ON MERCURIAL PREPARATIONS. 
New York, Feb. 13, 1844. 
Gentlemen : — 
In compliance with your request, I beg leave to state, 
that the following methods were adopted to ascertain the 
per centages of mercury in Blue Pill and Mercurial 
Ungt. 
The blue pill was washed with warm water, and also 
alcohol, to remove such organic matters as were soluble in 
these fluids ; it was dried until it was of the consistence of a 
thick paste, then mixed with an equal weight of sulphuric 
acid, — the whole being heated until the remaining organic 
matter was decomposed and carbonised ; the persulphate of 
mercury and carbonised matter so obtained were boiled 
with a solution of chloride of tin, to reduce the mercury ; 
the precipitate was washed and dried, and the mercury 
separated by sublimation in glass tubes. 
The mercurial ointment was treated with warm water, 
by which means the greatest part of the lard separated, 
floating on the surface of the water; it was then washed 
with a little alcohol to remove any water attached to it, and 
then triturated with hot spirits of turpentine, which dis- 
placed the remaining unctuous matters ; then washed with 
warm alcohol twice, to cleanse it from the turpentine and 
grease : upon drying it at a temperature of about 90° the 
mercury will assume the form of globules, or may be made 
to do so by pressing it together. 
Your most obedient servant, 
Lawrence Reid. 
To the Committee of the College of Pharmacy, ~) 
New York, on Mercurial Preparations. 5 
