BOOK REVIEW : Short Stories’ Leaps of Originality End as Often in Pratfalls as in Flight : LIPSTICK ON THE HOST, <i> by Aidan Mathews</i> ; Harcourt Brace, $21.95, 307 pages

The Irish writer Aidan Mathews is 36 or 37, but there is a suggestion of mad precocity in his writing: all fluttering wings and less in the way of legs. The six short stories collected in “Lipstick on the Host” possess many shining and original moments along with a tendency to fall flat, like a dancer whose jetes are splendid and whose ankles buckle when he lands.

Mathews’ protagonists are innocents, victims and in some fashion saintly. They are, variously, children, an old priest out of tune with modern times, a fiercely intelligent spinster who falls tardily in love and--in two of the stories--animals. Out of the mouths of these babes comes a disconcerting stream of images that are by turns scintillating, gnomic, sentimental and arch.

Do you want to be a pilot? the flight attendant asks the visibly unhappy little boy whose parents have sent him from Ireland for a stay with a German family. “No,” he tells her. “I want to be a Jew.” Nothing bad has ever happened to Timmy, but the more sheltered the child, the more vulnerable to rumors of the world’s evil.

Timmy has heard about the concentration camps and they haunt his visit. His German hostess’s gold fillings remind him of those taken from the Jews; her son’s model railroad reminds him of the tracks they rode along to Auschwitz. The Allies were at fault for not bombing those tracks, Timmy’s father explained, seeking to reassure him that all the evil was not on one side. It only makes Timmy see evil everywhere; even in the smell of his hosts’ soup: “The food was unintelligible.”

To this point, “Tracks” is an affecting sketch. But the author carries things further, with a dismayingly graphic account of Timmy’s constipation and of the lengths it leads him to. Suddenly we are in a fecal nightmare.

A similar scene--almost every story has images of feces, pus, vomit or, in one case, a mother who peels her sunburned skin and drapes the strips over the wastebasket--comes at the end of “Elephant Bread and the Last Battle.” Another little boy, entranced by the charm and sympathy of a shiftless family friend on a vacation at the Riviera, conducts a kind of protest against his parents’ disparaging remarks. He guides his pedal-boat into the effluent discharge of a sewer pipe and fills the water bottle his friend gave him.

In both these stories, an initially sensitive portrait is overborne by the author’s intervention, which gilds it until the portrait becomes a gilt mask. Mathews wields a penetrating light, but in his mannerisms and extremes he seems anxious that we remark the light rather than what it may reveal.

The two animal stories suffer particularly from this. One is narrated by the ass who carried Christ into Jerusalem; the other is told by a lamb delivered in a crate at the Last Supper. There are some witty lines--notably, the lamb’s complaint at being enlisted in the Gospels as a metaphor as well as food--but they represent Mathews, not the animals, being witty. And overwhelmingly sententious.

His portrait of a retired African missionary who lives uncomfortably in the order’s chapter-house with his young, up-to-date colleagues is considerably more successful. Father Basil, who genuinely believes in the power of prayer, who suspects a miracle when his potted plant moves at night, and who lies in wait with a tennis racket to bash nocturnal mice, is a genuinely appealing character. He has something of the quality of old Crouchback in Evelyn Waugh’s war trilogy.

Once or twice, “Moonlight the Chambermaid” goes rather soft, but it has some splendid passages. A self-absorbed young couple who briefly befriend Father Basil is particularly well done; when the wife stomped off to the kitchen in a huff, “she made less noise than was strictly necessary.” Father Basil’s collapse, while walking with their little daughter, is stunning. “He swung from God the Father’s hand like a boy in a plum tree.”

The title story is the strongest. A sharp-tongued 41-year-old schoolteacher has a brief, blinding affair with a middle-age doctor. The plot is melodramatic--he dies almost as soon as they meet--but the voice she uses and the sensibility she displays are unforgettable.

She has the anger of a national frustration, a scorn at the role women still play in Ireland. She denounces the unfairness of a fixed examination date for her girls: one-quarter of them will be menstruating at any one time. “How would you fancy writing half an exam-book on ‘Paradise Lost’ if you were passing kidney stones?” she demands of the principal.

Meggie is a wild spirit confined and fighting free with disconcerting intelligence. She rages against her lover’s death and bleakly gets hold of herself, preparing to return to her classes after a day off. “And I must make an appearance,” she tells herself. “Because, if I go on making an appearance, each morning, every morning, I may someday make a reality.”

The line is indelible; the next line streaks: “If I try to be on time for my appointments, perhaps I will be late for my disappointments.” Somewhere between those two lines the greatly gifted Mathews loses confidence in his gifts.