ARSENICAL POISONING FROM SMELTER SMOKE. 
397 
and other experiments that cattle will take without injury, over 
indefinite period's, doses of 0.5 to 0.7 gram (7.7 to 10.8 grains) 
of arsenic trioxide per day, and may indeed increase in weight 
under it. They first show toxic symptoms with doses of 1 gram 
(15.4 grains) per day. The maximum non-toxic dose for cattle 
is given as about 0.00015 P ar t of arsenious oxide per day for 100 
parts of body weight (1.5 mg. per kilo), or 10.5 grains per day 
for an animal weighing 1,000 pounds. They also cite the state¬ 
ment of Hertwig that he gave arsenic to eight different horses in 
doses beginning with 20 grains, but increasing to a dram, and 
continued these doses for from 30 to 49 days with no bad ef¬ 
fects ; on the contrary, the condition was improved. 
To obtain a clearer idea of the toxic dose for horses, Harkins 
and Swain (6) fed a horse on flue dust containing a total of 
20.65 P er cent, of arsenic calculated as trioxide, and 17.89 per 
cent, of soluble arsenic, also calculated as trioxide. Considering 
only the soluble arsenic, the horse was fed two 1 grams (30.8 
grains) of arsenic trioxide for 18 days in addition to hay con¬ 
taining about 0.003 P er cent. (5.2 grains per 25 lbs.). At the 
end of this period the animal died from poisoning. 
To a second horse they gave 2.8 grams (43.12 grains) of ar¬ 
senic trioxide in two doses, on the first day mixed with bran and 
on the second as a drench. On the fourth day the animal died. 
A third horse died on the third day after having been given 
two doses of 7.5 grams (115.5 grains). 
From all of these observations and experiments we must con¬ 
clude that the action of arsenic trioxide in powder is very irregu¬ 
lar. This irregularity probably depends partly upon the particu¬ 
lar specimen of arsenic and partly on the individual animal. The 
principal cause of this irregularity, however, is the physical prop¬ 
erty of this powder, already explained, which prevents it from 
being moistened by water and enables a great part.of it to pass 
through the digestive tube without going into solution. Never¬ 
theless, it seems clear from the experiments of Spallanzani that 
a daily dose of 1 gram will produce toxic symptoms in some of 
the cattle which receive that dose; and from the experiments of 
