One might well ask why another volume dealing with biological aspects of
compounds of fluorine should be offered to the scientific community,
already burdened with a literature too massive to be comfortably
ingested. Prior toW orld War II this question simply did not arise:
there was not sufficient interest or literature in the field to warrant
anything beyond the classical monograph pub- 1 lished by KAJ RoHOLM in
1937 - RoHOLM's work was directed chiefly toward a better understanding
of the effects of fluorides on the general health of workers in the
cyrolite industry. However, with the demonstration that water-borne
fluoride was a causative agent of both mottled enamel and increased
resistance to dental caries, the ground- work was laid in the 1930's and
early 1940's for a greatly increased interest in the biological effects
of fluorides in human beings. During this time and earlier for that
matter, work also had been going steadily ahead in the less spectacular
area of effects produced in poultry and livestock when
fluorine-containing rock phosphate was incorporated in the ration, and
when pasture land was contami- nated with fluorides released during the
large-scale conversion of rock phosphate to fertilizer and phosphoric
acid. These latter aspects of the problem had led to the development of
a respectable literature in plant physiology, dealing with the effects
of fluoride on vegetation.