TO CARRY OUT the "forbidden experiment" of Roger Shattuck's title would mean isolating a human baby and, after at least an initial provision of sustenance, letting it grow up wild -- without being taught a language and deprived of other sources of civilization -- in order to see what the infant would turn into. Such an experiment would test precisely what constitutes a human being.

A pharaoh, a Holy Roman Emperor and James IV of Scotland are all said to have commanded such investigations, but no reliable findings have come down to us. The nearest case we have, and not a deliberate experiment, is that of the wild boy of Aveyron (later named Victor) who was captured in the woods of southern France in 1800, taken to Paris, and there devotedly educated for five years by a young doctor, Jean-Marc-Gaspard Itard. Although the boy displayed in some respects an admirable power of assimilation, he never learned to speak; he could give no account of his previous existence, nor any assesstment of his changed conditions of life. The course of his training, however, was minutely set out by Itard in two moving memoirs, and in part it has been faithfully portrayed in the beautiful film L'Enfant savage by Francois Truffaut.

It was this film that led Shattuck, a professor of French, to take an interest, some 10 years ago, in this touching episode in the history of humanity. In The Forbidden Experiment his intention is to offer "a straightforward narrative account" of the wild boy. Within its limits, the book comes off perhaps well enough: it provides a chronological description of the events (divided by Itard according to theoretical interests), together with useful incidental materials. Inspired by the intrinsic poignancy of the tale, it makes a convenient introduction to an adventitious but inexhaustibly interesting experiment.

Yet there is something of a puzzle that it should have been put into print. As Robert Darnton has remarked in The New York Review of Books, the case has been studied so often from so many viewpoints that one wonders why a literary scholar should have devoted still another book to it. Moreover, as Shattuck informs us, a French psychiatrist, Thierry Gineste, is shortly to publish, with the aid of many new documents, a radical revision of our understanding of the relationship between Itard and Victor.

As it is, the book is described in the blurb as "authoritative," but no grounds are specified on which it might claim this decisive viture. In fact, Shattuck's own conclusions are few and undecided: e.g., "I cannot help nourishing an unprovable belief that the Wild Boy was . . . functionally retarded by years of deprivation"; "Did the boy have emotions" Was he happy alone in the woods? How can we know?"; or, concerning three theories relating to the boy's condition, "I can only state that none is either proven or disproven." Rather more seriously, the author treats superficially or else passes over a number of matters that have a very considerable interest.

"We never learn," he writes, "whether the boy was right- or left-handed or ambidextrous." It is true that we are not told specifically, but there are evidences which even if contradictory can make an argument: the methodical way the boy shucked beans points to him being right-handed, though on one occasion when he wanted water he tapped the pitcher with his left hand. Then there are the implications of the boy's remarkable sense of order: he would get up from his bed to put a piece of furniture or a utensil, which had been accidentally moved, back into its usual place; and he was even more particular about keeping things hanging on the wall in their correct places. He showed no such concerns when he first lived among humans, and apparently Itard did not deliberately teach it to him, so here is a characteristic that bears directly on questions of animality and latent inclinations. Even more fundamental is the progress of the boy's facility at classification, with the fascination of his operational grasp of similarity and difference, part and whole. And as for the famous incident in which Itard thought to discover in the boy a resentment of "injustice," here too Shattuck's conclusions are rather shallow and vague, not at all matching the seriousness of the issue or the intricacy of the analysis called for.

It is a relief to turn back to the acuity of observation, the scrupulous intelligence, and the warm sympathy of Itard's own accounts. In them we encounter directly the pathos, the philossophical challenge, and the moral quandary posed by the existence of the wild boy of Aveyron. From the pitch of comprehension achieved by Itard, in 1801 and 1806, it is possible to think anew about the appeal of imaginary Victors such as Mowgli and Tarzan -- and also to ponder more effectively the converse cases in which civilized man is cast away into animality. Ironically, in the present context, the fictions of Robinson Crusoe and Michel Tournier's Vendredi perform just the kind of licensed experiments from which a literary scholar might make a real advance in the diagnosis of our conceptions of humanity.