402 
D. E. SALMON. 
' very closely with the results obtained by Harkins and Swain and 
the writer, as well as with the opinion expressed by Kaufman. 
It appears, therefore, that a single dose by the mouth of 60 
grains of arsenious acid in solution will probably prove fatal to 
a horse of 400 kilos (880 lbs.) ; that a daily dose of 45 grains 
for two consecutive days proved fatal (Harkins and Swain) ; 
that five daily doses of 40 grains each have proved fatal (experi¬ 
ment of the writer) ; that four daily doses of 30 grains each have 
proved fatal (Finlay Dun). As to smaller doses continued daily 
for a longer time, we have the conclusion of Spallanzani, and, 
also, of Cocconi and Schappe that 1 gram (15.4 grains) will pro¬ 
duce toxic symptoms in cattle. 
As to sheep, Harkins and Swain (15) gave to one which 
weighed 95 pounds, 0.181 gram of arsenic trioxide twice a day 
(5.57 grains daily). It died in 7 days. To another weighing 
87.5 pounds they gave 0.123 gram (1.9 grains) of arsenic tri¬ 
oxide in the form of sodium arsenite once daily for 25 days. It 
died 8 days after the administration of arsenic was stopped, that 
is, 33 days after the beginning of the experiment. To a third 
sheep weighing 115 pounds they gave 0.055 g r am (0.85 grain) 
once a day of arsenic trioxide in the form of sodium arsenite. It 
died at the end of 69 days. To a fourth sheep weighing 90.5 
pounds they gave 0.021 gram (0.32 grain) of arsenic trioxide in 
the form of sodium arsenite for 35 days, and then increased the 
dose to 0.09 gram (1.39 grains). The experiment was con¬ 
cluded at the end of 90 days, when this animal was still living, 
but would probably have died soon had the arsenic been con¬ 
tinued, as it had lost 30 pounds in weight during the 55 days that 
it received the larger dose. 
Unusual Susceptibility to Arsenic. 
The susceptibility shown by the animals in the experiments 
referred to above may be regarded as the average susceptibility. 
Among a considerable number of individuals there are always a 
few which are very much more susceptible than the average. The 
two glandered horses reported by Percivall which died from 
daily doses of five grains, are examples of this. 
