1130 Wisconsin Academy of Sciences, Arts, and Letters. 
the temperature at which the preparation is finished—the tem¬ 
perature at which the liquid oily portion, which constitutes the 
official oleoresin, is separated from the deposited material, in¬ 
cluding the excess of piperine. In the case of commercial 
samples, the piperine content and, therefore, the refractive in¬ 
dex may also be affected by the presence of unevaporated 
solvent. The results obtained in the laboratory in the deter¬ 
mination of this property are given in the tables which follow. 
Table 121—Refractive indices of oleoresins prepared in the laboratory. 
Sample 
No. 
Date 
Observer 
Solvent 
Retractive 
index 
1 ... . 
1916 
DuMez.... 
Alcohol_................ 
At 25° C 
1.559 
1.696 
1.562 
1.521 
2..... 
Acetone..... 
3. 
Ether.. 
4.... 
“ 
Petrol, ether.. 
Table 128 —Refractive indices of commercial oleoresins . 
Sample 
No. 
Date 
Observer 
Source 
Refractive 
index 
1916 
DuMez..................... 
Sauibb & Sons..... ....... 
At 25° C 
1.501(a) 
1.560 
2.. 
Sharp & Dohme........... 
(a) Contained ether. 
Chemical Properties . 
Loss in weight on heating: A loss in weight varying from 
9.49 to 11.52 per cent, was obtained for the laboratory prepara¬ 
tions, when heated at 110°C, showing that the nature of the 
solvent employed in extracting the drug has but little influence 
on this property. With respect to the commercial samples ex¬ 
amined, the loss was much greater, being as high as 32.64 per 
cent, in one case. The comparatively great loss in the latter 
instance was due to the presence of unevaporated solvent 
(ether.) The results obtained in the determination of this 
constant in the laboratory follow. 
