"that a p$etty~sftro^ 
nyarogen and the test-tube is closed after a few 
seconds with the stopper bearing the glass tube. The escaping 
stream of hydrogen is then lighted, and the flame held close to a 
cold plate of white china. If no spot is produced, the acid and 
zinc are proved free from arsenic. Some of the gastric contents 
should then be added, the vessel closed, and after a few seconds’ 
escape of gas, the latter should be lighted and the flame again 
directed against the cold surface. If a dark spot shows itself, 
it is proven that arsenic or antimony is present in the contents of 
the stomach tested. 
The arsenical spot can be easily distinguished from that pro¬ 
duced by antimony by external marks. In case of doubt, a 
solution of chloride of lime or Javelle’s fluid should be poured 
over the spot. If the latter is dissolved, it consisted of arsenic, 
if not, of antimony. 
