FLUORINE IN SOILS, PLANTS, AND ANIMALS

Fluorine is a minor element in the plant and animal kingdoms in the sense that, with few exceptions, it occurs in minute amounts in vegetable and animal tissues. It is of minor importance also because it has not been found to have any well-defined function in living matter. No definite deficiency symptoms have been observed in plants or animals subsisting on a food supply containing the merest trace of fluorine. The element is of importance in plant, and particularly in animal, nutrition because of the harmful effects that it may exert when ingested even in homeopathic doses. Like many toxic substances, however, it may exert a favorable effect on some tissues when ingested in amounts not exceeding a certain very low level. Toxicity from excessive intake is discussed.