Detection of Arsenic, fyc. 
71 
preparation, and granted that in the case of small pox, his 
pills administered in strong doses, might cause death. The 
pills had been given to Richardson in the dose of ten, fifteen, 
and even twenty. The cause having been heard — Webb was 
declared guilty by the jury, and although it was shown 
that he had no interest in poisoning Richardson, he was con- 
demned to death. Tt is hoped that the sentence will be com- 
muted ; the members of the court uniting to petition his majesty. 
Journ. Chim. Medicate, for Dec. 1834. 
XXI.— DETECTION OF ARSENIC WHEN MIXED WITH ORGANIC 
SUBSTANCES. By M. Taufflier. 
The operations of legal chemistry are often directed to the 
detection of arsenic in organic substances ; for instance, in 
the matters found in the digestive canal of persons supposed 
to have been poisoned. In this case it is essential, before 
having recourse to reagents, to destroy the organic sub- 
stances mixed with the supposed poison. The various plans 
hitherto devised for this purpose, have been, to decompose 
these organic matters by fire, by acids, or by alkalies. These 
modes have given satisfactory results, but they present many 
difficulties. 
I have succeeded in getting rid of these substances, by a 
simple method, which enables the operator to detect very 
small proportions of arsenious acid. The mucilaginous fluids, 
arising from a decoction of the contents of the stomach, are 
to be treated by a solution of oxide of zinc in potash ; this 
oxide combines with the organic matters, and forms an inso- 
luble compound, which rapidly precipitates. The superna- 
tant fluid is clear and limpid, and may be filtered or decanted; 
it contains arsenite of potash and an excess of oxide of zinc 
dissolved in potash. This liquid being acidified with hydro- 
chloric acid, hydrosulphuric acid is to be added, when a yel- 
low colour will be developed, if there is the least trace of 
