280 Means of detecting Arsenic in the Animal Body, 6^c. 



" 6th. Thirty grains of colcothar boiled with sulphuric acid, 

 gave arsenical taches. 



*' 7th. 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 colcothar to three 

 dogs, tying the oesophagus 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 

 conld be obtained. The liquid of the stomach and intestines of 

 the first dog being separated from the colcothar, gave arsenical 

 taches, though its uritie 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 absorb- 

 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-jiu'ist should adopt, in a 

 case of this character, would be to examine the peroxide of iron 

 that the person had taken, should there be any of it remaining, 



