106 The Post-Mortem Imiibition of Poisons. (February, 
the hydrochloric acid and potassium-chlorate method, with the 
purification method of Otto. These are as follows: “ The organ 
is cut into small pieces, and hydrochloric acid and water added. 
The mass is heated to near but not quite the boiling point ona 
sand bath. Potassium chlorate is added, in portions, the mass 
being stirred continually. The chlorine evolved disintegrates the 
organic matter. The massis stirred and heated until all the chlo- 
rine is driven off, and it becomes homogeneous. The volume is 
kept up by adding water. Allow to cool and transfer to a moist : 
linen strainer, and strain until the filtrate is clear, restraining all 
that is turbid. The residue is washed well with water. The 
arsenious oxide has been oxidized by the potassium chlorate 
to arsenic oxide. Reduce to arsenious oxide by adding an 
excess of a solution of sulphurous acid gas, the excess of gas 
being known by the odor. 
The mass is evaporated to twice the volume of hydrochloric 
acid used; cool and filter if necessary. Thoroughly saturate while 
warm with a washed stream of sulphuretted hydrogen, which will 
throw down the arsenious oxide, organic matter, sulphur and the 
sulphides of other metals. Filter, wash the residue until the 
washings are free from chlorine. The residue is washed with a 
few c. c. of water containing ammonium hydrate. The sulphide 
of arsenic will be dissolved by the ammonia water and pass 
through. Evaporate to dryness in a water-bath, and add a few 
drops of nitric acid to destroy the organic matter; the nitric acid 
will also oxidize the sulphide of arsenic to arsenic oxide. Evapo- 
rate to dryness and repeat until the mass has a yellow color. To 
the dry residue add a small quantity of a solution of potassium 
hydrate and powdered carbonate of soda, and evaporate again. 
The potassium hydrate will combine with the arsenic oxide, form- 
ing potassium arsenate. Evaporate to dryness, and add three or 
four drops of concentrated sulphuric acid. Heat on naked flame 
until vapors of sulphuric acid cease to arise. The sulphuric acid 
will clear the organic matter. Pulverize the residue if necessary, 
add 25 c. c. of water, and one drop of sulphuric acid to acidulate. 
Boil and filter. The filtrate which contains arsenic oxide should 
be colorless. Reduce arsenic oxide to arsenious oxide by an 
excess of a solution of sulphurous acid. Concentrate until all of. 
the sulphurous acid is gone, and about 20 c. c. remain. 
The reagents employed in the extraction of arsenic, themselves 
a 
