1817.] On a Preparation of Cinchona. 451 
_ArTIcCLE VI. 
On a Preparation of Cinchona. By C. Johnson, one of the 
Surgeons to the Lancaster Dispensary. 
(To Dr. Thomson. ) 
SIR, 
One would suppose that Count Rumford’s elaborate essay on the 
subject of coffee would at least have brought his elegant apparatus 
for preparing that beverage into the shops of those who manufacture 
such articles for sale; but none could be procured in London by 
one of my friends, who made the proper inquiries with great dili- 
gence. 
I have for some time adopted this excellent method of making 
coffee, and extended its application to Peruvian bark. Several 
medical friends to whom I have shown this infusion (or rather per- 
haps perfusion) of cinchona have readily adopted it, and requested 
me to render more public what they think an improvement on 
pharmacy. 
The machine I use is similar to one made several years ago by 
Edmund Loyd and Co. 178, Strand ; and does not difler essentially 
from any of those described in Count Rumford’s 18th essay, and in 
the Repertory of Arts for April and May, 1813. 
Peruvian bark pounded and sifted through a wire sieve is placed 
in the strainer of this apparatus, and boiling water is poured upon 
it in successive portions. When about a quart of water has been 
thus passed through an ounce of cinchona, it forms a beautiful, 
clear solution of all that water can extract, and strongly exhibiting 
the sensible properties of cinchona. 
Dr. Dunean, jun. has long ago suggested that the precipitate 
which decoction of bark deposits on cooling may prove an useful 
and compendious medicine. ‘This suggestion seems well founded, 
and deserves the trial. ‘Those inclined to examine this matter may 
obtain a very abundant supply on cooling the strong infusion which 
first runs off. 
A little reflection on the chemical properties of cinchona, and a 
comparison of the infusion and decoction as usually prepared with 
the infusion just described will convince your readers that the last 
preparation must afford an useful and efficient medicine. The saving 
effected in this way will be asmall matter of consideration with 
medical practitioners as far as their interest only is concerned; but 
in dispensaries, infirmaries, and the public service, no item of ex- 
pense is unimportant: and since on some occasions a scanty supply 
of cinchona has been felt as a national calamity, it becomes a duty 
to prevent a wasteful consumption of this valuable remedy. On 
this account I mention that in the Lancaster Public Dispensary this 
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