Am.  Jour.  Pharm.\ 
January,  1902.  / 
Adulteration  of  Drugs. 
17 
four  drops  of  the  oil  to  this  mixture,  allowing  the  oil  to  float  on 
top;  if  oil  of  gurjun  balsam  is  present,  a  reddish  or  purplish  zone 
will  be  developed  between  the  layer  of  oil  and  the  acid  mixture  in  a 
few  minutes.    No  reaction  occurs  if  the  oil  is  pure. 
Oil  of  Peppermint  is  probably  one  of  the  most  liberally  adulterated 
oils  that  is  met  with,  and  especially  is  this  true  in  mixing  a  high- 
grade  oil  with  an  oil  of  poor  quality.  Several  years  ago  an  oil  was 
met  with  that  showed  upon  examination  to  contain  at  least  25  per 
cent,  of  added  oil  of  turpentine.  It  must  be  remembered  that  oil 
of  peppermint  is  liable  to  contain  a  small  percentage  of  terpenes, 
but  no  such  quantity  is  admissible,  and  it  also  should  be  said,  is  quite 
unnatural.  Notwithstanding  the  fact  that  this  oil  contains  such  a 
considerable  amount  of  added  turpentine,  the  specific  gravity  did 
not  fall  materially  below  the  recognized  lower  limit.  On  reporting 
this  condition  of  affairs  to  the  vendor  he  immediately  requested  the 
oil  to  be  returned,  and  he  gladly  paid  all  cartage,  freight,  etc.,  in 
addition  to  £25  for  analysis,  without  making  a  protest.  This  in 
itself  was  ample  evidence  that  the  article  was  known  to  be  of  a 
spurious  character. 
The  presence  of  the  turpentine  was  established  by  a  fractional 
distillation :  the  first  fraction  began  to  come  over  at  1500  C,  and  40 
per  cent,  distilled  before  the  temperature  reached  1800  C.  The 
specific  gravity  of  this  fraction  corresponded  to  that  of  turpentine, 
and  other  physical  and  chemical  properties  unmistakably  proved 
this  fraction  to  be  turpentine.  By  allowing  15  per  cent,  for  the 
possible  presence  of  a  natural  terpene  having  a  boiling  point  lying 
between  the  above  limits,  which  is  quite  improbable,  we  still  have 
left  25  per  cent,  of  added  turpentine.  Genuine  oil  of  peppermint 
contains  very  little  material  having  a  boiling  point  below  200°  C. 
The  per  cent,  of  menthol,  both  combined  and  free,  was  also  esti- 
mated and  found  to  be  very  low. 
It  is  hoped  that  the  present  Committee  on  Revision  will  see  its 
way  clear  to  introduce  a  lower  limit  of  boiling  point  and  a  method 
for  estimating  menthol.  For  the  benefit  of  some,  the  following 
references  to  the  methods  for  menthol  determinations  are  given  : 
Schimmel's  "  Semi-annual  Report,"  October,  1894, page  438  ;  "The 
Volatile  Oils,"  by  E.  Gildemeister  and  Fr.  Hoffmann,  translated  by 
E.  Kremers,  page  651,  and  the  Am.  Jour.  Pharm.,  1897,  page  189. 
Oil  of  Thyme  (  White). — It  is  well  known  that  white  oil  of  thyme 
