A. W. PEIRCE.
303
phosphatic deposits for a period.
Degenerative changes observed in the
livers of these animals were considered to be indistinguishable from those
associated with heavy metal poisoning (119). This symptom rarely, if ever,
occurs, however, in natural Darmous.
Chemical investigation of the soils of the vegetation and of the bones of
animals in affected areas indicates that the fluorine content may be ten times
that of similar materials from healthy areas. The disease does not occur
in localities where the soils contain less than 20 mg. fluorine per 100 g. (48.)
OBSERVATIONS IN AREAS IN PROXIMITY TO FACTORIES WHICH DISCHARGE
FLUOLRINE
The occurrence of a similar disease among animals grazing in the neigh-
bourhood of various factories appears to have been first ascribed to fluorine
in 1912 (8). The industries principally incriminated are those producing
superphosphate (80, 83), hydrofluoric acid (47, 83), glazed bricks (122)
copper (103), aluminium (7), glass and enamel (5, 58, 59, 84). All such
factories either emit effluents of hydrogen or silicon fluoride or give rise to
dust containing fluorine.
These papers are, for the most part, concerned with injury, to vegetation,
in one only a description of the disabilities, suffered by animals occurs and
this refers to the impairment of gait and the occurrence of spontaneous frac-
tures of the long bones of cattle grazing in the neighbourhood of a metallurgical
industry in Freiburg, Saxony (59) which utilised fluorspar as a flux. The
trouble was first ascribed to the combined effect of sulphuric acid and arsenic
ingestion, but this was disputed later (84).
The danger from hydrogen fluoride and silicon fluoride is enhanced by
the capacity of these compounds to form fogs which in the absence of winds,
do not readily dispurse and so allow relatively high concentrations to remain
in one locality for a considerable period. Such an effect was considered (64)
(100) to have been responsible for the fatalities associated with the disastrous
fog of 1930 in the Meuse Valley, Belgium, in which sixty human beings and
many stock perished. The affected area contained many industries utilising
materials containing fluorine and the symptoms suffered were those of acute
fluorine poisoning. Abnormal bone development was common among cattle
after the catestrophe.
Illness among animals grazing in the vicinity of superphosphate works
has been observed in France (104), in Germany (64) and in Italy (8, 9), and
near aluminium factories in Italy (7) in Norway (107) and in Switzerland
(16, 26, 27). The symptoms reported are similar. Difficulty of locomotion
emaciation, raggedness of coat, reduction of milk yield and especially abnormal
skeletal development manifested by swollen joints and exostoses of the long
bones and jaws have been described in cattle and sheep frequently these
areas. Fractures were observed to be a common feature of the disease in
Norway. Selective abrasion of the molars, with consequent excessive wear
of some teeth in one jaw and corresponding overgrowth in the teeth of the
opposite jaw, has been reported. Anaemia and conjunctival irritation have
also been described. Damage to the surrounding vegetation and an increase
in its fluorine content have been described in several localities (7, 25, 28, 43
64, 107, 121), and greatly increased concentrations of fluorine in the bones
E