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SELECTED ARTICLES. 
might destroy part of the product, and that it would color it. 
In consequence, I made many trials, and the results have 
demonstrated that the following process was the one to which 
preference should be given. 
It consists- — 1. In submitting the same bark to two decoc- 
tions, of but half an hour only. We obtain then a quantity 
of phloridzine as abundant, much less colored, besides more 
easy to purify, and with a saving of fuel and time, since one 
hour is sufficient in the place of six. 
2. To evaporate the mother waters to two-thirds. It lets 
fall, at the end of twenty-four hours, a greater quantity of 
phloridzine than the first decoction, but more colored. 
These two observations not having as yet been announced, 
and offering great advantages, I thought it might be useful to 
give them publicity. 
Journ. de Chimie Med. 
ART. XII.— ON CETRARINE. By Dr. Hekberger. 
Cetrarine, or the bitter principle of Lichen islandicus 
which M. Herberger has been the first to obtain in a pure 
state, is prepared in the following manner. The Lichen 
islandicus, in coarse powder, is to be boiled for half an hour 
in four times its weight of alcohol, of .883; the whole is to be 
left at rest until the extrication of vapors cease, to prevent 
the loss of alcohol. When they have ceased, the liquor is to 
be expressed, and diluted hydrochloric acid added, (three 
drachms to every pound of lichen.) There is then to be 
mixed with the liquid four and a quarter to four and a half 
times its bulk of water, and the mixture left for one night in 
a matrass, which is to be closed. The following day, the 
yellow wine colored liquor, which swims over an abundant 
deposit, is to be decanted, and the deposit, which is of a color 
