ARSENICAL POISONING FROM SMELTER SMOKE. 
401 
perimental animals may, therefore, be placed as follows per kilo 
of body weight: mice and rats, 20 mgs.; guinea pigs, 13 mgs.; 
rabbits, 10 mgs.; dogs, 3.5 mgs. 
Attention is directed to this diminution of the fatal dose per 
unit of body weight as the species increases in size, for the rea¬ 
son that efforts have frequently been made to< calculate the fatal 
dose for the larger animals and man from these determinations 
made with the smaller experimental animals. The results of 
such calculations evidently have little value and we can only con¬ 
clude in a general way that the fatal dose of absorbed arsenic for 
man and for horses and cattle is probably considerably less per 
kilo of body weight than for dogs. 
The writer attempted to determine the maximum dose which 
could be given subcutaneously to horses without fatal poisoning. 
I11 one case, mild symptoms (dullness, loss of appetite, diarrhoea) 
resulted from 0.9 mg. per kilo. The largest dose reached in an¬ 
other animal was 1.6 mg. per kilo, and in this case the general 
symptoms consisted of dullness, very marked venous pulse in the 
jugulars, tense artery and weak arterial pulse. It appeared, How¬ 
ever, that a great part of the arsenic was fixed at the points of 
inoculation, for notwithstanding great dilution (1 to 1000) and 
the injection at six different points, the skin over the entire area 
where the solution was diffused became necrotic and sloughed, 
as well as the subcutaneous tissues. The injections were aban¬ 
doned because of the intense local action. 
Holmes (13) fixes the maximum therapeutic dose of atoxyl 
subcutaneously for horses at 25 mgs. per kilo. Some writers 
have placed the toxicity of arsenic in solution at 40 times that of 
atoxyl, but according to Launoy (14). with whom the writer is 
inclined to agree, it is only 8 to 10 times as toxic. We might, 
therefore, conclude that about 3 mg. per kilo of absorbed arsenic 
would be a fatal dose for a horse. For a horse of 400 kilos that 
would be equivalent to 18.5 grains. As it probably requires 2% 
to 3 times as much by the mouth to produce the same effect, the 
fatal dose of arsenic in solution when ingested would be for a 
horse of that weight from 46 to 56 grains, which corresponds 
