1122 Wisconsin Academy of Sciences, Arts, and Letters. 
arate as a rule, but that the whole sets to form a semi-solid 
mass owing to the large amount of piperine present. The 
means by which the separation of the piperine was accomp¬ 
lished in the laboratory appears to be more rational and is as 
follows: the mixture was heated on the water bath until the 
portion constituting the oleoresin was quite fluid when it was 
filtered through cotton with the aid of a suction pump. The 
piperine which deposited from the filtered oleoresin on cool¬ 
ing was finally separated by decantation. 
9) As the oleoresin loses volatile oil on exposure to the air, 
it should be kept in well-stoppered bottles. 
Yield . 
The yield of oleoresin to acetone or ether is about 4.5 to 6.5 
per cent. With petroleum ether, a yield of 3.2 per cent, was ob¬ 
tained in the laboratory. Aside from the effect which the solvent 
has upon the amount of the oleoresin obtained, the temperature at 
which the piperin is separated is a factor to be considered. The 
higher the temperature at which this is accomplished, the greater 
the amount of piperine remaining in solution and the greater 
the yield of finished product, and visa versa. 
In the tables which follow, the yield of total extract is fre¬ 
quently reported as oleoresin. These reports should not be 
confused with those pertaining to the official preparation, which 
consists of the liquid portion only, the precipitated piperine 
and other insoluble material having been removed. Data of 
this kind have been included here for the sake of comparison 
with results of a like nature obtained in the laboratory and in 
order to point out the erroneousness of such reports. 
