Examination of the Peroxide of Manganese. 81 
ger of introducing it in the apparatus, and moreover, the tests 
already mentioned, are sufficient to enable us to Petey: be- 
tween antimony and arsenic. 
oI shall conclude what I have to say on this mahiaits with the 
résumé of the report of the Academy of Sciences 
“The committee, resuming the instruction wiiaadinad in ssin 
report, think that Marsh’s process, applied with all the precautions 
which have been indicated, satisfy the demand of medico-legal 
researches, in which the quantity of arsenic, which it is attempt- 
ed to exhibit, is always much gues to that which the delicacy 
of the apparatus exhibits; (+5545; of arsenic acid existing ina 
liquid, is about the extent of the delicacy of the apparatus.) 
At the same time it must be well understood, that it is always 
to be employed as a means of concentrating the metal, in order 
to study its chemical characters, and that we should consider as 
nothing, or as extremely doubtful, the indications which it fur- 
nishes, if the deposit which is foveeicil ith; teoramtotior part of the 
tube, does not permit the experimenter, on account of its very 
small quanity, to verify ina = manner, the ¢. harac- 
ters of arsenic.” 
*“ We will add that in etigg gebater number of ete epiediinks 
the examination of the matter vomited, and of that which re- 
mains in the intestinal canal, will convince the experimenter of 
the ; presence of the poison; and that he: will have only to proceed 
of the organs, in cases where the first efforts 
have. ‘been fruitless, or in those very rare cases, where preenaned 
Speurastadegs ne ee shall indicate to him the necessity.” 
is, June 28ih, 
pow IX.— Remarks upon an examination of the piodeoseros A 
eth an ad by Henry C. Lea. 
re of great importance, both to the practical and theoret- 
ical chemist, to have the combinations which the different me- 
tals form with the acids, investigated, in order that the proper 
degree of confidence may be reposed in the various theories 
which have been formed from time to time by so many celebra- 
wae iu a eden with this view y alone that re a Arn 3 ‘ 
Vol. 3 ten, Re 1 1 Dette: 4841. il 
