96 
RESEARCH FOR ARSENIC AND ANTIMONY. 
water and two of hydrochloric acid, gave a thin, but well- 
marked, steel-blue coating to the twelfth part of a square 
inch of bright copper-foil. On the introduction of a second 
piece of the same size, there was scarcely any perceptible de¬ 
posit. The arsenic in this experiment formed only the 
1-96,000th part of the weight of the liquid in which it was 
dissolved. When, however, the quantity of water was increased 
threefold, there was no deposit on the copper, even after boil¬ 
ing for a few minutes. By a still longer boiling, and a con¬ 
centration of the liquid, the arsenic would no doubt have 
revealed itself. 
It is proper to remark, in this place, that the delicacy of 
the process is affected, not only by the quantity of liquid in 
which the arsenic is diffused, but by the surface of metallic 
copper employed in the experiment. For the detection of 
minute quantities, the polished copper-foil employed should 
not exceed the eighth of an inch square, and the arsenic 
should be diffused through a minimum of liquid. By thus 
diminishing the amount of metallic surface to be coated, it is 
easy to demonstrate that a quantity of arsenic may be de¬ 
tected by Reinsch’s process which Marsh’s process would 
entirely fail to reveal, even under its most improved modifi¬ 
cations. 
Reinsch makes but a slight reference to the use of his 
process fo£ detecting arsenic in organic matter . He advises 
that the contents of the stomach and intestines should be 
boiled in pure hydrochloric acid mixed with distilled water, 
that the acid decoction should be filtered, and the filtered 
liquid boiled with one or more pieces of copper. The ex¬ 
istence of arsenic might, he states, be in this manner demon¬ 
strated even in the bones, although he relates no experiment 
in support of this opinion. 
At the date of publication of his process, it does not appear 
that Reinsch had practically applied it to the detection of 
arsenic in the fluids or solids of a dead body. He had no 
idea, apparently, of its important application to the separa¬ 
tion of arsenic from the tissues. The only fact which I have 
found recorded on this subject is that he made a mixture 
composed of potatoes, soup, milk, &c., and introduced into 
it half a grain of arsenic. He boiled the whole with pure 
hydrochloric acid, diluted with its weight of water, filtered 
the liquid, and treated the filtrate with metallic copper. He 
found that the arsenical deposit was as easily obtained on 
the copper, in this experiment, as if acidulated water only 
had been used. 
In the prosecution of his researches on arsenic, Reinsch 
