Note K — II. DETECTION OF POISONS, THE PRESENCE OF WHICH IS SUSPECTED.
Jesse P. (Jesse Park) Battershall translation
If an insoluble residue remains by the treatment with nitric acid, it may consist of tin. In this case, it is dissolved in aqua regia, the metal precipitated by immersing a plate of zinc in the solution and then re-dissolved in boiling hydrochloric acid. Upon adding chloride of gold to the solution so obtained, a purple precipitate is formed. Sulphuretted hydrogen produces a brown precipitate, soluble in sulphide of ammonium, in presence of tin.