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SELECTED ARTICLES. 
coagulation of the precipitate. When this had been obtained, 
the whole was cast upon a thick cloth. When the pre- 
cipitate was well drained, it was triturated in a marble 
mortar with fifty grammes of lime, the air being excluded, and 
it was then boiled twice over in six decilitres of alcohol at 
33°. The alcohol, filtered while boiling, was submitted to 
distillation so as to drive off f of its volume, and the remainder 
poured into a capsule and evaporated by a slow heat. Upon 
cooling, palmate crystals were obtained of a greenish colour, 
more or less deep, but which entirely disappeared upon solu- 
tion and crystallization anew. 
The principal varieties of coffee submitted to this treatment 
furnished us the following results for 500 grammes of each: — 
Grammes. Grains. 
Martinique coffee, caffein, 1.79 32 
Alexandria " " " 1.26 22 
Java « " 1.26 22 
Moka " " 1.06 20 
Cayenne " " 1.00 19 
St. Domingo " " ' • 85 16. 
We ought to remark, in conclusion, that we have not been 
enabled to extract from coffee the concrete volatile oil, which 
is supposed to exist in it, and we will add, relatively to the 
solid fixed oil having the smell of cocoa, spoken of as one of 
its products, — that it must exist in very small proportion, but 
that the principal oil met with is the fluid fixed oil, a little 
coloured in the first instance, but becoming brown from 
age. We may state, finally, that the major part of the 
acid which is isolated by the acetate of lead, is combined 
in the coffee with lime, and very probably it is not the same 
as the free acid which we believe to be the gallic. It is very 
certain that when the decoction of coffee is treated by acetate 
of lead, in order to separate the acid and the colouring mat- 
ter, if the excess of lead be precipitated by sulphuric acid, and 
then evaporated, a considerable quantity of sulphate of lime 
is obtained, which is sometimes taken for crystals of caffein. 
Journal de Pharmacie. 
