ISO OBSERVATIONS ON THE PRECEDING PAPER. 
The spirit obtained by distillation is to be diluted with dis- 
tilled water so as to reduce it to sp. gr. 0.915, and more 
spirit of this strength added, if necessary, to exhaust the 
valerian. All the liquors are to be mixed and filtered, and 
the spirit recovered from them by distillation. The residue 
is evaporated in the stove to a pillular consistence, when the 
first product is to be incorporated with it while hot. A per- 
fectly homogeneous mass is thus obtained, which repre- 
sents in a perfect state all the active parts of the valerian 
root. 
One part of the extract is equivalent to five parts of 
valerian. 
OBSERVATIONS ON THE PRECEDING PAPER. 
BY M. SOUBEIRAN. 
The object proposed in the preparation of extracts is to 
concentrate into a small mass the active parts of plants, 
without at all changing the state of combination in which 
they naturally exist. M. Burin proposes to extend the use 
of rectified spirit, which had been previously recommended, 
for concentrating the active parts, and separating the inert 
parts of plants. This object appears to me to be attained 
in regard to the Solanaceae. Is it equally with regard to 
the other plants selected by M. Burin ? I will only allude 
here to two sets of experiments, one on valerian and the other 
on gentian, the experiments being made, in each case, on 
the same roots, so as to have comparative results. 
Extract of Valerian. 
One kilogramme 
of the substance. 
Extract 
obtained. 
Kt-iation 
to the 
substance. 
"Water 
dissolves. 
ripirit, sp. gr. 
0.921 
dissolves. 
Spirit sp. 
gr. 0.834 
dissolves. 
Processof M. > 
Burin, 5 
Process of the ) 
Codex. $ 
255 gr. 
205 gr. 
:l::4 
:1::4.83 
80 per cent. 
88 per cent. 
88 per cent. 
94 per cent. 
96 per c. 
80 per c. 
