Am.  Jour.  Pharm.  1 
April,  1904.  / 
Seed  of  Rhus  Glabra. 
155 
as  would  almost  place  it  in  the  semi-drying  group.  The  following 
table  is  a  comparison  of  rhus  oil  with  wheat  and  linseed  oils.  The 
increase  in  weight  is  given  in  parts  per  hundred,  the  time  extending 
over  a  period  of  thirty  days : 
Number  of  days        5               10              15             20  25  30 
Rhus  oil,  gain .  .  .  0*005  0*027  0'054  0-071  0*104  0*142 
Wheat  oil    "     .  .0*037  0*077  °,][5  °"24  °'3°  °*37 
Linseed  oil  "     .  .0*037  0*13  0*28  1*74  4*82  7*55 
Saponification  Value. — The  determination  of  the  saponification 
value  was  made  by  the  common  method  of  saponifying  a  known 
quantity  of  the  pure  oil  with  standard  alcoholic  potassium  hydroxide, 
calculations  being  made  in  milligrams  of  hydroxide  per  gramme  of 
the  oil.    Three  determinations  gave  the  following: 
I.  2*0005  grammes  of  oil  required  .  .  0*39086  gramme  of  potassium  hydroxide 
II.  1*8923       "        "    "       "        .  .  0*26817       "       "         "  " 
III.  1*9096       "        "    "       "        .  -  0*3707         "       "  " 
1.         n.  in. 
Calculated  in  milligrams  of  KOH  per  gramme  of  oil  .  .195*3       i'94"9  I947 
These  values  indicate  a  non-drying  oil,  the  range  of  which  is  from 
190  to  200. 
Iodine  Value. — The  iodine  value  was  determined  by  the  Hiibl 
method.  The  time  required  for  the  complete  absorption  of  the 
iodine  was  much  greater  than  in  the  common  oil.  Three  determi- 
nations gave  the  following  : 
I.  0*1611  gramme  of  oil  absorbed  ....  0*014155  gramme  of  iodine 
II.    *i668       "       "  "       ....  0*014339       "       "  " 
III.    -1737       "       "    «        '*       ....  0*014848 
1.  II.  in, 
Per  cent,  of  iodine  absorbed  87*86       85*96  86*4 
Determination  of  Glycerol. — Glycerol  was  determined  by  the  well- 
known  method  of  Benedict-Zsigmondy,  which  consists  in  saponifying 
the  oil  and  oxidizing  the  glycerol  by  means  of  alkaline  potassium 
permanganate  to  oxalic  acid  according  to  the  simple  reaction, 
C3H803  +  302  =  C2H304  +  C02  +  3H20. 
The  oxalic  acid  was  then  determined  as  calcium  oxalate  and  the 
per  cent,  of  glycerol  calculated. 
I.  2*6859  grammes  of  oil  gave  .......  0*2493  gramme  of  glycerol 
II.2*53I4  "  "     "       "   0-2TI4  "  " 
i.  in. 
8-35 
