RESEARCH FOR ARSENIC AND ANTIMONY. 
171 
stance, to boil a piece of clean copper with the diluted hydro¬ 
chloric acid for four or five minutes; and if it did not acquire 
any tarnish or deposit, the copper and acid were to be re¬ 
garded as sufficiently pure for the detection of the poison. 
Undoubtedly a negative result of this kind would be a proof 
either of the entire absence of arsenic from the metal itself, 
or, if present, that it was so intimately combined with the 
substance of the copper as not practically to affect the appli¬ 
cation of the process in a medico-legal analysis. Resting 
upon this simple datum, Reinsch says of his method, “ Elle 
ne peut donner lieu a aucune meprise.”* Dr. C’nristison, 
w T ho has employed it during a period of fifteen years for 
detecting arsenic in the liver, says, in his last edition on 
Poisons,f that “ copper-leaf or copper-plate, worn thin by 
the action of diluted nitric acid or fine copper gauze , is the best 
form for use.In all medico-legal inquiries it is neces¬ 
sary to perform a preliminary experiment with distilled water 
and the hvdrochloric acid used, lest the acid contain arsenic . . . . 
It (the process) is not subject to any fallacy.” If any ad¬ 
ditional authority is required to show how little toxicologists 
of great repute and enlarged experience suspected that 
arsenic was lurking in the copper which they were so fre¬ 
quently using, or that there was any better method of testing 
the purity of the materials than that originally devised by 
Reinsch, it is furnished to us in the extensive experience of 
Mr. Iierapath of Bristol. In an article already referred to, 
this gentleman thus describes his mode of operating 
6C 1 take pieces of copper wire about No. 13 size, and two 
and a half inches long; these I hammer on a polished plane 
for half their length, and having brought the suspected 
matters to a state of dryness, and boiled the copper hlade in 
the pure hydrochloric acid, to prove that it (the acid) con¬ 
tains no metal capable of depositing, I introduce a portion 
of suspected matter, and continue the boiling,” &c. If there 
is a deposit, it is removed by scraping, and tested. Referring 
to the fallacious results which occasionally arise from acci¬ 
dental causes, Mr. Herapath further says : u As much of the 
sulphuric acid of commerce, and nearly all such hydrochloric 
acid, and some commercial zinc, contains arsenic, nothing can 
excuse a toxicologist w 7 ho attempts to try for arsenic if he 
has not previously experimented with all his reagents before 
he introduces the susnected matters. ,; § 
(To he continued .) 
* ‘Annales d’Hygiene, 5 1843, p. 452- 
T ‘ Treatise on Poisons, 5 fourth edition, 1845, p. 272. 
I ‘Ure’s ‘Dictionary of Arts,’ Part i, 1859, p. 191. 
$ Loc. cit. 
