Du Mez — The Galenical Oleoresins. 
1045 
only serves to load the percolate with undesirable extractive 
matter such as cubebin. 
6-7) The various editions of the Pharmacopoeia, since 1870, 
have directed that the greater part of the solvent be removed 
from the percolate by distillation on a water bath, and that 
the remainder be allowed to evaporate spontaneously. 
Experience in the laboratory has shown that it is impos¬ 
sible to obtain a uniform product, when operating according 
to the above directions, unless identical conditions are main¬ 
tained in each case. This is due to the fact that a compara¬ 
tively slight variation in the procedure, with respect to the 
quantity of the solvent removed by distillation or to the tem¬ 
perature at which spontaneous evaporation is allowed to pro¬ 
ceed produces a variation in the volatile oil content of the finished 
product, which in turn affects its physical and chemical proper¬ 
ties. It is thought, therefore, that the amount of solvent to be 
removed by distillation, as well as the temperature at which 
the last portions are to be removed, should be definitely stated 
by the Pharmacopoeia in order that a more uniform product 
may be obtained. 
8) For a statement concerning the nature of the precipitate 
which forms in the oleoresin upon standing, see page 1060 un¬ 
der “Other properties.” 
Since the greater part of the precipitate is composed of ma¬ 
terial which is of no therapeutic value, it should be removed 
before dispensing the preparation as directed by the Pharma¬ 
copoeia. 
9) The oleoresin should be kept in well stoppered bottles ow¬ 
ing to the fact that it loses volatile oil and undergoes other 
changes on exposure to the air. See cubeb camphor, page 
1050. 
Yield 
The amount of oleoresin obtained varies to a considerable 
extent, 10 to 30 per cent, having been obtained when alcohol, 
acetone or ether were employed as menstrua for the extraction 
of the drug. When petroleum ether is the solvent made use of, 
the yield is much lower, 4 to 18 per cent, having been reported 
in this case. Aside from the effect of the solvent, the principal 
