218  Adulteration  of  Volatile  Oils,  {^M^iISarm' 
must  depend  largely  on  the  integrity  of  the  distiller.  A  few  specific 
cases  may  well  be  considered. 
OLEUM  AMYGDALAE  AMAR^E. 
Gildemeister  and  Hoffmann  (page  437)  state  that  only  a  very  small 
amount  of  the  bitter  almond  oil  of  commerce  is  prepared  from 
bitter  almonds,  but  is  prepared  mainly  from  the  seeds  of  the  apricot 
(Prunus  armeniaca,  L.),  which  is  allowable  for  the  U.S.P.  product. 
Parry  states  ("  Chemistry  of  Essential  Oils,"  page  297)  that  the  true 
oil  may  be  grossly  adulterated  with  artificial  benzaldehyde,  and  if  the 
purest  variety  be  used,  it  is  impossible  to  detect  it  within  certain 
limits  except  by  the  odor.  Formerly  synthetic  benzaldehyde  always 
contai  ned  chlorinated  products  which  made  possible  its  detection  as 
an  adulterant. 
Another  adulterant  is  oil  of  mirbane,  which  may  readily  be  de- 
tected by  odor,  the  specific  gravity  and  by  its  reduction  to  aniline 
with  iron  filings  and  acetic  acid,  which  may  be  distilled  and  col- 
lected. To  the  distillate  a  few  drops  of  calcium  chloride  solution 
is  added  and  if  aniline  be  present  the  characteristic  violet  color 
is  produced.  Samples  adulterated  with  nitro-benzene  when  shaken 
with  an  excess  of  sodium  bisulphite  solution  have  the  characteristic 
coarse  nitro-benzene  odor. 
The  official  assay  for  Denzaldehyde  content  is  exceedingly  difficult 
and  a  decided  improvement  was  made  by  Roberts  and  Carwithen  by 
exactly  neutralizing  the  kerosene  before  beginning  the  assay  and 
keeping  the  flask  tightly  corked  as  much  as  possible. 
OLEUM  BETUL^E,  OLEUM  GAULTHERLE  AND    METHYLIS  SALICYLAS. 
One  offender  says,  "  Methyl  salicylate  is  just  as  official  as  oil  of 
birch ;  what  harm  can  there  be  in  mixing  them  ?  "  It  is  only  reason- 
able to  believe  that  Nature's  laboratory  is  more  efficient  than  our 
own,  and  this  has  often  been  demonstrated,  but  aside  from  this 
there  is  a  moral  obligation  which  should  not  be  overlooked,  even  if 
the  Pure  Food  and  Drugs  Law  were  not  in  existence. 
At  present  there  is  only  about  one-tenth  enough  wintergreen 
leaves  harvested  to  make  the  amount  of  oil  that  is  actually  sold. 
Where  does  the  rest  come  from  ?  Often,  undoubtedly,  the  product 
is  oil  of  birch  or  mixtures  of  it  and  synthetic  methyl  salicylate. 
