By Leslie Epstein

Houghton Mifflin. 419 pp. $19.95

LESLIE EPSTEIN's first-person pastiche of the Gold Rush western may test the patience of people who shy away from a genre we inevitably associate with the "Gun- smoke" kitsch of Hollywood movies and pulp bestsellers. For most of us, westerns are, at best, potboilers by mercenary hacks, the sort of commercial trash we are willing to take seriously only if authors give us sly assurances that they are in fact mocking and subverting their material.

It is to Epstein's credit that he refuses to give us this requisite apology of irony, of the knowing wink. Instead, he unselfconsciously indulges in the excitement of the narrative possibilities of this sprawlingly picaresque story. Admittedly, a degree of self-ironizing does go on here, but only as a result of the hero's exuberant optimism, which is continually ricocheting off of the uncooperative realities of the California gold fields. A Hungarian Jew, a quixotic empiricist, a passionate believer in the inductive method and a former student at Harvard Medical College, Adolf Pinto casts his lot with the '49-ers and the Modoc Indians of a small mining community, whose lives he attempts to improve by means of science. The most gripping incidents in the book revolve around the medical antics of this naive meliorist who sets himself up as the mentor of the book's "sons," the Modoc children he teaches to read with the sole available text, the collected poems of Robert Burns, which soon infect the speech of the young braves with a hilariously incongruous Scottish brogue. In the course of this episodic series of trials and errors (with the emphasis squarely on errors), Pinto blunders upon the discovery of ether, a cure for rabies and the invention of the modern machine gun, all of which are described in rich and believable detail. Epstein is at once sensitive to the attendant absurdities of his protagonist's unsuccessful quest for truth, and sincerely and affectingly respectful of the aims of this committed rationalist, who remains undeterred in his attempts to eliminate human suffering in the face of the agonizing defeats of his botched experiments.

In the hands of another novelist, Pinto's scientific proselytizing would have been too cerebral, too pedantic to generate any narrative interest, but Epstein thwarts all of his character's schemes at the crucial moment of their realization. This basic tension between Pinto's tenacity and the almost inevitable failure of his plans is made all the more vivid by Epstein's signature style of fiendish, unsparing morbidity, of chilling nonchalance before many of the novel's unspeakably grotesque episodes. At his best, in scenes like the Zolaesque collapse of the gold mine or the rampage of a rabid dog through the streets of the settlement, he writes with remorseless authenticity, troweling on macabre details about amputations and accidents: bodies that plummet down the shaft of the mine, splintering into pieces as they carom off the timbering on the walls, or the grisly fishing expeditions Pinto is forced to make for a Harvard anatomy instructor in the murky waters of the Charles River, which teems with the tubercular corpses that Massachusetts General Hospital jettisons from its morgue. The imperturbability of Epstein's ghoulishness transforms the book into a kind of hymn to the body in all its imperfections, disfigurements, and maladies.

Pinto and Sons is the sort of book whose seamlessly consecutive narrative, written in prose that seems to exist for the sake of its rambunctious verbs, has been designed not simply to be read but devoured. In fact, the one significant drawback to Epstein's storytelling lies in an excess rather than an absence of virtuosity: He piles up events in too rapid succession, careening from episode to episode with headlong recklessness, from amputation to epidemic to mining disaster to drought to battle to public execution. Moreover, his swashbuckling style relies too heavily on the volleys of frenzied exclamations that greet each event, the clamor of vacant expletives that assault us at every major juncture, as in the following passage in which Pinto discovers that his comrades have been cannibalized by the natives:

"Dead, then? Worse than dead: murdered! Butchered by this roving band. Half swooning, with a chill sweat on my skin, I looked at the savage faces. How sharp, how strong their teeth. How fierce the warpaint . . . Eaten! Devoured by the cannibal tribe!"

At times, this fresh and original novel about a subject we have long since mothballed in genre fiction seems to want to summon up with interjections of the picture-my-horror variety the excitement and sense of urgency its events are usually fully capable of summoning up by themselves.

Daniel Harris is a book reviewer and essayist whose work has appeared in the Nation, Salamagundi and the Antioch Review.