Effects of various flourine compounds on the albino rat.

At the beginning of the 19th century, an Italian chemist demonstrated the presence of fluorine in the teeth of both man and animals. This discovery created considerable interest at that time and can probably be considered the initial step in stimulating research on the problem. In the light of our present day knowledge, there is evidence that the ingestion of small amounts of fluorine may be distinctly beneficial to livestock. However, the primary problem in animal nutrition is concerned with definitely harmful effects resulting from an excessive intake. It was only a few years ago that farmers were using raw rock phosphats as a mineral supplement in rations for livestock. Although raw rock phosphate might supply the desired mineral ingredients at a lower cost than they might be obtained from other sources, it was learned that rock phosphate produced abnormal calcification of the teeth and possibly other changes which greatly limited its usage. These changes were the same as could be produced experimentally by using a chmically pure fluorine salt.