TOXICOLOGY. 
518 
meriting with it on the dog, M. Bouley selected the horse, partly 
because the difficulty of exciting vomiting in the horse rendered 
a painful and often fatal operation, the ligature of the esopha¬ 
gus, unnecessary; and partly because, by taking another species 
of animal, he might, while he would probably arrive at the same 
conclusion, have the benefit of some comparative, and therefore 
more conclusive results. 
His report of his experiments was presented to the Royal 
Academy of Medicine, approved of by that learned body, and 
entered among their records; and the readers of The Veteri¬ 
narian are now presented with a summary of it. 
The antidote consisted of the hydrate of the peroxide of 
iron. Ochre, according to Fleury, is a native hydrate of^the 
peroxide of iron, mechanically mixed with earthy ingredients. 
A pure hydrate is procured with much difficulty, on account of 
the facility with which it parts with its water. It is almost 
identical in its composition with the mineral called hrown hema¬ 
tite, and consists of forty parts or one atom of the peroxide, or 
nine parts or one atom of water*. M. Bunzen advocated its 
efficacy in cases of poisoning with arsenious acid, or the common 
white oxide of arsenic. M. Bouley was naturally anxious first 
to try its power over the arseniate of potash, of the virulence of 
which he had lately had such fatal proof. 
We will now, in the continuation of our summary, adopt 
nearly his own words. 
* The following was the method of preparing the hydrate as recom¬ 
mended by M. Lassaique :— 
‘^Take a certain quantity of iron filings, and pour on them, by little and 
little, in order to avoid too much etfervescence, four times the weight of the 
nitric acid of commerce. One part of the nitric acid yields its oxygen to the 
iron, and transforms it into a peroxide, which immediately combines with 
another part of the nitric acid not decomposed, and the result is a pernitrate 
of iron. From this reaction, which is very intense, there results a disen¬ 
gagement of heat, and of gas of deutoxide of azote, which is transformed, 
by contact with the atmospheric air, into suffocating vapours of nitric acid. 
When this action has ceased, ten or twelve parts of water are added, in 
order to dissolve the pernitrate of iron, and to detach the portion of iron 
filings that have not been acted upon, and which are precipitated to the 
bottom of the vessel. 
The solution being decanted or filtered, ammonia is added, by little and 
little, until reddened turnsole paper takes a blue colour, indicating that 
there begins to be an excess of alkali. There is immediately formed an 
abundant precipitate of a yellow brown colour, the hydrate of the peroxide 
of iron, which is received on a piece of linen stretched at the bottom, and 
then washed with boiling water until the turnsole paper is no longer acted 
upon. 
