If yall city folk thought it was jes a tale well it ain't......enjoy "It's after a rainfall, when the earth smells so rich and damp and flavorful, that Fannie Glass says she most misses having some dirt to eat. ''It just always tasted so good to me,'' says Mrs. Glass, who now eschews a practice that she acquired as a small girl from her mother. ''When it's good and dug from the right place, dirt has a fine sour taste.'' For generations, the eating of clay-rich dirt has been a curious but persistent custom in some rural areas of Mississippi and other Southern states, practiced over the years by poor whites and blacks. But while it is not uncommon these days to find people here who eat dirt, scholars and others who have studied the practice say it is clearly on the wane. Like Mrs. Glass, many are giving up dirt because of the social stigma attached to it. ''In another generation I suspect it will disappear altogether,'' said Dr. Dennis A. Frate, a medical anthropologist from the University of Mississippi who has studied the phenomenon. ''As the influence of television and the media has drawn these isolated communities closer to the mainstream of American society, dirt eating has increasingly become a social taboo.'' Geophagy, the Culture of Earth-Eating Dr. Frate says nearly every culture has passed through a phase of earth eating, known as geophagy. But it appears to be most prevalent these days among rural black women in the South, some of whom say they eat a handful a day, snacking from bags or jars in which they keep dirt that has been dug from a favorite clay bank, baked and, often, seasoned with vinegar and salt. In addition, families here in Leflore County sometimes mail shoe boxes full of dirt to relatives who have moved north but still crave the flavor of dirt dug from the clay hills back home. According to Dr. Frate and others, there is no evidence among those who have been surveyed that dirt eating is harmful to their health. Researchers say those who eat dirt do not do so to satisfy hunger or to meet a biochemical urge to acquire certain metals or minerals that might be missing from the diet. Rather, they do so because the practice has been learned culturally. Links Are Traced to West Africa Dr. Frate said dirt eating is one of the few customs surviving among some Southern blacks that can be directly traced to ancestral origins in West Africa. Dirt-eating is common among some tribes in Nigeria today. According to his research, Dr. Frate said it was not uncommon for slave owners to put masks over the mouths of slaves to keep them from eating dirt. The owners thought the practice was a cause of death and illness among slaves, when they were more likely dying from malnutrition. Instead of eating dirt, some women use packaged raw corn starch or baking soda as a substitute. Dr. Frate says these materials have a similar paste-like texture to the fine hill clays that have traditionally been eaten. But not everyone makes that switch. ''I don't hold with either baking soda or starch,'' said Mrs. Glass. ''Starch just don't take the place of dirt.'' It is difficult to say how prevalent dirt-eating is today. But in 1975, among 56 black women questioned by Dr. Frate as part of a larger study on nutrition in rural Holmes County, 32 of them said they ate dirt. The survey also showed that the ingestion of dirt tended to be more common in pregnancy. While it is was not unusual to find small boys who ate dirt, the practice appears to be shunned by adult males. Of 33 men questioned in the households studied, none said they ate dirt. Dirt-eating has also been practiced among poor, rural whites, who in the early part of this century were known as ''clay eaters.'' A Certain Kind of Dirt Those who do eat dirt make it clear that not any dirt will do. The dirt that is consumed by some of the people who live here in Cruger, a small collection of cinderblock homes and small clapboard houses huddled along Highway 49, comes from a single spot along a sloping bank above a gravel road in the hills about seven miles east of town. Such favored sites are not uncommon in rural Mississippi. Dr. Frate told of visiting another popular site one afternoon and finding three cars lined up there, ''like at a drive- in bank, so people could fill their bags with dirt.'' According to Mrs. Glass and others, ''hill dirt,'' which is rich in clay, is preferable to the dirt of the flatter landscape of the Mississippi Delta, which has a grittier, rougher texture and is popularly referred to as ''gumbo dirt.'' Rarely a Medical Problem, Doctor Says Dr. Frate said chemical investigation of dirt samples turned up no evidence that dirt eating is harmful. Not only is the dirt often baked, it is generally gathered from far enough below the surface to be free of chemcial contaminants, insects or parastic worms. Dr. Sidney A. Johnson, a rural physician in Goodman, a small community south of here, said that among the women he sees who eat dirt, only once was it the source of a medical problem. ''I had a patient who had eaten so much dirt that it had packed her large colon,'' said Dr. Johnson, who noted that fine clays have a tendency to adhere to lining of the intestines. For her part, Mrs. Glass says she has been off dirt for about a year now, after her husband complained to her that it was a bad habit ''that makes your mouth taste like mud.'' ''But there are times when I really miss it,'' said Mrs. Glass. ''I wish I had some dirt right now.''