246 ON HYDRATED PEROXIDE OF IRON, ETC. 
The Edinburgh college has introduced it into its pharmaco- 
poeia, with nearl}' identical directions, which I copy from Dr. 
Maclagan's paper, already referred to. " Dissolve sulphate 
of iron in water, with a little sulphuric acid, adding nitric 
acid by degrees till it is thus fully oxygenated, and then pre- 
cipitating the hydrated sesquioxide from this solution by an 
excess of ammonia. The product thus obtained is of a deep 
reddish brown." It should be carefully washed, to remove 
the ammonia ; but this can hardly be completely affected 
without the application of heat ; and I apprehend that this 
last is not to be recommended. 
The dry hydrated oxide is inert. It is therefore neces- 
sary to keep the antidote, when prepared, under water. It 
may thus be preserved uninjured in its qualities for a length 
of time. Professor Fisher, of Maryland, has shown this con- 
clusively in an elaborate paper in the twelfth volume of the 
American Journal of Pharmacy. " In the moist state, it 
is in the finest possible state of division, and hence best adapt- 
ed as an antidote." 
It is not necessary therefore to have it freshly prepared 
for every case, and the practitioner has only to keep a quanti- 
ty on hand in closely stopped bottles, remembering to shake 
it well before administration. 
As to the quantity necessary to be given, I will again quote 
Dr. Maclagan. " As far as chemical evidence goes, at least 
twelve parts of oxide, prepared by ammonia, and moist, are 
required for each part of arsenic, and this same proportion has 
been indicated by several of the French experimentalists as 
being required to insure its antidotal effects." 
But it may be said that in some instances we cannot ascer- 
tain how much arsenic has been taken, and the inquiry may 
be renewed, how are we then to act. To this, I reply, by 
recommending that to an adult, a tablespoonful, and for child- 
ren a desert spoonful, should be given every five or ten 
minutes until relief from the urgent symptoms is obtained. 
Albany, May 19, 1841. 
Amer. Joum. Med. Sci. 
