Means of detecting Arsenic in the Animal Bodi/, S/'c. 291 



quantity of muriatic acid is poured upon it, which decomposes 

 what nitrate of silver remains, and converts the precipitate into 

 chloride of silver. There remains now in solution arsenic and 

 arsenious acids, and by filtering and evaporating to dryness, they 

 are obtained. 



I propose to pass the arsenuretted hydrogen through a tolerably 

 strong solution of iodine in alcohol, in order to decompose it, 

 which it does effectually, there being formed the iodide of arse- 

 nic, which remains in solution. All that is now necessary to be 

 done, is to evaporate nearly to dryness, until red fumes make their 

 appearance, and then pour twice or thrice as much nitric acid as 

 there is residue into the capsule. Heat is again applied, and the 

 evaporation continued to dryness, when there will be remaining 

 arsenic and arsenious acids. The nitric acid in this case converts 

 the iodine of the iodide of arsenic, and the free iodine into iodous 

 and iodic acids, both of which are evaporated with the undecom- 

 posed nitric acid. 



Iodine also decomposes the antimoniacal hydrogen, first form- 

 ing iodide of antimony, which the water of the alcohol immedi- 

 ately decomposes into hydriodic acid and oxide of antimony, the 

 latter of which is precipitated. This then becomes a convenient 

 mode of separating the two substances, antimony and arsenic, for 

 by passing the compound gas through the alcoholic solution of 

 iodine, it becomes decomposed, and iodide of arsenic is formed, 

 which remains in solution, and the oxide of antimony which is 

 precipitated, can be separated by means of a filter. This, how- 

 ever, is not the plan that I would propose ; it would be better to 

 invert the precipitate as well as the liquid into a capsule, evapo- 

 rate and treat with nitric acid as in the case of arsenic, when 

 we shall have left the arsenic, arsenious and antimonious acids, 

 the two former of which are soluble in water. 



One may now imagine that there is nothing easier for the med- 

 ico-jurist than to form a correct opinion, and one that cannot be 

 doubted, concerning the poisoning by arsenic. Whether such is 

 the fact or not, he will find, in some cases, that all his skill and 

 care will be required, not only to convince the minds of others, 

 but even his own. It may not unfrequently occur, that arsenious 

 acid has been the poisoning agent, and still great difficulties pre- 

 sent themselves, which are enumerated in almost all works on 

 medical jurisprudence. 



