332 
ON POISONING BY ARSENIOUS ACID. 
of this oxide have not neutralized even 2 mille grammes of 
arsenious acid, which is the same as saying that it requires 
more than 2000 grammes (12^ ounces) to absorb one grain of 
this poison. It is evident from this fact that colcothar should 
be rejected in the treatment of poisoning by arsenic. May 
the same be said of the hydrated peroxide ? I do not think 
so, although I do not allow, that it is completely capable of 
neutralizing arsenious acid. Let us examine the facts of the 
case. 
M. Guibourt proved, in a paper printed in 1839, that 100 
grammes of hydrated peroxide of iron, inthe state of magma, 
was sufficient to absorb and neutralize 3§ decigrammes (7 
grs.) of arsenious acid. I have proven by numerous experi- 
ments, that if the hydrated peroxide, instead of being in the 
state of magma, be used dry, that is to say hydrated but not 
moist, and at the temperature of 36 or 40° C, 16 grammes 
will neutralize about 6 decigrammes (12 grs.) of arsenious 
acid. At least the aqueous liquor, resting over 16 gram- 
mes of the hydrated oxide, left for some hours in contact with 
6 decigrammes of arsenious acid, did not become yellow on 
the addition of a solution of hydrosulphuric acid, to which 
some drops of hydrochloric acid had been added. 
On the other hand, the experiments of MM. Leseur, Bou- 
ley, jr., Nonat, Deville and Sandras, &c, have established 
that animals never die poisoned by arsenious acid, although 
sufficient to produce death has been administered, provided 
they have taken the hydrated peroxide in sufficient quantity 
to neutralize the whole of the arsenious acid. MM. Nonat, 
Deville and Sandras, have advised, and with reason, to use 
in preference the dry hydrated peroxide, because it contains 
in the same weight, four or more times the amount that it 
does in the state of magma; and they also advise to give 16 
grammes of dry hydrated oxide for each grain of arsenious 
acid to be neutralized. 
It is curious and useful to resolve the problem, as to what 
extent the compound of arsenic acid and hydrated peroxide of 
iron formed in the stomach of individuals poisoned, retains its 
