"WHAT IS THERE to say about a 25-year-old girl who died?" A lot.

For gut-churning anguish, unrelenting pain and nearly limitless dramatic potential, few subjects are equal to death at an early age. When Mimi dies at the end of La Boheme, heads bow to weep while spirits soar at Puccini's artistic triumph. In the theater, The Lady from Dubuque by Edward Albee is the most recent in a long line of plays exploring the subject. In films, Bob Fosse's flashy All That Jazz plays on the audience's pity and sadness at the waste of a life cut short, just as Dark Victory did decades earlier.

Novelists are drawn to the subject also, and their work is as varied as their talent. "Oh, Mama, your eyes are so big! And you're so pale. You're sweating." Flaubert's genius lets one witness Madame Bovary's death through her daughter's eyes, as well as through those of other characters; as the focus changes, the reader sees the horror and the ugliness and even the banality of death, all the while remaining close enough to Emma Bovary to share in her final act.

One the other hand, Erich Segal's Love Story is so manipulative that one stamps one's foot in annoyance as the tears start flowing at Jenny's bedside.

But novelists persist in writing about early death. It is a natural, emotional and possibly the ultimate subject. The death in Hilma Wolitzer's Ending is effective because of its human scale and its honest simplicity. That of the main character in John Irving's The World According to Garp is effective because it is not completely on a human scale; rather, Garp is an archetype of a man of our time, and as such he is prey to all the unnatural shocks of our violent era.

The Delphinium Girl, Mark Smith's fifth novel, deals with the death of 36-year-old Sarah Keville, and its effect on her upwardly-mobile, intellectualizing circle of friends. Parts of the book, which takes place around a New Hampshire college town, are beautifully written, well worth reading and quoting: "The visit occurs. Death as whiteness, death as ice. It is on the lawn and weeds, on the vines and leaves. A death that passes, with the first touch of sunlight, from white to black. Death as the black spot. As the white visitor who blackens life. Death, once again, as ice." Parts of the book are interesting.

But the sum of the parts is not a whole. The Delphinium Girl is impressive, but it is not persuasive. Sarah's death is not touching or moving because her life is unconvincing.

For example, Sarah's ambition to grow old and become a grande dame with a salon is unusual for a young woman, and while Smith writes about it at some length, it is never credible. The reader never comprehends nor feels Sarah longing for a flamboyant or elegant old age. The reader is merely told about it. The author's writing is often fine, but it is too calculating, too self-conscious. One feels set up, as if Sarah's longing for a bright future is a novelistic device to contrast with what will be a dark present.

Sarah's husband, Toby, calls her the delphinium girl because her eyes are the color of the flower. But the symbol appears over and over, poking at the reader, demanding attention. "From the beginning his [Toby's] delphiniums had failed. For years now the bed had been plagued by microscopic mites that, like a cancer, turned the blossoms into blackned dwarfs and misshaped the leaves grotesquely." This foreshadowing of Sarah's death is so obvious that it pulls the reader away from the characters. Instead of enhancing the work, it overwhelms it.

The land, the environment and the people in The Delphinium Girl are entwined, and some of Smith's most skillful writing comes when he describes a charactrr in relation to his setting, Dr. Milton Cullenbine, the local curmudgeon who is adicted to both alcohol and barbiturates, is at his greatest ease when closest to nature, wearing a yellow flower in the band of his tennis hat, moving alomst like an English morris dancer. Normally though, he is receiving shock treatments or working as an executive of a chemical factory he founded, and he is nasty, tasteless and one of the better drawn characters in the book.

Beside the delphinium, the novel is strewn with flowers. Cullenbine, one supposes, is columbine. A character named Allen Orlovsky travels a great deal; presumably he is Zebrina pendula, Wandering Jew. But these devices are literary razzmatazz. Technical skill enriches a work with a strong story line and well-drawn characters. For a novel lacking either or both of these attributes, it becomes mere display.

In the world of The Delphinium Girl, a move away from nature is a move toward disaster. A defiled environment puts beauty and even life into peril. The dilettantism of the Keville's circle does the same thing. They dabble in wine, food, antiques. They flitter around art, around worthy causes. One senses that by jumping on bandwagons and leaping off again at whim, by ignoring the claims of humanity and nature, the characters doom themselves.

This is an ambitious book and in part Smith succeeds, for the novel, though complex, is well though-out. But it is often so well thought-out that it leaves no room for spontaneity. There is little that is repulsive or sad or sexual or funny that touches the reader. Instead, one is impressed by Smith's intellectual skills. But one wishes he had written a more human book, one for the individual reader instead of the graduate school seminar. One wants to be able to weep at the los of Sarah Keville, to feel what she and her friends feel. Unfortunately in The Delphinium Girl one understands, but one rarely feels.