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PHARMACEUTICAL PREPARATIONS. 
ified in three hours. These experiments were repeated with 
the same results, from which it would seem that for complete 
success the magnesia should be calcined immediately before 
using it for this purpose, and the copaiba heated till ebulli- 
tion commences. To prevent accident from the boiling 
over of the copaiba, on the addition of the magnesia, the 
vessel should be removed from the fire. 
3d. As these last experiments were made with very old 
and thick copaiba, in order to satisfy myself whether afresh 
article would answer, several varieties of copaiba were 
treated as in the second experiment, but using only the pre- 
scribed quantity of magnesia. They would not solidify until 
the second addition of magnesia, which caused them to 
assume a solid consistence in from five to seven hours. 
4th. A portion of Angustura copaiba, known] as " Solidi- 
fying Balsam," was heated until ebullition commenced, 
when one sixteenth[of its weight of freshly prepared and still 
hot magnesia was added and thoroughly stirred into it. At 
the expiration of six hours the mixture had acquired a good 
pilular consistence. On cutting open the mass, I found some 
of the magnesia uncombined. It should have been stirred 
occasionally whilst cooling. 
From the above experiment I conclude, firstly, that when 
it can be obtained, Augustura copaiba (supposing that its 
composition, &c, is always the same) should be preferred 
for this purpose ; and secondly, if any other variety than the 
Angustura be employed, one eighth of its weight of magnesia 
will be necessary to insure solidification. 
Dover's Powder, Powder of Ipecacuanha, and Opium. For 
the preparation of this valuable medicine, the Pharmacopoeia 
directs the dry ingredients to be rubbed into a very fine 
powder. It is generally admitted that the efficacy of this 
preparation depends in a great measure on the fineness of 
the powder,and with a view of reducing the opium and ipe- 
cacuanha to the finest condition, the sulphate of potassa is 
introduced; but we seldom meet with Dover's powder in 
