When Christmas lights wink on in this Lancaster County community, they're more often in the stores than in the homes. Here in the heart of Amish country, the seasonal glut of gifts and glitter so ingrained in the American spirit is still largely an alien force.

For the "plain people," who whenever possible shun autos, electricity and other aspects of modern life, even the colors of Christmas are looked on as a worldly excess.

"I like to see the Christmas lights . . . they make me happy." said Katie Fisher, a mother of eight who has lived all her life in the long dark dress and apron of the Amish woman. "But I never longed for it. I wasn't born to it. I guess it's just not for me."

For Katie Fisher and most of the 10,000 Old Order Amish in Lancaster County, Christmas is a religious holiday with no church service, a family reunion with few gifts, a feast without wine, a seasonal observance shorn of ever-green and holly.

On Christmas Eve she places a plate bearing nuts and fruit at each child's place at the dining room table, and possibly presents a simple toy to one or two of the youngest.

Occasionally, she says, Amish adults may exchange a gift - "usually an article of clothing or something that's needed. - But that isn't done to much," she say. "Most of us have large families and there just isn't money for such things."

Christmas, of course, comes anyway, creeping over the snow-dusted farm fields and silos of south-central Pennsylvania with all the hope and promise of ages past.

For the Amish, whose Anabaptist ancestors fled Zurich in the 17th century to escape religious persecution, it is a holiday pregnant with the same seriousness with which they view much of life itself.

There will be caroling and some seasonal treats - including, in the Fisher family, a red, white and green gelatin dish called Christmas salad.

But though there will be prayers, there will likely be no church service. Old Order Amish have no churches and hold religious services in members' homes only every other Sunday. And for most Amish districts in the county, last week was church week.

Christmas, moreover, is tied closely with the family traditions on which much of the Amish way of life is based. Many families gather together for the day with even more perserverance than their non-plain counterparts. An Amish family Christmas dinner may easily include 100 people, and the roads of the county are usually crowded on Christmas Day with Amish buggis packed with bearded men in broad-brimmed hats and their aproned wives and daughters and white-shirted sons.

For many years the Fishers traveled on Christmas to her family's place in Georgetown, 11 miles and an hour's buggy ride away.

"Sometimes I think a car might be nice - to get in and go someplace in a hurry," said Katie Fisher. "But if you've got a team (of horses and a buggy) you can't rush and so you see things along the way."

In her childhood, she remembers, there was a sleigh in which she rode, quite literally, over the river and through the woods to her grandmother's house on Christmas, and sleighs are still a common sight on the roads of Lancaster County when it snows.

But such accoutrements of agrarian life are growing rarer, due in part to the exploding population of the Amish themselves, which has made the family farm an increasingly scarce and high-priced commodity.

"We would love to have a farm, but who can afford one nowadays?" said Katie Fisher. Her husband, a cabinet-maker, took up his craft as one of the alternative livelihoods available.

The economics of the plain way of life causes other compromises with the Amish ideal. Traditionally for example, young people have courted only in open-sided carriages "so God and the world is their chaperone."

The price of carriages, however, has led some young swains to begin adult life with a cloed buggy of the type they will use after marriage, thereby presenting them with a taste of the very sort of prenuptial privacy of which the auto, to many Amish, is a symbol.

There are other compromises. With electricity banned, many Amish use kerosene for lighting. The Fishers use bottled gas.

The other night in their home, east of here on the road to Ronks, gas floor lamps on casters were rolled from room to room to illuminate such tasks as daughter Susie, 16, sewing a dark new Christmas gown (on a treadle sewing machine) next to the quilting frame and daughter Sally, 9, reading "Lori Adams and the Old House Mystery" in lieu of the television of more worldly households.

The evergreen wreaths of Christmas, whose pagan origins are spurned by the Amish, were absent, but across the kitchen a single string of Christmas cards shone in the gaslight.

But one of the most durable of the Amish traditions lived on. Outside, where Emmaunue Fisher's cabinet shop had burned to the ground Dec. 9, more than 30 neighbor men had been working since to erect a new building, in the heritage of the barn raisings of years past. The Amish, this Christmas, were taking care of their own.