398  Oils  of  Wintergreen  and  Birch.  {AmAJ5,mm' 
THE  OILS  OF  WINTERGREEN  AND  BIRCH. 
By  Henry  Trimble  and  Hermann  J.  M.  Schroeter. 
•Contribution  from  the  Chemical  Laboratory  of  the  Philadelphia  College  of 
Pharmacy. — No.  57. 
The  history  of  these  two  oils  has  recently  been  written  by  Dr.  E.  R. 
Squibb1  and  the  papers  there  referred  to  from  the  first  in  1842  by 
Professor  Procter  to  the  last  in  1884,  by  Mr.  H.  P.  Pettigrew,  can  all 
be  found  in  the  American  Journal  of  Pharmacy. 
From  a  perusal  of  the  papers  by  these  two  authors  and  that  of 
Cahours 2  one  finds  that  the  oils  are  similar  in  physical  properties,  that 
they  are  largely  composed  of  methyl  salicylate,  that  one  of  them,  oil 
of  wintergreen,  contains  approximately  10  per  cent,  of  a  terpene  ac- 
cording to  Cahours,  but  only  0.3  per  cent,  according  to  Pettigrew,  and 
according  to  the  latter  that  the  oil  of  birch  is  composed  of  methyl 
salicylate  only,  but  according  to  Procter  that  the  two  oils  are  identical. 
On  account  of  the  variance  of  these  authorities,  and  recent  statements 
about  the  "  Artificial  Oil  of  Wintergreen,"  we  have  been  led  to  inves- 
tigate anew  the  chemical  composition  of  the  oils  and  in  that  way 
compare  them.  It  is  the  exception  when  a  product,  as  simple  as  oil 
of  birch  is  described  by  Pettigrew  to  be,  is  produced  in  nature ;  such 
substances  are  more  frequently  found  to  be  made  up  of  a  series  of 
compounds.  With  this  principle  clearly  in  view,  we  procured  four 
samples,  two  of  each  oil. 
Sample  I,  wintergreen  oil,  was  obtained  through  the  kindness  of 
Mr.  C.  M.  Driggs,  of  White  Haven,  Penna.,  whose  acquaintance 
with  the  distillers  of  that  district  enabled  him  to  vouch  for  the  genu- 
ineness of  a  sample  of  each. 
Sample  II,  oil  of  birch,  from  the  same  source. 
Sample  III,  oil  of  wintergreen,  from  Mr.  Underhill,  of  New 
Hampshire. 
Sample  IV,  oil  of  birch,  this  and  sample  III  had  been  a  number 
of  years  in  the  collection  of  Prof.  J.  M.  Maisch,  and  were  kindly 
given  by  him  for  this  investigation.  At  least  one  of  them,  the  win- 
tergreen, was  examined  by  Mr.  Pettigrew. 
Physical  Properties. — The  following  tabular  statement  of  the  spe- 
1  Ephemeris,  October  1887,  p.  951. 
2  Ann.  Chim.  et  Physique,  [3]  x,  p.  327. 
