240 
ON HYDRATED peroxide of iron, etc. 
1834.* In the same year Drs. Bunsen and Berthoid jointly 
addressed a communication on the same subject to the Acade- 
my of Sciences at Paris.t It had been previously established 
by the experiments of Renault and others, that the native ar- 
senite of iron (mispickel^ is nearly innocuous to animals, and 
on this fact, the investigations of Drs. Bunsen and Berthoid 
seem to have been founded. They also ascertained that " a 
solution of arsenious acid is so completely precipitated by 
pure hydrate of iron recently precipitated and suspended in 
water, that a current of sulphuretted hydrogen gas passed into 
the liquor after Alteration, and the addition of a small quanti- 
ty of muriatic acid, does not indicate the presence of the 
smallest quantity of arsenious acid." Again, if a few drops 
of ammonia be added to the peroxide, and it be digested in a 
gentle heat, with arsenious acid, reduced to fine powder, a 
sub-perarsenite of iron is formed, which is perfectly insoluble. 
Encouraged by these results, they proceeded to perform 
II. Experiments on animals. From four to eight grains 
of arsenic were given to two young dogs, and the oesophagus 
was tied to prevent vomiting, and the peroxide was then ex- 
hibited. They lived more than a week without manifesting 
any of the symptoms of poisoning. A quantity equal to four 
or six drachms of the peroxide was deemed sufficient to 
transform in the stomach eight or ten grains of arsenious acid 
into insoluble arsenite. As, however, the hydrated oxide is 
innocuous, they advise its use in much larger quantity. Rab- 
bits also which are destroyed by very small doses of arsenic, 
were saved by the antidote. 
Orfila and Le Sueur repeated these experiments on animals 
and generally with favorable results. They found, however, 
that if the administration of the antidote was delayed beyond 
half an hour, all the symptoms of poisoning occurred, and 
» * London and Edinburg Philosophical Magazine, vol. vi. p. 237. 
f Lancet, Oct. 18th, 1834, and American Journal Medical Sciences, Feb- 
ruary, 1835, p< 537. 
