ON POISONING BY ARSENIOUS ACID. 
335 
iron. The arsenite of potassa dissolved in the water may 
be readily recognized, either by the apparatus of Marsh, or 
by the hydrosulphuric acid gas, after saturating the excess of 
alkali. 
If in place of acting in the cold, we boil, for two hours, the 
above proportions of peroxide of iron and potassa, the filtered 
liquor will contain arsenic, whether we operate with certain 
peroxides naturally containing arsenic, or with those which 
have absorbed an arsenical acid in the digestive canal. 
Presence of arsenic in the urine of individuals poisoned 
by an arsenical preparation. Since, latterly MM. Flandin 
and Danger, have doubted the existence of arsenic in the 
urine of certain animals, poisoned by arsenic, I judge proper 
to add to what I have already published on this point : 
1. This metal has been found in the urine of dogs poisoned 
by the application of a decigramme of arsenious acid, applied 
through the subcutaneous tissue of the thigh, or by means of the 
stomach, from the administration of 60 or 75 decigrammes of 
arsenious acid in fine powder, although the animals had taken 
neither food or liquids for twenty-four hours; or finally by the 
introduction into the stomach of 20, 30 or 40 centigrammes of 
this poison dissolved in water, 
2. That in fact, the urinary secretion is sometimes suspend- 
ed in this poisoning, and that there exists but a few drops of 
urine in the bladder. 
3. That it may likewise happen, when death takes place, at the 
end of a few hours, that the arsenious acid may not have as yet 
arrived at the bladder. I am so convinced of the truth of these 
assertions, that I willingly offer to demonstrate them to MM. 
Flandin and Danger. Of all the processes contrived to detect 
the presence of arsenic in the urine, that which in my opinion 
deserves the preference, consists in treating this liquid with 
nitrate of potassa, as I have previously pointed out in a 
former paper on arsenic. It was thus that M. Chevallier ex- 
tracted arsenic from a very small quantity of urine voided by 
the patient, who was the subject of M. Bouillet's observation 
laid before the Academy. 
