Am.  Jour.  Pharm. ) 
August,  1908.  J 
Assay  of  Oil  of  Peppermint. 
373 
test  with  a  definite  quantity  of  pure  atropine,  and  besides,  the  follow- 
ing statements  coincide  with  my  results. 
In  all  the  literature  of  pharmacy  and  pharmacognosy  you  may 
read  that  the  amount  of  alkaloids  varies  from  0-5  to  0-7  per  cent. 
This  is  quite  in  accordance  with  my  results.  With  the  U.S.P. 
method  you  never  have  found  more  than  0-40  per  cent,  alkaloid  in 
the  highest  analysis,  even  if  you  analyze  the  best  belladonna  root  in 
existence.    (?  W.  A.  P.    J.  G.  R.) 
Different  indicators  always  play  an  important  part  in  the  final 
results ;  therefore,  I  take  hematoxylin  as  your  Pharmacopoeia 
formerly  advised.  If  you  use  cochineal,  it  is  necessary  to  pre- 
viously test  the  tenth-normal  hydrochloric  acid  against  this  indicator, 
but  it  is  not  so  good  in  this  case. 
The  further  drying  of  the  root  before  powdering  is  necessary; 
otherwise,  you  never  compare  results  of  material  which  have  different 
percentages  of  moisture. 
We  are  greatly  indebted  to  Dr.  Enoch  for  his  co-operation  in  this 
work,  as  well  as  to  several  members  of  the  firm  we  represent. 
Research  Laboratory, 
Smith,  Kline  &  French  Company. 
POSSIBILITY  OF  ERROR  IN  THE  U.S.P.  ASSAY  PROCESS 
FOR  OIL  OF  PEPPERMINT. 
By  Dr.  Gunnar  Heikei,. 
Inasmuch  as  oil  of  peppermint  is  a  solution  of  about  40  to  45  per 
cent,  menthol  in  menthyl  acetate  and  other  liquid  constituents  of 
the  oil,  it  is  evident  that  after  elimination  of  a  certain  quantity  of 
the  latter  a  separation  of  menthol  crystals  will  occur. 
When  the  oil  is  saponified,  such  an  elimination  has  taken  place. 
All  menthyl  esters  have  been  transformed  in  alkali  salts  and  a  cor- 
responding amount  of  menthol  liberated.  By  washing  the  saponified 
oil  with  water,  as  prescribed  in  the  U.S.P.,  the  remaining  liquid 
constituents  may  not  be  present  in  a  sufficient  quantity  to  keep  the 
increased  amount  of  menthol  in  solution,  which  consequently  sepa- 
rates out  in  crystalline  form  in  the  wash-water. 
