606 ON DETECTING THE 
Review, for Jan., 1841, which contains a review 
of M. Orfila’s Memoirs on Poisoning, printed in 
the Memoirs of the Royal Academy of Medicine, 
Vol. VIIL, Paris, 1840; by this I find that the 
agency of heat spoken of by Orfila, is through 
the direct application of flame to the metal under 
examination. He says, that an arsenical stain, 
of whatever thickness, is entirely volatilized in 
from half a minute to a minute, when exposed to 
the flame of hydrogen gas, as in the common phi- 
losophical lamp ; the antimonial stain, on the con- 
trary, even when thin, is not volatilized until after 
the lapse of five or six minutes. This application 
of heat by flame is so indefinite in degree, and so 
wanting of that precision without which we great- 
ly risk the danger of deciding erroneously, that 
I hesitate not at announcing my mode of apply- 
ing heat, as one in which we may with more safety 
confide. 
It will be observed, that I enclose and herme- 
tically confine the metallic crusts in a tube, so 
that no portion can escape, although a volatile 
tendency be given them by the heat, which is an 
advantage not possessed when flame is directly 
applied to them unconfined, the metal then being 
dissipated and lost. When the temperature has 
