephew calls "the magics." Yet while he is at times a mage he is not always a sage. In encounters with old Vilitzer, Benn's unworldliness can seem muddled and naive. Saul Bellow is always ready to concede that, whether in ancient Babylon or modern Chicago, street-smartness will usually carry you further than erudition. Even in his own realm Uncle Benn can go comically wrong. He gains spiritual sustenance at one point by communing through a glass door with a particularly fine azalea bush -- only to discover that it is an artificial creation, its flowers fashioned from silk.

Critics of Bellow have complained that there is not enough action in his tales, and not much interaction either: his characters usually prefer talking to listening, monologues to dialogues. More Die of Heartbreak does lay itself open to such objections. Some of the observations on the state of post-modern America are tinged with elder-statesman peevishness. Not every bit of conversational epigram works. The book's title, for example, comes from a Benn Crader remark that heartbreak causes more deaths than atomic radiation. Well, true in general, perhaps; but in any case, not really apropos, since the Crader-Vilitzer clan are a pretty resilient bunch. Grumblers might say Bellow gives us the mixture as before, from Seize the Day, Henderson the Rain King, Herzog, Mr. Sammler's Planet, The Dean's December.

That may be so. But what a mixture! Though he is very much his own person, Bellow's fiction has something of the elegance, felicity, exactness and tartness of Vladimir Nabokov, or of John Updike at his best. More Die of Heartbreak moves unhurriedly, yet it does build up a carefully developed momentum. As a novel of ideas it sparkles. The author reminds us of the useful word "kleptocrats" which he credits to the Wall Street Journal -- a term for senior officials for whom theft is a governing rule. Crader nicely describes himself as "a phoenix who runs after arsonists." Bellow has, too, a sharp relish for the skulduggerries of the top-echelon rascals, the princes of "dirty realism." If this is the mixture as before, I for one am grateful and delighted; for Bellow himself is a marvelous blend of mage and wise guy, and his newest book has that special Bellovian quality of hustling lyricism. :: Marcus Cunliffe, University Professor at George Washington University, is the author of "The Literature of the United States."