554  Some  Official  Standards  and  Tests,  {^ecimber^ww?* 
which  we  mostly  have  to  deal.  Siam  benzoin  should  be  nearly  free 
from  cinnamic  acid ;  Sumatra  sometimes  contains  a  considerable 
amount  of  it.  Siam  benzoin  contains  about  0-15  per  cent,  vanillin* 
Sumatra  benzoin  contains  on  the  average  about  I  percent.  Although 
the  percentage  of  vanillin  in  the  Sumatra  varieties  is  therefore  six  to 
seven  times  higher  than  in  the  Siam  variety,  the  latter  has  a  more  pro- 
nounced vanilla-like  odor.  We  received  lately  a  refined  gum  benzoin 
of  an  extraordinarily  strong  vanilla-like  odor,  and  suspecting  a  cheap 
resin  flavored  with  vanillin  we  took  special  care  in  testing  the  same. 
The  sample  was  of  a  dark-reddish  brown  color,  brittle  and  trans- 
lucent, almost  perfectly  soluble  in  5  parts  of  warm  alcohol  and  also 
soluble  in  KOH  solution.  It  was  nearly  free  from  cinnamic  acid — 
there  as  cinnamic- phenyl-propyl  ether  and  cinnamic-benzyl-ether 
(test  made  with  potassium  permanganate) — and  left  only  0-58  per 
cent,  ash  on  incineration.  An  assay  for  benzoic  acid,  made  by  sub- 
limation, gave  1 1-74  per  cent.,  the  average  of  the  latter  being  about 
IO  per  cent,  in  a  good  quality  benzoin  (bisulphite  method  being 
used).  Although  the  vanillin  odor,  as  said  before,  was  extremely 
strong,  we  evidently  had  not  an  adulteration  but  a  high-grade 
quality  before  us,  probably  refined  Siam  benzoin  with  a  small  per- 
centage of  Sumatra  benzoin. 
ESSENTIAL  OILS. 
In  many  cases  the  different  oils  stood  the  U.S. P.  tests  for  specific 
gravity,  solubility,  general  appearance,  odor,  etc.,  but  did  not  answer 
U.S. P.  requirements  in  regard  to  optical  rotation.    For  example : 
Oil  of  Coriander  had  a  specific  gravity  of  0  87  at  250  C,  solubility, 
etc.,  was  O.  K.,  but  the  optical  rotation  at  25 0  C.  was  —  1 5-4,  instead 
of  _j-  70  to  -f  140 
Oil  of  Tkyme  was  O.  K.  in  regard  to  specific  gravity,  solubility, 
etc.,  and  was  free  from  official  phenol.  The  oil  assayed  23  per  cent, 
phenols,  3  per  cent,  more  than  the  U.S. P.  requires.  The  optical 
rotation,  however,  was  -f-  9-5,  the  U.S. P.  requiring  the  oil  to  be 
slightly  laevogyrate. 
In  testing  Oil  of  Orange,  Oil  of  Anise,  and  others,  we  found  the 
same  conditions. 
Oil  of  Eucalyptus  we  found  to  have  the  required  optical  rotation, 
but  the  percentage  of  cineol  was  in  most  cases  too  low,  some  oils 
assaying  only  10-15  per  cent,  instead  of  50  per  cent. 
