280 Means of detecting Arsenic in the Animal Body, fe. 
“6th. Thirty grains of colcothar boiled with sulphuric acid, 
. gave arsenical taches. ~ 
“Tth. Fifteen: grains of the same body, treated in the same 
way, gave no indications of arsenic. ‘ 
“8th. A solution of sulphate of iron gave no arsenical taches 
with the apparatus.” * 
'  M. Orfila next administered four ounces of ‘eolcothar to three * 
dogs, tying the esophagus to prevent vomiting. One of them» 
was examined thirty four hours after, the second fifty, and the 
third sixty. The liver, spleen, heart, and kidneys of these ani- 
mals, were submitted to investigation, but no trace of arsenic 
could be obtained. ‘The liquid of the stomach and intestines of 
the first dog being separated from the | aoa gave arsenical 
taches, though its urine did not indicate the presence of this me- 
tal. The intestinal liquid of the second dog gave some taches, 
less apparent and less numerous than that of the third, but on 
the contrary its urine gave strong indications of arsenic. 
The conclusions to be arrived at from these experiments are, 
that the hydrated peroxide of iron, and the colcothar, the former 
of which is administered as an antidote for arsenious acid, con- 
tain arsenic in minute quantities, (though the former being no 
doubt as often without as with it,) but that it requires the aid of 
a strong acid to develope it, and also, that when these substances 
are administered, the arsenic that they contain is slowly ab rb- 
ed, passes by the organs, and is eliminated by the urine. The 
organs never at any time retain sufficient arsenic to exhibit it 
when examined for. | 
This question being answered in the affirmative, would appear 
to throw a great obstacle in the way of pronouncing with cer 
tainty whether the arsenic found in the intestinal liquid of an 
individual supposed to have been poisoned, and to whom the hy- 
drated peroxide of iron had been administered as an antidote, was 
due to arsenious acid or to the oxide of iron. This difficulty 
would not arise except the quantity found be extremely small ; 
for the peroxide of iron, from the manner in which it is prepared, 
can contain but the smallest appreciable amount; and, moreover, 
as it has already been remarked, it is ‘not always that we find 
even that. The plan that the medico-jurist should adopt, in @ 
case of this character, would bé to examine the peroxide of irom 
that the person had taken, should there be any of it remaining; 
