IN CASES OF POISONING. 275 



separated by heating the substance carefully in a slow 

 current of hydrogen. All the arsenic will be sublimed. 

 If hydrogen gas containing arsenic, is passed into a 

 solution of nitrate of silver contained in a Liebig's 

 bulb tube, it forms a precipitate of metallic silver, and 

 arsenious acid, which is easily found in the liquid. 

 Antimonetted hydrogen forms in a solution of silver, 

 a precipitate of antimonide of silver. If a mixture of 

 arsenetted and antimonetted hydrogen from the Marsh 

 apparatus is conducted into a solution of silver, a 

 mixture of antimonide and metallic silver are precipi : 

 tated. If this precipitate is washed with hot water and 

 then boiled with a concentrated solution of tartaric acid, 

 the antimony alone is dissolved and is then easily 

 recognized by hydrosulphuric acid after acidifying 

 with hydrochloric acid. (See also No. 61.) 



III. If no arsenic was found in the stomach and 

 intestines, it must be supposed to have been partly 

 carried away in the vomited matters and faeces, and 

 partly absorbed into the mass of the blood, and into 

 those organs which are rich in blood. In this case, 

 the same process is employed as in the preceding, the 

 arsenic being sought, according to the same method, 

 in the liver, spleen, lungs, heart, and kidneys. If urine 

 were found in the bladder, or faecal matter in the large 

 intestines, they should be examined first. The urine 

 must not be introduced at once into Marsh's apparatus 

 since the frothing to which it gives rise would interfere 

 with the progress of the experiment ; the urine should 

 therefore be slightly acidified, with hydrochloric acid, 

 sulphuretted hydrogen passed through it, and the sub- 

 sequent process conducted as in the second case. 



Investigations of this description are in the highest 

 degree laborious, troublesome, and disgusting, when 

 the body to be examined has been interred for months 

 or years, and has passed into a state putrefaction. In 

 such a case, it is frequently no longer possible to dis- 



