ON THE DETECTION OF ARSENIC. 
149 
other plants from similar climates. For we are led to inquire 
whether it be so peculiar in nature, as to be the only useful 
plant from similar climates cultivable in India, or whether 
it may not rather be an instance which may be successfully 
imitated. Therefore that other plants, as important as articles 
of commerce, which like it succeed in the summer of Euro- 
pean climates, may with equal success be introduced into the 
cold weather culture of the plains, or into the summer culture 
of the mountains of India. 
ART. XXXII.— DETECTION OF ARSENIC. 
By H. Braconot. 
Having occasion, some time since, to search for arsenic in 
a jelly mixed with other food, I employed the ordinary means, 
that is, I boiled the suspected matter for a long time with wa- 
ter, and having separated the fat, attempted to filter; but I 
was able to obtain but a very small quantity of clear liquor. 
This was divided into two parts; to the first I added a solu- 
tion of sulphuretted hydrogen, which did not alter the trans- 
parency, even with the assistance of hydrochloric acid and 
heat. Nevertheless, the liquid had assumed an orange yellow, 
which caused the suspicion that sulphuret of arsenic was held 
in solution by the gelatine. In fact, having ascertained that 
arsenious acid is soluble in alcohol, I poured a sufficient quan- 
tity of this liquid upon another portion of the filtered liquor. 
The gelatin was separated, and the alcoholic liquor, tested 
with sulphuretted hydrogen, gave an abundant precipitate of 
orpiment. 
We know that sulphuretted hydrogen, although a very de- 
licate reagent to detect minute quantities of arsenic, does not 
offer the same amount of certainty when organic matter is 
present. To obviate this inconvenience, it has been proposed 
