Am.  Jour.  Pharm.  ) 
December,  1920.  ) 
Tests  for  Methyl  Salicylate. 
893 
of  gaultheria  and  birch  and  methyl  saHcylate,  respectively.  As- 
suming that  the  pure  products  give  these  reactions,  the  chances  of 
detecting  methyl  salicylate  in  either  of  the  natural  oils  would  be 
very  slight  even  if  large  amounts  were  added.  Another  reaction 
proposed  by  these  authors  is  based  upon  colors  produced  by  a  mix- 
ture of  sulphuric  acid  and  an  alcoholic  solution  of  heliotropin.  The 
reactions  produced  in  gaultheria,  birch  and  methyl  salicylate,  respec- 
tively, are  crimson,  less  intense  crimson  and  yellow.  It  is  obvious 
that  the  same  criticism  applies  here  as  to  the  previously  mentioned 
test  with  regards  to  the  possibility  of  its  being  applied  quantita- 
tively even  in  an  approximate  manner.  Still  another  test  proposed 
by  these  same  authors  is  applied  by  adding,  successively,  sulphuric 
acid  and  a  saturated  aqueous  solution  of  chloral  hydrate.  With 
this  test  the  color  reactions  are  more  distinctive.  The  gaultheria 
gives  a  green  color,  the  birch  a  violet,  while  methyl  salicylate  gives 
no  color. 
I  have  found  this  test  to  give  very  satisfactory  results  when 
some  pure  samples  of  the  respective  products  are  used,  but  with 
mixtures  there  is  no  quantitative  distinctiveness  about  the  test, 
the  shades  of  color  being  influenced  more  by  slight  variations  in 
the  proportions  of  the  reagents  than  by  differences  in  the  amounts 
of  the  respective  oils,  and  the  hope  that  the  authors  express,  that  the 
test  may  be  made  quantitative,  has  not  been  substantiated  by  any 
subsequent  work  done  by  the  authors  of  the  test  themselves  or  by 
any  other  worker  who  has  published  his  results,  although  four 
years  have  passed  since  the  test  was  first  published. 
In  1914^  F.  C.  Umney  {Perfumery  and  Essential  Oil  Record,  p.  60) 
published  a  test  which  has  been  widely  quoted  and  frequently  used, 
as  follows: 
"To  five  drops  of  the  oil  in  a  test-tube  add  five  drops  of  a  five 
per  cent,  alcoholic  solution  of  vanillin  and  i  Cc.  of  alcohol.  Shake 
well  and  add  2  Cc.  of  concentrated  sulphuric  acid  and  mix  thor- 
oughly." Oil  of  gaultheria  by  this  test  is  reported  to  give  an  in- 
tense crimson  color;  oil  of  birch  a  reddish  brown  and  methyl  sali- 
cylate a  yellow  color. 
This  test  is  subject  to  the  same  defects  as  some  of  those  pre- 
viously criticised,  in  that  the  methyl  salicylate  reacts  negatively 
and  very  large  amounts  must  be  added  before  one  can  state  with 
certainty  that  the  sample  is  not  pure.  It  certainly  does  give  a  dis- 
tinctive reaction  with  some  specimens  of  gaultheria  oil. 
